Page 1 of 59 DR. RAJENDRAN’S INSTITUTE OF MEDICAL EDUCATION AIIMS NOVEMBER 2011 - QUESTIONS & ANSWERS MEDICINE 1) Limb girdle muscle dystrophy includes all of the following groups of disorder except a. Sarcoglycanopathy b. Dystroglycanopathy c. Dysferlinopathy d. Calpainopathy Ans: (B) Muscular dystrophies - Myopathy simply refers to an abnormality of the muscle. Muscular dystrophies are genetic myopathies usually caused by a disturbance of a structural protein or enzyme, resulting in necrosis of muscle fibers and replacement by adipose and connective tissue. www.medicinemcq.com Page 2 of 59 Sarcoglycanopathies - Mutations in sarcoglycans (α, β, γ, and δ) result in limb-girdle muscular dystrophy types 2C to 2F. Sarcoglycanopathies often start in childhood. These diseases present initially as pelvic muscle weakness, including a waddling gait and difficulty performing common tasks, such as getting up from the floor, climbing the stairs, and running. The trunk muscles are prominently affected. Distal muscles are generally spared until later in the disease process. These progressive disorders result in very high levels of serum CK early in the disease; the levels decrease when patients become wheelchair bound by 12 to 16 years of age. Dilated cardiomyopathy is often seen. Muscle biopsies show marked regeneration and necrosis. Dysferlinopathy - Genetic defects in the dysferlin gene result in limb-girdle muscular dystrophy type 2B and distal muscular dystrophy of the Miyoshi type. These diseases can appear in the late teens or early 20s. The weakness in the limb-girdle type 2B phenotype affects the quadriceps muscle first, followed by weakness in the arms in the later stages of the disease. The weakness in the Miyoshi phenotype occurs predominantly in the gastrocnemius and soleus muscles, thereby affecting the ability to walk on the toes. The weakness is slowly progressive, with loss of ambulation generally occurring in the fourth decade, but earlier in some cases. Serum CK levels are very high during the active phase of the disease. Dystrophinopathies are caused by mutations in the dystrophin gene. Dystrophin is associated with Duchenn’s and Becker type of muscular dystrophies and is not associated with limb girdle dystrophies. These are X-linked recessive disorders. An elevation in serum CK levels is seen in asymptomatic patients. LIMB-GIRDLE DYSTROPHIES LGMD1A AD 5q22.3-31.3 Myotilin LGMD1B AD 1q11-21 Lamin A and C LGMD1C AD 3p25 Caveolin-3 LGMD1D AD 6q23 ? LGMD1E AD 7q ? LGMD2A AR 15q15.1-21.1 Calpain 3 LGMD2B* AR 2p13 Dysferlin LGMD2C AR 13q12 γ-sarcoglycan www.medicinemcq.com Page 3 of 59 LGMD2D AR 17q12-21.3 α-sarcoglycan LGMD2E AR 4q12 β-sarcoglycan LGMD2F AR 5q33-34 δ-sarcoglycan LGMD2G AR 17q11-12 Telethonin LGMD2H AR 9q31-33 E3-ubiquitin-ligase (TRIM 32) LGMD2I AR 19q13 Fukutin-related protein (FKRP) LGMD2J AR 2q31 Titin LGMD2K AR 9q31 POMT1 LGMD2L AR 11p14.3 Anoctamin 5 LGMD2M AR 9q31-33 Fukutin LGMD2N AR 1p32 POMGnT1 LGMD2O AR 14q24 POMT1 th Firestein: Kelley's Textbook of Rheumatology, 8 edition. th Bradley: Neurology in Clinical Practice, 5 edition. 2) Which of the following is the most specific test for rheumatoid arthritis? a. Anti-ccp antibody b. Anti-Igm antibody c. Anti-IgA antibody d. Anti-IgG antibody Ans: (A) www.medicinemcq.com Page 4 of 59 Rheumatoid arthritis – The primary target of this disease is the synovium. Synovial tissues proliferate in an uncontrolled fashion, resulting in excess fluid production, erosion of surrounding bone, and damage to tendons and ligaments. See figure below. The distribution of involved joints is important for diagnosis. Most patients have involvement of small joints first, classically the proximal interphalangeal, metacarpophalangeal, and metatarsophalangeal joints, with involvement of large joints occurring later. See figure below. Of particular importance, rheumatoid arthritis almost always spares the distal interphalangeal (DIP) joints. In contrast, these joints are often involved in osteoarthritis and psoriatic arthritis. www.medicinemcq.com Page 5 of 59 CRITERIA FOR RHEUMATOID ARTHRITIS Must be present for more than 6 weeks Morning stiffness Arthritis of three joint areas Arthritis of the hands Symmetric arthritis Rheumatoid nodules Serum rheumatoid factor Radiographic changes Rheumatoid factor is antibody directed against the Fc region of IgG. IgM, IgG, and IgA isotypes of rheumatoid factor occur in sera from patients with rheumatoid arthritis, although the IgM isotype is the one most frequently measured by commercial laboratories. Serum IgM RF is been found in 75–80% of patients with rheumatoid arthritis. Rheumatoid factor is positive in about 50% of cases at presentation and an additional 20–35% of cases become positive in the first 6 months after diagnosis. www.medicinemcq.com Page 6 of 59 Rheumatoid factor is not specific for rheumatoid arthritis. It can be seen in wide range of autoimmune disorders, inflammatory disease and chronic infections. It is found in primary Sjögren's syndrome, systemic lupus erythematosus, type 2 mixed essential cryoglobulinemia, subacute bacterial endocarditis and hepatitis B and C. Serum rheumatoid factor may also be detected in 1–5% of the healthy population. DIFFERENTIAL OF A POSITIVE RHEUMATOID FACTOR Rheumatic diseases o Infections o Viral: Hepatitis B and C, EBV, parvovirus, influenza o Bacterial: Endocarditis, osteomyelitis Chronic inflammatory conditions o RA, Sjögren syndrome, SLE Liver disease, inflammatory bowel disease, others Aging Anti-cyclic citrullinate peptide antibody (anti-ccp) test is more specific than rheumatoid factor for diagnosis of rheumatoid arthritis. It may be positive every early in the course of the disease. AntiCCP antibodies are present in 60–70% of patients with RA at diagnosis, are 90–98% specific for RA. It correlates strongly with erosive disease. Ordering anti-CCP along with the rheumatoid factor increases the sensitivity of detecting early rheumatoid arthritis. Anti-cyclic citrullinate peptide (anti-ccp) antibody testing has ability to identify patients who are likely to have severe disease and irreversible damage. Anti ccp antibodies have not been found at a significant frequency in other diseases to date. www.medicinemcq.com Page 7 of 59 Serum anti-CCP antibodies have the same sensitivity as serum rheumatoid factor for the diagnosis of rheumatoid arthritis. However, its diagnostic specificity approaches 95%. Therefore, a positive test for anti-CCP antibodies in an early inflammatory arthritis is useful for distinguishing rheumatoid arthritis from other forms of arthritis. Rheumatoid arthritis is associated with multiple other autoantibodies, including antinuclear antibodies (seen in 30% of patients) and antineutrophilic cytoplasmic antibodies, particularly of the perinuclear type (seen in 30% of patients). th Firestein: Kelley's Textbook of Rheumatology, 8 edition. th CURRENT Rheumatology Diagnosis & Treatment, 2 edition; John B. Imboden, David B. Hellmann, John H. Stone. th Harrison's principles of internal medicine, 18 edition. Preclinical rheumatoid arthritis: identification, evaluation, and future directions for investigation. Deane KD - Rheum Dis Clin North Am - 01-MAY-2010; 36(2): 213-41. Rational use of laboratory testing in the initial evaluation of soft tissue and joint complaints.Waits JB - Prim Care - 01-DEC-2010; 37(4): 673-89, v 3) A young male patient presents with LDL 600 mg/dl and triglycerides 140 mg/dl. What would be the most likely finding on physical examination? a. Tendon xanthoma b. Lipemia retinalis c. Palmar xanthoma d. Eruptive xanthomas Ans: (a) www.medicinemcq.com Page 8 of 59 Cholesterol and triglycerides are the two main circulating lipids. Elevated levels of LDL cholesterol are associated with increased risk of atherosclerotic heart disease. Very high LDL levels are associated with tendinous xanthomas. Extremely high levels of chylomicrons or VLDL particles are associated with eruptive xanthomas. Very high triglycerides (> 2000 mg/dL) are associated with lipemia retinalis (cream-colored vessels in the fundus). Normal L.D.L Desirable → <130 mg/ dl Borderline high → 140 – 160 mf/dl High risk → 200 – 500 mg/dl Norma triglycerides Desirable → <150 mg/ dl Borderline high → 150 – 200 mf/dl High → 200 – 500 mg/dl Increased LDL cholesterol and normal triglycerides suggests hypercholesterolemia. Most patients presents with cutaneous xanthomas on the hands, wrists, elbow, knees, heels or buttocks. Arcus cornea is present and some patients have xanthelasmas. ETIOLOGY OF HYPERCHOLESTEROLEMIA Idiopathic Hypothyroidism Nephrotic syndrome Chronic renal insufficiency Obstructive liver disease Diabetes mellitus Anorexia nervosa Cushing’s syndrome Familial hypercholesterolemia Drugs: oral contraceptives, thiazides (short-term effect), beta blockers (short-term effect), corticosteroids, cyclosporine www.medicinemcq.com Page 9 of 59 Xanthomas - Eruptive xanthomas are the most common form and are associated with hypertriglyceridemia (types I, III, IV, and V). They occur primarily on the extensor surfaces of the extremities and the buttocks. See figure below. The most common setting for eruptive xanthomas is uncontrolled diabetes mellitus. Eruptive xanthomas Increased beta-lipoproteins (primarily types II and III) result in xanthelasma, tendon xanthomas, and plane xanthomas. Xanthelasma are found on the eyelids. See figure below. www.medicinemcq.com Page 10 of 59 Xanthelasma Tendon xanthomas are frequently associated with the Achilles (see figure below) and extensor finger tendons. Plane xanthomas usually occur over the palmar creases, face, upper trunk, and scars. www.medicinemcq.com Page 11 of 59 Tuberous xanthomas are frequently associated with hypertriglyceridemia, but they are also seen in patients with hypercholesterolemia (type II). They are found most frequently over the large joints or hand. The least specific sign for hyperlipidemia is xanthelasmas. At least 50% of the patients with this finding have normal lipid profiles. 4) C V junction abnormalities are seen in all of the following except a. Rheumatoid arthritis b. Ankylosing spondylitis c. Odontoid dysgenesis d. Basilar invagination Ans: (b) Disorders of the craniovertebral junction are relatively uncommon. The problem common to these disorders is compression of the CNS at the level of the upper spinal cord and medulla. They present with brainstem or lower cranial nerve signs and symptoms such as tinnitus, vertigo, hearing loss, pharyngeal dysfunction, hoarseness, or airway obstruction. Atlantoaxial dislocation - The most common acquired cause of craniovertebral abnormality is rheumatoid arthritis. A high incidence of atlantoaxial instability, resulting from destruction of the normal stabilizing mechanisms by inflammatory tissue, has been reported in patients with rheumatoid arthritis. Atlantoaxial instability is common in children with Down syndrome because of hypotonia and ligamentous laxity, including especially the annular ligament of C1. Cervical neck films in flexion, extension and neutral position evaluate the atlanto-dens interval (ADI). ADI is normally less than 2.5 mm, but up to 4.5 mm is acceptable in this population. Children with an ADI greater than 4.5 mm should be restricted from contact and collision activities. www.medicinemcq.com Page 12 of 59 Basilar invagination is a craniocervical junction abnormality where the tip of the odontoid process projects above the foramen magnum. As the odontoid projects intracranially, it compresses the medulla. There is stenosis of the foramen magnum and compression of the medulla oblongata resulting in neurological symptoms, obstructive hydrocephalus, syringomyelia or even death. 1. Sup. Articulating Process; 2. Transverse Foramina; 3. Transverse Process; 4. Odontoid Process; 5. Spinous Process Causes - Basilar invagination may be congenital or acquired. Congenital Osteogenesis imperfecta Klippel-Feil syndrome Achondroplasia Chiari malformation Cleidocranial dysostosis Schwartz-Jampel syndrome www.medicinemcq.com Page 13 of 59 Acquired Rheumatoid arthritis Paget's disease Hyperparathyroidism Osteomalacia / rickets Basilar invagination occurs in around 5 - 10% of patients with cervical rheumatoid arthritis due to loss of axial supporting structures in the upper cervical spine. Chiari malformations are characterized by herniation of the contents of the posterior cranial fossa through the foramen magnum into the upper cervical spine. The diagnosis is confirmed by lateral radiographic views of the skull. It shows the tip of the odontoid either extends above Chamberlain's line (a line extending from the posterior edge of the hard palate to the posterior lip of the foramen magnum) or projects posterior to Wackenheim's clivus-canal line. Rheumatoid arthritis - Atlantoaxial and subaxial subluxations as well as basilar invagination can develop in patients with rheumatoid arthritis. Although basilar invagination is less common than atlantoaxial and subaxial subluxations, it is more dangerous. Since the compression caused by basilar invagination affects the brain stem at the level of the foramen magnum, the autonomic centers may be compromised, resulting in labile blood pressures, arrhythmias, or sudden death. Ankylosing spondylitis is unlikely to be associated with CV junction anomaly. Neuroimaging in craniovertebral anomalies as seen in the tropics. Sankhe SS Neuroimaging Clin N Am - 01-NOV-2011; 21(4): 879-95, ix. th CURRENT Diagnosis & Treatment: Pediatrics, 20 edition William W. Hay, Jr., Myron J. Levin, Judith M. Sondheimer, Robin R. Deterding. www.medicinemcq.com Page 14 of 59 5) All of the following are true about SIADH except a. Vaptans are approved for its treatment b. Water-loading test can be used for diagnosis of the condition c. Urine sodium is usually low or normal d. Serum sodium may be as low as 125 mEq/L Ans: (c) The only physiologic action of AVP is to increase the concentration of urine. ADH increases the permeability of cells that line the distal tubule and medullary collecting ducts of the nephron. These cells are permeable to water only in the presence of AVP. They cannot reabsorb water without AVP. Low AVP concentration results in water diuresis (i.e., the production of large amounts of urine that is maximally dilute). Excessive or inappropriate production of AVP results in the production of decreased volumes of concentrated urine. If water intake is not reduced, water retention and a decrease in plasma sodium results. + Hyponatremia (i.e., serum Na < 135 mEq/L) is a defining feature of SIADH. Hyponatremia is a + result of an excess of water and not a deficiency of Na . Enhanced water reabsorption leads to dilutional hyponatremia. Ingestion of water is an essential prerequisite to the development of the syndrome; hyponatremia does not occur if water intake is severely restricted. ADH does not have + a significant effect on the rate of Na reabsorption. SIADH (Syndrome of inappropriate antidiuretic hormone secretion) is the most common cause of euvolemic hyponatremia in hospitalized patients. SIADH consists of hyponatremia, inappropriately elevated urine osmolality (>100 mOsm/kg), and decreased serum osmolality in a euvolemic patient. www.medicinemcq.com Page 15 of 59 + Urine Na concentration in persons with SIADH is usually more than 40 mEq/L. In SIADH, + + + Na handling is not abnormal. The urine Na concentration reflects Na intake, which is generally + + more than 40 mEq/d. On a low-Na diet, patients with SIADH may have a urine Na level of less than 40 mEq/L. Vasopressin receptor antagonists (aquaretics) - The antidiuretic effect of AVP is mediated via a G protein-coupled V2 receptor. Inhibition of the AVP V2 receptor reduces the number of aquaporin-2 water channels in the renal collecting duct and decreases the water permeability of the collecting duct. There are 2 aquaretics that are currently approved by the US Food and Drug Administration. Conivaptan is a parenteral nonpeptide dual AVP V1a- and V2-receptor antagonist. It is approved for use in hospitalized patients with euvolemic (dilutional) and hypervolemic hyponatremia. Tolvaptan is a selective oral V2 receptor antagonist also approved for use in hospitalized patients for hypervolemia and euvolemic hyponatremia. th Harrison's principles of internal medicine, 18 edition. th Goodman and Gilman’s Pharmacological Basis of Therapeutics, 12 edition. th Williams Textbook of Endocrinology, 11 edition. 6) A 17-year-old female presents with fever, headache and altered sensorium. CT scan shows basal exudates with meningeal enhancement. The CSF is most likely to show- a. Lymphocytic pleocytosis, low sugar, low protein b. Polymorphonuclear pleocytosis, normal sugar, high protein c. Lymphocytic pleocytosis, low sugar, high protein d. Lymphocytic pleocytosis, normal sugar, high protein Ans: (C) www.medicinemcq.com Page 16 of 59 TB meningitis - Meningitis with basal exudates is most likely tuberculous. TB meningitis is usually characterized by less than 2 weeks of fever, headache, and meningismus. There may be depressed levels of consciousness, diplopia, and rarely, hemiparesis. Physical examination shows a stiff neck and, occasionally, cranial neuropathy (VI, III, IV, VII in order of frequency) and long-tract signs. CT of the head may show contrast enhancement over the basilar meninges, hypodense areas consistent with infarcts, hydrocephalus, and sometimes focal inflammatory lesions (tuberculomas). Diagnosis is made by CSF analysis. The typical CSF abnormalities in tuberculous meningitis are elevated opening pressure, lymphocytic pleocytosis, elevated protein concentration and decreased glucose concentration. Lymphocytic and mononuclear cell pleocytosis of 50–500 cells/mL is most often seen, but polymorphonuclear pleocytosis can occur early and may give an erroneous impression of bacterial meningitis. CSF protein is usually more than 100 mg/dL and may exceed 500 mg/dL, particularly in patients with spinal subarachnoid block. The glucose level is usually decreased and may be less than 20 mg/dL. Other causes of chronic lymphocytic meningitis include fungal infection, HIV infection, syphilis, brucellosis, leptospirosis and neurocysticercosis. PCR nucleic acid amplification for detecting Mycobacterium tuberculosis DNA-specific sequences shows great promise in the rapid and accurate diagnosis of tuberculous meningitis. However, a negative PCR result does not exclude the diagnosis of tuberculous meningitis. If high clinical suspicion remains, empirical therapy should be initiated. th Clinical Neurology, 7 edition Roger P. Simon, David A. Greenberg, Michael J. Aminoff. McPherson & Pincus: Henry's Clinical Diagnosis and Management by Laboratory st Methods, 21 edition. th Goldman: Goldman's Cecil Medicine, 24 edition. Infectious Diseases and Impaired Consciousness, Neurologic Clinics - Volume 29, Issue 4 (November 2011). www.medicinemcq.com Page 17 of 59 7) All are true regarding universal definition of MI except a. Sudden death is MI b. New region wall motion with increased biochemical marker is MI c. 3 times troponin elevation is required for CABG related MI d. Reinfarction can be diagnosed if elevation in troponin level by 5 to 7% on serial sampling Ans: (C) CABG causes the troponin to rise and may remain elevated for 10 days. CPK usually returns to normal by 48 to 72 h. It peaks at 24 h. Troponin is the contractile regulatory protein of striated muscle. It contains three subunits: T, C, and I. Troponin I is released into the circulation after cellular necrosis. Cardiac troponin I is expressed only in cardiac muscle. Therefore, its presence in serum can distinguish between myocardial injury and skeletal muscle injury. Cardiac troponin I is measured by immunoassay using monoclonal antibodies. CAUSES OF INCREASED CARDIAC TROPONIN Myocardial infarction (sensitivity 50% at 4 hours, 97% at 6 hours; specificity 95%) Cardiac trauma Cardiac surgery Myocardial damage following PTCA, CABG and other cardiac interventions Non-ischemic dilated cardiomyopathy Prolonged supraventricular tachycardia Acute dissection of the ascending aorta Slight elevation is noted in patients with recent aggravated unstable angina, muscular disorders, CNS disorders, HIV infection, chronic renal failure, cirrhosis, sepsis, lung diseases, and endocrine disorders. www.medicinemcq.com Page 18 of 59 Cardiac troponin is not increased in skeletal muscle disease (myopathy, myositis, dystrophy), external electrical cardioversion, non-cardiac trauma or surgery, rhabdomyolysis, severe muscular exertion, or in chronic renal failure. Cardiac troponin I is a more specific marker for myocardial infarction than CK-MB with roughly equivalent sensitivity early in the course of infarction (4–36 hours). Sensitivity and specificity for peak concentrations of cTnI (100%; 96%) are equivalent to or better than those for CK-MB (88%; 93%) and total CK (73%; 85%). cTnI appears in serum approximately 4 hours after onset of chest pain, peaks at 8–12 hours, and persists for 5–7 days. This prolonged persistence gives it much greater sensitivity than CK-MB for diagnosis of myocardial infarction beyond the first 36–48 hours. MARKER TIMES TO INITIAL ELEVATION (h) MEAN TIME TO PEAK ELEVATIONS (NONTHROMBOLYSIS) TIME TO RETURN TO NORMAL RANGE cTnI 3 – 12 24 hr 5 – 10 d cTnT 3 – 12 12 hr – 48 hr 5 – 14 d MB - CK 3 – 12 24 hr 48 – 72 hr MOST COMMON SAMPLING SCHEDULE Once at least 12 hr after chest pain Once at least 12 hr after chest pain Every 12 hr × 3 REVISED UNIVERSAL DEFINITION OF MYOCARDIAL INFARCTION Criteria for Acute, Evolving, or Recent MI Either of the following criteria satisfies the diagnosis for acute, evolving, or recent MI: 1 Typical rise and/or fall of biochemical markers of myocardial necrosis with at least one of the following: a Ischemic symptoms b Development of pathologic Q waves in the ECG c Electrocardiographic changes indicative of ischemia (ST-segment elevation or depression) d Imaging evidence of new loss of viable myocardium or new regional wall motion abnormality 2 Pathologic findings of an acute myocardial infarction www.medicinemcq.com Page 19 of 59 Criteria for Healing or Healed Myocardial Infarction Any one of the following criteria satisfies the diagnosis for healing or healed MI: 1 Development of new pathologic Q waves in serial ECGs. The patient may or may not remember previous symptoms. Biochemical markers of myocardial necrosis may have normalized, depending on the length of time that has passed since the infarction developed. 2 Pathologic findings of a healed or healing infarction Universal definition of myocardial infarction - Myocardial infarction is classified by the clinical scenario into 5 subtypes. 1 Spontaneous myocardial infarction related to ischemia caused by a primary coronary event such as plaque erosion and/or rupture, fissuring, or dissection 2 Myocardial infarction secondary to ischemia caused by increased oxygen demand or decreased supply (e.g., coronary artery spasm, coronary embolism, anemia, arrhythmias, hypertension, hypotension) 3 Sudden unexpected cardiac death, including cardiac arrest, often with symptoms suggestive of myocardial ischemia, accompanied by presumably new ST-segment elevation, or new LBBB, or presumably new major obstruction in a coronary artery by angiography and/or pathology, but death occurring before blood samples could be obtained, or before the appearance of cardiac biomarkers in the blood 4a Myocardial infarction associated with PCI 4b Myocardial infarction associated with stent thrombosis, as documented by angiography or autopsy 5 Myocardial infarction associated with CABG CABG related MI www.medicinemcq.com Page 20 of 59 PERIOPERATIVE MYOCARDIAL INFARCTION - DIAGNOSTIC CRITERIA <24 hours postoperatively CK-MB (or CK) at least five times the upper limits of normal > 24 hours postoperatively CK-MB (or CK) at least five times the upper limits of normal + one of the following: Evolutionary ST-segment elevation New Q waves in two or more contiguous leads New left bundle branch block CK-MB (or CK) at least three times the upper limits of normal th Braunwald's Heart Disease - A Textbook of Cardiovascular Medicine, 9 edition. McPherson & Pincus: Henry's Clinical Diagnosis and Management by Laboratory st Methods, 21 edition. CURRENT Diagnosis & Treatment: Cardiology, third edition, Michael H. Crawford. 8) All of the following are approved for the treatment of RRMS type of multiple sclerosis except a. Interferon β 1a b. Interferon β 1b c. Glatiramer acetate d. Mycophenolate Ans: (d) www.medicinemcq.com Page 21 of 59 Multiple sclerosis - Acute demyelinating attacks (relapses) of multiple sclerosis are treated with high-dose corticosteroid and, in severe cases, plasma exchange. If marked acute disability and acute corticosteroid therapy has failed, plasma exchange (5 to 7 exchanges on alternate days) have shown benefit. Corticosteroids shorten the duration and severity of symptoms from an acute exacerbation but have no proven effect on long-term disability. Chronic therapy for relapsing forms of MS ((RRMS, SPMS with exacerbations) - First line drugs used are IFN-β-1a, IFN- β -1b, glatiramer acetate, and fingolimod. Second-line therapy includes natalizumab or mitoxantrone. Cladribine is currently awaiting approval. Chronic therapy for secondary progressive MS is with mitoxantrone. No evidence-based recommendation can be made with regard to its use in this setting. st Ferri’s clinical advisor, 2012, 1 edition. Bope and Kellerman: Conn's Current Therapy 2012, 1st edition. th Harrison's principles of internal medicine, 18 edition. th Goldman: Goldman's Cecil Medicine, 24 edition. 9) Systemic eosinophiluria with renal failure is least likely to be due to a. Drug induced interstitial nephritis b. Contrast nephropathy c. Atheroembolic renal failure d. Polyangitis nodosa Ans: (D) www.medicinemcq.com Page 22 of 59 Interstitial nephritis - Allergic interstitial nephritis can develop in the setting of infection, malignancy, or systemic disease or as an idiopathic condition. Antibiotics and nonsteroidal antiinflammatory drugs are the most common causative agents of interstitial nephritis, although it can occur with almost any medication. The classic triad of fever, rash, and eosinophilia is seen in only 20% of patients. The urine findings include sterile pyuria, white blood cell casts, non–nephroticrange proteinuria, hematuria, and eosinophiluria. Eosinophiluria is more than 1% of urine leukocytes. It is present in more than 90% of cases of antibiotic-induced allergic interstitial nephritis when studied using Hansel's stain (demonstrates the eosinophilic granules more clearly). Lymphocytes may predominate in allergic interstitial nephritis induced by NSAIDs. Eosinophiluria is not specific for allergic interstitial nephritis. CAUSES OF EOSINOPHILURIA Acute interstitial nephritis (drug induces, contrast agents) Acute cystitis or prostatitis Pyelonephritis Postinfectious or rapidly progressive glomerulonephritis Renal atheroembolic disease Acute rejection of renal allograft th Brenner: Brenner and Rector's The Kidney, 8 edition. Current Diagnosis & Treatment: Nephrology & Hypertension Edgar V. Lerma, Jeffrey S. Berns, Allen R. Nissenson. www.medicinemcq.com Page 23 of 59 10) Which of the following statements is not true? a. Parathyroid hormone-related protein is responsible for causing hypercalcemia in cancer patients b. The unionized fraction of calcium in the plasma is an important determinant of PTH secretion 2+ c. Magnesium influences PTH secretion in the same direction as Ca , but is a less potent secretagogue d. Ca2+ influences PTH secretion by acting on a calcium sensor G-protein coupled receptor located in the parathyroid gland Ans: (B) PTH secretion is regulated by the extracellular ionized calcium concentration. Circulating ionized calcium acts directly on the parathyroid glands in a negative feedback fashion to regulate the secretion of PTH. Parathyroid cells sense changes in extracellular calcium concentration through a G protein–coupled receptor (GPCR) known as the calcium-sensing receptor (CaR). In the parathyroid, its activation inhibits PTH secretion. In this way, when the plasma Ca PTH secretion is inhibited and the Ca 2+ 2+ level is high, is deposited in the bones. When it is low, secretion is 2+ increased and Ca is mobilized from the bones. Hypercalcemia - Primary hyperparathyroidism and malignancy account for 90% of cases. Hypercalcemia is common in patients with cancer. The hypercalcemia in 80% of these patients is due to the elevated circulating levels of parathyroid hormone-related protein or PTHrP (humoral hypercalcemia of malignancy. Tumor production of PTH-related proteins (PTHrP) is the most common paraneoplastic endocrine syndrome. The tumours responsible for the hypersecretion include cancers of the breast, kidney, ovary and skin. Measurements of PTH and PTHrP levels help distinguish between hyperparathyroidism (elevated PTH) and malignancy-associated hypercalcemia (suppressed PTH and elevated PTHrP). About 20% of hypercalcemic patients have bone metastases that produce hypercalcemia by eroding bone (local osteolytic hypercalcemia). This erosion is produced by prostaglandins such as prostaglandin E2 from the tumor. www.medicinemcq.com Page 24 of 59 Magnesium is required to maintain normal parathyroid secretory responses. Plasma Mg 2+ concentrations also regulate PTH secretion in a similar manner to that of calcium. The balance of magnesium is closely linked to that of calcium; magnesium depletion or deficiency is frequently associated with hypocalcemia. This combined decrease in Mg 2+ and Ca 2+ leads to impairment in the individual's ability to secrete PTH. th Ganong’s Review of Medical Physiology, 23 edition; Kim E. Barrett, Susan M. Barman, Scott Boitano, Heddwen Brooks. th Greenspan's Basic & Clinical Endocrinology, 8 edition David G. Gardner and Dolores Shoback. th Williams Textbook of Endocrinology, 11 edition. rd Endocrine Physiology, Patricia E. Molina, 3 edition. 11) A 60-year-old male patient with rheumatoid arthritis presents with the following: Hb = 4.5g/dL. Platelet count = 2 lac/mm3. TLC = 6000/mm3. Serum Ferritin = 200 µg/dl. Serum iron = 30 mg/dL. TIBC = 280 ng/L. Which of the following is the most likely diagnosis? a. Anaemia of chronic disease b. Thalassemia minor c. Iron deficiency anaemia d. Autoimmune haemolytic anemia Ans: (A) Ferritin is the major storage protein for iron. Normal serum ferritin level is 15-300 µg/L. The serum ferritin level is the best indicator of total body iron stores. Serum ferritin is the test of choice for diagnosis of iron deficiency anemia. Serum ferritin is decreased in iron deficiency anemia. It is the earliest and most sensitive test before RBC morphologic change. Serum ferritin is a more sensitive test for iron deficiency than serum iron and iron-binding capacity (transferrin saturation). www.medicinemcq.com Page 25 of 59 Serum ferritin is clinically useful in distinguishing between iron deficiency anemia (serum ferritin levels diminished) and anemia of chronic disease or thalassemia (levels usually normal or elevated). Normal serum iron = 50-150 microgram/dl. Normal TIBC = 300 - 400 microgram/dl. In anaemia of chronic disease there will be decreased serum iron, increased storage iron (i.e., serum ferritin), decreased serum transferrin and decreased total iron binding capacity. 12) A 29-year-old, 4 month pregnant primigravida has been regularly taking sodium valproate for juvenile myoclonic epilepsy. She is now seeking an opinion for her antiepileptic regimen. What would you suggest her? a. Immediately taper valproate and start lamotrigine b. Continue valproate with monitoring of drug level c. Switch to carbamazepine d. Add lamotrigine to valproate Ans: (B) The majority of women with seizure disorders who become pregnant have an uneventful pregnancy with an excellent outcome. Levels of anticonvulsant medications can change dramatically during pregnancy. They usually decrease in total concentration as pregnancy progresses. With close surveillance, seizure frequency should remain the same or even improve in most epileptic patients during pregnancy. Monitor anticonvulsant levels when necessary. All anticonvulsants interfere with folic acid metabolism. Anticonvulsant levels should be checked frequently after implementing or increasing folic acid administration, because folate leads to lower anticonvulsant levels. Folic acid deficiency has been associated with neural tube defects and other congenital malformations. www.medicinemcq.com Page 26 of 59 Anticonvulsant medications are associated with a small increase in congenital malformations (e.g., cleft lip and palate, congenital heart disease, limb anomalies). Valproate and phenytoin are the two most teratogenic medications. Valproic acid and carbamezapine increase the risk of neural tube defects. Monotherapy is associated with a lower birth defect rate compared with multiagent therapy. Women with seizure disorders are at increased risk of IUGR and stillbirth. Early hemorrhagic disease of the newborn can occur in infants exposed to anticonvulsants in utero, and this appears to be due to a deficiency of the vitamin K–dependent clotting factors II, VII, IX, and X. The obstetrician must stress that controlling seizures is of primary importance. The potential harm of uncontrolled seizures on the mother and fetus is greater than the teratogenic effects of antiepileptic drugs. The patient will need to take whatever medication or medications are necessary to achieve this goal throughout her pregnancy. When possible, it seems prudent to have the patient on monotherapy at the lowest effective dose, especially during the first trimester. Juvenile myoclonic epilepsy is a generalized seizure disorder of unknown cause that appears in early adolescence. It is usually characterized by bilateral myoclonic jerks that can be provoked by sleep deprivation. Consciousness is preserved unless the myoclonus is especially severe. Many patients also experience generalized tonic-clonic seizures, and up to one-third have absence seizures. Complete remission is relatively uncommon. The seizures respond well to appropriate anticonvulsant medication. th Gabbe: Obstetrics: Normal and Problem Pregnancies, 5 edition. Williams Obstetrics, 23edition; F. Gary Cunningham, Kenneth J. Leveno, Steven L. Bloom, John C. Hauth, Dwight J. Rouse, Catherine Y. Spong. www.medicinemcq.com Page 27 of 59 13) A lady presents with complaints of abdominal pain. Contrast enhanced CT shows bilateral papillary necrosis. Which of the following test should not be done to investigate the cause of her papillary necrosis? a. Culture for bacteria b. Sickling test c. Urine acidification d. Urine PCR for TB Ans: (d) Renal papillary necrosis is ischemic necrosis of the renal papillae or of the entire pyramid. This is most commonly a complication of diabetes, analgesic abuse, sickle cell hemoglobinopathy, or obstruction. The role of infection in the development and progression of renal papillary necrosis is controversial. CONDITIONS ASSOCIATED WITH RENAL PAPILLARY NECROSIS Diabetes mellitus Pyelonephritis Urinary tract obstruction Analgesic abuse Sickle cell hemoglobinopathies Renal transplant rejection Cirrhosis of the liver Dehydration, hypoxia, and jaundice of infants Miscellaneous: renal vein thrombosis, cryoglobulinemia, renal candidiasis, contrast media injection, amyloidosis, necrotizing angiitis, rapidly progressive glomerulonephritis, hypotensive shock, acute pancreatitis. www.medicinemcq.com Page 28 of 59 The symptoms are usually those of chronic cystitis with recurring exacerbations of pyelonephritis. The patient usually has hematuria, renal colic, and often a high fever. Laboratory findings consist of pyuria, hematuria, occasionally glycosuria, and acidosis. It is treated by intravenous administration of appropriate antibiotics. In the majority of cases relief of the obstruction caused by necrotic papilla leads to improved renal function. The disease has a rapid course toward uremia and, if untreated, death. In severe cases, the prognosis is poor. Renal transplantation may be required. Analgesic abuse nephropathy is the most common cause of chronic interstitial nephritis. all analgesics, including acetaminophen, and aspirin can cause the same disease process. Renal dysfunction is manifested by isosthenuria (impaired urinary concentration) and impaired sodium conservation that may predispose to intravascular volume depletion. Hematuria can be a common presenting complaint but it is usually microscopic. Occasionally, patients can present with flank pain or gross hematuria associated with papillary necrosis. Renal colic occurs when necrotic renal papillae slough away. Polyuria may be prominent. Signs of acidosis (hyperpnea), dehydration, and pallor are common. Infection is a frequent complication. Urinalysis may show evidence of sterile pyuria, urinary tract infection, microscopic or macroscopic hematuria, and mild proteinuria. Elevated blood urea nitrogen and creatinine and the electrolyte changes characteristic of metabolic acidosis and renal failure are typically present. Urinary concentrating impairments are usually present. Renal tubular acidification defects are also seen. Patients with analgesic nephropathy are also at increased risk for transitional cell carcinoma of the uroepithelium. Bacterial culture is done for UTI. Sick cell disease can be diagnosed by sickling test. Analgesic nephropathy can be diagnosed by urine acidification. TB is least likely cause of papillary necrosis. Therefore, urine PCR for TB is not indicated. Current Diagnosis & Treatment: Nephrology & Hypertension Edgar V. Lerma, Jeffrey S. Berns, Allen R. Nissenson. th Brenner: Brenner and Rector's The Kidney, 8 edition. th CURRENT Diagnosis & Treatment: Surgery, 13 edition Edited by Gerard M. Doherty. www.medicinemcq.com Page 29 of 59 14) In Alzheimer’s disease, all are seen except a. Aphasia b. Acalculia c. Apraxia d. Agnosia Ans: (?) The Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition criteria for dementia require a decline in memory, as well as an impairment of at least one other domain of higher cognitive function (e.g., aphasia, apraxia, agnosia, or executive dysfunction [such as difficulty in planning, organizing, sequencing, or abstracting]). Agnosia is a loss of ability to recognize objects, persons, sounds, shapes, or smells while the specific sense is not defective nor is there any significant memory loss. Visual agnosia is inability to recognize visual objects. Prosopagnosia is the inability to recognize faces. Apraxia is the inability to carry out a motor task in the absence of sensory loss, weakness, incoordination or difficulty in comprehension. Ideational apraxia is loss of ability to carry out learned complex tasks in the proper order, such as putting on socks before putting on shoes. Ideational apraxia is commonly associated with confusion states and dementia. Acalculia is difficulty performing simple calculations such as adding, subtracting, or multiplying. Acalculia is associated with lesions of the parietal lobe (especially the angular gyrus) and the frontal lobe. It can be an early sign of dementia. Alzheimer's disease is the most common cause of dementia in the elderly. The features of classic dementia of the Alzheimer type include memory impairment, executive dysfunction, aphasia, visuospatial deficits, and impaired ability in calculation (acalculia) and abstraction. Disturbances of other cortical functions such as agnosia (impaired recognition) and apraxia may be observed. th Bradley: Neurology in Clinical Practice, 5 edition. th Duthie: Practice of Geriatrics, 4 edition. www.medicinemcq.com Page 30 of 59 15) Diabetes is diagnosed when a. The level of fasting glucose is ≥100 mg/dL and that of postprandial glucose is ≥ 140 mg/dL b. The level of fasting glucose is ≥ 125mg/dL and that of postprandial glucose is ≥199 mg/dL c. The level of plasma insulin is ≥ 6 IU/dL d. The HbA1c level is ≥ 5.5% Ans: (B) The American Diabetes Association defines DM as follows: A fasting plasma glucose (FPG) ≥126 mg/dl, which should be confirmed with testing on a different day; fasting is defined as no caloric intake for at least 8h. The ADA also defines a value <100 mg/dl on fasting blood sugar as the upper limit of normal for glucose; a fasting glucose level between 100 and 126 mg/dl is classified as “impaired fasting glucose” (IFG). Symptoms of hyperglycemia and a casual (random) plasma glucose ≥200 mg/dl; random plasma glucose is defined as any time of the day without regard to time since last meal; classic symptoms of hyperglycemia include polyuria, polydipsia, and unexplained weight loss An oral glucose tolerance test (OGTT) ≥200 mg/dl in the 2-hour sample; OGTT using glucose load containing the equivalent of 75 g (100 g for pregnant women) anhydrous glucose dissolved in water; furthermore, when results of the OGTT are between 140 and 199 mg/dl, the patient is classified as “impaired glucose tolerance” (IGT) A 2010 update to the ADA Guidelines for Standards of Medical Care in Diabetes included a hemoglobin A1C value ≥6.5% within the diagnostic criteria for diabetes mellitus. An A1C level of greater than 6.5 percent on two separate occasions is considered diagnostic of diabetes. www.medicinemcq.com Page 31 of 59 Gestational diabetes OGTT (100-g load): o Fasting, 95 mg per dL (5.3 mmol per L) o One hour, 180 mg per dL (10.0 mmol per L) o Two hour, 155 mg per dL (8.6 mmol per L) o Three hour, 140 mg per dL Need at least two abnormal results st Ferri’s clinical advisor, 2012, 1 edition. 16) All of the following features are seen in myelopathies except a. Facial sensory impairment b. Brisk jaw jerks c. Brisk pectoral jerks d. Urgency and incontinence of micturition Ans: (B) Trigeminal nerve - The three divisions of the trigeminal nerve—ophthalmic, maxillary, and mandibular—convey information about facial pain, temperature, vibration, and proprioception. The V nerve also provides sensation to the mouth and part of the dura, and motor supply to the muscles of the jaw involved in chewing. The trigeminal sensory nucleus receives the primary afferents of the trigeminal nerve. It is a large nucleus extending from the midbrain into the cervical spinal cord. The principal and largest division of the nucleus is located in the pontine tegmentum. www.medicinemcq.com Page 32 of 59 The main sensory nuclei of nerve V is in the upper half of the pons. There are three sensory nuclei: The principal sensory nucleus (touch, joint position sense) The mesencephalic nucleus (unconscious proprioception) The spinal trigeminal tract and nucleus (pain and temperature). The spinal trigeminal tract and nucleus descends from the pons to the C3/C4 segment of the spinal cord. See figure below. These carry sensations of the face. Hence, a high cervical cord lesion can cause facial sensory impairment. Facial sensation is involved because the spinal trigeminal nucleus and tract are located in the upper cervical cord. www.medicinemcq.com Page 33 of 59 Jaw jerk is elicited by the examiner placing their index finger over the middle of the patient’s chin with the mouth slightly open and the jaw relaxed. The index finger is then tapped with a reflex hammer, delivering a downward stroke. The afferent impulse for this reflex is the sensory portion of the trigeminal nerve. The efferent limb is through the motor (V3) branch of the trigeminal nerve. Normally, this reflex is absent or very slight. However in individuals with bilateral upper motor neuron lesions (pseudobulbar palsy), the jaw jerk reflex may be pronounced. Exaggerated contraction of the masseter suggests bilateral pathology (UMN lesion) above the mid pons. Bladder is innervated from autonomic nervous system with relay via spinal cord. Diseases of spinal cord may affect the bladder. Pectoralis reflex – Keep the patient’s arm in mid-position between abduction and adduction. Place your finger on the tendon of pectoralis major muscle near its insertion on the greater tuberosity of the humerus. Tapping the finger causes adduction and slight internal rotation of the arm of the shoulder. A normal response is little, if any, contraction of the pectoralis muscle. This reflex is mediated by the medial and lateral anterior thoracic nerves (C5-T1). If there is hyperreflexia when compared to the opposite side, it is indicative of a corticospinal tract lesion above the level of the fifth cervical segment. www.medicinemcq.com Page 34 of 59 th Gray's Anatomy, 40 Edition - The Anatomical Basis of Clinical Practice. th Clinical Neuroanatomy, 26 edition Stephen G. Waxman. th Bradley: Neurology in Clinical Practice, 5 edition. th Clinical Neurology, 7 edition Roger P. Simon, David A. Greenberg, Michael J. Aminoff. 17) A 17-year-old girl with short height has an enlarged pituitary gland. Her T4 was low and TSH was increased. Which of the following is the most likely diagnosis? a. Pituitary adenoma b. TSH-secreting pituitary tumour c. Thyroid target receptor insensitivity d. Primary hypothyroidism Ans: (d) In pituitary adenoma (TSH secreting pituitary tumor) increased TSH with increased T3/4 will be seen. In thyroid hormone resistance, increased T4/3 with low TSH will be seen. In primary hypothyroidism due to defect in the gland itself, high TSH with low T4 will be seen. The pituitary is often quite enlarged in primary hypothyroidism due to reversible hyperplasia of TSHsecreting cells. The concomitant hyperprolactinemia seen in hypothyroidism can lead to the mistaken diagnosis of a TSH-secreting or PRL-secreting pituitary adenoma. th Harrison's principles of internal medicine, 18 edition. th Williams Textbook of Endocrinology, 11 edition. www.medicinemcq.com Page 35 of 59 18) What is the most common cause of Addison’s disease in India? a. Post-partum pituitary insufficiency b. Tuberculous adrenalitis c. HIV d. Autoimmune adrenal insufficiency Ans: (B) CAUSES OF PRIMARY ADRENOCORTICAL INSUFFICIENCY Autoimmune Metastatic malignancy or lymphoma Adrenal hemorrhage Infectious o Tuberculosis, CMV, fungi (histoplasmosis, coccidioidomycosis), HIV, syphilis Adrenoleukodystrophy Infiltrative disorders o Amyloidosis, hemochromatosis Congenital adrenal hyperplasia Familial glucocorticoid deficiency and hypoplasia Drugs o Ketoconazole, metyrapone, aminoglutethimide, trilostane, mitotane, etomidat Tuberculosis is the most common cause of Addison’s disease in India. TB of the adrenal glands usually is a tertiary disease due to the hematogenous spread of infection to the adrenal glands, but clinical evidence of the primary infection is not always present. Autoimmune destruction of the adrenals is the most common cause of Addison disease in the United States (accounting for about 80% of spontaneous cases). The enzyme 21-hydroxylase is the main autoantigen. Idiopathic autoimmune adrenocortical atrophy and tuberculosis (TB) account for nearly 90% of cases of Addison disease. www.medicinemcq.com Page 36 of 59 HIV - The adrenocortical insufficiency in patients with AIDS tends to occur late and usually in the setting of a low CD4 cell count. It is caused by opportunistic infections such as cytomegalovirus, Mycobacterium avium intracellulare, cryptococci, or Kaposi sarcoma. Adrenocortical hypofunction in patients with HIV may be due to glucocorticoid resistance syndrome. Sheehan syndrome is pituitary insufficiency due to postpartum necrosis of the anterior pituitary gland in women with severe blood loss and hypotension during delivery. Failure to lactate, breast involution, and, if untreated, breast atrophy may occur. Fatigue, weight loss, and postural hypotension are common complaints. Hyponatremia and anemia (usually normocytic and normochromic) are frequent laboratory abnormalities. There is low thyroxin, TSH, estrogen, gonadotropin, cortisol, and ACTH levels. Bilateral adrenal hemorrhage may occur during sepsis, heparin-associated thrombocytopenia or anticoagulation, or with antiphospholipid antibody syndrome. It may occur in association with major surgery or trauma, presenting about 1 week later with pain, fever, and shock. It may also occur spontaneously. th Williams Textbook of Endocrinology, 11 edition. th Greenspan's Basic & Clinical Endocrinology, 8 edition David G. Gardner and Dolores Shoback. th Harrison's principles of internal medicine, 18 edition. th Current Diagnosis & Treatment: Emergency Medicine, 6 edition, C. Keith Stone, Roger L. Humphries. www.medicinemcq.com Page 37 of 59 19) All of the following are true about Alzheimer’s disease except a. Number of senile plaques correlate with age b. Underlying tau proteins suggest neurodegeneration c. Number of neurofibrillary tangles is associated with the severity of dementia d. Extracellular inclusions can be found in the absence of intracellular inclusions Ans: (B) Tau proteins are present normally. Alzheimer’s disease is the most common cause of dementia. The characteristic microscopic findings of Alzheimer’s disease are neurofibrillary tangles and senile plaques (beta-amyloid plaques). Neurofibrillary tangles are intracellular deposits containing hyperphosphorylated tau protein (a microtubule-associated protein) and ubiquitin. In Alzheimer’s disease, hyperphosphorylated tau accumulates in the perikarya of large and medium pyramidal neurons. Tau protein is the main constituent of neurofibrillary tangles. Neurons have microtubules that act like tracks, guiding nutrients and molecules from the cell body down to the ends of the axon and back. A special kind of protein, called tau, binds to the microtubules and stabilizes them. In Alzheimer’s disease, tau is changed chemically and the microtubules disintegrate, collapsing the neuron’s transport system. Tau hyperphosphorylation result in neuronal death. Neurofibrillary tangles represent a nonspecific response to a cellular injury that is triggered by beta-amyloid. The hippocampus and entorhinal cortex (medial temporal lobe) are the initial sites of tangle deposition and neuronal atrophy. This can be seen on brain MRI early in Alzheimer’s disease and helps in the diagnosis. Neuritic plaques are extracellular deposits. Plaques are made of beta-amyloid. They also contain presenilin 1, presenilin 2, alpha1-antichymotrypsin, apolipo-protein E, alpha2-macroglobulin, and ubiquitin. The neuritic plaque is most pathogenically relevant. Beta-amyloid is a protein fragment snipped from a larger protein called amyloid precursor protein (APP). See figure below. www.medicinemcq.com Page 38 of 59 APP is associated with the cell membrane. APP sticks through the neuron's membrane, partly inside and partly outside the cell. Enzymes act on the APP and cut it into fragments of protein, one of which is called betaamyloid. www.medicinemcq.com Page 39 of 59 The beta-amyloid fragments clump together outside the cell and then join other molecules and non-nerve cells to form insoluble plaques. Beta-amyloid begins to accumulate in the brain as long as 20 years before dementia occurs. By the time that clinical dementia due to Alzheimer's disease is present, large numbers of betaamyloid peptide–containing deposits invariably are found in neuritic plaques. Neuritic plaques represent the end-stage of the Alzheimer process. The amount of beta-amyloidosis does not closely mirror the severity of dementia in Alzheimer's disease. The neurofibrillary tangles and neuronal alterations and loss, not the plaques, correlate best with the severity of the dementia. Many older people develop some plaques and tangles and their numbers correlate with age. The brains of people with Alzheimer’s disease have them to a greater extent, especially in certain regions of the brain that are important in memory. The most consistent neurotransmitter deficit in Alzheimer's disease is in cholinergic neurotransmission. th Clinical Neurology, 7 edition Roger P. Simon, David A. Greenberg, Michael J. Aminoff. th Bradley: Neurology in Clinical Practice, 5 edition. Kumar: Robbins and Cotran Pathologic Basis of Disease, Professional Edition, 8th edition. www.medicinemcq.com Page 40 of 59 st Stern: Massachusetts General Hospital Comprehensive Clinical Psychiatry, 1 edition. 20) A 20-year-old female presents with following lab values: Hb = 9gm%, MCV = 55%, RBC = 4.5 million. There is no history of blood transfusion. What could be the probable diagnosis? a. Thalassemia major b. Thalassemia minor c. Iron deficiency anemia d. Anemia of chronic disease Ans: (B) As there is no history of blood transfusion, thalassemia major is unlikely. Anemia is a decrease in RBC mass. Methods for measuring RBC mass are time consuming and expensive. In practice, anemia is diagnosed by measurement of the Hb concentration, hematocrit or RBC count. Anemia is present if the hemoglobin concentration or the hematocrit is below the lower limit of the 95% reference interval for the individual's age, sex, and geographic location (altitude). See table below. Iron deficiency is the most common cause of anemia. All cases of iron deficiency anemia in adult males are due to chronic blood loss. NORMAL VALUES FOR PERIPHERAL BLOOD Males Females Hb (g/dL) 13.5 - 17.5 11.5 - 16 PCV (haematocrit; L/L) 0.4 - 0.54 0.37 - 0.47 RBC count (1012/L) 4.5 - 6.0 3.9 - 5.0 MCV (fL) 80 - 96 MCH (pg) 27 - 32 MCHC (g/dL) 32 - 36 www.medicinemcq.com Page 41 of 59 RDW (%) 11 - 15 WBC (109/L) 4.0 - 11.0 Platelets (109/L) 150 - 400 Reticulocytes 0.5 - 2.5% (50-100 × 109/L) Hemoglobin is a measure of oxygen-carrying capacity of blood. Hematocrit is a measure of solid elements of blood (mostly RBCs), as percentage of whole blood (remainder is plasma). Both hematocrit and hemoglobin are low in anemia. The mean corpuscular volume (MCV) of red cells is the most useful of the RBC indices to classify and to determine the cause of anemia. Normal MCV is 80 to 100fL (femto litre). Microcytosis is MCV less than 80fL. Macrocytosis is MCV more than 100fL. There are only 3 causes of anemia - blood loss, increased RBC destruction (hemolysis), and decreased production of RBCs. See table below. CAUSES OF MICROCYTIC HYPOCHROMIC ANEMIA Serum Total Iron- Bone Iron Binding Capacity Marrow (TIBC) Iron Condition Comment Iron deficiency ↓ ↑ 0 Responsive to iron therapy Chronic ↓ ↓ ++ Unresponsive to iron therapy ↑ N ++++ Reticulocytosis and indirect inflammation Thalassemia major Thalassemia bilirubinemia N N-↓ ++ minor Elevation of fetal hemoglobin and Hb A2, target cells, and poikilocytosis Lead poisoning N N ++ Basophilic stippling of RBCs Sideroblastic ↑ N ++++ Ring sideroblasts in marrow Hemoglobin N N ++ Hemoglobin electrophoresis www.medicinemcq.com Page 42 of 59 The first step to find the cause of anemia is to classify the anemia, based on MCV, as microcytic (<80 fL), normocytic (80-100 fL), or macrocytic (>100 fL). Microcytic hypochromic anemia - The anemia is microcytic if the MCV is < 80. The 3 commonest causes of microcytic anemia are iron deficiency, thalassemia and anemia of chronic diseases. Ferritin – With a microcytic anemia, an important test is the serum ferritin level. Measurement of serum ferritin is the most useful indirect estimate of body iron stores. The first test to become abnormal in iron deficiency anemia is a fall in serum ferritin level. The normal plasma ferritin levels are between 30–200 ng/mL (=μg/L) for males, and 15–200 ng/mL (=μg/L) for females. Serum ferritin level less than 15 ng/mL is diagnostic of iron deficiency anemia. In iron deficiency anemia, the MCV is low, and Hb and hematocrit are relatively lower than the erythrocyte count. Thalassemia - Hemoglobin consists of heme and globin. Heme is made up of porphyrin and ferrous iron. Globin is a protein with four polypeptide chains – 2 alpha and 2 beta chains. The hemoglobin is highly soluble but individual alpha and beta chains are insoluble. Thalassemia is one of the most common genetic disorders worldwide. Thalassemia is caused by a partial or complete deficiency of alpha or beta globin chain synthesis. Alpha -thalassemia refer to reduced synthesis of alpha chains. Relative excess of beta chains due to impaired production of alpha globin results in less stable chains. This leads to the clinical disease known as alpha thalassemia. Beta-thalassemia refers to decreased production of beta-chains. Impaired production of beta globin chains manifests with a more severe disease known as beta thalassemia. The synthesis of the unaffected alpha or beta globin occurs at normal rate. Therefore, there is accumulation of either alpha or beta subunits. Accumulation of the unaffected globin chain (i.e., alpha chain in beta thalassemia and beta chain in alpha thalassemia) causes hemolysis. Hemoglobin production is decreased. This cause hypochromic and microcytic anemia. Clinical classification - Thalassemia major is severe and transfusion-dependent form; thalassemia intermedia has less severe symptoms; and thalassemia minor (carrier state or trait) is without clinical symptoms, but with hematologic abnormalities. Thalassemia major (Cooley's Anemia) can be diagnosed easily during childhood. There is severe anemia, hepatosplenomegaly and microcytosis. Many patients require chronic blood transfusion. Thalassemia minor (i.e., thalassemia trait) usually presents as microcytosis and hypochromia, but only minimal or mild anemia. The MCV is reduced (less than 75 fL). These patients can be www.medicinemcq.com Page 43 of 59 misdiagnosed as iron deficiency anemia. RBC counts are usually higher than normal. Increased RBCs in the presence of decreased MCV is the hallmark of thalassemia trait. An MCV/RBC ratio <13 suggests thalassemia trait; a ratio >13 is more consistent with iron deficiency, but this and other formulas are not conclusive enough for diagnosis. Anemia of chronic diseases - MCV is normal or low. Serum iron is low. TIBC is normal or low. Percent transferrin saturation is low. Serum ferritin is normal or high. 21) A person with aortic stenosis could perform an exercise for 11 minutes in Bruce protocol. Exercise had to be stopped due to fatigue. He had a peak systolic gradient of 60 mm Hg across the aortic valve at rest. What is the best management for him? a. Medical management b. Aortic valve balloon dilation to prevent worsening c. Aortic valve replacement d. Coronary angiography Ans: (A) Aortic stenosis (AS) - Left ventricular and aortic pressure is normally nearly equal during systole (i.e., there is no gradient across the aortic valve during systole). In aortic stenosis, intracavitary LV pressure must increase above aortic pressure to produce forward flow across the stenotic aortic valve. Thus, there is a systolic pressure gradient between the LV and aorta in aortic stenosis. Critical aortic stenosis - The effective cross-sectional area of the normal aortic valve is 2.5 - 4 cm2. Clinically significant aortic stenosis develops only when the aortic valve orifice is narrowed to less than 1 cm2. Critical aortic stenosis is present when the systolic pressure gradient across the aortic valve is more than 50 mm Hg with normal cardiac output or the valve is narrowed to less 2 than 0.7 cm2 in an adult. A gradient > 50 mm Hg or an aortic valve area < 0.7 cm indicates that the aortic stenosis is severe enough to cause the patient's symptoms. www.medicinemcq.com Page 44 of 59 Doppler echocardiography is an accurate means of determining the severity of aortic stenosis in most patients. The Doppler study can be used to determine the gradient across the aortic valve and to calculate aortic valve area. Management - The absolute valve area (or transvalvular pressure gradient) is not the primary determinant of the need for aortic valve replacement. Therapeutic decisions related to corrective surgery are based largely on the presence or absence of symptoms. Treat asymptomatic patients conservatively. Recommend surgery in patients with symptoms due to AS. Asymptomatic patients with calcific AS and severe obstruction should be followed clinically for the development of symptoms. They need serial echocardiograms for evidence of deteriorating LV function. Asymptomatic adult patients – Obtain a Doppler echocardiographic study. If the mean gradient is more than 30 mm Hg, the patient should undergo a history and physical examination every 6 months. When symptoms have developed, repeat the Doppler echocardiographic study to confirm that the aortic stenosis has worsened. Prognosis is excellent until the classic symptoms of aortic stenosis (i.e., exertional angina, syncope or fatigue) develop. Even severe AS may exist for many years without producing any symptoms because of the ability of the hypertrophied LV to generate the elevated intraventricular pressures required to maintain a normal stroke volume. In asymptomatic patients with peak Doppler gradients > 50 mm Hg, the incidence of sudden death is less than 1% per year. Therefore, surgery is generally not indicated for asymptomatic patients with aortic stenosis. Symptomatic adult patients - After the onset of symptoms, average survival is 2 to 3 years, with a high risk of sudden death. Adults with aortic stenosis should be operated on shortly after the development of symptoms. Treatment modalities include aortic balloon valvotomy, valve débridement, and valve replacement. There is no effective pharmacologic treatment for severe aortic stenosis. Although ACE inhibitors prolong life in most cases of congestive heart failure, they are contraindicated in severe aortic stenosis. Children in whom the disease has been present from birth respond differently, and sudden death in the absence of symptoms is common. Asymptomatic children with aortic stenosis should probably undergo surgery once a peak gradient of 75 mm Hg develops, and sooner if symptoms are present. www.medicinemcq.com Page 45 of 59 Aortic balloon valvuloplasty is preferable to operation in many children and young adults with congenital, noncalcific AS. It is not commonly used in adults with severe calcific AS because of a very high restenosis rate (80% within 1 year) and the risk of procedural complications. It produces only transient mild hemodynamic benefits. It should be considered only a palliative measure for patients whose other severe systemic illnesses preclude surgery. It has been used successfully as a "bridge to operation" in patients with severe LV dysfunction and shock who are too ill to tolerate surgery. Cardiac catheterization – The main purpose is coronary angiography. If the patient is in the coronary-disease-prone age range, cardiac catheterization to confirm the hemodynamics and to define coronary anatomy should be performed. It is indicated when symptoms such as angina pectoris could be caused by coronary disease or aortic stenosis or when valve replacement surgery is planned. th Braunwald's Heart Disease - A Textbook of Cardiovascular Medicine, 9 edition. Hurst's The Heart, 13e Current Diagnosis & Treatment: Cardiology, third edition, Michael H. Crawford. 22) Which of the following clinical features of demyelinating myelopathy least likely suggests a progression to multiple sclerosis? a. Complete cord transaction b. Bilateral visual loss c. Absence of oligoclonal bands d. Poor prognosis Ans: (C) Patients with acute complete transverse myelitis have a cited risk of MS of only 5-10%. www.medicinemcq.com Page 46 of 59 CSF studies suggest that patients with monosymptomatic disease with positive oligoclonal bands (OCB) have higher risk of evolution to MS than without OCBs. 23) A 72-year-old man with normal renal function presents with new onset focal seizures. Which is the best drug to manage this patient? a. Sodium valproate b. Oxcarbazepine c. Levetriacetam d. Pregabalin Ans: (B) Focal Seizures - With the new classification system, the subcategories of "simple focal seizures" and "complex focal seizures" have been eliminated. Instead, they are classified as focal seizures with dyscognitive features and focal seizures without dyscognitive features. Focal seizures without dyscognitive features - Focal seizures can cause motor, sensory, autonomic, or psychic symptoms without impairment of cognition. "Jacksonian march" - The motor movements begin in a very restricted region such as the fingers and gradually progress (over seconds to minutes) to include a larger portion of the extremity. This is due to the spread of seizure activity over a progressively larger region of motor cortex. Focal seizures with dyscognitive features - Focal seizures may be accompanied by a transient impairment of the patient's ability to maintain normal contact with the environment. The patient is unable to respond to visual or verbal commands during the seizure and has impaired recollection or awareness of the ictal phase. The start of the ictal phase is often a sudden behavioral arrest or motionless stare. The behavioral arrest is usually accompanied by automatisms (involuntary, automatic behaviors). www.medicinemcq.com Page 47 of 59 Cerebrovascular disease is the most common cause (about 50%) of new cases of epilepsy in patients older than age 65. CAUSES OF SEIZURES Neonates (<1 month) Perinatal hypoxia and ischemia Intracranial hemorrhage and trauma Acute CNS infection Metabolic disturbances (hypoglycemia, hypocalcemia, hypomagnesemia, pyridoxine deficiency) Drug withdrawal Developmental disorders Genetic disorders Infants and children (>1 month and <12 years) Febrile seizures Genetic disorders (metabolic, degenerative, primary epilepsy syndromes) CNS infection Developmental disorders Trauma Idiopathic Adolescents (12–18 years) Trauma Genetic disorders Infection Brain tumor Illicit drug use Idiopathic Young adults (18–35 years) Trauma Alcohol withdrawal Illicit drug use Brain tumor Idiopathic www.medicinemcq.com Page 48 of 59 Older adults (>35 years) Cerebrovascular disease Brain tumor Alcohol withdrawal Metabolic disorders (uremia, hepatic failure, electrolyte abnormalities, hypoglycemia, hyperglycemia) Alzheimer's disease and other degenerative CNS diseases Idiopathic Almost all patients with new-onset seizures should have a brain MRI (CT scan is not adequate) to exclude the presence of a structural brain lesion. If no cause is found, begin chronic anticonvulsant therapy based on the probability of recurrence. Most epileptologists do not recommend chronic anticonvulsant drug treatment following a single seizure unless an underlying cause is found that is not correctable and is likely to produce recurrent seizures (e.g., brain tumor). However, recurrent seizures do require anticonvulsant treatment. Carbamazepine (or oxcarbazepine), lamotrigine and phenytoin are the drugs of choice for the initial treatment of focal seizures. Valporate and levetiracetam may also be used th Harrison's principles of internal medicine, 18 edition. th Clinical Neurology, 7 edition Roger P. Simon, David A. Greenberg, Michael J. Aminoff. th Bradley: Neurology in Clinical Practice, 6 edition. Adams and Victor's Neurology www.medicinemcq.com Page 49 of 59 24) Primary hyperaldosteronism can be diagnosed by all of the following criteria except a. Diastolic hypertension without edema b. Metabolic acidosis present c. Low plasma rennin activity that is not stimulated by volume depletion d. Hyperaldosteronism, i.e., increased aldosterone secretion which is not suppressed by volume expansion Ans: (b) Primary hyperaldosteronism – There is autonomous overproduction of aldosterone, with resultant suppression of the renin-angiotensin system and decreased plasma renin activity. CAUSES Solitary aldosterone-secreting adenomas (Conn's syndrome) are small (<2 cm in diameter), well-circumscribed lesions, more often found on the left than on the right. They tend to occur in the 30s and 40s, and in women more often than in men. These lesions are often buried within the gland and may not be visible on CT scanning. Idiopathic bilateral adrenal hyperplasia rarely occurs before age 40 years and is more common in males. Glucocorticoid-remediable hyperaldosteronism is an uncommon cause of primary familial hyperaldosteronism. In some families, it is caused by a chimeric gene resulting from fusion betweenCYP11B1 (the 11β-hydroxylase gene) and CYP11B2 (the aldosterone synthase gene). Adrenocortical carcinoma is rare. Pathophysiology – Aldosterone secretion is regulated by renin, serum potassium and sodium levels, intravascular volume status, and adrenocorticotropic hormone (ACTH). In primary hyperaldosteronism, there is autonomous aldosterone production (nonsuppressible aldosterone production). Plasma renin level is suppressed. There is mildly expanded intravascular and extravascular fluid volume. www.medicinemcq.com Page 50 of 59 Clinical features - There is excess aldosterone production leading to sodium retention, hypertension, and hypokalaemia (due to urinary potassium loss). The usual presentation is hypertension. Hypokalaemia (< 3.5 mmol/L) is frequently absent (up to 40%). Normal serum potassium does not exclude the diagnosis. Rarely muscle weakness, nocturia and tetany are seen. Primary hyperaldosteronism may present with hypokalemic metabolic alkalosis (due to increased renal hydrogen ion loss mediated by hypokalemia and aldosterone). Primary aldosteronism is typically not associated with edema, despite the volume-expanded state associated with it. This is due to spontaneous natriuresis and diuresis (aldosterone escape) mediated by atrial natriuretic peptide. Screening test - Plasma aldosterone:renin ratio (ARR) is the most frequently used screening test, but raised ARR alone does not confirm the diagnosis. Diagnosis is by elevated plasma aldosterone levels that are not suppressed with 0.9% saline infusion (2 L over 4 hours) or fludrocortisone administration. About 40% of patients with raised ARR on screening will suppress normally, excluding the diagnosis. The 24-hour urinary aldosterone (U-Aldo) excretion test is one of the most useful confirmatory diagnostic tools because it is an index for total daily aldosterone secretion. Adenoma is differentiated from hyperplasia by adrenal CT or MRI. The distinction between these 2 major causes is vital because the treatment of choice for each is different. Treatment - The treatment of choice for aldosteronomas is surgical extirpation. The treatment of choice for idiopathic bilateral adrenal hyperplasia is medical therapy with aldosterone antagonist spironolactone. th Kumar and Clark's Clinical Medicine 7 edition. Kumar: Robbins and Cotran Pathologic Basis of Disease, Professional Edition, 8th edition. th Goldman: Goldman's Cecil Medicine, 24 edition. www.medicinemcq.com Page 51 of 59 25) A 30-year-old man has complaints of falling asleep at work frequently. He attributes this to disturbed sleep at night. He also gives history of frequent falls while partying with friends. Which of the following additional problems might he be facing? a. Paralysis during sleep-wake transition with hallucinations b. Snoring and apneas c. Leg problems while going off to sleep d. Generalized seizures in the wake state Ans: (A) Narcolepsy is characterized by the tetrad of excessive daytime sleepiness, cataplexy, hypnagogic hallucinations, and sleep paralysis. Narcolepsy is associated with uncontrollable sleep attacks in inappropriate, embarrassing, and even dangerous situations (e.g., while driving). Most narcoleptics also have cataplexy (a sudden loss of muscle tone), hypnagogic hallucinations (dreamlike experiences while falling asleep), and sleep paralysis (brief paralysis associated with the onset of sleep or wakefulness). However, only 10–15% of narcoleptic patients have all four major symptoms. Sleep apnea - Respiratory dysfunction during sleep is a common cause of excessive daytime somnolence and disturbed nocturnal sleep. These episodes may be due to an occlusion of the airway (obstructive sleep apnea), absence of respiratory effort (central sleep apnea), or a combination of these factors (mixed sleep apnea). Sleep apnea is particularly prevalent in overweight men and in the elderly. Restless leg syndrome – The four core symptoms required for diagnosis are: (1) an urge to move the legs, (2) symptoms begin or worsen with rest, (3) partial or complete relief by movement, (4) worsening during the evening or night. www.medicinemcq.com Page 52 of 59 In about 80% of patients, restless leg syndrome is associated with periodic leg movements during sleep and occasionally while awake. These involuntary movements are usually brief, lasting no more than a few seconds, and recur every 5–90 seconds. The restlessness and periodic leg movements cause of sleep disturbance and daytime sleepiness. Primary restless leg syndrome is genetic with an autosomal dominant pattern of inheritance. Secondary restless leg syndrome may be associated with pregnancy, anemia, ferritin deficiency, renal failure, and peripheral neuropathy. The pathogenesis probably involves disordered dopamine function, in association with an abnormality of iron metabolism. Periodic leg movements also occurs with narcolepsy, sleep apnea, following the use of tricyclic and serotonin reuptake inhibiting antidepressants, L-dopa, and withdrawal from anticonvulsants and sedative-hypnotic drugs. History of fall is highly suggestive of atonia or paralysis that may be due to narcolepsy. In obstructive sleep apnea, patient usually falls asleep during day with no loss of postural tone. th Harrison's principles of internal medicine, 18 edition. Adams and Victor's Neurology st Stern: Massachusetts General Hospital Comprehensive Clinical Psychiatry, 1 edition. 26) Which of these is not a deleterious effect of hypothermia? a. Cardiac arrhythmias b. Decreased peripheral resistance c. Reversible coagulation d. Renal failure Ans: (b) www.medicinemcq.com Page 53 of 59 Systemic hypothermia is a reduction of core (rectal) body temperature below 35°C. To accurately measure hypothermia, an intravascular, esophageal, rectal or bladder probe that measures temperatures as low as 25 degrees C is required; oral, axillary, and otic temperatures are inaccurate and unreliable. Ventricular fibrillation and asystole may occur spontaneously at core temperatures below 28°C (82.4°F). Mild [ 35°C (95°F) – 32.2°C (90°F)] CVS changes Tachycardia, then progressive bradycardia Vasoconstriction Increase in cardiac output and blood pressure CNS changes Depression of cerebral metabolism Amnesia Impaired judgment Moderate [32.2°C (90°F) – 28°C (82.4°F)] CVS changes Progressive decrease in pulse and cardiac output Increased atrial and ventricular arrhythmias ECG changes (J- wave) CNS changes EEG abnormalities Progressive depression of level of consciousness Pupillary dilation Hallucinations www.medicinemcq.com Page 54 of 59 Severe [<28°C (82.4°F)] CVS changes Progressive decrease in pulse and cardiac output Increased atrial and ventricular arrhythmias ECG changes (J- wave) CNS changes Loss of cerebrovascular autoregulation Decline in cerebral blood flow Coma Loss of ocular reflexes Progressive decrease in EEG th Harrison's principles of internal medicine, 18 edition. th Marx: Rosen's Emergency Medicine, 7 edition. th CURRENT Diagnosis & Treatment: Emergency Medicine, 6 edition, C. Keith Stone, Roger L. Humphries. 27) Lid retraction is seen in a. Brimonidine b. Apraclonidine c. Trovaprost d. Bimatoprost Ans: (b) www.medicinemcq.com Page 55 of 59 Apraclodine decreases intraocular pressure by 25% when applied topically. This is achieved by decreasing aqueous production by primary α2 and subsidiary α1 action in the ciliary body. Its use restricted to control spikes of intraocular pressure after laser trabecuoplasty or iridoplasty. Brimonidine is more α1 selective and lipophilic than apraclonidine. It reduces aqueous production and increases uveoscleral outflow. Both apraclonidine and brimonidine can cause lid retraction. However, frequency is greater with apraclonidine. 28) A 25-year-old asymptomatic female underwent a pre-op coagulation test. BT = 3minutes. PT = 15/14. aPTT = 45/35. Platelet count = 2.5 lac/mm3. Factor VIII levels = 100%. What is the most likely diagnosis? Normal BT = < 7 minutes Normal PT = 12.7–15.4 seconds Normal APPT= 26.3–39.4 seconds Normal factor VIII = 0.50–1.50 (50–150%) a. Factor IX deficiency b. Lupus anticoagulant c. Factor VIII inhibitors d. VWD – Type III Ans: (b) Normal hemostasis - Disturbance of any one of the mechanisms may produce abnormal bleeding or abnormal thrombosis. 1) Vessel wall - Following minor injuries, the blood vessels undergo vasoconstriction, thereby preventing bleeding from the injured site and permitting repair. Vasoconstriction is an effective method of hemostasis in small vessel injuries but is not adequate when large vessels are damaged. 2) Platelets form the initial hemostatic plug that seals a site of vascular injury. Platelets also play a major role in forming the permanent thrombus that seals the injury www.medicinemcq.com Page 56 of 59 3) Blood coagulation is the formation of fibrin from plasma precursors. Fibrin and platelets constitute the permanent hemostatic plug. 4) Fibrinolysis is the production of plasmin that lyse and remove fibrin thrombi which have formed in the circulation. Bleeding time - A bleeding time and a platelet count are the most important screening tests of vessel wall and platelet abnormalities. Prolonged bleeding time is commonly due to thrombocytopenia. It is advisable to check the platelet count before carrying out the bleeding time test. Patients with a platelet count below 50,000/ml may have a very long bleeding time and the bleeding may be difficult to arrest. A prolonged bleeding time with a normal platelet count indicate abnormal platelet function. Normal BT is < 7 minutes. Any patient with a bleeding time >10 min has an increased risk of bleeding, but the risk does not become great until the bleeding time is >15 or 20 min. CAUSES OF PROLONGED BLEEDING TIME Thrombocytopenia Disorders of platelet function (e.g., aspirin, uraemia, paraproteinemia, or myelodysplastic syndromes thrombasthenia, storage pool defect) VWD Vascular abnormalities (e.g., Ehler-Danlos's syndrome, pseudoxanthoma elasticum) Severe deficiency of factor V or XI Afibrinogenaemia This 25-year old asymptomatic female has normal BT and platelet count. Therefore, thrombocytopenia and vessel wall disorders can be ruled out. You have to consider disorders of coagulation. Coagulation disorders - There are three principal groups of coagulation disorders. Deficiency of Coagulation Factors - Of these, factor VIII deficiency (hemophilia A and von Willebrand's disease) and factor IX deficiency (Christmas disease) are the most common. Acquired deficiencies of coagulation factors occur in severe liver disease (affects all factors produced by the liver) and in vitamin K deficiency (prothrombin and factors VII, IX, and X). www.medicinemcq.com Page 57 of 59 Presence of Circulating Anticoagulants – This group includes anticoagulant therapy, factor VIII inhibitor and lupus anticoagulant. Fibrinolytic Activity - Increased fibrinolytic activity in the blood results from increased activation of the plasmin system. Prothrombin time screens the extrinsic or tissue factor-dependent pathway. It tests factor VII. Factor VII has the shortest half-life of about 7 hours. Therefore, PT may become abnormal earlier than APPT. Normal PT = 12.7–15.4 seconds. The activated partial prothrombin time (APTT) measures XII, XI, IX, VIII, X, V, prothrombin and fibrinogen (i.e., intrinsic pathway). It does not measure factor VII and factor XIII. The normal APPT is 30 to 50 seconds. CAUSES OF A PROLONGED APTT Disseminated intravascular coagulation Liver disease Heparin or other anticoagulants A circulating anticoagulant (inhibitor) Deficiency of a coagulation factor other than factor VII DIFFERENTIAL DIAGNOSIS OF ABNORMAL COAGULATION SCREENING TESTS Abnormal Activated Partial Thromboplastin Time (APTT) Alone Associated with bleeding: VIII, IX, and XI defects Not associated with bleeding: XII, prekallikrein (PK), high molecular weight kininogen, lupus anticoagulants Abnormal Prothrombin Time (PT) Alone Factor VII defects www.medicinemcq.com Page 58 of 59 Combined Abnormal APTT and PT Medical conditions: Anticoagulants, disseminated intravascular coagulation, liver disease, vitamin K deficiency, massive transfusion Rarely dysfibrinogenemia; factor X, V, and II defects Heparin, which accelerates the inactivation of thrombin and other coagulation factors (such as factor Xa), preferentially blocks the intrinsic system, leading to prolonged APTTs but not to significant elevations in PT. On the other hand, the vitamin K antagonist coumadin preferentially blocks factor VII in the extrinsic system, leading to prolonged PTs but not APTTs. Normal factor VIII in the above case rules out Hemophilia A and Von Willebrand disease. Factor IX deficiency (Hemophilia B or Christmas disease) is an X-linked inherited bleeding disorder. It usually manifested in males. It is transmitted by females when they carry the abnormality on the X chromosome. A prolonged aPTT with a normal PT and Factor VIII is typical of hemophilia B. Prolongation of PT alone, or both the PT and aPTT, is not consistent with hemophilia B alone. Among those with residual FVIII or FIX activity >25% of normal, the disease is discovered only by bleeding after major trauma or during routine presurgery laboratory tests. The sex of the case in question is against this diagnosis. Lupus anticoagulant – It is a misnomer because the lupus anticoagulant is more frequently encountered in patients without lupus and is associated with thrombosis rather than with bleeding. The lupus anticoagulant can also present with a prolonged aPTT and can also be associated with the presence of a specific factor VIII inhibitor. Factor VIII inhibitors - If the PT or the APTT becomes elevated in the absence of treatment with heparin or coumadin, and the platelet count is normal, it is important to perform mixing studies of the patient's plasma with normal plasma to determine if the coagulation time normalizes (i.e., whether there is a factor deficiency). If mixing studies do not completely correct the prolonged coagulation times, the presence of coagulation inhibitors, such as circulating lupus anticoagulant or antifactor antibodies, should be suspected. www.medicinemcq.com Page 59 of 59 The presence of a factor VIII inhibitor should be suspected whenever a patient with no prior bleeding history presents with spontaneous massive bruising or with large, unexplained hematomas. The aPTT is prolonged, whereas the prothrombin time is normal. The aPTT of a mixture of the patient's plasma and normal plasma is also prolonged. Confirmation that an inhibitor acts specifically with factor VIII requires incubating the patient's plasma diluted with an equal volume of normal plasma and performing assays of factors VIII, IX, XI, and XII at 0, 60, and 120 minutes. If the inhibitor is specific for factor VIII, only factor VIII decreases over time. th Hoffman: Hematology: Basic Principles and Practice, 5 edition. th Harrison's principles of internal medicine, 18 edition. www.medicinemcq.com
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