INTRODUCTION AND CLINICAL MANIFESTATIONS OF RENAL DISEASE (1) LEARNING OBJECTIVES  At the end of the lecture students should be able to  Describe basic structure and functions of the kidney  Illustrate main symptoms of renal disease  Assess kidney functions ANATOMY • The kidneys are retroperitoneal organs lie on either side of the spine at level of T12-L3 • Normal kidneys are 11-14 cm in length • Right kidney lies 1.5 cm lower than the left because of the liver Each kidney contains one million nephrons comprising a glomerulus, PCT, Loop of Henle, distal tubule and collecting duct Blood and nerve supply to the kidney • • • The kidneys receive 25% of the cardiac output T10-12/L1 roots innervate the renal capsule and the ureter and pain from these structures is felt in these dermatomes The Glomerulus A glomerulus is a capillary tuft that is surrounded by Bowman's capsule Receives its blood supply from an afferent arteriole Unlike most other capillary beds, the glomerulus drains into an efferent arteriole The resistance of these arterioles results in high pressure within the glomerulus, aiding the process of ultrafiltration, where fluids are forced out of the capillaries and into Bowman's capsule Glomerulus and its surrounding Bowman's capsule constitute a renal corpuscle, the basic filtration unit of the kidney The rate at which blood is filtered through all of the glomeruli, and thus the measure of the overall renal function, is the glomerular filtration rate (GFR). THE GLOMERULAR LAYERS Primary functions of the kidneys  Excretion of waste products e.g. urea  Maintain body water and electrolytes  Regulation of BP through renin angiotensin system  Endocrine function in erythropoiesis and vitamin D metabolism The kidneys produce urine which passes to the bladder through the ureters As the bladder fills completely, the smooth muscle layer (detrusor) contracts under parasympathetic control to allow urine to pass through the urethra Symptoms of renal disease  Kidney (upper urinary tract symptoms): Pain ,swelling,hematuria  Lower urinary tract symptoms: voiding pain (pain passing urine), frequency, urgency, hesitancy  Change in urine volume (polyuria, oliguria, anuria) or color (haematuria), content (proteinuria)  General symptoms: oedema, fatigue, nausea, vomiting, shortness of breath Kidney (Upper urinary tract) symptoms Pain • • • • • Renal colic A severe sudden sustained loin pain It often radiates to the groin It is caused by sudden obstruction in the urinary tract usually by a calculus or a blood clot It is often associated with nausea and vomiting may be associated with smokey urine. B.Dull ache in the loins • • • Usually due to stretch of the capsule of the kidney e.g. in glomerulonephritis, polycystic kidney and hydronephrosis Loin pain with fever, rigors, pain on voiding suggest infection of the kidneys (acute pyelonephritis) Many patients with chronic obstruction are however pain-free Lower urinary tract symptoms Dysuria • • Pain or discomfort felt during or immediately after passing urine It is often described as a burning sensation felt at the urethral meatus , or the suprapubic region • The most common cause is infection and /or inflammation of the bladder[cystitis]and frequency(desire to pass urine more often) is usually present Voiding symptoms • During storage phase • During voiding phase • After micturition • Incontinence Urgency • Storage symptoms A sudden strong need to pass urine and may cause incontinence if there is no opportunity to urinate. Is due to overactivity of detrusor muscle or abnormal stretch receptor activity from the bladder Frequency • Means frequent micturition of relatively small amounts of urine • • • • • Causes Cystitis, urthritis or stone bladder causing irritation of the bladder wall Contracted bladder as occurs in Bilharziasis; the diminished capacity of the bladder leads to frequent micturition Chronic retention of urine e.g. by enlarged prostate small amount of urine overflow from the bladder at frequent intervals Cancer bladder Psychogenic factors as anxiety. Voiding phase symptoms  Hesitancy: delay or difficulty in initiating urine flow  In men over 40, it is commonly due to bladder outlet obstruction by prostate enlargement  In women, it suggests urethral obstruction due to stenosis or uterine prolapse  Poor flow: reduction in urinary stream After micturation symptoms • Dribbling and incomplete emptying are caused by obstruction • • • Incontinence : involuntary release of urine may occur With the need to void (urge incontinence) caused by overactive detrusor or with increased intra abdominal pressure (stress incontinence) due to weakness of pelvic floor following childbirth Symptoms of bladder outlet obstruction • Urgency • Frequency • Hesitancy • Poor flow • Dribbling Change in urine volume Polyuria Means increased volume of urine as the capacity of the bladder is limited, polyuria is associated with frequency N.B : In healthy adults urine out put will approximate to the fluid intake minus the insensible fluid losses through the skin and respiratory tract[500-800 ml/day], average 2-3 liters/day Causes 1-Diabetes mellitus (due to osmotic effect of glucose) 2-Chronic renal failure especially with chronic tubulointertsitial fibrosis 3-Diabetes insipidus 4- Hypercalcaemia (due to impaired tubular concentrating mechanism) 5- Hypokalemia (due to impaired tubular concentrating mechanism) 6- Excessive fluid intake due to psychiatric disease. Oliguria Means diminished volume of urine <500 ml\day Causes 1- Diminished intake of fluids 2- Hot weather 2- Pre-renal failure 3- Initial stage of acute renal failure 4- Terminal stage of chronic renal failure Anuria Means complete absence of urine formation so that no urine reaches the bladder and the patient has no desire to micturate Causes • • lower urinary tract obstruction when bladder neck or urethral obstruction causes urinary retention Spinal injury through neurological damage Change in urine colour Haematuria • Means passage of red blood cells in urine • It can be • Macroscopic causing a reddish discoloration of the urine • Microscopic when excess red cells are detected in urinary sediment • Causes 1- Prerenal e.g. Haemoragic diseases as purpura and over dose of anticoagulants 2-Renal e.g. Stones, tumours, glomerulonephritis, and renal T.B 3-Ureter: stone and tumours 4- Bladder : cystitis, stone and tumours 5- Prostate : prostatitis, prostatic hypertrophy and tumours 6- Urethra: trauma, stricture, stone and tumours It should be noted that • • Terminal haematuria indicates a lesion in the urethra, prostate , or bladder neck while total haematuria means the lesion is higher up Haematuria associative with renal colic is suggestive of stone • Painless frank haematuria is suggestive of tumour • Microscopic haematuria is suggestive of a parenchymatous lesion as glomerulonephritis • Differential diagnosis of haematuria (causes of reddish urine) • Contamination of urine by menstrual blood • Free hemoglobin due to intravascular hemolysis • Free myoglobin in rhabdomyolysis • Drug therapy : rifampcin Change in urine contents Proteinuria  Proteinuria is usually asymptomatic unless gross > 2-3 g/day  Severe proteinuria may produce frothy urine  Lowering the plasma albumin concentration, oncotic pressure  Generalized oedema and nephrotic syndrome Causes of proteinuria 1. Renal disease • • • Glomerulonephritis Diabetes mellitus Lupus nephritis • Non renal disease • Fever • • Severe exertion Heart failure General symptoms of chronic kidney disease General symptoms of renal disease • Broadly non specific • Occur in chronic kidney disease due to retention of uremic toxins • Nausea vomiting itching disturbed consciousness • Fatigue and pallor secondary to anemia • Bony aches and muscle weakness • Shortness of breath (anemia, volume overload) Uremic symptoms Symptoms secondary to anemia Symptoms secondary to bone disease Symptoms secondary to volume overload 1. Lower limb swelling 2. Pleural effusion 3. Pulmonary edema Investigations Renal function tests • Serum creatinine • Blood urea • Serum electrolytes • Complete blood count • Creatinine clearance • Serum calcium and phosphorus Urine analysis Flat colorless hexagonal plates, which often aggregate Urine analysis Flat colorless hexagonal plates, which often aggregate Stix test for blood protein sugar Red cell cast Cystine crystals Flat colorless hexagonal plates which often aggregate Microscopic examination Radiologic assessment of UT Plain X-ray Abdomen Detection of calcification and radiopaque stones Ureteric stone bilateral staghorn stones Right staghorn stone Intravenous Pyelogram (IVP) Hydronephrosis Renal ultrasonography No exposure to radiation and no dye is used 1. Assess renal dimensions 2. Exclude obstruction 3. Polycystic kidney Disease Renal biopsy Indications • Nephrotic syndrome • Nephritic syndrome • Acute renal failure • Proteinuria, haematuria Normal glomerulus Membranous nephropathy Necrotizing GN THE END XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX