A Case of Back Pain
Kimberly Collins, MSIII Gillian Lieberman, MD March 2007 A Patient with Low Back Pain Kimberly Collins, Harvard Medical School Year III Gillian Lieberman, MD Kimberly Collins, MSIII Gillian Lieberman, MD Case Presentation MJ is a 48 year-old male with a five month history of increased low back pain that radiates down his left leg, left leg weakness, new onset constipation, and slow urination. 2 Kimberly Collins, MSIII Gillian Lieberman, MD Low Back Pain About 70% of adults have low back pain at some time Low back pain is second only to upper respiratory illness as a symptom-related reasons for visits to the physician 3 Deyo, 1992 Kimberly Collins, MSIII Gillian Lieberman, MD Differential for Back Pain Mechanical Low Back Pain 97% • • • • • Lumbar strain, sprain 70% Degenerative processes of disks and facets 10% Herniated disk 4% Spinal stenosis 3% Spondylolisthesis 2% Non-Mechanical Spinal Conditions ~1% • Neoplasia 0.7% • Infection 0.01% • Inflammatory arthritis 0.3% Visceral Disease 2% • • • • Disease of pelvic organs Renal disease Aortic aneurysm Gastrointestinal disease 4 Deyo, 2001 Kimberly Collins, MSIII Gillian Lieberman, MD Deciding whether to image Back pain in a patient <50 with no neurological deficits should be followed conservatively with follow-up in 6 weeks Patients with back pain associated with neurological signs should have imaging Back pain lasting more than 3 months is considered chronic and should be imaged 5 Jarvik, 2002 Kimberly Collins, MSIII Gillian Lieberman, MD Deciding whether to image MJ’s symptoms: low back pain that radiates down his left leg, left leg weakness, new onset constipation, and slow urination. Indications for imaging MJ: • Left leg sciatica and weakness • Changes in bowel and bladder function 6 Kimberly Collins, MSIII Gillian Lieberman, MD Imaging modalities for patients with low back pain ADVANTAGES IMAGING MODALITY DISADVANTAGES Plain film Allows visualization of bony structures, low cost CT Detailed visualization of bony structures, some visualization of soft tissue structures Best modality for soft tissue visualization, no radiation exposure. Test of choice for back pain with neurological signs! Can screen the entire skeleton, good for detecting diffuse bone processes, metastases Soft tissue is not well visualized, radiation exposure Not great for evaluating soft tissue, radiation exposure, expensive MRI Bone scan Difficult to evaluate cortical bone and calcifications, very expensive Low specificity 7 Kimberly Collins, MSIII Gillian Lieberman, MD Imaging modalities for patients with low back pain IMAGING MODALITY ADVANTAGES DISADVANTAGES CT Myelography Used when MRI is contraindicated, allows visualization of spinal cord and nerve roots, can evaluate for lesions within the spinal canal Evaluate for disc disease, such as tears Invasive, involves the injection of contrast into the thecal sac Discography Bone densitometry/ DEXA Spinal angiography Invasive, rarely used Measures bone marrow density, good for determining fracture risk Evaluate for AVM, vascular tumors of spinal cord Invasive, rarely used 8 Kimberly Collins, MSIII Gillian Lieberman, MD Anatomy of the lower spine 9 Moore, 2002 Kimberly Collins, MSIII Gillian Lieberman, MD Patient MJ: Axial CT and MRI Courtesy Fabio Komlos, MD CT w/o contrast Courtesy Fabio Komlos, MD T1W Gad+ A gadolinium-enhancing mass with central calcification is seen within the spinal canal. The mass is better visualized on MRI. 10 Kimberly Collins, MSIII Gillian Lieberman, MD Patient MJ: Sagittal CT and MRI CT Courtesy Fabio Komlos, MD T1W gad+ Courtesy Fabio Komlos, MD A gadolinium-enhancing mass with central calcification is seen within 11 the spinal canal. The mass is better visualized on MRI. Kimberly Collins, MSIII Gillian Lieberman, MD Patient MJ: T2 Sagittal MRI of Lumbar Spine The mass is located within the spinal column below the level of the cona medullaris and is seen compressing the cauda equina. The location of the mass can explain MJ’s symptoms, which are consistent with cauda equina syndrome. 12 Courtesy of Fabio Komlos, BIDMC Kimberly Collins, MSIII Gillian Lieberman, MD Cauda Equina Syndrome Symptoms include: • urinary retention • saddle anesthesia - sensory loss occurring over the buttocks, posterior-superior thighs, and perianal regions • unilateral or bilateral sciatica • leg weakness • diminished anal sphinctor tone Usually caused by a tumor or massive midline disk herniation. 13 Deyo, 1992 Kimberly Collins, MSIII Gillian Lieberman, MD Intraspinal Masses Extradural Intradural Intramedullary Extramedullary 14 Courtesy of Fabio Komlos, BIDMC Kimberly Collins, MSIII Gillian Lieberman, MD Differential for Intraspinal Masses Extradural Intradural Extramedullary Intramedullary • Disk disease • Meningioma • Ependymoma • Metastases, myeloma and lymphoma deposits • Neurofibroma • Astrocytoma • Metastases = “drop mets” • Infarct • Hematoma • Hematoma • AVM • Abscess 15 http://intl.elsevierhealth.com/e-books/viewbook.cfm?ID=576 Kimberly Collins, MSIII Gillian Lieberman, MD Patient MJ: T2 Sagittal MRI A second intraspinal mass can be seen on this sagittal MRI. 16 Courtesy of Fabio Komlos, MD Kimberly Collins, MSIII Gillian Lieberman, MD Patient MJ: Coronal and Axial T1 Enhanced Cranial MRI Bilateral acoustic schwannomas are a hallmark of NF2. 17 Courtesy of Fabio Komlos, MD Kimberly Collins, MSIII Gillian Lieberman, MD MJ’s Diagnosis The multiple intraspinal masses and bilateral acoustic schwannomas seen on MRI was suggestive of neurofibromatosis 2. The diagnosis was confirmed by pathology after removal of the intraspinal masses. 18 Kimberly Collins, MSIII Gillian Lieberman, MD Neurofibromatosis There are two types: Neurofibromatosis Types 1 and 2 Neurocutaneous syndromes Development of neoplasms primarily in organs derived from embryonic mesoderm (skin, central and peripheral nervous systems, eyes) Inherited as autosomal dominant conditions with variable penetrance 19 Kimberly Collins, MSIII Gillian Lieberman, MD Neurofibromatosis NF1 Chromosome 17 Gene product: GTPase activating protein One of the most common autosomal dominant disorders Cutaneous features: peripheral neurofibromas, café au lait spots, freckling of axilla Nervous system tumors: plexiform neurofibromas, gliomas, ependymomas, meningiomas, astrocytomas, pheochromocytomas NF2 Chromosome 22 Gene product: cytoskeletal protein Less common autosomal dominant disorder Cutaneous features: café au lait spots and peripheral neurofibromas occur rarely Nervous system tumors: schwannomas, meningiomas, ependymomas 20 Ruggieri, 1999 Kimberly Collins, MSIII Gillian Lieberman, MD Companion Patient 1: Plain radiograph Cutaneous neurofibroma seen as a soft tissue swelling on plain radiograph. 21 Courtesy of Jim Wu, MD Kimberly Collins, MSIII Gillian Lieberman, MD Companion Patient 2: Chest MRI STIR T1W Gad+ Plexiform neurofibroma seen in a patient with NF1. 22 Courtesy of Jim Wu, MD Kimberly Collins, MSIII Gillian Lieberman, MD Companion Patient 3: Plain radiograph Radiographs taken before and after the onset of leg pain in a patient with NF1. Fibular fracture is seen in the second radiograph. 23 Courtesy of Jim Wu, MD Kimberly Collins, MSIII Gillian Lieberman, MD Companion Patient 3: MRI T1W Gad+ T2W The fibular fracture occurred due due to mass effect 24 Courtesy of Jim Wu, MD from a neurofibrosarcoma. Kimberly Collins, MSIII Gillian Lieberman, MD Summary The most common causes of back pain are mechanical. Not all back pain requires imaging. MRI is the best modality for imaging back pain with neurological signs. The differential for intraspinal masses can be divided into extradural, intradural extramedullary, and medullary. Neurofibromatosis is a neurocutaneous syndrome characterized by tumors of the skin and nervous system. 25 Kimberly Collins, MSIII Gillian Lieberman, MD References Deyo RA, Weinstein JN. Low Back Pain. N Engl J Med 2001;344(5):363-370. Deyo RA, Rainville J, Kent DL. What Can the History and Physical Examination Tell Us About Low Back Pain? JAMA 1992;268: 760-764. Moore KL, Agur AMR. Essentials of Clinical Anatomy. 2nd edition. Baltimore: Lippincott Williams & Wilkins, 2002. p 307. Jarvik JG, Deyo RA. Diagnostic evaluation of low back pain with emphasis on imaging. Ann Intern Med 2002;137:593. Kasper, Braunwald, et al. Harrison’s Principles of Internal Medicine. 16th edition. New York: McGraw-Hill, 2005. p 2457. Ruggieri M. The different forms of neurofibromatosis. Child’s Nerv Sys 1999;15:295-308. http://www.theuniversityhospital.com/healthlink/archives/articles/ne urofibromatosis.htm http://intl.elsevierhealth.com/e-books/viewbook.cfm?ID=576 26 Kimberly Collins, MSIII Gillian Lieberman, MD Acknowledgements Fabio Komlos, MD Jim Wu, MD Gillian Lieberman, MD Pamela Lepkowski Larry Barbaras, webmaster 27
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