What I Have Learned About Infectious Diseases With My Sleeves Rolled Up

Karen L. Roos, MD

Disclosures

Semin Neurol. 2002;22(1) 

In This Article

Transverse Myelitis

Transverse myelitis, by definition, is an inflammatory condition of the spinal cord. The etiology may be infectious, parainfectious, due to other systemic inflammatory disorders, a spinal form of multiple sclerosis, or idiopathic. Infectious myelitis presents with fever and paraparesis. The thoracic cord is most commonly affected. Initially the lower extremities will be flaccid, but then become spastic. Back pain may be present, and there may be a sensory level and bowel and bladder dysfunction. The symptoms may either evolve over a few hours or progress over a number of days. Emergent neuroimaging is indicated to rule out a compressive extramedullary mass lesion. Spinal magnetic resonance imaging (MRI) is the neuroimaging modality of choice and should include images of the spinal cord several levels above and below the level of the lesion suggested by the findings on neurological examination. If a single hyperintense lesion is imaged that extends over a number of levels, particularly in the thoracic region, be suspicious of an infectious etiology of the myelitis. There are a number of viruses that may cause an infectious myelitis, of which enteroviruses, herpes simplex virus-2, and VZV are the most common. Myelitis may complicate acute varicella or zoster, or may occur without a history of shingles. Cerebrospinal fluid should be sent for PCR for viral DNA (herpes simplex virus, VZV, Epstein-Barr virus, cytomegalovirus), and reverse transcriptase PCR for viral RNA (enteroviruses and HIV). Serum and CSF should be sent for antibody detection to herpes simplex virus and VZV. When symptoms and signs of myelitis develop in a diabetic patient, be suspicious of VZV infection. There are a number of noninfectious causes of transverse myelitis, of which multiple sclerosis and a parainfectious autoimmune disorder are the most common. A cranial MRI scan may be helpful in these patients by demonstrating more than one demyelinating lesion. The diagnosis of multiple sclerosis and of acute disseminated encephalomyelitis is supported by evidence of other demyelinating lesions in the nervous system. Antimicrobial therapy should be initiated for myelitis until an infectious etiology is ruled out by smears, cultures, PCR, and antibody titers. Antiviral therapy, including acyclovir for HSV myelitis, ganciclovir or foscarnet or both for CMV myelitis, and acyclovir or valaciclovir for VZV myelitis, should be initiated promptly if a viral etiology is a possibility. Transverse myelitis due to multiple sclerosis and that due to postinfectious encephalomyelitis is treated with corticosteroids to attenuate the inflammatory response. Neurosarcoidosis may also present as a myelitis, and in these patients the serum angiotensin converting enzyme, lymph node biopsy, and the chest X-ray are helpful in making a diagnosis.

The human T-cell lymphotropic virus type 1 (HTLV-1) causes a chronic myelopathy known as HTLV-1-associated myelopathy/tropical spastic paraparesis. This is an insidiously progressive paraparesis. Bladder disturbance and impotence may be early features. There is typically hyperreflexia with clonus and Babinski signs. The diagnosis is made by detecting antibodies to HTLV-1 in serum and CSF.

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