An Approach to the Diagnosis of Acute Transverse Myelitis
Total Page：16
File Type：pdf, Size：1020Kb
An Approach to the Diagnosis of Acute Transverse Myelitis Anu Jacob, M.D.,1 and Brian G. Weinshenker, M.D., F.R.C.P.(C.)2 ABSTRACT The differential diagnosis of acute inflammatory transverse myelitis (ATM) is broad. Therefore, physicians must be aware of the many potential etiologies for acute myelopathy, and should pursue an ordered, efficient, and cost-effective approach to the diagnosis based on the patient’s clinical history, examination, and magnetic resonance imaging (MRI) findings. Clinical, immunological, and radiological findings of non- compressive myelopathies are reviewed, as are how these findings can be used to distinguish between demyelinating, infectious, other inflammatory, vascular, neoplastic, and paraneo- plastic etiologies. We also review predictors of further episodes of ATM in patients with demyelinating disorders. We discuss the diagnostic clues and pitfalls of the not uncommon clinical scenario of a presumed ‘‘myelopathy with normal MRI.’’ Finally, we suggest an algorithm for the diagnosis and management of acute myelopathies. KEYWORDS: Myelitis, neuromyelitis optica, multiple sclerosis Acute transverse myelitis (ATM), an inflamma- tion followed by focused investigations are needed. In tory myelitis, is one of the causes of acute transverse the following sections, clinical presentations of myelo- myelopathy. The three main categories in the differential pathies are discussed followed by diagnostic categories of diagnosis of ATM are demyelination, including multiple acute myelopathy. Only the classical presentations of the sclerosis (MS), neuromyelitis optica (NMO), and idio- diseases are covered here. The predictors of relapses in pathic transverse myelitis; infections such as herpes demyelinating myelopathies are included, followed by an zoster and herpes simplex virus; and other inflammatory algorithm on diagnosis and treatment. Although we disorders such as systemic lupus erythematosus (SLE) have used available literature and guidelines throughout, and neurosarcoidosis. However, whether the cause of the there may be instances where our personal clinical acute myelopathy is inflammatory or not is not self- practice and experience have influenced our opinions evident; therefore, the clinical and diagnostic workup for and approach. ATM requires that other causes of acute myelopathies be excluded. When faced with a patient with an acute myel- CLINICAL PRESENTATION OF SPINAL opathy, excluding an acute compressive cause is of CORD DISORDERS utmost priority. A magnetic resonance imaging (MRI) Spinal cord disorders are conventionally classified as scan is invaluable in this regard. Having excluded a ‘‘syndromes’’ due to the typical signs and symptoms compressive cause and having found an intrinsic spinal produced because of the location of the lesion and specific cord lesion on MRI, a detailed history and an examina- tract involvement. The Brown-Se´quard hemicord 1Division of Neurology, Walton Centre for Neurology and Neuro- Multiple Sclerosis and the Spectrum of CNS Inflammatory surgery, Liverpool, United Kingdom; 2Department of Neurology, Demyelinating Diseases; Guest Editor, Claudia F. Lucchinetti, M.D. Mayo Clinic College of Medicine, Rochester, Minnesota. Semin Neurol 2008;28:105–120. Copyright # 2008 by Thieme Address for correspondence and reprint requests: Brian G. Medical Publishers, Inc., 333 Seventh Avenue, New York, NY 10001, Weinshenker, M.D., F.R.C.P.(C.), Department of Neurology, Mayo USA. Tel: +1(212) 584-4662. Clinic College of Medicine, 200 First Street SW, Rochester, MN DOI 10.1055/s-2007-1019132. ISSN 0271-8235. 55905 (e-mail: [email protected]). 105 106 SEMINARS IN NEUROLOGY/VOLUME 28, NUMBER 1 2008 Table 1 Clinical Presentation of Acute Spinal Cord Disorders Type of Lesion Tracts Involved Clinical Signs Examples Complete All tracts Pyramidal, sensory, and autonomic Trauma or acute necrotizing dysfunction* below lesion viral myelitis Brown-Se´ quard Ipsilateral corticospinal, Ipsilateral pyramidal weakness and Multiple sclerosis, hemicord syndrome posterior columns; loss of posterior column function; compression contralateral spinothalamic contralateral spinothalamic loss Anterior cord Bilateral anterior horn cells Acute bilateral flaccid weakness, loss Anterior spinal artery syndrome corticospinal tracts, of pain temperature and sphincter/ occlusion spinothalamic and autonomic autonomic dysfunction; preservation of dorsal column modalities such as joint position sense Posterior cord Bilateral posterior columns Bilateral loss of light touch, vibration B12 or copper deficiency and joint position (usually chronic) Central Crossing spinothalamic, Dissociated sensory loss (loss of pain Syrinx, neuromyelitis corticospinal, and and temperature with preserved optica autonomic fibers vibration and joint position); pyramidal distribution weakness below lesion; autonomic dysfunction below the lesion Conus medullaris Autonomic outflow and Early sphincter dysfunction, sacral Post viral myelitis sacral spinal cord sensory loss and relatively mild motor segments dysfunction Cauda equina Spinal nerve roots of the Early often asymmetric flaccid weakness Acute cytomegalovirus cauda equina of the lower limbs, sensory loss in polyradiculitis, root distribution followed by autonomic compression dysfunction Tractopathies Selective tract involvement Selective pyramidal, posterior column B12 deficiency, paraneoplastic involvement myelopathy, multiple sclerosis *Autonomic dysfunction: bladder, bowel, and sexual. syndrome is an example. Table 1 summarizes the clinical matory disorders, vascular, and neoplastic and paraneo- presentation of acute spinal cord disorders. plastic. The first three are considered inflammatory Myelopathies with selective tract involvement are disorders. Among these, demyelinating disorders are characteristic of metabolic or degenerative myelopathies the most common. The initial task of the clinician is (which are usually chronic) rather than inflammatory or to determine which of these is most likely. In general, infectious disorders (e.g., corticospinal and posterior inflammatory disorders have an inflammatory cerebro- columns in B12 deficiency, adrenomyeloneuropathy, spinal fluid (CSF) manifested by either pleocytosis, and Friedreich’s ataxia). However, paraneoplastic mye- raised IgG index or both. Fig. 1 is an algorithm on the lopathies, which are rare, often produce tract-specific diagnosis and management of acute noncompressive involvement and should be considered when investiga- myelopathies. tions to exclude a metabolic or degenerative myelopathy are negative in acute symmetric ‘‘tractopathy.’’ Occasion- ally, inflammatory demyelinating syndromes may Demyelinating Disorders present with a very selective tractopathy due to discrete Typically, the onset of neurological symptoms in mye- lesions (e.g., the classical acute ‘‘sensory useless hand litis due to demyelination occurs over days with sensory syndrome’’ with acute proprioceptive loss due to poste- motor symptoms and bladder and bowel disturbances, rior column involvement in patients with MS). although occasionally necrotizing demyelinating mye- lopathies, including NMO, may progress over hours. They usually occur in individuals who are otherwise in NONCOMPRESSIVE CAUSES OF ACUTE good health and may be preceded by a nonspecific viral MYELOPATHIES illness. Table 2 provides the differential diagnoses of The five groups of disorders that present as acute demyelinating myelopathies and their clinical-radio- myelopathy are: demyelination, infections, other inflam- logical features. APPROACH TO DIAGNOSIS OF ACUTE TRANSVERSE MYELITIS/JACOB, WEINSHENKER 107 Figure 1 Diagnostic approach to acute myelopathy. MRI, magnetic resonance imaging; CSF, cerebrospinal fluid; NMO, neuromyelitis optica; MS, multiple sclerosis; IgG, immunoglobulin G; SS-A, Sjo¨ gren’s syndrome antibody (anti-Ro). MULTIPLE SCLEROSIS of the cervical posterior columns, but can be, although In MS, lesions are usually small (< 2 vertebral segments rarely, seen in other conditions that involve the same in length) and peripheral, and therefore cause asymmet- site. Other characteristic syndromes include isolated ric symptoms and signs (Fig. 2). Lhermitte’s sign (par- proprioceptive loss of an upper extremity (‘‘sensory use- esthesias spreading down the spine, often into the legs, less hand syndrome’’),1 Brown-Se´quard syndrome, or, on neck movement) is typical for a demyelinating lesion more commonly, incomplete versions thereof. Early in 108 SEMINARS IN NEUROLOGY/VOLUME 28, NUMBER 1 2008 Table 2 Causes of Acute Demyelinating Myelopathies and Diagnostic Clues Condition Clinical Presentation MRI Spinal Cord MRI Brain CSF Multiple sclerosis Partial myelopathy, e.g., Lesion less than 2 spinal cord White matter lesions; Dawson’s OCB and raised IgG index Brown-Se´ quard; previous segments, usually peripherally fingers; periventricular, episodes of neurological located; predilection for lateral juxtacortical, infratentorial dysfunction with recovery and posterior funiculi lesions Neuromyelitis 90% women; typically severe Long cord lesion > 3 segments; Lesions present in up to 60% Prominent CSF pleocytosis, optica deficits; may have experienced cord swelling and gadolinium of patients, often subtle, occasionally with neutrophilic previous myelitis or optic enhancement in acute lesions usually periventricular; occasionally /eosinophilic predominance neuritis hypothalamic or brainstem lesions during acute attacks; no OCB in > 80%; usually normal or transiently elevated CSF IgG index Acute disseminated Monophasic;