Chapter 30: Neuroimmunology & Neuroinflammatory Disorders
You are evaluating a 39-year-old woman in the hospital for a new event of transverse myelitis that has resulted in her inability to walk and severe bladder and bowel dysfunction. When reviewing her images, you note that her lesion extends through most of her thoracic spinal cord and into her lower cervical spinal cord with patchy enhancement in the central portion. The fact that this lesion is longitudinally extensive—defined as being longer than 3 vertebral body heights—makes which of the following diagnoses less likely?
B. Idiopathic transverse myelitis
C. Neuromyelitis optica spectrum disorder
A. Longitudinally extensive transverse myelitis is a hallmark of neuromyelitis optica and idiopathic transverse myelitis (TM). Multiple sclerosis–related TM is almost always shorter than 2 vertebral body heights in length.
A patient presents to your clinic with a 2-year history of worsening gait trouble. He reports that he is not sure when it began but that he now has trouble walking short distances and has noticed increasing difficulty feeling where his feet are placed and controlling his bladder and bowel functioning. You suspect a diagnosis of progressive multiple sclerosis (MS). Which of the following findings would not help you fulfill the diagnostic criteria for progressive MS?
A. Brain magnetic resonance imaging (MRI) with 1 or more lesions suggestive of demyelination
B. Spinal fluid with elevated immunoglobulin G (IgG) index or oligoclonal bands
C. Abnormal somatosensory evoked potentials of the lower extremities
D. Spinal cord MRI showing 2 lesions typical of MS
C. A diagnosis of progressive MS according to the 2010 revised McDonald Criteria must include a history of 1 year of progressive myelopathy plus 2 of the following 3 findings: (1) brain MRI with 1 or more lesions typical of demyelination; (2) spinal MRI with 2 or more lesions typical of demyelination; and (3) spinal fluid with elevated IgG index or oligoclonal bands unique to the cerebrospinal fluid. Abnormal somatosensory evoked potentials would be further confirmation of spinal dysfunction but would not be sufficient to support a diagnosis of MS.
Myasthenia gravis is a disorder of neuromuscular junction transmission resulting in weakness of the extremities and musculature of the head and neck. The primary pathogenesis of this illness is through which of the following mechanisms?
A. Decreased production of acetylcholine
B. Impaired release of acetylcholine from vesicles at the presynaptic membrane