Chapter 21: Demyelinating Diseases of the Central Nervous System

CHAPTER SUMMARY FROM CURRENT DIAGNOSIS & TREATMENT

For a clinical review of the topic in Current Diagnosis & Treatment, 3e please go to Chapter 17: Multiple Sclerosis & Demyelinating Diseases.

INTRODUCTION

This chapter focuses on the following central nervous system demyelinating diseases:

• Multiple sclerosis (MS)

• Neuromyelitis optica spectrum disorder (NMOSD)

• Myelin oligodendrocyte glycoprotein-antibody disease (MOG-antibody disease)

• Acute disseminated encephalomyelitis (ADEM)

• Optic neuritis

• Transverse myelitis

Optic neuritis and transverse myelitis may be caused by a primary central nervous system (CNS) demyelinating disease (e.g., MS, NMOSD, MOG), systemic autoimmune disease, or may occur in the setting of infection, following infection, or as paraneoplastic conditions.

Demyelinating diseases of the peripheral nervous system (e.g., acute inflammatory demyelinating polyradiculoneuropathy [AIDP] and chronic inflammatory demyelinating polyradiculoneuropathy [CIDP]) are discussed in Chapter 27.

MULTIPLE SCLEROSIS

Clinical Features of Multiple Sclerosis

Multiple sclerosis (MS) is a demyelinating disease of the CNS that occurs more commonly in young women and is more prevalent further from the equator. In its most common clinical course, patients have multiple flares of symptoms at multiple time points, and recover from these attacks to varying degrees (relapsing-remitting MS). On average, relapses occur approximately every 1–2 years, though some patients have a more aggressive disease course and others have milder disease. Later in the disease, patients with a relapsing-remitting course may enter a period of progressive decline, a scenario referred to as secondary progressive MS. Primary progressive MS is the least common clinical phenotype of MS, and is typically a spinal cord predominant illness with steady clinical decline from the time of onset rather than relapses and remissions. Even more rarely, the disease may present fulminantly with large tumor-like lesions (Marburg variant, tumefactive demyelination, or Balo’s concentric sclerosis).

Flares of MS present as focal neurologic deficits that emerge and evolve over hours to days and usually resolve completely or near completely in subsequent weeks to months. Relapses in MS cause symptoms referable to central nervous system sites (brain, brainstem, optic nerve, cerebellum, and/or spinal cord). Some of the most common presenting symptoms of relapse or first presentation of MS include:

• Monocular visual loss due to optic neuritis (see “Optic Neuritis”)

• Diplopia due to internuclear ophthalmoplegia caused by a lesion in the MLF (see “Internuclear Ophthalmoplegia” in Ch. 11)

• Weakness, numbness, and/or urinary urgency/retention most commonly due to spinal cord lesion(s)

• Ataxia most commonly due to a lesion in one of the cerebellar peduncles

• Vertigo due to demyelination of the cranial nerve 8 entry zone or the cerebellum

Between flares of MS, the accumulation of subclinical lesions may cause cognitive symptoms, neuropsychiatric symptoms, and/or fatigue. On neurologic examination, patients may demonstrate signs outside of regions of new or prior ...