🧠 Demyelinating diseases are neurological disorders caused by damage to the myelin sheath – the protective covering of nerve fibers in the central and peripheral nervous systems. Myelin enables rapid, efficient nerve conduction, and its loss disrupts neuronal communication, leading to a wide range of neurological symptoms.

📌 Common Demyelinating Diseases

Multiple Sclerosis (MS): The most common demyelinating disease. An autoimmune condition where the immune system attacks the CNS, causing plaques of scar tissue in the brain and spinal cord.
Neuromyelitis Optica (NMO / Devic’s disease): Primarily affects the optic nerves and spinal cord, causing recurrent visual loss and paralysis. Now recognised as distinct from MS (anti-AQP4 antibody mediated).
Acute Disseminated Encephalomyelitis (ADEM): Rare, usually post-infectious or post-vaccination; causes a sudden widespread attack on myelin, especially in children.
Chronic Inflammatory Demyelinating Polyneuropathy (CIDP): A peripheral nervous system disorder with gradual limb weakness and sensory loss due to immune attack on peripheral myelin.
Progressive Multifocal Leukoencephalopathy (PML): A rare, often fatal CNS infection with JC virus, seen in immunocompromised patients (e.g. HIV, transplant, natalizumab therapy).

⚠️ Causes & Pathogenesis

Immune system dysfunction – myelin misidentified as foreign.
Genetic susceptibility – e.g. HLA associations in MS.
Infections – molecular mimicry may trigger autoimmunity.
Environmental factors – low vitamin D, smoking, migration risk patterns.

🩺 Symptoms

Weakness & fatigue
Numbness, tingling, or sensory loss
Balance & coordination problems (ataxia)
Visual symptoms – blurred vision, diplopia, optic neuritis
Cognitive impairment – poor concentration, memory loss
Spasticity, stiffness, painful spasms
Neuropathic pain (burning, shooting sensations)
Bladder & bowel dysfunction

🔬 Diagnosis

Clinical assessment: Pattern of relapsing-remitting or progressive neurological deficits.
MRI: White matter lesions (periventricular, juxtacortical, infratentorial, spinal cord).
CSF: Oligoclonal bands (esp. MS).
Blood tests: To exclude mimics (B12 deficiency, vasculitis, infections).
Electrophysiology: Nerve conduction studies for CIDP.
Use of diagnostic frameworks: e.g. McDonald criteria for MS.

💊 Treatment

Corticosteroids: High-dose IV methylprednisolone for acute relapses.
Disease-modifying therapies: e.g. Interferon-β, glatiramer acetate, natalizumab, fingolimod, ocrelizumab (MS).
Immunosuppressives: Rituximab, azathioprine, mycophenolate for NMO/CIDP.
Plasma exchange (plasmapheresis): For severe, steroid-refractory attacks.
Symptomatic therapies: Baclofen for spasticity, gabapentin for neuropathic pain, bladder management, physio/OT.
Supportive care: Rehabilitation, counselling, lifestyle modifications (exercise, vitamin D, smoking cessation).

📈 Prognosis

The outlook depends on the disease and its aggressiveness. 🌿 MS often follows a relapsing-remitting course with variable disability. ⚡ NMO tends to be more aggressive without immunotherapy. ADEM usually resolves, while PML carries a poor prognosis. 👉 Early diagnosis & disease-modifying therapy are key to slowing progression and preserving quality of life.

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Demyelinating Diseases