Other demyelinating diseases
- Lesion
Several diseases besides multiple sclerosis destroy myelin: antibody attacks on astrocytes, immune reactions after infection, and rapid sodium shifts.
What it is
Demyelinating diseases other than MS differ in their target and timing. Neuromyelitis optica is an antibody disease against aquaporin-4 on astrocyte end-feet, with severe optic neuritis and long cord lesions. MOG antibody disease targets oligodendrocyte surface protein. Acute disseminated encephalomyelitis is a monophasic immune attack after infection or vaccination, and its hyperacute hemorrhagic form is often fatal. Osmotic demyelination (central pontine myelinolysis) follows too-rapid correction of low sodium.
Structure
- NMO lesions are often necrotic, with thickened hyalinised vessels and loss of aquaporin-4 and GFAP staining.
- Osmotic demyelination: myelin loss with oligodendrocyte death but relatively preserved axons and neurons, without inflammation.
Demyelinating diseases compared
| Disease | Target or trigger | Lesions | Course |
|---|---|---|---|
| Multiple sclerosis | Myelin, T and B cells | Plaques of different ages | Relapsing, then progressive |
| Neuromyelitis optica | Aquaporin-4 on astrocytes | Optic nerves, long cord segments, area postrema | Relapsing, severe attacks |
| MOG antibody disease | Myelin oligodendrocyte glycoprotein | Optic nerve, cord, brain | Monophasic or relapsing |
| ADEM | Recent infection or vaccination | Perivenous demyelination, all the same age | Monophasic |
| Acute hemorrhagic leukoencephalitis | Post-infectious, hyperacute | Hemorrhagic necrosis of venules | Often fatal within days |
| Osmotic demyelination | Rapid rise in sodium | Central pons, symmetric | Quadriparesis, locked-in state |
Clinical notes
- Bilateral or severe optic neuritis, or a long spinal cord lesion, should prompt testing for aquaporin-4 and MOG antibodies.
- Sodium is corrected slowly in chronic hyponatremia to prevent osmotic demyelination.
Test yourself
Think of the answer, then tap the question to see it.
What is the target antigen in neuromyelitis optica?
Aquaporin-4, a water channel on astrocyte end-feet; the disease is an astrocytopathy.
How does ADEM differ from MS in timing?
ADEM is usually monophasic, after infection or vaccination, with lesions all of the same age; MS relapses with lesions of different ages.
What causes central pontine myelinolysis?
Overly rapid correction of chronic hyponatremia, which injures oligodendrocytes osmotically.
Elsewhere in DurgiPedia
Connections
Educational content on the mechanisms of disease; not a diagnostic or treatment guide and no substitute for a health professional's advice. No doses are given.
Sources: Neuromyelitis optica: MedlinePlus Genetics (MedlinePlus, US National Library of Medicine, 2026).
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Representative model, for educational purposes only.