Makindo Medical Notes

Related Subjects: |Neurological History taking |Motor Neuron Disease (MND-ALS) |Miller-Fisher syndrome |Guillain Barre Syndrome |Multifocal Motor Neuropathy with Conduction block | Multiple Sclerosis (MS) Demyelination | Transverse myelitis | Acute Disseminated Encephalomyelitis | Inclusion Body Myositis |Cervical spondylosis |Anterior Spinal Cord syndrome |Central Spinal Cord syndrome |Brown-Sequard Spinal Cord syndrome |Spinal Cord Compression |Spinal Cord Haematoma |Spinal Cord Infarction |Anti-NMDA (NMDAR) receptor encephalitis |Herpes Simplex Encephalitis (HSV) |Acute Encephalitis |Limbic Encephalitis |Paraneoplastic Limbic Encephalitis (Dementia) |Hashimoto's (Steroid responsive) Encephalopathy |Acute Disseminated Encephalomyelitis

About

• A significant stroke mimic; identifying it can aid in accurate diagnosis.
• Primarily affects children but can also present in adults.
• An inflammatory condition of the brain and spinal cord that damages myelin, often following a viral illness or other precipitating factor.
• Acute demyelinating disease with approximately 2% mortality; occasionally presents with intense inflammation of the brain and spinal cord.
• Typically a monophasic (one-time) illness.

Aetiology

• Incidence has decreased with childhood vaccinations, such as MMR.
• Pathology shows perivenular inflammation and potential hemorrhage.
• CSF may show elevated myelin basic protein, reflecting demyelination, though this finding is non-specific.
• Often preceded by infections (e.g., measles, mumps, rubella, Mycoplasma, EBV, influenza, varicella-zoster) or vaccination (e.g., smallpox).

Clinical

• More common in children but can also affect adults; typically a one-time illness.
• Acute encephalitis symptoms: fever, fatigue, headache, nausea, vomiting.
• May progress to coma, neck stiffness, and seizures.
• Neurological signs: hemiparesis, ataxia, bilateral optic neuritis, and transverse myelitis.

Investigations

• CT: May show cerebral edema.
• MRI: Reveals large symmetrical lesions affecting basal ganglia and thalamus. Lesions represent inflammation and demyelination, with possible cerebral edema and focal hemorrhage.
• Lumbar Puncture: Important for ruling out other differentials. CSF may show elevated protein and white cell count (<300), but no oligoclonal bands (differs from MS). Elevated levels of IFN-gamma, IL-6, and IL-8.
• Brain Biopsy: May confirm demyelination, used in complex cases where diagnosis remains unclear.

Differentials

• Multiple Sclerosis
• Susac Syndrome
• Progressive Multifocal Leukoencephalopathy

Management

• First-line Therapy: IV methylprednisolone after ruling out CNS infection. Mortality can reach 30% in severe cases.
• Second-line Therapy: Plasmapheresis or IV immunoglobulin for corticosteroid-resistant cases; rituximab may also be considered in severe cases.
• Symptomatic and Supportive Care: Additional management is primarily supportive.
• Rehabilitation: Physical therapy, occupational therapy, and tailored neurorehabilitation are essential for recovery.

Further Reading

• Acute Disseminated Encephalomyelitis: Current Understanding and Controversies