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🧠 About
- Poliomyelitis is a viral infection that selectively damages the anterior horn cells of the spinal cord, causing motor neuron loss and flaccid paralysis.
- Brainstem involvement (bulbar polio) can impair breathing, swallowing, and facial movements, sometimes fatal without support.
- Rarely, the virus affects ocular muscles, causing ophthalmoplegia.
⚠️ Aetiology
- Spread mainly by the faeco-oral route → highly contagious in poor sanitation settings.
- Most infections are asymptomatic or mild; only 1–2% progress to neurological disease.
- Incubation: 3–20 days, with viral replication in the gut and lymphoid tissue before CNS invasion.
🩺 Clinical Features
- Prodrome: Febrile illness, headache, neck stiffness, and meningism.
- Motor weakness: Rapidly progressive, asymmetric limb paralysis due to anterior horn cell destruction.
- Bulbar features: Facial weakness, dysphagia, and eye movement abnormalities.
- Respiratory failure: From diaphragmatic involvement — historically managed with the “iron lung.”
🔬 Investigations
- CSF: Early neutrophilia → later lymphocytosis with raised protein.
- Poliovirus antibodies: Elevated titres confirm exposure.
- PCR / Viral culture: From stool, throat swabs, or CSF in specialist labs.
🔎 Differential Diagnosis
- Guillain–Barré Syndrome (GBS): Ascending, symmetrical weakness with demyelination (different CSF findings).
- Transverse Myelitis: Sensory + motor impairment from cord inflammation, unlike pure motor polio.
💉 Management
- Prevention (Vaccination):
- 💉 1953 – Jonas Salk: Inactivated injectable vaccine (IPV).
- 💊 1962 – Albert Sabin: Oral live-attenuated vaccine (OPV), widely used for eradication but carries a rare risk of VAPP (vaccine-associated paralytic polio).
- Supportive Care: No cure once paralysis develops.
- Physiotherapy to prevent contractures.
- Ventilatory support if respiratory muscles involved.
- Rehabilitation for mobility and independence.
- Prognosis: Bulbar/respiratory involvement → poor outcomes; some patients regain partial motor function over months.
⚡ Complications
- Post-Polio Syndrome (PPS): Decades later, new weakness, fatigue, and joint pain from overworked surviving motor neurons.
