18/12/2025
Reye’s syndrome (Reyes syndrome)
Definition
Reye’s syndrome is a rare but life-threatening acute encephalopathy with hepatic dysfunction, seen mostly in children, classically occurring after a viral illness (influenza, varicella) and associated with aspirin (salicylate) use.
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Etiology / Risk factor
• Aspirin use in children with viral infection (strongest association)
• Viral illness: Influenza A/B, Varicella
• Mitochondrial dysfunction → impaired fatty acid oxidation
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Pathophysiology
• Mitochondrial injury → ↓ β-oxidation of fatty acids
• → Microvesicular fatty infiltration of liver
• → Hyperammonemia, hypoglycemia
• → Cerebral edema → raised ICP → encephalopathy
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Clinical features
Usually start 3–7 days after viral illness
Early
• Persistent, profuse vomiting
• Lethargy, irritability
Progressive
• Altered mental status
• Delirium, agitation
• Seizures
• Coma
Liver signs
• Hepatomegaly usually absent or mild
• No jaundice (important clue)
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Investigations
• ↑ Serum ammonia (key)
• ↑ AST, ALT
• Prolonged PT / INR
• Hypoglycemia
• ↑ Lactate
• CSF: normal (helps exclude meningitis)
• Liver biopsy (rarely needed): microvesicular steatosis
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Diagnosis
Clinical diagnosis based on:
• Acute encephalopathy
• Hepatic dysfunction
• History of viral illness ± aspirin use
• Exclusion of other causes (meningitis, metabolic disorders)
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Management (Emergency)
No specific antidote – supportive care
• ICU admission
• Control raised ICP (head elevation, mannitol if needed)
• Maintain euglycemia (IV dextrose)
• Correct electrolytes & coagulopathy
• Manage seizures
• Avoid hepatotoxic drugs
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Prognosis
• Mortality: 20–30%
• Survivors may have permanent neurological deficits
• Early diagnosis improves outcome
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Prevention (Very important)
❌ Never give aspirin or salicylates to children
✔ Use paracetamol or ibuprofen instead
