A child post-influenza with delirium, vomiting, hepatomegaly: Most likely diagnosis?

• A. Acute bacterial meningitis
• B. Guillain-Barré syndrome
• C. Reye syndrome
• D. Measles encephalitis

Answer: (C)

Reye syndrome is the likely diagnosis here. It’s an acute encephalopathy with hepatic dysfunction that occurs in children after a viral illness, most classically influenza or varicella, and is strongly associated with aspirin use during that illness. The key features are sudden delirium or confusion and persistent vomiting, along with hepatomegaly. In the liver, there is microvesicular fatty change, and labs often show elevated liver enzymes, hyperammonemia, and sometimes hypoglycemia. The underlying issue is mitochondrial dysfunction triggered by aspirin in the setting of a viral infection, leading to impaired fatty acid oxidation and dangerous brain edema.

This pattern helps distinguish it from other conditions. Acute bacterial meningitis would typically present with fever, neck stiffness, and a CSF profile showing infection, not primarily liver enlargement. Guillain-Barré syndrome presents with progressive, symmetric weakness and areflexia, not encephalopathy with liver involvement. Measles encephalitis would be tied to active measles infection with its own characteristic rash and timeline, not the post-viral aspirin-related encephalopathy with hepatomegaly.