Neurology · MU Sofia

44. Viral meningitis

Covers viral meningitis as an acute, usually milder, self-limiting inflammation of the meninges, starting with its common viral causes such as enteroviruses, herpes simplex, varicella-zoster, mumps and early HIV. It then moves through the route of spread to the CNS, the clinical picture, and the typical CSF pattern with lymphocytic pleocytosis and normal glucose. The note closes with diagnosis by lumbar puncture and PCR, a three-way differential against bacterial, tuberculous and encephalitic meningitis, supportive treatment with acyclovir where indicated, and prognosis.

Inside: 1 section · 15 flashcards · 2 min

Topic 44 of 88 in the MU Sofia syllabus for Neurology (Medicine, Year 4). The free AceMed note covers it in 1 section, about 229 words (2 min of reading), with 15 flashcards.

In this note

  1. Viral meningitis

Viral meningitis

Definition: Viral meningitis is an acute inflammation of the meninges caused by viruses, typically resulting in a milder, self-limiting course compared to bacterial meningitis.

  • Also called aseptic meningitis.

Etiology

Most common viruses: Enteroviruses (Coxsackie, Echovirus) – most common overall. Herpes simplex virus (HSV-2 > HSV-1). Varicella-zoster virus (VZV). Mumps virus. HIV (early infection)

Pathogenesis

  • Viral entry via respiratory or gastrointestinal tract
  • Hematogenous spread → CNS
  • Infection of meninges → inflammatory response without bacterial pus formation

Clinical Features

  • Onset: Acute or subacute. Usually less severe than bacterial meningitis
  • Meningeal Syndrome: Headache. Low to moderate fever. Neck stiffness (milder than bacterial). Photophobia. Nausea/vomiting
  • General Condition: Patient usually less toxic than in bacterial meningitis. Consciousness usually preserved. Neurological signs. Mild or no focal deficits. Rare seizures

CSF Findings

Typical viral CSF pattern: ↑ Opening pressure (mild/moderate). Clear CSF. ↑ Lymphocytes (lymphocytic pleocytosis). Mild ↑ protein. Normal glucose (key distinction)

Diagnosis

  • Lumbar puncture (primary test)
  • PCR for viral DNA/RNA (highly specific)
  • Exclusion of bacterial meningitis is essential

Differential Diagnosis

1. Bacterial meningitis: Neutrophils in CSF. ↓ glucose. More severe, toxic patient

2. Tuberculous meningitis: Subacute/chronic. ↑ protein much higher. ↓ glucose

3. Encephalitis: Prominent altered consciousness. Focal neurological deficits. Seizures early

Treatment

  • Mostly supportive therapy: Hydration. Analgesics. Antipyretics
  • Specific therapy (if indicated): Acyclovir (HSV/VZV suspected)

Prognosis: Usually excellent. Self-limiting (days to weeks). Full recovery common

Complications: Rare. Persistent headache or fatigue. Post-viral asthenia

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