Drug induced aseptic meningitis

Background

• Abbreviation: DIAM
• Two proposed mechanisms
  • Direct meningeal irritation by intrathecal drug
  • Hypersensitivity reaction to drug (type III and IV)

Causes

• NSAIDs
  • Most common cause
• Antibiotics
  • Sulfamethizole
  • TMP-SMX
  • Isoniazid
  • Ciprofloxacin
  • Amoxicillin
  • Gentamicin
  • Penicillin
  • Metronidazole
  • Cephalosporins
  • Pyrazinamide
• Immunoregulating agents
  • IVIGs
  • OKT3 monoclonal antibodies
• Misc
  • Sulfasalazine
  • Carbamazepine
  • Azathioprine
  • Indinavir
  • Valacyclovir
  • Ranitidine
  • Famotidine
  • Methylprednisolone acetate
  • Allopurinol

Diagnosis

• Drug history with focus on time of ingestion and symptom onset
• CSF studies
  • Pleiocytosis (primarily neutrophilic)
  • Elevated protein levels
  • Normal glucose
  • Negative cultures
• Challenge test with suspected drug
  • Only confirmatory test
  • Requires informed written consent
  • Due to associated risk, should only be done if suspected drug is irreplaceable

Clinical presentation

• Headache
• Fever
• Nuchal rigidity
• Nausea/vomiting
• General malaise
• Less common symptoms include rash, arthralgia, myalgia, facial edema