Meningitis

Background

• Inflammation or infection of the meninges and subarachnoid spact
• May be acute, subacute, or chronic (≥4 weeks)
• May be caused by bacteria, viruses, fungi, parasites, or non-infectious causes
  • See also aseptic meningitis

Diagnosis

• Typically confirmed by lumbar puncture demonstrating pleocytosis, with or without MRI brain

Parameter	Normal	Bacterial	Viral	Tuberculous	Fungal
Opening pressure	12 to 20 cmH2O	raised	normal or raised	raised	raised
Appearance	clear	cloudy	clear	clear or cloudy	clear or cloudy
WBC count	<5	>100	5 to 100	5 to 500	5 to 500
Differential		PMN	lymphocyte	lymphocyte	lymphocyte
Protein	0.4 g/L	high	somewhat high	very high	high
Glucose	>2/3 of plasma	very low	normal to low	very low	low