CSF Studies:
	Normal	Bacterial Meningitis	Viral Meningitis	Fungal/TB
Opening Pressure (cm H2O)	< 15	↑↑	Normal/mild ↑	Variable
Protein (mg/dL)	15-45	↑	Normal/mild ↑	↑
Glucose (mg/dL)	40-70	↓	Normal	↓
WBC	0-8	↑↑ (>1000)	↑ (5-300)	↑
WBC differential	Even	>80% PMNs	>50% Lymphs, <20% PMNs	50-80% Lymphs
Gram Stain	Normal	60-90 % +	N/A	37-87% AFB +

Differentiate between meningitis and encephalitis:

Brain function: abnormalities of brain function expected with encephalitis: AMS, motor/sensory deficits, speech/movement disorders

*distinction frequently blurred – meningioencephalitis both parenchymal and meningeal process.

Kernig Sign: inability/reluctance to allow full extension of the knee when hip is flexed at 90 degrees.

Brudzinski Sign: spontaneous flexion of the hip during attempted passive flexion of the neck.

*5% sensitivity and 95% specificity!

Characteristic MRI patterns for encephalitis:

• HSV – temporal distribution
• WNV – thalamic distribution
• MS – periventricular (Dawson’s fingers)

Mallaret’s Meningitis: >3 recurrent episodes of HSV2 meningitis