Biology 216 - Lect 12
Acute Bacterial Meningitis 
I. Definitions
	Meningitis - inflammation of meninges 
		(membrane of brain and spinal cord)
	Septic meningitis - bacterial or fungal
	Aseptic meningitis - viral (less inflammation)
II. Acute bacterial meningitis - 70 %fatal if untreated; 
	10 % if treated early.
A. Etiology - bacteremia (from lung, endocarditis, ear....or trauma)

Age	Organism	Source
0 - 1 month	E. coli K1, Listeria, GpB Strept	Vaginal Tract
6 - 24 month	Neisseria meningitidis, Hib	Loss of maternal protection
15 yr to adult	N. meningitidis	Institutional epidemic
Elderly	Streptococcus pneumoniae	Follow pneumonia, multiple serotypes

B. Pathogenesis and Disease

	1. Blood (from lung, endocarditis, ear, trauma, 
		mucosal membrane (most IgAase+, and
		 intra or inter-epithelial passage)
		Associated with arid regions with dry seasons
		 -> blood-brain barrier (choroid plexis)
		 -> inflammation -> CSF (no defense)	
	2. Headache, intolerance to sound/light, fever, 
			delerium, convulsions, coma,
		Stiff neck, dehydration, loss appetite; 
		Difficult to diagnose with infants.
C. Lab
	1. CSF (sterile) -> Lumbar spinal puncture; 
		Fetal position; Local; 10 ml
		Centrifuge and gram stain pellet
		Enrich 37 C/2 hours
		Culture - BAP, chocolate
		Immuno ID - CIE, quellung...
	2. CSF abnormalities

Type	Cells	Glucose	Protein	Appearance
Bacterial	PMN	Low	High	Cloudy
Mycobacterial	Monocytes	Low	High	Hazy
Viral	Monocytes	Normal	Normal	Clear

D. Vaccines - capsule
	Haemophilus (capsule/protein conjugate), 
	Neisseria, Streptococcus (adult and child conjugate)
E. Treatment
	1. Antibiotics immediately (and high levels; 
		iv or intrathecal; 10x MBC)
	2. SAIDs antiinflammatory to reduce effect of bacterial lysis 
		(more effective in kids)
		MOA - reduces cytokine release.
	3. Mannitol for cerebral edema; 
		Correct fluid loss; Dissolve clots (heparin)