CSF- Dr. Fowler
Terms
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- major indications for examination of CSF
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I- infections
S- subarachnoid hemorrhage
M- malignancy (CNS)
D- demyelinating disease
**meningeal infection is most important indication - causes of elevation of CSF pressure on opening
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psychological and physical stuff- sitting up, tense, obese
diseases- CHF, SVC syndrome, venus sinus thrombosis
brain stuff- cerebral edema, hypo-osmolality, mass lesions, meningitis - causes of depression
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spinal-subarachnoid block (shock situations), dehydration, circulatory collapse, and CSF leakage
*not as much of a concern as elevation - do not remove >2ml if...
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1. OP > 200 mmH20- could herniate cerebellar tonsils
2. if pressure drops precipitously after removal of small amt- could indicate herniation or block in spinal canal - 4 tubes
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Chemistry
Cell Count
Critters (Microbiology)
Cytology (tumors) - Emergency LP
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1. suspected meningitis
2. CNS leukemia
3. subarachnoid hemorrhage - complications
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1. headache
2. precipitation of cerebellar tonsillar herniation
3. intro of infection
4. progression of paralysis - xanthochromia
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pink to orange to yellow
1. pink-red to clear orange-red from oxyhemoglobin; w/in 2-4 hours, peaks at 24-36 hours, gone at 4-8 days
2. yellow from billirubin; after 12 hours, peaks at 2-4 days, persists for 2-4 wks - other causes for xantho
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1. yellow- increased protein- bilirubin and carotene
2. yellow-red- merthiolate disinfectant contamination, rifampin therapy
3. brown- melanin - high CSF protein...
- causes clot formation--may interfere with cell count by entrapping inflammatory cells; NOT seen in subarachnoid hemorrhage
- viscosity increased by...
- metastatic mucin-producing adenocarcinomas, cryptococcal meningitis, and nucleus pulposus injury
- WBC count normal
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adult <6 mononuc; 0 RBC
infant <19
neonate <30 - lymphocyte:monocyte
- 70:30 in adults; opp in neonates
- pleocytosis
- pathological increase in the number of CSF leukocytes. reflects type, duration, and intensity of injury
- increased neutrophils
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bacterial meningitis in 70%
perisistent neutrophilia may be due to non-infectious causes or unusual organisms - increased lymphocytes
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viral meningitis
non meningitis--MS, SSPE, sarcoid, vasculitis, chemicals, drugs, Guillain barre - inc eosinophils
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eosinophilic meningitis
funcal infection- parasitic CNS, allergic rxn - inc monocytes
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lack diagnostic specificity
"mixed cell reaction" - mixed cell pattern
- if without neutrophils, then characteristic of early viral or syphilitic meningoencephalitis, otherwise in many conditions
- macrophages
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seen in hemorrhages
erythrophages appear 12-14 hours; siderophages appear 2-3 days. contain hemosiderin; macrophages may also contain hematoidin - parts of micro exam
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1. gram stain- best rapid test for meningitis; 60-90% sensitive
2. cultures
3. latex agglutination (pediatric cases mostly) H.flu 90% and B strep. - neurosyphilis
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1. darkfield microscopy- demonstrates spirochetes
2. VDRL- not very sensitive but it is very specific; used to confirm diagnosis, NOT to screen
3. FTA-ABS and RPR- not usually used b/c too sensitive, but negative test rules out disease - viral meningitis
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1. enteroviruses- 80% of cases, peak in late summer
2. diagnosis of exclusion
3. viral culture is gold standard; other tests include immunofluorescence tests, brain biopsy, serologic methods, PCR in future - HIV
- lymphocytic pleocytosis, elevated IgG indexes, oligoclonal bands, and identification of opportunistic infections.
- amebic meningoencephalitis
- caused by naegleria fowleri or Acanthamoeba species; trophozites may be visualized by light or phase contrast microscopy; acridine orange stain helps differentiate ameba from WBC
- elevated CSF protein
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assoc with xanthochromia, moderate pleocytosis, spontaneous clotting
1. increased perm of BBB
2. CSF circulation defects
3. increased IgG synthesis
4. increased IgG synthesis and blood-CSF permeability - low CSF protein
- young children, removal of large volumes of CSF, CSF leaks, increased intracranial pressure, and hyperthyroidism
- albuminocytologic dissociation
- increased CSF protein within normal cells--classically Guillain Barre, but can be seen in other conditions
- normal glucose
- 60% of plasma level; 50-80 mg/dl with rations of 0.3-0.9
- low glucose
- hypoglycorrhachia <40 mg/dl ratios <0.3
- tumor markers
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CEA- metastatic adenocarcinoma
HCG and DFP- germ cell tumor