CSF interpretation

Question 1

what are the normal values

Answer 1

pressure 5-20 cm H2O
normal appearance
protein 0.18 - 0.45
glucose 2.5-3.5 about 60% of blood glucose
WCC less than 3

Question 2

bacterial infection results

Answer 2

pressure over 30
turbid appearance
protein over 1
low glucose e.g. under 2.2 or under 40%
gram stain positive in 60-90%
WCC over 500
90% PMNs

Question 3

viral infection results

Answer 3

normal or mildly increased pressure
clear
protein under 1
normal glucose and gram stain
WCC under 1000
usually monocyte heavy but can be PMN sometimes.

Question 4

fungal/TB infection

Answer 4

‘fibrin web’
low glucose
raised WCC 100-500\
principally monocytes

Question 5

wcc

Answer 5

WCC

normally scant monocytes
in traumatic tap classically taught to expect 1 WCC : 500 RCC (if normal in peripheral cell counts) but this is not reliable
polymorphonuclear leukocytosis: bacterial infection
lymphocytosis: viral, Tb, cryptococcal and listerial infections
mixed lymphocytosis/monocytosis in GBS and status epilepticus

Question 6

protein

Answer 6

PROTEIN

increased in infection: Tb > bacterial > viral
increased in GBS, vasculitis and sarcoidosis
oligoclonal bands in multiple sclerosis
increased in CNS inflammation (including CSF drains and blood in CSF)

Question 7

glucose

Answer 7

GLUCOSE

normally at least 75% serum glucose
less than half serum in infections (bacterial, Tb and fungal infections) and vasculitis and sarcoidosis