A 27 year old male with a prolonged ICU stay following a subarachnoid
haemorrhage has a CSF specimen taken  from his external ventricular drain.

The CSF gram stain result is:

Red Blood Cells

1946 x 106/L

(0-5 x 106/L)

Polymorphs

198 x 106/L

(0-5 x 106/L)

Mononuclear cells

74 x 106/L

Gram stain:                  scant gram positive cocci.

a). What is your assessment  of the CSF result and provide a reason ?

b). List two likely organisms commonly reported on the Gram stain in this setting.

c). List 2 therapies you may consider based on this report .

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College Answer

a). What is your assessment  of the CSF result and provide a reason ?
Ventriculitis : due to raised WCC:RCC ratio and a positive gram stain


b). List two likely organisms commonly reported on the Gram stain in this setting.
Staphylococcus epidermidis
Staphylococcus aureus


c). List 2 therapies you may consider based on this report .
Removal of EVD / replacement
Vancomycin

Discussion

This patient has ventriculitis. The ratio of WCCs to RBCs is around 1:10, rather than 1:500-1500. Therefore, there is "CSF pleocytosis". The presence of monocytes is also much higher than would be expected purely from the presence of the EVD.

The gram positive cocci found in this CSF sample are likely tourist organisms from the skin, which took a ride into the brain on the back of the EVD. Likely, these are going to be either Staphylococcus aureus, Staphylococcus epidermidis or Streptococcus pyogenes.

The two things one should immediately consider is

1) Get the infected EVD out

2) Start some antibiotics, which in the context of unknown sensitivities should consist of cephalosomething and vancomycin.

The normal properties and contents of the CSF are discussed in detail elsewhere.

Meningitis is favoured with a chapter in Oh's Manual, and is also discussed elsewhere.

References

Beer, R., P. Lackner, and B. Pfausler. "Nosocomial ventriculitis and meningitis in neurocritical care patients." Journal of neurology 255.11 (2008): 1617-1624.