Question 6.1

Angoff score
6.41
Highest mark
9.25
Pass rate
??
Other SAQs in this topic:
Other SAQs in this paper:

A 69-year-old patient was intubated and ventilated for a reduced level of consciousness, with a 4-day
history of neurological deterioration. Lumbar puncture was performed.
Cerebrospinal fluid (CSF) analysis revealed

Parameter

Patient

Reference

Polymorphonuclear cells

0 x 106/L

Range: 0 cells

Mononuclear cells

3 x 106/L

Range: 0-5 cells

Red blood cells

1640 x 106/L*

10-20

No bacteria seen. Blood stained.

Protein Level CSF

7.35 g/L*

0.15-0.45

i) List TWO causes for the raised CSF red blood cells in this patient. (2 marks)

ii) List FOUR likely causes for the raised CSF protein level in this patient. (2 marks)

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College answer

Syllabus topic/section:
2.1.8 Neurological Intensive Care: Interpretation of cerebrospinal fluid: L1


Discussion: 

Part a) was a straightforward question with most candidates successfully listing the causes of high protein and red blood cells within CSF

Discussion

The extremely high Angoff mark suggests that "the borderline candidate" should be know this very well, and the author (having an extensive history of being a borderline candidate) confirms that this would indeed have been the case during his written attempts, as the CSF questions are frequent in the past papers and everyone is expected to have done those to the point of sullen tedium.

Causes of proteorrhachia include:

  • Raised protein because contaminated with blood (blood LP or EVD in ICH)
  • Ischaemic stroke 
  • Infection: menigitis/encephalitis, which for this patient would have to be viral (as the CSF is minimally cellular)
  • Neoplasm (eg. Froins syndrome, except the protein is probably not high enough, as Froin syndrome can make is supra-systemic)
  • Alcoholism
  • Congenital hydrocephalus
  • Idiopathic causes, eg. diabetic neuropathy, seizures, 
  • Autoimmune encephalitis, CNS vasculitis, demyelinating infllamatiry disease (eg. GBS, MS, ALS)
  • Head injury
  • Myxoedema

References

Venkatesh, B., P. Scott, and M. Ziegenfuss. "Cerebrospinal fluid in critical illness." Critical care and resuscitation 2 (2000): 42-54.

SCHAIN, RICHARD J. "Cerebrospinal fluid and serum cation levels." Archives of Neurology 11.3 (1964): 330.

POSNER, JEROME B., AUGUST G. SWANSON, and FRED PLUM. "Acid-base balance in cerebrospinal fluid." Archives of neurology 12.5 (1965): 479.

Brown, P. D., et al. "Molecular mechanisms of cerebrospinal fluid production."Neuroscience 129.4 (2004): 955-968.

Steele, Russell W., et al. "Leukocyte survival in cerebrospinal fluid." Journal of clinical microbiology 23.5 (1986): 965-966.

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

Zaret, Deborah L., et al. "Immunofixation to quantify beta 2-transferrin in cerebrospinal fluid to detect leakage of cerebrospinal fluid from skull injury."Clinical chemistry 38.9 (1992): 1908-1912.

Swedenborg, E. "The Brain." Considered Anatomically, Physiologically and Phylosopically.(translated and edited by RL Tafel), London (1887).

Hajdu, Steven I. "Discovery of the cerebrospinal fluid." Annals of Clinical & Laboratory Science 33.3 (2003): 334-336.

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