Online OSCEs - Station FIVE - Cerebrospinal Fluid Analysis

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A 17 year-old student complains of headache and is brought to hospital by his concerned housemates.

Lumbar puncture was performed and is shown here:

Appearance: cloudy

No organisms seen

White cell count: 257/mm³ (predominantly neutrophils)

Red cell count: 2/mm³

Glucose = 1.6 mmol/l (plasma glucose 5.5 mmol/l)

Total Protein = 0.94 g/l (plasma total protein 0.43 g/l)

Pressure = 21 mmH₂0

Question 1: What is the commonest side effect after lumbar puncture is performed? (1 mark)

Question 2: Is the CSF:Plasma glucose ratio of concern? (1 mark)

Question 3: Summarise the CSF abnormality (2 marks)

Question 4: What is the likely diagnosis? (1 mark)

Question 5: What immediate treatment is required? (2 marks)

Question 6: Name 3 complications of this condition (3 marks)

Answer 1:	What is the commonest side effect after lumbar puncture is performed? Headache (1 mark)
Answer 2:	Is the CSF:Plasma glucose ratio of concern? Yes. The ratio is low. It is normally greater than 2/3. In this case it is less than one third, ie: 1.6/5.5 = 0.29 (1 mark).
Answer 3:	Summarise the CSF abnormality. The WCC count is high and mostly neutrophils (suggestive of a bacterial infection) (1 mark) The CSF glucose is low and the total protein a little high (1 mark) The CSF is cloudy and the pressure a little elevated (1 mark)
Answer 4:	What is the likely diagnosis? Bacterial meningitis (1 mark)
Answer 5:	What immediate treatment is required? Intravenous antibiotics (2 marks) (ie. 1 mark for "Intravenous (IV)", 1 mark for "Antibiotics")
Answer 6:	Name 3 complications of this condition. Brain Abscess Hydrocephalus Seizures Visual & Hearing Loss (* a point for any of the causes above to a maximum of 3.)