FRCS (ORL-HNS) · SECTION 1 SBA

CSF rhinorrhoea confirmation

A patient has unilateral watery rhinorrhoea that increases on bending forward after skull-base surgery. Which laboratory test is most specific for confirming CSF?

CHOOSE ONE ANSWER

Best of five

  1. A. Nasal-fluid glucose strip
  2. B. Serum sodium
  3. C. Skin-prick testing
  4. D. Routine bacterial culture
  5. E. Beta-2 transferrin in the nasal fluid
ANSWER AND REASONING

E. Beta-2 transferrin in the nasal fluid

Beta-2 transferrin is highly specific for CSF and supports targeted high-resolution imaging for localisation. Glucose testing is unreliable.

Why every option is right or wrong

A. Nasal-fluid glucose strip: Glucose is affected by blood, tears and nasal secretions and lacks specificity.

B. Serum sodium: This does not identify the nature of nasal fluid.

C. Skin-prick testing: Allergy testing cannot confirm a CSF leak.

D. Routine bacterial culture: Culture may assess infection but not prove CSF.

E. Beta-2 transferrin in the nasal fluid: Beta-2 transferrin is highly specific for CSF and supports targeted high-resolution imaging for localisation. Glucose testing is unreliable.

What if the scenario changed?

If meningism or sepsis were present, emergency treatment for meningitis would not wait for leak confirmation.

EDUCATIONAL USE

Independent Clinora educational preparation material; not official JCIE content, an accredited programme, clinical advice, or a substitute for current guidance, local policy and specialist judgement.

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