How will you diagnose a case of idiopathic CSF rhinorrhoea.

Spontaneous CSF rhinorrhoea occurs in patients without antecedent cause and they are termed if no aetiology leading to it could be identified. However recent evidence has led us to realize that idiopathic CSF rhinorrhoea are possible due to intermittent increase in the intracranial pressure(ICP).

There are several causes of elevated ICP, however the proposed mechanism underlying idiopathic CSF rhinorrhoea is idiopathic intracranial hypertension. Despite the multifactorial causes, the expected area of anterior skull base such as the lateral lamella of the cribiform or lateral recess of the sphenoid sinus results in bone remodeling and thinning. Ultimately a defect is formed.

History: A through history to the first step towards accurate diagnosis

For idiopathic : there should be no trauma in surgery h/o headache relieved by CSF drainage visual disturbance. Flow may be intermittent as the fluid accumulates in one of the paranasal sinuses and drains externally with changes in head position (reservoir).

Physical examination: Most unremarkable especially in intermittent can

• Complete rhinological (including endoscope)
• Otology
• Head and neck neurological evaluation

Endoscopy may reveal

• meningocele or encephalocele
• Sometimes site of leakage may often be elicited and seen on endoscopy by having the patient perform a Valsalva manoever or by compering both jugular veins(Queckensted -stookey test)

Bed side test

A) Halo sign/Ring sign/Double ring-sigh: not exclusive of CSF in difficulty to diagnosis  if mixture of blood and CSF.

B) Handkerchief stiffening tests.

Laboratory tests

A) Glucose content by glucose oxide paper:

• rapid but not reliable(Past)
• glucose may be lower in active meningitis
• Not specific to site
• If CSF is contaminated by blood test invalid.
• Lacrimal and nasal secretion have reducing substance which may cause +ve even with 5mg /dl glucose conventional
• A concentration of 30 mg/dl glucose confirmatory.

B) B-trace protein:

• help in diagnosis but not specific as this protein is present in cells choroid plexus, serum, testes and at least by  CRF MS cerebral infarction and CNS tumours.