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
Endoscopy may reveal
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.
A) Glucose content by glucose oxide paper:
B) B-trace protein: