Drainage of Clear Fluid from Ears or Nose (CSF Leak)

Clinical Significance

Clear fluid draining from the nose (CSF rhinorrhea) or ear canal (CSF otorrhea) following head trauma represents a neurological emergency. This fluid is cerebrospinal fluid (CSF) — the protective fluid circulating in the subarachnoid space around the brain and spinal cord — and its leakage almost always indicates a defect in the dura mater overlying a skull base fracture.

CSF leaks carry a significant risk of ascending bacterial meningitis (predominantly Streptococcus pneumoniae), with estimated meningitis rates of approximately 10–25% in untreated post-traumatic CSF leaks. The risk increases with duration of the leak.

Ziu M, Savage JG, Jimenez DF. Diagnosis and treatment of cerebrospinal fluid rhinorrhea following accidental traumatic anterior skull base fractures. Neurosurg Focus. 2012;32(6):E3. doi:10.3171/2012.4.FOCUS1264 — Key reference for post-traumatic CSF leak management.

Common Causes

• Basilar skull fracture (anterior or middle cranial fossa)
• Severe blunt head trauma
• Penetrating skull injuries
• Surgical complications (post-neurosurgical)
• Spontaneous CSF leak (idiopathic intracranial hypertension — non-traumatic)

Investigations

• CT Head (initial imaging)
• High-resolution CT Skull Base (thin cuts, 1mm)
• MRI Brain with cisternography (to localise leak site)
• Beta-2 transferrin assay (gold standard biochemical test for CSF identification)
• Fluorescein nasal endoscopy (specialist setting)

Beta-2 transferrin is a protein almost exclusively found in CSF, vitreous humor, and perilymph. Its identification in nasal or aural discharge is the most reliable biochemical confirmation of CSF leakage.

Management

• Conservative: bed rest, head elevation, avoid nose blowing, stool softeners, avoid straining
• Lumbar drain (selected cases to reduce CSF pressure)
• Neurosurgical repair: endoscopic or open surgical repair when conservative management fails (typically after 7–14 days)
• Antibiotics: prophylactic antibiotic use remains controversial; most guidelines advise against routine prophylaxis