Cerebrospinal fluid leak

Background

• CSF leaks are associated with a high risk of meningitis (10-25%, depending on etiology and chronicity)
• May be spontaneous (may be a cause of idiopathic intracranial hypotension), traumatic, or post-neurosurgical
• Spontaneous leaks are more common in overweight or obese patients

Clinical Manifestations

• May follow head trauma or skull-base surgery
• Symptoms of IIH, including headache, visual defects, and pulsatile tinnitus
• Symptoms of low ICP, including orthostatic headache and nuchal rigidity
• CSF rhinorrhea
  • Typically unilateral and watery
  • Typically triggered by changes in posture

Investigations

• Beta-2 transferrin or beta trace protein, which is positive in CSF
  • Best way to differentiate CSF from normal rhinorrhea
• High-resolution CT of the sinuses and skull base without contrast
  • Looking for defects in lateral lemella/olfactory cleft/ethmoid roof, roof of the lateral recess of the sphenoid sinus, supraorbital ethmoid roof/frontal sinus posterior table, and planum sphenoidale and posterior wall of sphenoid sinus and temporal bone
• High-resolution MRI to assess the area of suspected leak as well as signs of IIH
• Imaging may show suggestive signs: empty sella, arachnoid pits, erosion of skull base, widening of the subarachnoid space around the optic nerves, tortuous optic nerves, posterior globe flattening, dilated Meckel cave
• May need MRV (or CTV) to exclude a transverse venous sinus stenosis

Management

• Per consensus guidelines, the following assessments are recommended:
  • All patients with suspected CSF rhinorrhea should have ENT exam including nasal endoscopy and otologic exam
  • May benefit from ophthalmologic assessment for papilledema as well as assessment of visual fields
• Current IDSA guidelines1 recommend:
  • No routine prophylactic antibiotic in patients with basilar skull fractures and CSF leak
  • Surgical repair if leak lasts more than 7 days
  • Pneumococcal vaccination
• International consensus guidelines suggest:
  • If CSF rhinorrhea is proven, they should undergo closure
  • Patient should be counselled on risk of meningitis
  • No routine prophylactic antibiotics

Further Reading

• International Consensus Statement: Spontaneous Cerebrospinal Fluid Rhinorrhea. Int Forum Allergy Rhinol. 2021;11(4)794-803. doi: 10.1002/alr.22704
• Clinical Practice Guidelines for Healthcare-Associated Ventriculitis and Meningitis. Clin Infect Dis. 2017;64(6):e34-e65. doi: 10.1093/cid/ciw861