see also:

• headache
• cerebrospinal fluid (CSF)
• post LP headaches (PLPH)

• CSF leaks occur when there is a tear in the dura and may cause intracranial hypotension

• most occur due to facial/head injury (~80%) or are iatrogenic (~16%)¹⁾
  • fracture base of skull
    • the cribriform plate, ethmoid bone, and sphenoid sinuses are thin and closely associated with the dura mater and enjury may result in CSF rhinorrhoea
    • fractures of the temporal bone, which houses the middle ear and mastoid air cells, are commonly associated with dural disruption and may result in CSF otorrhea
    • rarely, trauma involving the orbit can lead to CSF oculorrhea due to disruption of the orbital roof or adjacent skull base structures
  • endoscopic sinus surgery or pituitary tumor resections
    • endoscopic endonasal approach for tumor resection showed an overall postoperative CSF leak rate of 10.1%²⁾
  • spinal surgery
    • incidence of CSF leaks after primary spine surgery ranges from 5.5% to 9%, and from 13.2% to 21% after the second surgery³⁾
  • post LP headaches (PLPH)
    • lumbar puncture (LP)
    • lumbar-peritoneal shunt placement
    • epidural anesthesia
• ~4% are spontaneous and are usually spinal CSF leaks rather than cranial
  • most are in the thoracic levels
  • most occur in adults 33-52 years ⁴⁾
  • some are due to genetic factors
  • some are a complication of benign raised idiopathic intracranial hypertension which may cause CSF rhinorrhoea - MRI is the preferred Ix
  • spinal leaks are generally divided into 4 main types

• may be clear fluid flowing from nose, ear or orbit if post-traumatic head injury or iatrogenic cribriform plate damage
  • early onset type (50%) commences in first two days following trauma
  • delayed type presents at least 1 week after the trauma
  • late-onset/occult type presents within 3 months after the trauma
  • 70% develop in the 1st week after trauma ⁵⁾
• severe postural headaches worse on standing up
• nausea
• neck pain
• open leaks may have risk of subsequent meningitis 18-30% of cases if traumatic
• less commonly,
  • brain abscess formation (0.9%)
  • subdural haematoma (0.3%)
  • olfactory impairment
• chronic CSF leaks may also cause:
  • low-pressure headaches, neck pain, ringing in the ears, and loss of smell or taste
  • obtundation, memory deficits, frontotemporal dementia, Parkinsonism, and ataxia

• ascertaining if leaking fluid is CSF:
  • testing rhinorrhea or otorrhea for beta-2 transferrin (a protein found only in CSF and perilymph), is a highly specific and sensitive test
  • previously used glucose testing is not reliable
• CT scan +/- MRI

• see also post LP headaches (PLPH)
• Rx depends on the dural tear's underlying cause, size, and location
• small leaks may resolve spontaneously, but larger leaks may require surgical intervention
• bed rest
• encourage oral fluid intake
• simple analgesics / non-steroidal anti-inflammatory drugs (NSAIDs)
• avoid activities that increase pressure on the affected area, such as coughing, sneezing, or straining
• caffeine can worsen symptoms and should be avoided or limited⁶⁾ - unless it is a post LP headaches (PLPH)?
• consider epidural blood patches
  • this injects a small volume of the patient's blood into the epidural space surrounding the spinal cord to seal the leak and prevent further loss of CSF fluid
  • 10 to 15 mL blood has an 80% success rate, and 20 mL blood has a success rate of more than 95%
• if traumatic or iatrogenic cranial leak:
  • watch for meningitis in those with open leaks as risk is as high as 29%
  • nasal CSF leak may consider endoscopic nasal packing, endoscopic repair, and surgical repair
    • abducens nerve palsy is a potential complication of skull-base surgery for repair of a CSF leak
• if spontaneous leak or high intracranial pressure:
  • acetazolamide, 500 mg twice daily for the first week, followed by a lower dose of 250 mg twice daily for the second week, has a high success rate in closing the primary defect in spontaneous CSF leaks⁷⁾
    • acetazolamide reduces CSF synthesis by 48%, decreasing the volume and reducing pressure
    • should be administered to patients with spontaneous CSF leaks who exhibit signs of increased intracranial pressure
  • if refractory or particularly high intracranial pressure, ventriculoperitoneal shunt placement can be effective but has relatively high complication rates