Cerebrospinal fluid leak
Background
Cerebrospinal fluid (CSF) surrounds the spine and brain acting mainly as a protective buffer. A tear in one of the membranes containing the CSF allows the fluid to leak out. It can leak out through the nose, ears, or from a head or spinal wound. As the fluid drains, its cushioning power decreases, and the brain begins to rest directly on the skull. The result is headaches, which worsen upon sitting or standing.
An opening in the membranes also makes the nervous system more susceptible to infection. When left untreated, 25-50% of CSF leaks lead to meningitis.
Causes
CSF leaks can be caused by:
- trauma to the head or spine
- surgery
- tumors
- conditions that increase pressure in the brain, such as hydrocephalus
CSF leaks can also be spontaneous. These leaks are usually associated with developmental defects of the skull bones that cause the meninges (membranes) to protrude or by chronically elevated intracranial pressure.
Symptoms
The characteristic symptom is orthostatic headache, a headache which worsens when the patient is in the upright position and is alleviated by lying down. Drainage from the nose (rhinorrhea), ear (otorrhea), or surgical wound may also be present.
Diagnosis
If the patient has drainage, a sample may be collected and tested. If it contains beta-2-transferrin, a protein specific to CSF, a positive diagnosis can be made. MRIs, CTs, cintilography and or cisternography may be done to confirm the diagnosis and locate the leak.
Treatment
Many CSF leaks repair themselves within a week to six months, especially those that have a traumatic origin. The patient may be instructed to rest and given pain relievers for the headache. If leakage persists, an epidural blood patch may be injected at the site of the leak to block it.
In some cases surgery is necessary. It is obligatory for repair of spontaneous cases and most of the traumatic ones involving skull-base defects, which require repair of the bone as well as the meningeal tear. The endoscopic endonasal approach is usually preferred avoiding a craniotomy to repair the skull base defect.
The endoscopic endonasal approach (EEA) is a state-of-the-art surgical procedure that can be used to treat CSF leaks of the skull base.
Prevention
Most CSF leaks cannot be prevented. Following sports safety guidelines, such as wearing a helmet, can help to prevent some injuries that may lead to CSF leaks.