The human brain is cushioned by clear, colorless liquid called cerebrospinal fluid (CSF). Flowing through the ventricles in the brain, this important fluid protects the cerebral tissue from injury and infections. CSF is constantly made by the brain and reabsorbed back into the blood system. A cerebrospinal fluid leak is rare but CSF can leak through the brain covering and into the nose. Leaks are most typically a result of a skull fracture, weakness of the brain covering (dura), intracranial surgery or growth of a brain tumor. CSF leaks can also be associated with meningoencephalocele - this is a rare condition present at birth where the brain and its lining (meninges) protrude through a hole in the base of the skull). Sometimes leaks occur in overweight patients who have high cranial pressure, and the membrane between the brain and sinus "pops open." Sometimes a car accident or head trauma can cause a tear. This is a potentially very dangerous condition and these leaks must be repaired in order to prevent an infection of the CSF (meningitis) or of the brain itself (brain abscess).
Up to 94% of CSF leaks are initially misdiagnosed. Incorrect diagnoses include allergies, rhinitis, sinusitis, migraines, meningitis, and sinus headache. Common symptoms include clear fluid leaking from the nose (usually from only one nostril but can be both sides), headache that is worse when upright and better when horizontal (but other patterns do occur), nausea and vomiting, neck pain or stiffness, a change in hearing, a sense of imbalance, changes in cognition (brain fog) and dizziness.
The most common tests for CSF leak are through examination from an ear, nose and throat (ENT) physician. The ENY may use nasal endoscopy, CT and MRI imaging, and chemical tests of the fluid that is leaking (beta 2 transferrin test).
Treatment can be either medical or surgical. In cases of spontaneous CSF leak or head trauma conservative treatment is usually recommended first. Depending on the cause of the leak, many symptoms improve on their own after a few days. Complete bed rest for several days is usually recommended. Patients are encouraged to avoid coughing, sneezing, and heavy lifting. Straining is avoided by taking stool softeners.
Surgical treatment of CSF leaks is used when conservative treatment fails. Two decades ago, cerebrospinal fluid (CSF) leaks were often surgically managed through external (scalp) incisions and craniotomies (opening the bone of the skull with a saw). The introduction of nasal endoscopes and specialized instruments has allowed successful treatment through the nose for many of these problems, avoiding any incisions on the face and scalp. These "endoscopic" approaches decrease the amount of discomfort for the patient and shorten hospital stays. Endoscopic treatment requires specialized training of the ENT surgeon and their team.