The brain is protected from physical trauma and infection by a clear fluid called cerebrospinal fluid, or CSF. It is possible for tiny breaks to develop in the barrier between the roof of the sinuses and the brain, which can allow small amounts of cerebrospinal fluid to leak out through the nasal cavity. The diagnosis of a CSF leak is complicated by the fact that the colorless fluid resembles normal nasal drainage caused by inflammatory conditions, such as allergies and sinusitis.
Causes of CSF Leaks
The majority of cerebrospinal fluid leaks are the result of trauma following a head injury or surgery involving the head or sinuses. In rare cases, a patient with increased intracranial pressure may develop a spontaneous CSF leak in the absence of trauma. This is referred to as idiopathic intracranial hypertension, or IIH. This condition affects approximately 1 in 100,000 people.
Cerebrospinal fluid leaks are most common in adults between the ages of 20 and 45. Women and individuals who are obese are also at greater risk of developing a CSF leak.
Symptoms of a CSF Leak
Most patients with a cerebrospinal fluid leak experience a steady drip of clear fluid draining from the nose. The drip normally affects only one nostril and may be accompanied by headaches. If left untreated, a CSF leak can lead to meningitis, which is a life-threatening infection involving the lining of the brain. Patients who develop meningitis as the result of a CSF leak require hospitalization along with intravenous antibiotics. The suspicion of a cerebrospinal fluid leak increases in patients who have had a recent meningitis infection at the time that they are evaluated, even if the location of the leak is unclear.
How Cerebral Spinal Fluid Leaks are Diagnosed
The diagnosis of a CSF leak begins with a complete evaluation that includes the patient’s current symptoms, past medical history, and a physical examination. The doctor may use a sterile container to collect a sample of fluid in order to determine if it is cerebrospinal fluid. Once a CSF leak is confirmed, an MRI or CT of the sinuses may be used to pinpoint the location of the leak and determine the best strategy for repairing the defect.
How CSF Leaks are Treated
In most cases, the management and treatment of CSF leaks requires a multidisciplinary approach involving various specialties. Prior to surgery, a neurosurgeon may be consulted to insert a lumbar drain that will help decompress the cerebrospinal fluid space. Most defects can be repaired using a minimally invasive approach without the need for an external incision. An endoscope is inserted through the nose that allows the doctor to visualize the exact location of the leak and repair the defect. The leak is repaired using tissue that is typically taken from inside the patient’s nose.