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Cerebrospinal fluid commonly referred to as CSF, is a naturally produced fluid in the body that surrounds the delicate structures of the brain and spinal cord. It can sometimes be referred to as spinal or brain fluid. It acts as a soft cushioning fluid that insulates the brain and spinal cord from their hard bony enclosures. The average adult has approximately 200 ml of CSF total circulating in their body at any given time, about the same amount as a can of soda. However, the body will constantly absorb and re-produce CSF at a rate of about 700 ml per day, about the same amount as a liter bottle of soda.
CSF leak refers to leakage of the fluid from their normal bony enclosure into surrounding areas. This could mean the fluid that surrounds and cushions the brain leaking into your nose or ear.
CSF may leak from the skull or from the spinal cord. Skull based leakage may occur from the ears or from the nose.
CSF rhinorrhea refers specifically to leakage of brain fluid into the nose.
CSF rhinorrhea may be difficult to diagnose due to its nonspecific symptoms that can mimic other common medical problems. Patients may complain of large amounts of clear and odorless fluid from the nose. This fluid may be from both sides of the nose, but more often it is limited to only one side. This is frequently initially diagnosed as allergies, the common cold, or a sinus infection. A 2007 study from Cedars-Sinai demonstrated that 0% of CSF leaks were diagnosed in the emergency department, with an average delay of 8 months to accurately make the diagnosis. This study shows that CSF leaks are missed with long delays in making an accurate diagnosis. This results in patients being placed on incorrect medications that have no impact on the drainage from the nose, causing even longer delays in diagnosis. However, certain characteristics can help distinguish CSF rhinorrhea from these other common disorders.
Given the large amounts of CSF that the body produces daily, patients may report waking up with their pillows soaked in a clear fluid. Allergies or sinus infections should not leak that much. Nasal drainage may also get worse when patients lean over or change position in bed, which shouldn’t occur with allergies or the common cold either. Some patients may complain of a salty metallic taste. Other symptoms include spinning sensations, vision changes, fatigue, nausea, and vomiting.
CSF leaks, depending on the cause, may be associated with headaches. Sometimes the headache may be sudden in onset, while other headaches may be subtle and long-lasting. Finally, the headaches may worsen when laying in different positions.
There are many causes of leakage of CSF into the nose. CSF rhinorrhea may be caused by prior surgeries involving the nose, sinuses, or brain. Such surgeries may cause damage to the bony enclosure of the brain that leads to communication with the nose. CSF rhinorrhea may also be caused by head trauma, specifically those involving blunt trauma to the skull as experienced in high-speed motor vehicle collisions. CSF leaks may also occur spontaneously secondary to underlying medical conditions such as Polycystic Ovarian Disease, or uncontrollable hypertension. Other causes of CSF rhinorrhea may be due to benign or malignant tumors of the brain. However, often times CSF rhinorrhea is idiopathic, having no identifiable cause.
Spontaneous CSF leaks are used to refer to CSF leaks that occur suddenly, without any identifiable cause. These are also referred to as idiopathic CSF leaks.
CSF leaks are concerning as it demonstrates communication between the sterile and clean environment of the brain and spinal cord, and the non-sterile conditions of the nose and sinus areas. Although not imminently life-threatening, CSF leaks may have debilitating consequences when unrecognized and untreated. Bacteria may travel from the nose to the brain causing infections that result in meningitis or brain abscesses. For these reasons a timely and accurate diagnosis should be made so that appropriate steps can be taken to treat and prevent such debilitating infections.
There is often a delay in diagnosis of CSF leaks from the nose because of the similarities the symptoms share with other disorders. Diagnosis is based on a combination of a patient’s history and some diagnostic studies including lab work and imaging.
In order to verify that drainage is, in fact, CSF, the fluid must be tested for specific proteins that help distinguish it from other bodily fluids. The most commonly used test looks for a protein called beta-2-transferrin. This is a protein only found in the CSF fluid, and not found anywhere else in the body. If this protein is determined to be present in the fluid collected from your nose, it confirms that you have a CSF leak.
A simple sample collection may be obtained in the office. However, a minimum of 1 mL of fluid is needed to accurately run the test. So if your doctor cannot collect the full amount in the office, they may send you home with a container to collect it yourself. Once enough fluid is obtained, the specimen can be sent to the laboratory for special testing.
There are currently no home kits or over the counter testing methods for patients to obtain. If you are concerned about a CSF leak, you should contact your primary physician immediately and see a specialist.
Imaging studies may also help in identifying points of leakage in the brain and nose. These imaging studies include CT (Computed Tomography) scans and MRI (Magnetic Resonance Imaging) Scans. CT scans are most commonly used as they give details of the bony anatomy of the brain and can demonstrate any weaknesses or defects of the skull bone. MRI scans help image the soft tissue of the brain and nasal sinuses and gives valuable information about other underlying processes that may be causing the CSF leak.
Despite there being many causes to CSF leaks, they are generally uncommon and occur in about 3-5 in 100,000 individuals.
Treatment of CSF leaks depends on the underlying cause. For CSF leaks with identifiable causes, treatment of the underlying disorder may resolve the fluid leakage. For idiopathic CSF leaks, where there is no known cause, treatment options may include conservative and surgical methods.
Conservative methods are designed to reduce the amount of pressure in the brain, or intracranial pressure, By reducing the pressure in the skull, the pressure placed on the site of leakage is reduced, allowing for the tissue to heal and the leak to resolve on its own. It’s the same as allowing a leaky pipe to heal by reducing the amount of water pressure in the pipes, and giving the pipe a chance to heal itself (if the pipe had healing abilities like your body), This may include strict bed rest for 7-10 days to prevent changes in pressure inside the head that might negatively affect healing. Additionally, patients may be required to keep their head elevated while in bed, as laying down would further increase the pressure in the area of the leak. Often times, patients may be placed on stool softeners to reduce increases in pressure caused by bearing down while going to the bathroom. Some practitioners may place patients on antibiotics to prevent bacterial infections from spreading to the brain. Additionally, for difficult to treat CSF leaks, a lumbar drain may be placed. This is a drain placed in the back that diverts the flow of CSF away from the head. By reducing the amount of CSF flow to the head, it causes lower intracranial pressure which may allow the point of CSF leakage to heal on its own. This would be the same as diverting flow away from a leaking pipe to other pipes, while pipe heals itself.
Some medications are used to also enhance and support conservative treatment measures. Certain classes of medications called diuretics are designed to reduce the amount of produced CSF leak in the body. Diuretics help by dehydrating your body in a controlled fashion so that there is less CSF available, decreasing the pressure. Additionally, other medications such as steroids and carbonic anhydrase inhibitors may also reduce the amount of CSF that your body naturally produces, which causes less pressure at the area of the leakage.
CSF leaks are often unrecognized and untreated for long periods of times. The most common symptom of delayed diagnosis is simply clear runny discharge associated with positional headaches (headaches that get worse when standing up, or change in quality when laying down). However, other side effects include vision changes, ringing in the ear (known as tinnitus), and nausea. The most dreaded side effect of an undiagnosed and untreated CSF leak is an infection in the brain or spinal cord (known as meningitis). Fortunately, meningitis is a rare long term complication and does not happen frequently. However, a timely diagnosis is important so that the CSF leak can be managed appropriately.
Surgery is often times reserved for those patients who have failed medical and conservative management. CSF leaks can be repaired through the use of cameras and telescopes through the nose. These are called minimally invasive techniques because they do not involve big cuts on or around the face region, Using state of the art technology, image guidance is utilized to identify the source of the leak. Through telescopes placed in the nose, the leak location can be identified with certainty. Mucosal tissue or fat is then harvested and used as a plug to stop the drainage. The surgeon may then place tissue sealant in the area of the leak to further support the closure. Surgery may also be used in combination with some conservative techniques to further facilitate closure and resolution of the leak.
Dr. Mourad is highly trained and skilled in the diagnosis, management, and treatment of CSF leaks. In the past, CSF leaks were treated almost exclusively by Neurosurgeons. With advancements of endoscopic techniques inside the nose, repair of CSF leaks is now most often most appropriately managed by an Otolaryngologist. An ENT surgeon has the most extensive training of any specialty with respect to the anatomy and surgical techniques inside the nose. Dr. Mourad Moustafa is experienced and extensively trained in correcting CSF leaks. He is a leader in the field with numerous scientific publications relating to CSF leaks and skull base surgery. If you have a CSF leak and its resultant complications, please feel free to call our office.