What is cerebrospinal fluid (CSF)?
Cerebrospinal fluid (CSF) is a clear fluid that surrounds the brain and spinal cord. It cushions the brain and spinal cord from injury and also serves as a nutrient delivery and waste removal system for the brain. CSF is manufactured continuously in areas of the brain called ventricles and is absorbed by the bloodstream.
What is a cerebrospinal fluid (CSF) leak?
Cerebrospinal fluid (CSF) leak occurs when CSF escapes through a small tear or hole in the outermost layer of connective tissue (called the dura mater) that surrounds the brain and spinal cord and holds in the CSF. The tear or hole allows the CSF to leak out.
The loss of CSF causes the previously cushioned brain to sag inside the skull, which results in a headache. Loss of fluid also causes a lowering of pressure within the skull, a condition called intracranial hypotension.
CSF leaks can occur in the brain (cranial CSF leak) or at any point along the spinal column (spinal CSF leak).
How common is a cerebrospinal fluid (CSF) leak?
Cerebrospinal fluid (CSF) leaks are a rare event. Researchers estimate that they occur in about 5 in every 100,000 people. However, they also believe that this is an underestimate and that the true number of people affected remains unknown. They are mostly found in people in their 30s and 40s. CSF leaks are commonly misdiagnosed as migraines, other headache disorders or sinusitis.
Are certain people more prone to a cerebrospinal fluid (CSF) leak?
Anyone can get a cerebrospinal fluid (CSF) leak. However, they tend to occur more often in:
- People with certain connective tissue disorders such as Ehlers-Danlos and Marfan syndromes
- People who are obese or have high blood pressure
What are the complications from having a cerebrospinal fluid (CSF) leak?
Meningitis is the most significant risk associated with cranial CSF leaks. There is no increased risk of meningitis with a spinal CSF leak.
Symptoms and Causes
What causes a cerebrospinal fluid (CSF) leak?
Many cases of cerebrospinal fluid (CSF) leak have no known causes. This is called a spontaneous CSF leak. The following are other possible common causes:
- Head trauma or spine injury
- Lumbar puncture (spinal tap)
- History of epidurals or spinal catheters
- Certain head and spine surgeries
- Epidural injection (for pain relief)
- Skull base defects (such as meningoencephaloceles)
- High pressure intracranial hydrocephalus (an abnormal buildup of CSF in the brain)
- Underlying and untreated intracranial hypertension (elevated pressure in the brain fluid)
- Underlying and untreated connective tissue diseases, such as Ehlers-Danlos and Marfan syndromes
- Bone spurs along the spine
What are the symptoms of a cerebrospinal fluid (CSF) leak?
Symptoms of a cerebrospinal fluid (CSF) leak can include:
- Headache, which feels worse when sitting up or standing and better when laying down; may come on gradually or suddenly
- Vision changes (blurred vision, double vision, visual field changes)
- Hearing changes/ringing in ears
- Sensitivity to light
- Sensitivity to sound
- Balance problems
- Neck stiffness and pain
- Nausea and vomiting
- Pain between the shoulder blades
- Arm pain
In addition to these symptoms, other symptoms unique to cranial CSF leaks include:
- Clear, watery drainage usually from only one side of the nose or one ear when tilting the head forward
- Salty or metallic taste in mouth
- Drainage down back of throat
- Loss of smell
Diagnosis and Tests
How are cranial cerebrospinal fluid (CSF) leaks diagnosed?
Your doctor will perform a history and physical exam. Often, the doctor will examine your nose with an endoscope. Your doctor may also ask you to lean forward for several minutes to see if drainage comes out your nose. If the drainage can be collected, it is often sent for laboratory testing to confirm that it is cerebrospinal fluid. Your ears will also be examined. One or more of the following other tests may be ordered to determine the location of the leak as well as changes in structures and features in the brain or spinal cord area:
Management and Treatment
What is the treatment for a cerebrospinal fluid (CSF) leak?
Treatment options for a CSF leak depend on its cause and the location of the leak (cranial vs spine). In general, conservative treatments are usually tried first for leaks at either location.
- Bed rest (days to up to 2 weeks)
- Hydration (2 to 3 quarts)
- IV caffeine infusions
- Saline infusions
Additional instructions for patients with cranial CSF leaks are to avoid coughing, sneezing, nose blowing, heavy lifting and to take stool softeners to avoid straining during bowel movements.
If conservative treatments are not successful in stopping the leak, more invasive procedures are tried.
Cranial CSF leaks. Repair of cranial CSF leaks depend on the size and the location of the leak. CSF leaks from your nose can usually be repaired using nasal endoscopy (using a camera and a thin long lens through your nostril). CSF leaks into your ear will usually need the use of a microscope. Options including using a synthetic graft; using a piece of your own tissue including fat, muscle, and mucosal lining; or using a flap of tissue. In addition, various surgical adhesives (glues) and bony cement could also be used. If hydrocephalus is suspected to be the cause of the CSF leak, a lumbar drain may also be placed in the lower back to decrease intracranial pressure.
Spinal CSF leaks. After conservative treatments have been tried, an epidural blood patch is the most common treatment for spinal CSF leaks. In this procedure, your own blood is injected into the spinal canal. The blood clot that forms creates a seal to stop the leak. If several attempts of epidural blood patches do not work, other grafting materials, such as epidural fibrin glue, or fat or muscle patches, may be tried. If these methods are not successful, other surgical approaches to repair the leak include using stitches (sutures) or aneurysm clips.
What precautions should I take following a CSF leak repaired?
Your doctor will give you additional instructions, but these are also some reasonable precautions to follow for 4 to 6 weeks after your CSF leak repair:
- Avoid lifting anything over 10 pounds
- Avoid bending, lifting, stretching and twisting
- Avoid straining to have bowel movements; a stool softener is often prescribed
- Avoid coughing and sneezing, but if you must, do so with your mouth open
- Do not blow your nose
- Avoid use of straws
- Keep your back straight during all movements (bend at knees and hips)
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