A cerebrospinal fluid leak (CSF) is when you're leaking the fluid that surrounds your brain and spinal cord. CSF is vital to how your brain and spinal cord work, protecting and cushioning them from outside forces. CSF leaks can often cause severe symptoms, but this condition is very treatable, and up to 98% of people with it will recover.
A cerebrospinal fluid leak is when the fluid surrounding your brain and spinal cord leaks out from where it’s supposed to be. If the leak is large enough, it can cause severe symptoms that make it hard or even impossible to go about your life as usual.
Your brain and spinal cord have a surrounding protective layer of cerebrospinal fluid (CSF). CSF contains nutrients that your brain can use. The CSF layer also supports and cushions your brain and spinal cord from sudden movements.
The effect is similar to putting a grape inside a jar. If the jar is empty and you give it a good shake, you’ll bruise or damage the grape. That’s what would happen to your brain if you had no CSF. But if you fill the jar with water and then shake it, the water slows down how fast the grape moves and cushions it, preventing damage.
Spontaneous CSF leaks are more likely in people over 30 (the average age to have them is 42). People assigned female at birth are also much more likely to develop spontaneous CSF leaks.
Having a CSF leak causes a drop in fluid pressure inside your head. That causes a condition known as intracranial hypotension (“intracranial” means “inside your skull” and “hypotension” means “lower than normal pressure”). Intracranial hypotension is a rare condition, and about 5 people out of every 100,000 have it.
However, it's very likely that CSF leaks happen more often than that number suggests. Experts don't know exactly how common CSF leaks are because they're difficult to diagnose. It's also common for healthcare providers to misdiagnose a CSF leak as another condition, like migraine, sinus infections or allergies.
There's less fluid to surround, support and cushion your brain when you have a CSF leak. If the leak is small, it might not cause noticeable effects, or you might notice symptoms and mistake them for something else.
If the leak is large enough to cause intracranial hypotension, your brain will sink downward in your skull, putting too much pressure on its lower sections. That can disrupt how those parts of your brain work, causing symptoms ranging from minor and barely noticeable to severe and unbearable.
When CSF leaks are small enough that they don’t noticeably affect your brain, you may not notice any symptoms or might mistake the symptoms for something else. When a CSF leak is large enough that it causes intracranial hypotension, you’ll have symptoms related to pressure on the lower areas of your brain.
The most common symptom of intracranial hypotension from a CSF leak is a postural headache, which means a headache that changes depending on your posture. A postural headache with a CSF leak worsens when you sit up or stand and improves when you lie down.
Some possible symptoms of CSF leak depend on the location of the leak. Two likely places that CSF can leak into are your sinuses or your nose. In either case, you’ll have a runny nose (rhinorrhea) with thin, clear fluid. CSF coming out of your nose has two key differences from nasal mucus:
Another place where leaking CSF can cause symptoms is your ears. Clear fluid coming out of your ears (otorrhea) is a symptom of a CSF leak. However, it's less likely to happen because for the fluid to leak out, you'd also have to have a hole or tear in your tympanic membrane (also known as your eardrum).
Experts estimate that about 90% of CSF leaks happen because of injuries. The remaining 10% happen spontaneously or for unknown reasons.
Many injuries can cause CSF leaks. These include:
In about 10% of cases, CSF leaks happen for unknown reasons. However, experts have connected this problem to a few other medical conditions. Whether or not they cause CSF leaks is not yet known, but they do happen often enough that researchers are now looking to see if there is a cause-effect relationship.
CSF leak is not contagious. You can’t give it to or get it from others.
A healthcare provider can diagnose a CSF leak using a physical examination, along with gathering information about your symptoms, and asking questions about your medical history and circumstances. It’s also very likely that they’ll use certain kinds of lab tests and diagnostic imaging scans to confirm or rule out a CSF leak.
The combination of tests and methods they use depends on the suspected location of the leak, and whether or not you have any injuries (past or present) that could play a role.
There are several possible tests for CSF leaks. Most of them are imaging tests, which offer healthcare providers a way to look inside your head and back to locate possible leaks or damage that could contribute to them.
If you have CSF leak symptoms specific to your nose or face (especially a runny nose), your provider will likely want to test that fluid. The most likely lab test to help is a beta-2 transferrin test. This test looks for tau, a protein found in CSF but not in nasal mucus. Another possible test is a glucose test, as CSF has about the same amount of glucose as your blood, while nasal mucus has little-to-no glucose.
The most likely imaging and diagnostic tests include:
*This is usually not a first-line test for CSF leak.
In many cases, healthcare providers recommend no direct treatments for CSF leaks. That's because time and rest are all it takes for many injury-related CSF leaks to heal on their own.
In cases where a CSF might not or definitely won’t heal on its own, there are many different treatments and methods that can help. In most cases, it's possible to repair or seal the leak, stopping it from worsening or causing symptoms.
Chronic conditions, especially connective-tissue disorders like Marfan syndrome or Ehlers-Danlos syndrome, aren't curable. When this condition isn’t treatable or repairable directly or is the result of another condition, healthcare providers will try to treat your symptoms.
The treatments you receive depend most on what caused the CSF leak and its location. Medications, surgeries and other non-surgical procedures can often help. Your healthcare provider is the best person to tell you about the medications they recommend and why they feel those will help in your specific case.
Conservative treatment is a non-direct way of treating CSF leaks. This treatment calls for a person to lie down and rest for a period of time. They'll also need to stay hydrated, and medications to treat inflammation and pain are common. Caffeine and salt may also be part of the treatment guidelines in cases where a leak causes low CSF pressure. If conservative treatment doesn’t work after one to two weeks, your provider will likely recommend moving to direct treatments.
Surgery is a common method to repair CSF leaks. The surgery can either directly close a leak or help reconstruct a damaged area when the leak is from a significant injury. Some surgeries may go through your skull to access a leak, while others might try to repair a leak through your nose or mouth. The location, cause and severity of the leak are often key factors in deciding the type of surgical procedure.
The most likely treatment for CSF leaks that don’t involve surgery is a procedure known as a blood patch. During this procedure, a healthcare provider inserts a needle into the lumbar section of your lower back. Once it’s in position, they’ll slowly inject some of your own blood into the CSF surrounding your spinal cord and the injected blood “patches” the leak. In some cases, more than one blood patch is necessary, but most people who need more than one will still feel some improvement after the first.
Several medications can help with a CSF leak. Some lower the pressure inside your skull, while others treat severe symptoms like pain. Antibiotics are also possible because bacteria that reach your brain through your CSF can lead to dangerous infections like meningitis and encephalitis.
The possible complications and side effects from treatment depend on the location and severity of your CSF leak, what caused it, and what treatments you received. Your healthcare provider can explain the possible complications and side effects in your case and what you can do to limit or avoid these.
A CSF leak isn't something you can diagnose or treat on your own. If you suspect you have this condition, you should talk to a healthcare provider as soon as possible. That's because this condition has symptoms that are possible with severe conditions that need immediate medical attention.
The time to recover and start feeling better depends on treatment. Many people will feel some relief just by laying down and resting. But other people might need days or even weeks to recover.
CSF leak happens unpredictably, so it’s not preventable. However, you can try to reduce the risk of it happening by protecting yourself from conditions or circumstances that might cause a leak. However, that only works with causes related to injuries.
The most important thing you can do to avoid an injury-related CSF leak is to wear safety equipment. Face, head, neck and back injuries can cause the kind of damage that makes a CSF leak possible. Whether you're on the job or on your own time, using safety gear and equipment can help you avoid this possibility.
CSF leaks are sometimes tricky to diagnose, but the overall outlook for this condition is good. While the symptoms can be unpleasant, severe or disruptive, this condition is usually treatable. The overwhelming majority of people who have CSF leaks will either recover when the leak heals or with treatments or surgeries.
CSF leaks can last days, weeks or even months, depending on the size of the leak and why it happened. Treatment can also greatly shorten how long you feel the effects of a CSF leak. Your healthcare provider is the best person to tell you more about how long this condition will affect you and what you can do to help yourself.
Overall, the outlook for CSF leaks is very good. About 98% of people with CSF leaks will recover from them, no matter the cause.
If you have a CSF leak, you should follow your healthcare provider's guidelines on how to care for yourself. They're the best source of information for what you can and should do. They can also tell you what problem signs or warning indications to watch for and avoid.
You should talk to or see a healthcare provider if you think you have a CSF leak. While this condition doesn't usually cause severe or life-threatening complications, it shares symptoms with urgent and dangerous conditions.
If you know you have a CSF leak, your healthcare provider will schedule follow-up visits to monitor you as you recover. You should also see them if you notice symptoms getting worse or causing new disruptions in your daily life.
If you have a CSF leak, you should go to the ER if you have a sudden, severe headache, muscle weakness or trouble standing up. You should also see them if you notice any tingling or numbness anywhere on your body, especially in your hands, feet, legs and arms. Those can be a sign of injury to your spinal cord, which can lead to permanent paralysis.
You should also get emergency medical attention if you have stroke-like symptoms. These include:
A note from Cleveland Clinic
Cerebrospinal fluid leaks are an uncommon problem, but they can cause extremely unpleasant or severe symptoms. Advances in modern medicine and technology mean healthcare providers better detect and diagnose this problem quickly and easily. Providers can also do more to treat this problem than in years past, so the outlook for this condition tends to be very positive.
Last reviewed by a Cleveland Clinic medical professional on 04/26/2022.
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