Imagine waking up with a headache that just won't quit — and it gets even worse when you sit or stand. It might feel like you were in the sun too long or became dehydrated the day before, but you're not sure. And it might last several days, or even weeks or months.
A severe headache that gets better when you're lying down could be a sign of a cerebrospinal fluid (CSF) leak, a condition where fluid leaks from your spine. If left untreated, a CSF leak can become serious, depending on its location and the severity.
"When a CSF leak happens, it changes the level of fluid pressure in the space between the brain and the dura," says Dr. Kurt Yaeger, a neurosurgeon at Houston Methodist. "This is what causes the telltale severe headache. It feels better when you lay down because it relieves some of that pressure change."
What happens when cerebrospinal spinal fluid leaks?
Cerebrospinal fluid is a protective substance that surrounds your brain and spinal cord, cushioning it from injury. It's a clear, colorless liquid that's about 99% water. The remaining 1% contains proteins, glucose and electrolytes.
This fluid is held in place by a membrane called the dura. If a tear or hole occurs in this membrane, the fluid can leak out. A CSF leak can occur after a medical procedure, such as spinal surgery or an epidural, or as the result of a traumatic head or neck injury. In some cases, the cause of the leak remains a mystery.
A few medical conditions are associated with weakness in the dura membrane, which increases a person's risk of developing a spontaneous CSF leak or recurring leak:
- Prior head, sinus or spinal surgery
- Obesity
- Obstructive sleep apnea
- Connective tissue disorders, such as Ehlers-Danlos syndrome or Marfan syndrome
- Intracranial hypertension
- An irregular skull base
"While a CSF leak can sometimes resolve on its own, treatment is often needed," says Dr. Yaeger. "If symptoms progressively worsen or don't go away after a week, seek medical attention. And if you've had a head injury or a recent medical procedure, in particular, be sure to keep a close eye on your symptoms."
CSF leak symptoms: Can you have a leak and not know?
A CSF leak can cause symptoms that mimic other conditions, such as migraine, dehydration or concussion. The key warning sign is a severe headache that worsens when you sit or stand. This is called an orthostatic, or low pressure, headache.
Other symptoms include:
- Sensory changes, such as ringing in your ears or sensitivity to light
- A runny nose or fluid in your ear — the discharge will be thin and clear, unlike the thick mucus associated with a respiratory infection
- Neck pain or stiffness
- Nausea
- Dizziness
- Cognitive issues like difficulty concentrating
"Some of the less common symptoms might appear before or after the headache, or you might have just the positional headache," Dr. Yaeger says. "Your doctor will want to know when your headache started, how quickly it became severe and how it changes when you move."
When to see a doctor for a CSF leak
In most cases, a CSF leak is not a medical emergency. However, it can be difficult to diagnose and a delay in treatment can lead to complications. A CSF leak can affect blood supply to the brain, and it increases the risk of trauma to brain tissue.
"Our biggest concern with an untreated CSF leak is infection," Dr. Yaeger explains. "Any hole or tear in that protective layer can let a serious infection like meningitis take hold, causing dangerous inflammation."
If you develop a headache that intensifies when you sit or stand, your first stop should be your primary care physician or an urgent care clinic. If your provider suspects a CSF leak, they will refer you to a neurologist or neurosurgeon.
How is a CSF leak diagnosed and treated?
To diagnose a CSF leak, your care team may order a CT scan or MRI of your head and neck. If your symptoms include a runny nose or ear drainage, a lab test can determine if a sample of that discharge contains a compound known as beta-2 transferrin.
Your initial treatment will focus on rest, fluids and over-the-counter pain relievers. Your symptoms will likely improve within a few days. If there is any sign of infection, your provider will prescribe an antibiotic.
"For cases where we're unable to pinpoint the cause of the leak, we might use an outpatient procedure called a blood patch," says Dr. Yaeger. "We inject a small bit of the patient's own blood below the dura. This causes a small blood clot that closes the leak."
If a neurologist has identified the specific cause and location of the CSF leak, they may be able to repair it using a catheter. This is also an outpatient procedure, similar to other types of minimally invasive endovascular treatments.
Surgery might be necessary if the leak is severe or the neurosurgeon cannot access the location using a catheter.
"Whatever the cause of a CSF leak, it's a condition that can be fully treatable," says Dr. Yaeger. "The sooner we can diagnose, the sooner you can get back to feeling like yourself again.
