A CSF leak is an escape of the fluid that surrounds the brain and spinal cord.

The dura is the membrane that surrounds the brain and spinal cord and contains the cerebrospinal fluid (CSF). CSF can leak from any hole or tear in the dura.

Causes of a tear in the dura include:

• Certain head, brain, or spinal surgeries
• Head injury
• Placement of tubes for epidural anesthesia or pain medications
• Spinal tap (lumbar puncture)

Sometimes there is no cause.

Symptoms may include:

• A headache that is worse when you sit up and improves when you lay down
• Drainage from the ear (rarely)
• Runny nose

Diagnosis is usually based on your history of injury, surgery, or lumbar puncture.

Tests may include:

• Injection of a radioisotope in the spinal fluid to track the leakage
• MRI
• X-ray with contrast dye

Depending on the cause of the leak, many cases go away on their own after a few days. Complete bed rest for several days is usually recommended.

Headache may be treated with pain relievers and fluids. If the headache lasts longer than a week after a lumbar puncture, a procedure may be done to block the hole that may be leaking fluid. This is called a blood patch, because a blood clot can be used to clog the leak. In most cases, this makes symptoms go away. Rarely, surgery is needed to repair a tear in the dura and stop the headache.

If symptoms of infection occur (fever, chills, change in mental status), antibiotic therapy is needed.

The outlook is usually good depending on the cause. Most cases heal by themselves with no lasting symptoms.

Complications may occur if the cause is surgery or trauma. Infections can cause serious complications, such as swelling of the brain.

Call your health care provider if:

• You have a headache that gets worse when you sit up, especially if you have recently had a head injury, surgery, or childbirth involving epidural anesthesia.
• You have a moderate head injury, and then develop a headache along with a thin, clear fluid draining from your nose or ear.

Measures such as wearing a helmet when riding a bicycle or motorcycle can help prevent head injuries that can lead to CSF leak.