Intracranial hypotension

Alternative names
CSF leak

CSF leak is an escape of the fluid that surrounds the brain and spinal cord, from the cavities within the brain, or from the central canal in the spinal cord.

Causes, incidence, and risk factors

The dura is the membrane that surrounds the brain and spinal cord and contains the cerebrospinal fluid (CSF). A tear in the dura may occur under the following circumstances:

  • Spontaneously  
  • After surgery:       o Spinal       o Sinus       o Brain       o Head  
  • After penetrating head trauma.

CSF leak can also be caused by a lumbar puncture (spinal tap) or by epidural placement of catheters for anesthesia or pain medications.


Symptoms usually include a headache that is worse with sitting up and improves when the affected person is lying down. Leakage of CSF from a tear of the dura in the head can also cause a runny nose.

Signs and tests
Diagnosis is usually based on clinical suspicion following a history of trauma, surgery, or lumbar puncture. An MRI may be done to try to confirm the diagnosis.


Depending on the cause of the leak, many cases resolve spontaneously 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 persists longer than a week after a lumbar puncture, a blood patch procedure may be done to block the hole that may be leaking fluid. In most cases, this resolves the symptoms.

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

Expectations (prognosis)
Prognosis is usually good depending on the cause. Most cases heal spontaneously with no lasting symptoms. If the leak is due to head trauma or surgery, complications may be caused by underlying conditions. Careful attention should be paid to the possibility of infection, which can also cause serious complications.

Complications may occur if the underlying cause is surgery or trauma. Infections can cause serious complications such as swelling of the brain. CSF leak due to a lumbar puncture usually resolves satisfactorily.

Calling your health care provider
Call your health care provider if you have symptoms of a headache which gets worse when you sit up, particularly if you have recently had Head injury, surgery, or childbirth involving epidural anesthesia.


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

Johns Hopkins patient information

Last revised: December 4, 2012
by Janet G. Derge, M.D.

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