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:

  • Women
  • 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.

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

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