What is a CSF leak?

A CSF leak, or cerebrospinal fluid leak, is a serious condition where there is a hole in the dura, the membrane which surrounds the brain and spinal cord, causing the clear fluid inside to leak out. This fluid is responsible for protecting the brain and spinal cord.

A loss of cerebrospinal fluid in the spine reduces pressure in the brain and can cause headaches. It can also increase your risk of developing meningitis.

What are the symptoms of a CSF leak?

The main symptom of a CSF leak is a headache, particularly when standing or sitting in an upright position. A CSF headache can take around 15 minutes to develop, and is generally improved by lying down. Other common symptoms include:

• nausea and vomiting
• problems with balance
• neck stiffness
• ringing in the ears
• fatigue

What causes a CSF leak?

Most causes of CSF leak are due to medical procedures such as:

• epidural injections
• spinal tap
• spinal surgery
• surgery on the brain
• surgery to the nose

CSF leak can also be caused by trauma, such as whiplash, a severe head injury, or more minor accidents.

In some cases, it is not immediately clear what the cause of the CSF leak is. This is known as a spontaneous CSF leak. Medical understanding of spontaneous CSF leaks is still relatively limited, but some rarer causes have been identified including:

• bone spurs
• connective tissue diseases including polycystic kidney diseases, Marfan syndrome, and Ehlers-Danlos syndrome

How is a CSF leak diagnosed?

Diagnosing a CSF leak involves scanning the brain and the spinal cord using computerised tomography (CT) or magnetic resonance imaging (MRI).

When scanning the brain, the radiologist will look for “sagging” of the brain as a result of low pressure, and rule out other causes of your symptoms such as a bleed in the brain. If the CSF is due to a hole in the dura in the brain, it will be located at this stage.

When scanning the spine, the radiologist might inject a contrast dye to locate the hole in the dura if it was not found in the brain. In some cases, a CSF leak causes nasal drainage. If the patient complains about having a runny nose, a sample of the fluid from the nose can be analysed to check for proteins present in cerebrospinal fluid.

How is a CSF leak treated?

In many cases, the body is able to heal a hole in the dura by itself, and the symptoms associated with CSF should improve on their own. However, depending on the location of the leak and the risk of developing meningitis, surgery to repair the dura may be recommended. This involves using stitches and synthetic materials to seal the dura and prevent any further leaks.

After the operation, you may need to rest in bed for several days while the stitches dissolve and the dura heals fully, as any pressure from standing or sitting up may cause the weak part of the dura to puncture again.