Definition Cerebrospinal fluid (CSF) leak is an abnormal drainage of cerebrospinal fluid from the subarachnoid space in the brain. The fluid may leak out into the body, but it is usually seen leaking through the ears, nose, or an open wound.
What is going on in the body? CSF is formed within the inner cavities of the brain called the ventricles. The fluid travels through the ventricles and exits the brain beneath the cerebellum at the base of the head. It then travels down the spine, around the spinal cord and nerves, and back up to the head. It finally passes over the top of the brain where it is absorbed. The fluid is contained between the arachnoid and dura membranes, the membranes that enclose the brain and spinal cord. Leakage occurs when the arachnoid membrane is ruptured.
What are the signs and symptoms of the condition? The leaking CSF presents as a clear, watery liquid passing out of the nose, ear, or a wound. Headache is common and may be relieved when the person sits upright from a lying position. However, changing to this position may cause the flow of fluid to increase. Coughing or sneezing will also cause an increased flow of CSF.
What are the causes and risks of the condition? A CSF leak is caused by a rupture of the arachnoid membrane. This usually results from trauma, although it can occur spontaneously such as from tissue destruction caused by tumours.
What can be done to prevent the condition? There is no way to prevent this disorder, except by avoiding trauma. Sports safety guidelines for children, adolescents, and adults can help avoid head injury during sports.
How is the condition diagnosed? Diagnosis is made by testing any suspicious watery fluid for glucose, which is present in cerebrospinal fluid. X-ray studies may be necessary to identify the exact location of the rupture in the membrane. Other studies may include CT scans.
What are the long-term effects of the condition? Chronic leakage is occasionally seen. It is most commonly seen from the nose. A long-term result may involve the loss of the sense of smell.
What are the risks to others? There are no risks to others.
What are the treatments for the condition? Leakage through the nose or ears following trauma usually resolves with rest. Antibiotics are given if an infection is present. If the leakage persists, the CSF may be re-routed through catheters placed in the lumbar spine. Rarely is surgical closure of the ruptured membrane necessary. If leakage is caused by erosion due to tumour or infection, treatment of the underlying cause is necessary.
What are the side effects of the treatments? Infection of the surgical site and failure of the rupture to close spontaneously may occasionally occur. In cases of a skull fracture, swelling may damage a cranial nerve, leading to weakness or paralysis on the side of the face. These injuries commonly result in hearing loss on the affected side.
What happens after treatment for the condition? Treatment is usually successful, although complications such as infection can occur.
How is the condition monitored? A person should be monitored for infection and recurrence of CSF leakage. A change of therapy may be necessary if infection or recurrence takes place.
Author: Reviewer: HealthAnswers Australia Medical Review Panel Editor: Dr David Taylor, Chief Medical Officer HealthAnswers Australia Last Updated: 1/10/2001 Contributors Potential conflict of interest information for reviewers available on request
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