Cerebrospinal fluid, also known as 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 more often it is seen leaking through the ears, nose, or an open wound.
CSF is formed within the inner spaces of the brain called ventricles. The fluid travels through the ventricles and exits the brain beneath the cerebellum, which is at the base of the head. It then travels down the spine, around the spinal cord and nerves, and back up to the head. The final step is passing over the top of the brain where it is absorbed. The fluid is held between the arachnoid and dura membranes. These membranes enclose the brain and spinal cord. Leakage occurs when the arachnoid membrane is ruptured.
CSF is a clear, watery liquid that leaks out of the nose, ear, or a wound. Headache is common with a CSF leak. It 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 can also cause an increased flow of CSF.
A CSF leak is caused by a rupture of the arachnoid membrane. This usually results from trauma, although it can occur spontaneously. Tissue destruction caused by tumors could lead to a CSF leak.
There is no way to prevent a CSF leak except by avoiding trauma. Sports safety guidelines for children, adolescents, and adults can help avoid head injury during sports.
Diagnosis is made through observation and by testing any suspicious watery fluid for glucose, which is present in cerebrospinal fluid. X-ray studies may be needed to find the exact place where the membrane has ruptured. Other studies may include CT scans.
Chronic leakage may occur at times. The leak most commonly comes from the nose. A long-term result may result in the loss of the sense of smell.
There are no risks to others.
Leakage through the nose or ears following trauma usually gets better with rest. Antibiotics are given if an infection is present. If the leakage persists, the doctor may place catheters in the lumbar spine to reroute the CSF. Surgical closure of the ruptured membrane is rarely needed. If leakage is caused by erosion due to tumor or infection, the underlying cause must be treated.
Infection of the trauma site and failure of the rupture to close spontaneously may sometimes 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.
Treatment is usually successful, although complications such as infection can occur.
A person should be monitored for infection and recurrence of CSF leakage. A change of therapy may be needed if infection or recurrence takes place. Any new or worsening symptoms should be reported to the doctor.