What does CSF stand for?

A cerebrospinal fluid fistula is usually caused by a tear in the dura mater in the context of cranial trauma or surgery and corresponds to a pathological connection between the cerebrospinal fluid and the nose or ear space. CSF leaks out of the nose or ear as a key symptom. The treatment involves microsurgical closure of the liquor leak.

What is a liquor fistula?

According to Abbreviation Finder, CSF is formed by the choroid plexus and circulates through the central nervous system in a communicating system of cavities. The cavity system is called the liquor space. Liquor enables the metabolism of the neurons in the central nervous system and, in the form of a water cushion, also protects the brain from mechanical influences.

The liquor and the liquor space can be affected by changes in various diseases of the central nervous system. If, for example, there is a connection between the outside world and the liquor system after a traumatic brain injury, this pathological phenomenon is referred to as a liquor fistula. Depending on the type of connection, different types of liquor fistula are distinguished.

In addition to the otogenic indirect liquor fistula and the ontogenous direct liquor fistula, the neurologist knows, for example, the nasal liquor fistula. Directly otogenic liquor fistulas create a connection between the liquor space and the middle ear. Indirectly otogenic CSF fistulas connect via the ear labyrinth and nasal fistulas connect via the nasal cavity.


The causes of a liquor fistula are to be found in traumatic skull injuries. In most cases, the connection is due to a tear in the dura mater, which often results from a skull base fracture. Skull base fractures are often the result of accidents or are caused by hard blows. Other traumatic injuries to the skull are also conceivable as the cause of the liquor fistula.

For example, the dura mater does not have to be torn in all cases. In addition to accidents and traumatic injuries, operations on the skull are also possible causes of a liquor fistula. The pathological connection of the liquor spaces with the outside world in the context of some cranial operations represents a possible postoperative complication.

Symptoms, Ailments and Signs

Patients with a CSF fistula usually have no pain. In most cases, you notice the connection between the liquor space and the outside space through liquorrhea. This symptom is to be understood as the main symptom of the liquor fistula and describes the flow of cerebrospinal fluid from the nose or the ear.

The liquor escapes from the liquor space to the outside via the connection that has been created. When liquor leaks through the ear, it is called otoliquorrhea. If, on the other hand, the brain water escapes via a connection between the nasal and liquor space, the doctor speaks of rhinoliquorrhea. When connected to the ear cavity, CSF can also enter the tympanum, causing symptoms such as hearing loss.

Liquorrhea as a result of traumatic brain injury usually occurs in the first three days after the trauma. The CSF outflow then usually corresponds to a slight drip in the nose or watery, drop-by-drop outflow from the auditory canal. The amount of discharge is usually small and is a few milliliters. Depending on the cause of the CSF fistula, patients may suffer from other symptoms, such as pain in the case of a skull fracture. In some cases, the discharge goes away within a week.

Diagnosis and course of the disease

Since liquor fistulas usually manifest themselves symptomatically through liquorrhea, the doctor first clarifies the causes of the liquor flow. To do this, he must clarify whether the discharge is actually liquor. This clarification corresponds to a determination of the βeta-2-transferrin or beta-trace protein. Determination via glucose test strips is also conceivable. This diagnostic step is followed by the localization of the CSF source.

Imaging such as CT and MRI are used for this. The suspicion of a CSF fistula is substantiated at the latest with the imaging procedures. Sodium fluorescein is usually injected intrathecally, which becomes visible in the course of the fistula and at the exit of the fistula. The prognosis for patients with a CSF fistula is favorable.

Treatment & Therapy

The therapy of a CSF fistula is usually causal. The leak in the CSF space must be closed for this purpose. Intervention is not indicated in all cases. Some CSF fistulas close by themselves, especially otogenic CSF fistulas. It can therefore make sense to initially observe the patient in such cases, which may save the person concerned from an invasive procedure.

The situation is different with rhinogenic liquor fistulas. Invasive treatment to close the leak is indicated in nearly all cases of connections to the nasal cavity. CSF fistulas at this location do not usually close by themselves and therefore require immediate intervention. An observation period therefore makes little sense for nasal CSF fistulas. In most cases, surgical closure occurs immediately after diagnosis.

The treatment of choice is usually a microsurgical closure of the fistula. Before the procedure, the patient is injected intrathecally with a dye so that the doctor can clearly understand the course of the fistula and its exit during the procedure and can seal the connection to the nasal cavity with pinpoint accuracy. In small children, anesthesia may be useful prior to the microsurgical procedure. In adults, anesthesia is not necessary in most cases.

Outlook & Forecast

Under optimal conditions, the symptoms of a liquor fistula can be alleviated within a week. The fistulas often close themselves later on. The development must nevertheless be closely monitored by doctors. Since it is a complication of an operation and a consequence of a skull injury, the person concerned is usually already receiving medical treatment. If the complaints increase or if the irregularities persist for a longer period of time, another intervention is carried out. The developments are assessed according to the individual circumstances. Nevertheless, most patients have a good prognosis.

Since it is usually sufficient to observe the self-healing process of the organism, no long-term complications or consequential disorders are to be expected. In exceptional cases, a closure is made, which is handled as a routine intervention. Should any complications arise, damage to the surrounding tissue areas can occur and this can lead to permanent functional disorders.

In addition, there is a possibility that the person affected will develop blood poisoning. Sepsis is a potentially life-threatening development and can result in the premature death of the patient. Therefore further health developments should be monitored and negative changes should be discussed immediately with the doctor.


CSF fistulas can be prevented in moderation. However, since accidents involving a fracture of the base of the skull cannot be prevented with absolute certainty, there is always a residual risk of liquor fistulas. During operations, physicians can prevent liquor fistula by carefully proceeding in the area of ​​the dura mater.


Even during the treatment of a liquor fistula, regular visits to the doctor should not be missed. Otherwise, there may be serious complications that cannot be restored afterwards. Appropriate aftercare is also very important and significant in this case.

Any complications can be identified, treated and eliminated at an early stage. Even if the liquor fistula could be treated successfully, further visits to the doctor are necessary. With appropriate aftercare, later brain damage can be diagnosed at an early stage, so that long-term effects can be avoided.

Even several years later, check-ups should always be carried out. Appropriate and regular follow-up care is just as important as the treatment itself. This is the only way to recognize and treat long-term effects or other diseases that can be attributed to the development of a liquor fistula. A full and lasting recovery is therefore very much dependent on proper aftercare.