A carotid sinus-cavernosus fistula is a vascular anomaly. In this case, an unnatural connection occurs behind the eye between the venous plexus located there and a neck artery.
What is a carotid sinus cavernosus fistula?
A carotid sinus cavernosus fistula (CSCF) is when an abnormal connection forms between the venous plexus located behind the human eyes and a cervical artery. The cavernous sinus refers to a small venous space behind the human eyes. In it there are veins whose function is the return of blood from the brain and face. On each side of the neck there are two paired internal and external carotid arteries (carotid arteries). From them the brain is supplied with blood. Sometimes a small tear forms on the carotid arteries. If this process happens to the veins of the cavernous sinus, it is possible for a smaller channel to form between them, which physicians call a fistula. This fistula causes blood to be diverted from an artery toward a vein. Near the cavernous sinus are the cranial nerves that control the movements of the eyes. Their functions also include sensing sensations in certain parts of the head and face. Due to the formation of a fistula, there is a risk that the pressure in the cavernous sinus will increase, resulting in compression of the nerves. This threatens functional impairment, which is manifested by various complaints.
Causes
Carotid sinus cavernosus fistulas are divided into two different types. These are the direct as well as the indirect fistula. A direct CSCF involves a connection between some internal carotid artery areas and the veins located in the internal portion of the cavernous sinus. In most cases, there is an increased rate of blood flow. This CSCF variant is most commonly seen. In the case of indirect carotid sinus-cavernosus fistula, it occurs between the sinus cavernosus veins as well as the carotid branches within the membranes that envelop the brain. A typical feature of this form is low blood flow velocity. Causes of direct carotid sinus cavernosus fistulas are injuries or accidents in which a tear of the carotid artery wall occurs. These are most often caused by falls, car accidents or violence. However, surgery can also be responsible for the development of a direct fistula. The formation of indirect carotid sinus cavernosus fistulas usually occurs quite abruptly. It has not yet been possible to determine what causes them. However, specific risk factors are known. These include high blood pressure, diseases of the connective tissue, arteriosclerosis, and pregnancy and the birth process.
Symptoms, complaints and signs
The symptoms that occur with a carotid sinus cavernosus fistula depend on its form. For example, indirect fistulas usually cause less pronounced symptoms, which is due to the relatively low blood flow velocity. In direct fistulas, on the other hand, the symptoms are more intense. In both forms of carotid sinus cavernosus fistula, symptoms include redness of the eye, bulging and pulsation of the eye, a protruding eye, loss of vision, and double vision. Other possible complaints include ringing in the ears (tinnitus), a buzzing in front of the eye that can be heard, faint eye movements, facial pain, nosebleeds and headaches. Because the brain is no longer optimally supplied with blood by the arteries, there is a risk of complications such as multiple ischemic seizures. In addition, the risk of a cerebral blood clot increases. Other complications that may be considered include rupture of the cavernous sinus or formation of glaucoma due to aqueous humor outflow obstruction.
Diagnosis and course
To diagnose carotid sinus cavernosus fistula, the physician performs a careful examination of the affected eye. In some cases, examination of the cavernous sinus and adjacent blood vessels may also be necessary. For this purpose, sonography (ultrasound examination), computed tomography (CT) or magnetic resonance imaging (MRI) are performed. Angiography may also take place to confirm the diagnosis.During this procedure, the doctor injects a contrast medium into the patient’s blood vessels, which can be seen on the subsequent X-ray images. This is followed by an X-ray examination of the neck and head. If a carotid sinus cavernosus fistula is treated professionally, there is usually a noticeable improvement in symptoms after just a few days or even hours. Thus, most patients are free of symptoms again after about six months. However, in the case of direct CSCF associated with pronounced symptoms, not every patient recovers completely.
Complications
Symptoms and complications are relatively dependent on the extent of the carotid sinus cavernosus fistula. In most cases, there is severe redness in the eye, which is not due to a foreign body. The patient also suffers from a pulsating eye, which may be associated with headaches and other facial pain. The function of the eyes is also impaired, so that veil vision or double vision may occur. Vision itself may also be reduced due to carotid sinus cavernosus fistula. It is not uncommon for tinnitus and nosebleeds to occur as well. The daily life of the affected person is severely restricted by the carotid sinus cavernosus fistula. There are also concentration disorders and often a lack of sleep. Treatment is not necessary in all cases; often the occlusion resolves itself without the need for a physician to intervene. However, if the symptoms and complaints are relatively severe, surgical intervention may be required. The operation proceeds without complications. To prevent the eyes from drying out, the affected person is usually also dependent on eye drops. After the treatment, the discomfort in the eye and face disappears completely.
When should you go to the doctor?
If eye discomfort such as redness, pulsation, and pain, as well as loss of vision, is noticed after an injury or accident, the attending physician should always be informed. Carotid sinus cavernosus fistula is also manifested by ringing in the ears, facial pain, headache, and nosebleeds, among other symptoms. In the case of these warning signs, a physician should be consulted in any case, who can clarify the complaints and, if necessary, treat them directly. At the latest, if CSVF leads to restrictions in the daily life of the affected person, it must be treated. A medical emergency exists when the first warning signs of a cerebral blood clot or stroke appear – in these cases, the emergency services should be alerted immediately. Complications such as the development of glaucoma should also be clarified immediately. If the symptoms are severe, surgery may be necessary. Thereafter, regular follow-up examinations are indicated, during which the physician ensures that no complications arise. In addition to the appropriate general practitioner, those with a carotid sinus cavernosus fistula may also want to see an eye disease specialist.
Treatment and therapy
Indirect carotid sinus cavernosus fistula does not always require therapy. Thus, in numerous cases, the fistula closes on its own. However, if the symptoms are severe or worsen, surgical intervention may be necessary. In such cases, endovascular embolization is usually performed. In this procedure, the surgeon inserts a narrow tube into an inguinal artery and advances it toward the fistula. Once the tube reaches the fistula, sealing of the abnormal connection takes place with the help of metal coils. However, there are other therapeutic options, such as the administration of medications. These include special agents that have a reducing effect on the pressure in the eye. It may also be useful to administer eye drops that counteract dryness of the visual organ. The last treatment option is surgical closure of the eyelid with stitches. In this way, the surface of the eye is protected. After a successful course of therapy, the doctor removes the stitches again.
Outlook and prognosis
Carotid sinus cavernosus fistula has a favorable prognosis. Because of the self-healing powers of the human organism, natural closure of the fistula occurs in many patients without further intervention. Spontaneous healing follows after a few days of fistula occurrence. No further treatment or additional medical care is required. Consequential symptoms are also absent.If the self-healing process does not occur, various complaints develop. These reduce the quality of life for the time of treatment, but are not permanent. The fistula is normally separated or sealed off by embolization. The procedure is routine and involves few risks. Normally, patients tolerate it well. Afterwards, the disturbed processes regenerate again and freedom from symptoms sets in. Many patients receive follow-up treatment with the administration of eye drops or other medications. These support the healing process and can be discontinued after a few days or weeks. In rare cases, temporary closure of the eyelid is initiated within the treatment process. As soon as the therapy is finished, the occlusion is removed and the patient is free of symptoms. Carotid sinus cavernosus fistula can recur at any time during life. The prognostic outlook is favorable even if the fistula recurs.
Prevention
Effective preventive measures against carotid sinus cavernosus fistula are not known.
Follow-up
Direct follow-up is usually not always necessary for a carotid sinus cavernosus fistula. In many cases, the fistula also does not require surgical treatment because it does not cause any particular discomfort and also does not negatively affect the life of the affected person. Only in rare cases does the fistula need to be treated by surgery. As after any surgical intervention, the affected person must take care and offer the body plenty of rest. Above all, the eyes must be spared. Often, eye drops are also administered to alleviate discomfort or speed healing after the surgical procedure. In severe cases, the eyelids are also completely closed with surgical stitches and reopened after healing. The patient should avoid stressful situations and relax in those involving a carotid sinus cavernosus fistula. Various techniques can also help in this regard. Likewise, vitamin K has a very positive effect on the healing of the fistula, and a healthy diet can also accelerate it significantly. The affected person should avoid anticoagulants and antibiotics if possible. Life expectancy is not usually negatively affected by carotid sinus cavernosus fistula.
Here’s what you can do yourself
Self-care and recommended adjustments for direct or indirect carotid sinus cavernosal fistula depend on the intensity and causation of symptoms. If symptoms of a direct connection between arterial vessels of one of the carotid arteries and the venous vasculature in the area of the cavernous sinus are mild to moderate, low arterial blood pressure will promote self-healing. This means that the fistula, which provides the connection between the two vascular systems bypassing the capillary structures, can close again on its own. In order to keep systolic blood pressure as low as possible, chronic stressful situations in everyday life should be avoided as far as possible, as they increase blood pressure by activating the sympathetic nervous system and constricting certain arteries. Practicing relaxation techniques such as meditation, yoga, and endurance sports can also promote self-occlusion of fistulas. In addition, care should be taken in the diet to ensure that foods contain sufficient vitamin K. Fat-soluble vitamin K has a significant influence on the blood’s ability to clot. Vitamin K is found in many naturally left foods such as spinach, Brussels sprouts and chives, as well as many other vegetables. Often, vitamin K deficiency is caused by antibiotics or other medications. Anticoagulants have an unfavorable effect on the chances of self-healing of the carotid sinus cavernosus fistula because they complicate the process of physiological closure of one or more fistulas.
