Carotid cavernous fistulas

Carotid cavernous fistulas of the cerebral vessels are an acquired intracranial vascular anomaly with the formation of a connection between the internal carotid artery or one of its branches and the cavernous sinus, through which arterial blood is discharged into the venous system. Rupture of the internal carotid artery into the cavernous sinus cavity may be associated with trauma or occur spontaneously with atherosclerosis and arterial hypertension, less often as a result of infectious processes, developmental anomalies of the internal carotid artery. Traumatic ruptures are caused mainly by a hydraulic shock of blood along the arterial wall at the time of head injury, as well as by direct mechanical action from the outside (for example, with a fracture of the base of the skull or with a wound penetrating the cranial cavity).

Arterial blood under high pressure rushes into the cavernous sinus and then against the flow of venous blood into the veins flowing into the sinus. The larger the size of the anastomosis, the more blood enters the sinus and, accordingly, less into the middle and anterior cerebral arteries. Over time, the blood flow shifts more and more towards the anastomosis, through the veins draining the sinus, retrograde outflow of arterial blood occurs, and insufficiency of the blood supply to the brain increases. Venous outflow is impaired with congestion in the orbit and brain. The sinus itself noticeably stretches and increases in size, the cranial nerves passing through it are compressed - III, IV, VI and the first branch of the V (trigeminal) nerve.

Symptoms

• aneurysmal noise (train noise);
• pulsating exophthalmos;
• dilation and pulsation of the veins of the face and cranial vault;
• phenomena of blood stagnation in the eyeball, conjunctival edema (chemosis);
• dilation of the veins, blood stagnation and retinal vessels;
• increased intraocular pressure;
• impaired mobility of the eyeball;
• diplopia;
• drooping of the upper eyelid (ptosis).