carotid cavernous fistula
Introduction
Introduction to carotid cavernous fistula Carotid cavernous fistula (CCF), a direct communication between the carotid artery and the cavernous sinus, is a relatively common neuro-ophthalmologic syndrome. Due to special anatomical reasons, the cavernous sinus area is the site of the most common arteriovenous fistula. More than 80% of patients first have eye symptoms and signs, such as eyeballs, congestion, eye movement disorders, etc. and see an ophthalmologist. basic knowledge The proportion of illness: the incidence rate is about 0.0002% - 0.0004% Susceptible people: no special people Mode of infection: non-infectious Complications: intracranial hemorrhage
Cause
Carotid cavernous fistula
(1) Causes of the disease
Carotid cavernous fistula is divided into three types according to the causes of trauma, spontaneous and congenital.
Trauma
Car accidents, falling, impact and other indirect trauma and shrapnel, cone shear and direct trauma can cause carotid cavernous sinus fistula, indirect trauma caused by skull base fracture, carotid artery is fixed in the cavernous sinus by the meninges, tearing; The needles, cones, and scissors in the area directly pierce the cavernous sinus and the internal carotid artery. The projectile can also penetrate into the skull and penetrate the cavernous sinus. After the internal carotid artery rupture, there are often three kinds of results: 1 arterial blood Entering the cavernous sinus, movement, and vein direct traffic, this kind of traffic can be formed after the injury, or due to indirect trauma, the internal carotid artery intima is split, the blood is immersed in the wall of the tube to form an aneurysm, and finally it is broken into sputum, some Symptoms and signs of arteriovenous traffic appear only a few months after the trauma of the case, which may belong to this category; 2 sphenoidal fractures and internal carotid artery rupture exist simultaneously, and communicate with each other, arterial blood is drained from the sinuses, causing uncontrollable bleeding and death; 3 trauma also tears the dura mater, the internal carotid artery blood directly into the subarachnoid space, can also die due to high intracranial pressure, cerebral palsy, fracture in the skull base, while damaging the internal carotid artery trunk, blood flow, prolonged shape Carotid cavernous fistula is a good outcome. The internal wall of the internal carotid artery in the cavernous sinus is very thin. A slight head turbulence can cause the rupture of the pituitary gland or the cavernous sinus artery, resulting in a low flow rate. .
2. Spontaneity
The internal fixation of the internal and external arteries and their branches, aneurysms and other arterial wall lesions spontaneously form fissures or ruptures, and the trunk or branch blood directly flows into the cavernous sinus.
3. Congenital
There are embryonic arteries or movements between the internal carotid artery and the cavernous sinus. The venous traffic is malformed. Symptoms can be found after birth. There are also congenital arterial wall weak, can not withstand high arterial pressure, spontaneous rupture, most scholars believe that the latter is causing hard The main cause of meningococcal sinus fistula.
(two) pathogenesis
Under normal circumstances, the cavernous sinus receives blood flow from the occipital and inferior venous sinus, and is exported through the rock and the inferior sinus. When the artery communicates with the cavernous sinus, the arterial blood is perfused with the high pressure in the cavernous sinus. In the blood, in the eye, the veins under the eyes are enlarged under the influence of a large amount of high-pressure blood, and the blood inside them flows forward. The upper sinus and the lower sinus are bound by the meninges formed by fibrous tissue, which can resist high intravascular pressure and are not easy to expand. The internal iliac vein is surrounded by a soft fat body and cannot withstand the pressure. Therefore, the arterial blood in the cavernous sinus flows back to the upper and lower veins, and is drained to the facial vein through the superior ocular vein. The ocular and inferior veins are dilated and arterialized. Increased venous pressure, increased blood flow resistance of the internal iliac vein, causing venous dilatation of various stages, edema of the iliac crest, and a series of signs, such as large arterial pupil, ipsilateral middle cerebral artery, anterior cerebral artery and eye The blood in the arteries flows back through the pupil and enters the venous system. Before the collateral circulation is not fully established, the blood supply to the affected side can be incomplete due to "stealing blood"; Decreased, slow blood flow, combined with increased venous pressure, eye ischemia, hypoxia, corneal degeneration, lens opacity, vitreous hemorrhage, optic atrophy, carotid cavernous sinus and eye signs appear early on the affected side The late stage can also occur on the healthy side, or first seen in the affected side of the eye and then relieved, and then alternate to the contralateral side, which is related to the cavernous sinus and its associated blood vessels:
1 If the cavernous sinus and the ipsilateral venous vein are unobstructed, the ipsilateral eye symptoms will appear. For a long time, the arterial blood can be drained to the contralateral cavernous sinus through the interspontaneous sinus, and two eyes will appear;
2 If the cavernous sinus and the ipsilateral venous vein are not well communicated, the ipsilateral side may be asymptomatic, passing through the interscapular sinus, showing the contralateral eye sign;
3 If the cavernous sinus blood is first drained through the ipsilateral ocular vein, thrombus is formed, and the eye signs are relieved. The interphalangeal sinus is passed to the contralateral sinus, and the symptoms of the contralateral eye appear. Although the contralateral eye can appear in the low salivation There may be alternations, but most of them are not caused by the connection between the veins, but by the small arteries and veins on both sides.
There are many branches of the normal internal carotid artery and the meningeal artery. The meninges of the internal carotid artery, the external carotid artery and the vertebral artery communicate with each other. The communication between any artery and the cavernous sinus is often the bilateral internal carotid artery. The external carotid artery supplies blood, and sometimes the vertebral artery participates in blood supply. The cavernous sinus collects part of the intracranial vein. When the meningeal artery communicates with the veins of the same person, the arterial blood can be drained into the cavernous sinus by the vein and the cavernous sinus syndrome appears. The vascular connection of the cavernous sinus fistula is very complicated, especially the dural cavernous sinus fistula. In some cases, the bilateral internal carotid artery, the external carotid artery, and even the vertebral artery are involved. Before treatment, they should be comprehensively examined. In the lateral neck, extra-cervical and vertebral angiography, many factors can be considered to receive better treatment results.
Prevention
Carotid cavernous fistula prevention
Prevention of trauma; in addition to the necessary life treatment after trauma, the possibility of internal carotid cavernous fistula should be considered for timely treatment.
Complication
Carotid cavernous fistula complications Complications intracranial hemorrhage
Internal carotid artery-cavernous sinus fistula associated with trauma can present with complications such as traumatic intracranial hemorrhage and skull fracture.
Symptom
Symptoms of carotid cavernous sinus common symptoms fundus changes retinal hemorrhage eyeball edema palsy diplopia hyperemia intraocular pressure increased red eye high intraocular pressure
The primary site of carotid cavernous fistula is in the brain, but due to the special relationship between sputum and cranial vein, its symptoms and signs are almost always in the eye. Most patients are first diagnosed in ophthalmology, and the clinical symptoms and signs of this disease are serious. The degree depends on:
1 the position of the pupil in the cavernous sinus;
2 pupil size;
3 different degrees of venous and cavernous sinus opening;
4 changes in abnormal arterial and venous traffic can be clinically performed as follows:
Pulsatile eyeball
High salivation has this sign, the difference of eyeball protrusion on both sides is more than 3~11mm, and the protruding direction is mostly axial. When the ocular vein is more severely dilated, the eyeball shifts slightly downward, and the eyeball is protruding due to sputum. Endovenous dilatation and congestion, sputum fat and extraocular muscle edema enlargement, eyeballs protruding and synchronous with heartbeat, both subjective and objective may smell murmur, oppression of the ipsilateral carotid artery, pulsation and murmur disappear, dural cavernous sinus fistula Its eyeballs are relatively light, sometimes even without such signs, and generally no pulsation.
2. Ocular surface angulation and red eye
Almost every patient has this sign, and they are all the first signs. After the formation of high salivation, there is obvious conjunctival edema and venous dilatation. The occurrence of low salivation is gradual, and it is difficult to determine the start date. 2~ After 3 weeks, the peak is reached, the blood vessel is highly tortuous and dilated, and it is screw-like, with bright red or purple red. This is because the blood vessels are filled with arterial blood. It is lighter than the general venous congestion. The dilated blood vessels are from the dome to the limbus. The center, radially, after a low flow, months or years, the vascular diameter begins to decrease, and finally only the dilated blood vessels near the limbus are left. This special form of red eye and vasodilation is rare in other diseases ( figure 1).
3. Double vision and extraocular muscle paralysis
Most cases complain of double vision, extraocular muscle paralysis is often the main contradiction, but this paralysis is partial, the most common manifestation of incomplete nerve paralysis, is also one of the earliest signs, the oculomotor nerve, the trochlear nerve through the outer wall of the cavernous sinus, Paralysis of these two cranial nerves can also occur, but it is rare.
4. Fundus changes
Due to increased venous pressure on the eye, retinal venous return is blocked, which can cause optic disc congestion, retinal vein tortuosity and retinal hemorrhage. However, due to the influence of intraocular pressure, the degree of central retinal vein expansion is much lighter than that of the surface of the eyeball. A small amount, can be absorbed in a short period of time, occasionally optic disc edema and choroidal detachment, oppression of the eye can be seen in the central retinal vein.
5. Schlemm's sinus congestion and increased intraocular pressure
Under normal circumstances, the aqueous humor flow through the anterior ciliary vein, the ocular vein to the cavernous sinus, such as arteriovenous traffic, venous blood reflux, through the aqueous humor vein, can flow into the scleral sinus, iris keratoscopy is easy to observe Intravenous venous reflux, scleral sinus widening and hyperemia changes, blood color is lighter than the surface of the eyeball. This is due to the mixed aqueous humor, and the intraocular pressure is related to the scleral venous pressure. According to Goldmann's traditional formula, it can be expressed as: Intraocular pressure = flow resistance × aqueous humor outflow resistance + scleral surface venous pressure, blood flow in the carotid cavernous fistula, aqueous humor vein, aqueous humor outflow resistance, scleral venous pressure also increased, intraocular pressure is high Generally, it is mild or moderately high intraocular pressure.
6. Vision loss
Vision loss is rare. If there is retinal hemorrhage, glaucoma or choroidal detachment, it can lead to decreased vision. The visual acuity caused by retinal hemorrhage is temporary. It can be recovered after hemorrhage, and the intraocular pressure is increased for a long period of time. Can cause permanent vision loss, high salivation, reversible ophthalmic artery, long-term ocular ischemia and hypoxia, leading to optic atrophy, cataract and corneal degeneration and loss of vision.
7. Headache
There are l/4~1/2 patients with pain, and the pain area is mostly limited to the forehead and temporal region of the affected side. This is caused by the cavernous sinus and intracranial vasodilation, which is caused by compression of the meningeal pain nerve. Patients can also have migraine headaches due to glaucoma.
According to the medical history, clinical manifestations and imaging examinations, especially DSA results can be clearly diagnosed.
Examine
Examination of carotid cavernous fistula
Pathological examination: the cavernous sinus segment of the internal carotid artery often has weak wall lesions, such as atherosclerosis, aneurysm, arteritis, etc. Once the artery is ruptured, the sinus cavity adjacent to the pupil is highly dilated, and the sinus is filled with arterial blood. The wall fibers proliferate and become thicker. The ocular veins are subjected to arterial blood and arterial pressure. At the same time as the veins expand, the surrounding fibrous tissue proliferates, and the wall of the veins also thickens. This vascular change affects the entire iliac crest, and the internal iliac artery is depressed and the venous pressure is high. The vein is filled with arterial and venous blood flow, the color is brighter than the pure venous blood, the muscle circulation in the sputum is not smooth, the fibrosis is proliferated, the chronic inflammatory cells infiltrate, the extraocular muscles are thickened, the venous pressure of the aqueous humor is increased, and the scleral sinus is affected, causing expansion. The eyeball is in a state of high venous pressure and venous congestion. The intraocular pressure is increased and the retinal optic disc is damaged. Pathological depression, retinal edema and other glaucoma changes, venous exudate, accumulated in the choroidal cavity, causing ciliary body-choroidal detachment. Carotid cavernous fistula will cause peripheral arterial ischemia and peripheral venous congestion, resulting in a series of pathological changes.
Imaging examination is crucial in the diagnosis of assisted CCF. Typical clinical signs combined with one or more imaging findings can often make a correct clinical diagnosis. Ultrasound is indispensable in the diagnosis of adjuvant CCF. Standardized A/B Not only can you find SOV, IOV expansion, extraocular muscle thickening, but also accurate measurement of blood vessel diameter, the most important thing is to dynamically observe SOV (intraocular vein), IOV (under the eye vein) and pulse pulse in the same cycle, this is Direct evidence of arterial blood perfusion to the vein.
Ultrasound examination
A super shows a typical low reflection peak and obvious blood flow peak between the optic nerve and the superior rectus muscle, that is, there is a low blood flow pulsation in the dilated intraocular vein. If the peak pulse can cause the image above the peak to be unclear, other Shows extraocular muscle thickening, optic nerve thickening and other manifestations.
At present, it is commonly used in ophthalmology (10MHz) type B ultrasound. It is generally difficult to find normal supraorbital vein. The expansion of the supraorbital vein is a characteristic manifestation of this disease. The supraorbital vein is located between the superior rectus muscle and the optic nerve. The shape or tubular hypoechoic, the dilated intraocular vein extends from the supraorbital direction of the supraorbital sinus. Ultrasound finds that the venous dilatation of the eye is accompanied by a probe to compress the visible dilated blood vessels, and the compression of the ipsilateral carotid artery can make the pulsation disappear. The blood velocity and the size of the fistula in the supraorbital vein are slightly or moderately dilated. In severe cases, it can be expanded to more than 10 mm. In some cases, the dilated veins of the eyes can be displayed at the same time. Other ultrasounds have extraocular muscles and optic nerves. Coarse and rare choroidal detachment.
2. CDI color Doppler shows that the venous dilatation of the eye is in the arterial spectrum, showing a low-resistance arterial spectrum. According to hemodynamic measurement, high-flowing and low-flowing sputum can be identified, and color Doppler ultrasound can be measured. Out of the SOV, the blood flow parameters in the IOV are the systolic flow rate, the diastolic flow rate and the resistance index. The follow-up changes of these parameters are of great value for understanding the blood supply status and judging the prognosis, and are irreplaceable for any other imaging examination.
3.CT scan
CT examination can show thickened SOV and extraocular muscles. In a few cases, the cavernous sinus can be enlarged, the density is increased, and the display is more clear after strengthening. The advantage of the horizontal axis CT is to show the thickening of the SOV in the sputum and the whole process. Morphological changes; IOV tube diameter is thin, horizontal axis is not easy to display, and coronary CT can be found thickening of IOV, CT examination can also find whether with skull base, wall fracture, thus providing support for traumatic CCF diagnosis, but The CT signs of CCF have many similarities with painful ophthalmoplegia. The important point of identification is that the former has dilated veins and pulsation, and CT cannot be displayed dynamically. Therefore, experienced doctors can combine ultrasound and CT to make correct The clinical diagnosis, CT shows that the eyeball is prominent, the extraocular muscles are thick, the venous veins are thickened, and the enlarged cavernous sinus can be displayed at the same time. If the head trauma occurs, the affected eyelid fracture or skull fracture can be indicated.
4. MRI can not only show the morphological changes of CCF, but also the blood flow velocity is also a factor of imaging: MRI imaging has a flow phenomenon, the faster the blood flow velocity, the lower the signal, the expanded SOV is on the T1, T2 weighted image Low signal, longer duration, venous thrombosis, slower flow rate, medium to low signal, arterial blood intrusion in the cavernous sinus, T1, T2 weighted images all showed a low signal shadow of the enlarged cavernous sinus area. MRI can be used as an examination method for identification of other similar diseases. MRI is an important means of examining vascular lesions. CCF patients can see that the expanded cavernous sinus and the distorted SOV have a high signal. A single examination can confirm the diagnosis. In short, A variety of imaging examinations have been used in the discovery of SOV, morphological changes in the cavernous sinus, exclusion of intraorbital tumors, thyroid-associated eye diseases, etc. MRI can show that the expanded supraorbital vein communicates directly with the cavernous sinus.
5. DSA angiography is the most reliable method for diagnosing CCF, also known as "gold standard". Selective angiography can show the development of arterial cavernous sinus and supraorbital vein, determine the position and size of the fistula, and provide a basis for treatment. Suspected to be CCF and economic conditions permit, no obvious contraindications, should do DSA examination, in the CCF DSA examination, the positive rate of detection is 100%, the source and size of blood supply directly determines the choice of surgical plan and the timing of surgery, Direct internal blood supply to the internal carotid artery, severe clinical symptoms, ocular venous return obstruction, eventually secondary to glaucoma, loss of vision, intracranial arteries "stolen blood" is increasingly serious, abnormal drainage can induce neurological symptoms such as epilepsy, it should be treated early The direct internal blood supply of the internal carotid artery is promptly involved in embolization after clear diagnosis. The prognosis is good. The clinical manifestations of dural cavernous sinus are closely related to the number of blood supply arteries, blood flow and drainage, and the internal and external carotid arteries. Both are involved in the supply of cavernous sinus and dura mater, so DSA examination of these patients often presents multiple small arteries for blood supply, ipsilateral, contralateral or even Simultaneous blood supply to the side, the drainage direction of blood stasis is also an important purpose of DSA examination. Generally, patients have drainage of ocular veins, so ocular symptoms appear. The inferior sinus and intersulnar sinus are also important drainage pathways. Although the drainage of cortex and deep veins is A small number, but easy to induce nervous system symptoms, should be highly valued.
It should be pointed out that a small number of cases have complex blood supply arteries, many congenital vascular variability, and a long history. It is still quite difficult to fully understand the pathophysiological process. After the left head car accident, the left eye has lost vision, the left eye is prominent, and the upper eyelid is drooping. Eyeball fixation, conjunctival congestion and edema, with left tinnitus, posterior ocular bulging, tinnitus, conjunctival congestion and edema gradually subsided, similar symptoms appeared in the right eye after 3 months, DSA examination showed: left internal carotid artery blood directly into the cavernous sinus Through the interspontaneous sinus to the right cavernous sinus drainage, and drainage to the right eye vein, the left eye vein is not developed, analysis of the medical history, considering the pathogenesis may be: the early stage of the left internal carotid artery bloody into the cavernous sinus, inflow Left eye vein, causing the above symptoms of the left eye, posterior left venous thrombosis, blood stasis after the forward resistance increased, drainage through the intersponge sinus to the right side, causing the right cavernous sinus pressure to rise, blood stasis into the right Eye veins, right eye symptoms.
Diagnosis
Diagnosis and differentiation of carotid cavernous fistula
In addition to the disease, clinically caused diseases of the ocular veins have many lesions, but the degree of expansion is low, such as dural cavernous sinus fistula, thrombophlebitis, apical tumor, thyroid-related eye disease, inflammatory pseudotumor, Compared with the disease, the dural cavernous sinus fistula is only mild and the various manifestations are very similar. Other lesions have related ultrasound findings, such as intraorbital masses and extraocular muscle hypertrophy.
