This pathology is widely known due to its origin in the central nervous system, but it can form anywhere in the body. Genetic predisposition to AVM and the facts of its transmission by inheritance are unknown. It is believed that this is not a hereditary disease.
Arteriovenous malformation is a vascular pathology - abnormal development of the vessels of the nervous system. To be more precise, we are talking about a congenital anomaly of the vascular structure of the brain or spinal cord. The term "malformation" itself, translated from Latin, means "poor formation", that is, any deviation from he althy physical development with a gross change in the structure and functions of an organ or tissue is implied. Such a defect may be congenital or acquired as a result of injury or disease. A similar deviation develops on the skin, in the lungs, kidneys, but most often occursprecisely in the nervous system.
What is the essence of the disease?
This deviation is more common in the brain, in the posterior regions of the hemispheres, the thoracic or cervical spine is often affected. In the spinal cord, an anomaly also occurs, but this happens rarely. Arteriovenous malformation varies from one centimeter to a very large size in the cranial cavity.
The resulting defect usually looks like a tangle of thin, thinned and tortuous vessels, in which arteries meet veins directly, which occurs without the participation of capillaries. Thus, arterial blood does not enrich tissues and organs in any way.
This disease is chronic and occurs mainly in men at a young age. In one family, such a pathology sometimes manifests itself in several members at once, but it is not considered hereditary. For the first time, pathology manifests itself at the age of ten to thirty years, and its peak occurs at twenty years. Violation of vascular formation occurs in the second month of fetal development, and the exact causes of such an anomaly have not been established. The incidence of the disease in the world is one person per hundred thousand of the population.
Development mechanism
Normally, oxygenated blood flows from the heart to various tissues and organs. At first, it passes through the arteries. Then the artery passes into the arteriole, through which the blood already enters the capillaries. Here is the capillary bed, in which cell exchange takes place. Cells take oxygen from arterieswaste products with carbon dioxide. Then the blood flows further through the veins, from there rising again to the heart.
In the presence of arteriovenous malformation, blood from the arteries enters the veins through a tube called a fistula, and hypoxia develops directly in the tissues against this background. Increased pressure builds up in the veins that carry blood.
With the passage of time, the fistulas can gradually expand and increase, and the arterial walls thicken. If the malformation is very developed, then the blood flow in it is strong, and at the same time, cardiac output also increases. In such cases, the arteries and veins look like giant pulsating vessels. They are not able to withstand such pressure, because they are not adapted for this, therefore they stretch and often break. A similar state of blood vessels can be observed in any part of the body. In the event that the malformation touched only the veins, then they speak of the presence of venous angioma.
Varieties
The following varieties are distinguished by structure:
- Malformation, in which there are no veins in the ball of blood vessels, there are only arteries.
- A fistulous type of arteriovenous malformation may occur in the dura mater.
- Racemose branched malformation occurs in seventy-five percent of cases.
- Cavernous malformation occurs in eleven percent of cases. It contains only small capillaries, and the arteries and veins are completely absent here, while the pressure is not disturbed. The subspecies in this case is telangiectasia.
Distinguish by size:
- Micromalformation is considered the smallest in size.
- Minor malformations that are less than one centimeter.
- Small malformations, whose size is from one to two centimeters.
- Up to four centimeters are medium malformations. The risk of rupture is quite high.
- Up to six centimeters are large malformations that are very dangerous.
- More than six centimeters are already gigantic, while they break less often, but it is difficult to cure them.
Arteriovenous malformation is subdivided according to the nature of drainage and its localization. It can be located in the cerebral cortex, that is, directly on its surface. In this regard, they are also called cortical. Other forms are internal malformations, which are often localized in the brain stem or hypothalamus. An arteriovenous fistula may be located inside the dura mater.
Symptomatic manifestation of brain malformation
Arteriovenous malformation of cerebral vessels, also called cerebral, is accompanied by the following main symptoms:
- The appearance of cephalalgia of varying intensity, without any characteristics of regularity and duration. In this case, the pain does not coincide with the localization of the malformation, and its intensity is different.
- Presence of convulsions. In this case, general or partial convulsions are observed in various parts of the body. Loss of consciousness is not observed.
- Appearancedizziness and fainting.
- Development of muscle weakness along with limb paresis.
- In the event that the cerebellum is affected, gait is disturbed. Staggering and lack of coordination are observed.
- There may be loss of vision in the frontal lobes.
- The appearance of dysarthria.
Symptomatics of arteriovenous malformation of the right parietal lobe may not appear for a very long time and sometimes it is accidentally detected during examinations.
Neuralgic symptoms
During the growth of the malformation, when pressure on the brain begins, neurological symptoms occur. The following manifestations may be present:
- Intracranial pressure increases, there are persistent pains in the head of a pressing or pulsating nature.
- The appearance of apathy, lethargy, decreased performance.
- Impaired coordination of movements.
- Intelligence reduction.
- The appearance of speech disorders in the form of motor aphasia.
- Innervation failure of certain areas of the body.
- Wobbling gait with sudden falls on the back.
- Appearance of seizures and muscle hypotension.
- Paresis of limbs.
- Vision problems in the form of strabismus or blindness.
Against the background of the gradual development of arteriovenous malformation of cerebral vessels, neurological symptoms can increase sequentially. After reaching middle age, the disease becomes stable, and new disorders no longer occur. Women may feel worse andnew symptoms occur in the event of pregnancy. Hemorrhagic stroke in pregnant women is caused by this disease in twenty-three percent of cases.
Arteriovenous malformation of the spinal cord
In this case, the symptoms will be as follows:
- Problems with sensation in the limbs, for example, pain or touch may not be felt.
- The onset of intense pain.
- The appearance of a sudden progressive paralysis of the lower extremities. Arteriovenous malformation is a very serious disease.
- Appearance of tingling in the limbs.
- Failure of sphincter activity and urodynamics, when it is impossible to control defecation or urination.
Most people recover almost completely from their first attack, but there is a risk of recurring symptoms. In the absence of treatment, over time, the patient may become helpless and will be completely dependent on their loved ones.
Symptoms of vascular rupture
Rupture of blood vessels against the background of malformation is possible in every second patient. Increased workload, stress and alcohol consumption play a significant role in this. Hemorrhage occurs suddenly. Often it is subarachnoid in nature. The symptoms are similar to those of a stroke. The patient complains of a severe headache, from which he may even lose consciousness. Without visible prerequisites, vomiting occurs, and after cleansing the stomach, no relief appears. There is a fainting state. There is irritation with pain in the eyes, whichcaused due to bright light, vision is impaired, complete blindness develops, speech disorders are noted.
Seizures along with hearing loss are not ruled out. Visual disturbances may occur, paralysis of the limbs develops. When hematomas appear, meningeal syndrome is often diagnosed, while the pressure is increased. The next day the temperature rises. With proper treatment, after five days, he alth improves. After a hemorrhage in the first year, the risk of recurrence remains. Moreover, in the event that treatment is not carried out, the risk increases three times.
Diagnostics
Sick people most often seek help after a hemorrhage. The doctor conducts a detailed examination of the patient, finds out the presence of injuries and diseases, determines the neurological status. Then a CT and MRI scan and an angiogram are scheduled.
These methods for diagnosing AVMs allow for a layer-by-layer study of the brain structure, while determining the presence of a malformation with its size, and assessing the general state of the brain. With computed tomography, thanks to x-rays, it is possible to determine the anomaly inside the parenchyma. When performing CT angiography, the arteries of the brain are even more detailed. Computed tomography is the fastest method, but not the most effective, it is more like detecting hemorrhage.
MRI for arteriovenous malformation is more informative. Thanks to it, this disease is easily detected and the severity of the patient's condition is determined. Highlya cerebral angiogram accurately assesses the patient's condition, but this is a rather expensive examination. As part of its conduction, a catheter is inserted into the peripheral artery, which advances to the vessels of the brain. After that, pictures of the vessels are taken. Although there is a risk of complications after this manipulation, but only this method allows you to accurately determine the causes of the hemorrhage.
Electroencephalography determines the foci of excitation, finding the zone of its localization. When performing Doppler ultrasound, doctors determine the speed of blood flow and consider the spatial position of the vessels in the affected area. Angiography is also performed. But this procedure takes a long time, and it is done under anesthesia. Angiography is indispensable if it is necessary to determine the increase in venous pressure, it is very important in the choice of surgical treatment of arteriovenous malformation (ICD Q28.2.).
Treatment
There are three options when choosing a treatment method. We are talking about the method of surgical operation, embolization of arteriovenous malformations and radiosurgical treatment. It is important to determine the degree of risk of the operation and assess the possible consequences. The main goal of any technique in this case is to achieve absolute obliteration in order to avoid further possible hemorrhage into the cranial cavity.
Surgical treatment
As part of this method, a complete removal of a malformation is carried out with its volumes up to 100 milliliters. The surgical technique involves opening the skull infor the detection of malformations. In addition, its subsequent cauterization with a laser or with the help of other tools is carried out. The cauterized area is completely removed from the tissues. If the operation is successful, the patient recovers completely. But complications are still possible in the form of strokes.
After the operation, a full rehabilitation course is carried out for one week. After the patient is discharged, he is recommended treatment with nootropics and angioprotectors. As part of the prevention, it is necessary to periodically be examined by a vascular surgeon and a neuropathologist, and you also need to undergo magnetic resonance imaging.
Embolization, or Endovascular Surgery
Endovascular surgery involves the removal of a malformation from the general circulation by gluing blood vessels. Against this background, complete gluing of the vessels is feasible in thirty percent of patients, in other patients it turns out to be partial. This technique is very often used, and it effectively prevents hemorrhages. The embolization technique in endovascular surgery involves the supply of a special adhesive element through the catheter.
Carrying out radiosurgical treatment
When using this method, obliteration of a malformation is possible if its size is less than three centimeters. Eighty-five percent of patients recover after such an operation for arteriovenous malformation. This method is used when the localization of the malformation is not available for performing a classical operation. As part of this techniquethe radiation is focused, which is directed to the place of the anomaly, such a procedure lasts exactly an hour. Further, the vessels are independently sclerosed within two years and are replaced by connective tissue. The disadvantage of this technique is that before the development of sclerosis, hemorrhage in this area is possible.
Currently, various types of operations are being actively combined. This allows you to expand the possibilities of radical approaches, reducing the percentage of complications.
Treatment of arteriovenous malformation of the spinal cord is carried out with the help of surgical intervention. It is also possible to use the interventional method. The latter method is less invasive. It involves the introduction of a special adhesive element, which immediately hardens, clogging the vessel. When using this method, there is a risk of damage to he althy vessels. In this regard, the introduction of the substance is carried out as close as possible to the anomaly.
Sometimes, special microcoils are introduced, which are adjacent to the abnormal vessels and block the access of blood to them. In addition, detachable coils subsequently aid in the development of collaterals. The blockade of blood vessels is carried out with a substance that resembles sand particles. But such particles can lead to new recanalization. In this regard, for the purpose of prevention, angiography should be performed annually. In the event that a malformation has been discovered, embolization is done again. It is usually carried out under anesthesia, and the duration of the procedure is from three to six hours. In the event that the patient after the procedure has a smallsoreness in the incision area, analgesics are prescribed.
Carrying out preventive measures
Arteriovenous malformation of vessels is the result of abnormal and disturbed embryogenesis. In this regard, prevention should be reduced solely to the prevention of ruptures, which are provoked by a number of factors in the form of heavy physical exertion, stress, smoking, alcohol intake, high blood pressure, etc. Those people who have already undergone surgery should regularly undergo magnetic resonance imaging.
