ناهنجاری شریانی وریدی (AVM) , (arteriovenous malformation ) یک در هم پیچیدگی غیرطبیعی عروق خونی در مغز یا ستون فقرات است که می‌تواند درهر جای بدن رخ دهد AVM .های مغز به علت آسیب‌هایی که هنگام خونریزی ایجاد می‌کنند نگران کننده هستند. برخی از ناهنجاری‌های شریانی وریدی علائم خاصی ندارند و برای زندگی یا سلامتی فرد خطرناک نیستند، در حالیکه دیگر انواع آن هنگام خونریزی، اثرات شدید و ویرانگر دارند. گزینه‌های درمان بسته به نوع، علائم و محل ناهنجاری شریانی وریدی، جراحی بصورت محافظه کارانه انجام می‌گیرد.

ناهنجاری‌های شریانی وریدی نسبتا نادر هستند و در کمتر از 1درصد کل جمعیت اتفاق می‌افتند، بیشتر در مردان دیده می‌شوند و اغلب بین 10 تا 40 سالگی علائم خود را نشان می‌دهند. AVMها هر ساله حدود 2درصد از تمام خونریزی‌ها و سکته‌های مغزی که اتفاق می‌افتند را تشکیل می‌دهند. اکثر ناهنجاری‌های شریانی وریدی رشد یا تغییر زیادی نمی‌کنند، اگر چه عروق درگیر ممکن است گسترش یابند. به علت لخته شدن خون در بخشی از همین ناهنجاری‌ها ممکن است گسترش آن‌ها کاهش یابد. بعضی‌ها ممکن است بزرگتر شوند تا خون را از عروق مجاور به سمت ناهنجاری‌های شریانی هدایت کنند.

به طور معمول شریان‌های بزرگ (سرخرگ‌ها) خون را از قلب به تمام قسمت‌های بدن منتقل می‌کنند. شاخه‌های شریانی کوچکتر و کوچکتر می‌شوند تا به مویرگ تبدیل شوند که تنها یک سلول را تشکیل می‌دهند. بستر مویرگ جایی است که خون مبادله اکسیژن و مواد مغذی با بافت‌های بدن انجام داده و مواد زائد را جمع آوری می‌کند. بازگشت خون مویرگ ها به سمت قلب از طریق سیاهرگ ها انجام می‌گیرد. در ناهنجاری شریانی وریدی، شریان‌ها به طور مستقیم با ورید‌ها و بدون هیچ مویرگی به یکدیگر متصل می‌شوند. این باعث ایجاد مشکل شانت یا فیستول فشار بالا می‌شود. سیاهرگ‌ها قادر به کنترل فشار خون بالا که به طور مستقیم از سرخرگ‌ها می‌آیند، نمی‌باشند. سیاهرگ‌ها با پذیرش میزان خون اضافی کشیده و بزرگتر می‌شوند. رگ‌های خونی ضعیف شده پاره شده و خونریزی پیدا می‌کنند و احتمال ایجاد آنوریسم افزایش پیدا می‌کند. The surrounding normal tissues may be damaged and the AVM takes blood from those parts. AVM (AVM): The most common cerebrovascular malformation that involves an abnormal occlusion between an artery and a vein without any brain tissue between them. Cavernoma: An abnormally enlarged branch of a capillary while the arterial and venous supplies are significantly absent. Blood pressure is low. Venous malformations: Abnormal branches of enlarged veins without feeding arteries; With low pressure, bleeding rarely occurs and is usually not treated. Telangiectasia or dilated capillaries: Abnormally enlarged capillaries (similar to cavernoma), very low pressure, bleeding rarely occurs and is usually not treated. One or more arteries and veins become a duct. Cerebral veins enter the venous sinuses that are located in the blood-filled areas of the dura before leaving the skull and entering the heart. Dura mater fistulae and carotid cavernous fistula (CCF) are the most common.

Arteriovenous malformations can occur anywhere there are arteries and veins. Cerebral EVM diseases can occur on the surface or in the cerebral cortex, deep in the thalamus, basal ganglia, brain stem, and in the dura mater (hard protective covering of the brain). Spinal arteriovenous abnormalities can occur on the surface (extraspinal) or inside the spinal cord (intraspinal), which are divided into 4 types. They are:

• Type 1, which is more common, is called a dural arteriovenous fistula, which usually has an arterial blood supply, and venous hypertension seems to cause symptoms in this type.
• Type 2, also called glomus, is intraspinal and involves a tangled area on part of the spinal cord.
• Type 3, which is also called the young type, is an AVM with non-vessels. It spreads naturally inside and outside the medulla.
• Type 4 arterial fistulas in the dura mater that is placed on the spinal cord.

The cause of this disease is not known. It seems that cerebral vascular malformation is due to the abnormal expansion of blood vessels in the womb or from the time of birth. EVM is not cancer and does not spread to other parts of the body. Cerebral vascular malformation related to dura mater is a disorder in adults that can occur after an injury or trauma.

Symptoms

Symptoms of brain arteriovenous abnormalities vary depending on their type and location. While migraines are common symptoms like headaches and seizures, most of these disorders are asymptomatic (asymptomatic) until bleeding occurs. Common symptoms of arteriovenous malformations of the brain include:

• Sudden attacks of severe headache, vomiting, neck stiffness (described as the worst headaches of a lifetime.)
• Seizures
• Migraine like headaches
• Tinnitus: an abnormal ringing or hissing sound caused by high blood pressure of the VM.

Common symptoms of spinal cord VM include: From:

• Back painSevere and sudden
• Weakness in legs and arms
• Paralysis

Injuries caused by arteriovenous malformation of the brain or spine can be done in three ways:

• Arteriovenous malformation can be separated and ruptured and brain bleeding can occur. It can be intracerebral hemorrhage (ICH) or bleeding into the space between the brain and skull, called subarachnoid hemorrhage (SAH). Small arteriovenous malformations (less than 3 cm) are more likely to rupture than larger malformations. Bleeding can cause a stroke (link to stroke).
• Arteriovenous malformations can enlarge and put pressure on the brain, leading to seizures and hydrocephalus, which is common with larger malformations.
• Malfunctions can reduce the amount of oxygen delivered to surrounding tissues. Because the blood flow is directly from the artery to the vein, the cells that normally receive oxygen from the capillaries are destroyed. Death due to primary bleeding is between 10 and 30%. Patients often want to consider their lifetime risk of bleeding if they are at risk and have surgery. You can calculate the risk probability using the following formula:

  Lifetime risk probability(%) = 105 - patient age

  For example, a 25-year-old man has a risk of bleeding at least once in his lifetime. Many factors affect this percentage, including where in the body the arteriovenous malformation occurs and what type of malformation it is. It is best to talk to your doctor about your personal risk.

  Bleeding risk

  The risk of recurrent intracranial bleeding is higher shortly after the first bleeding. In two studies, the risk was 6% in the first year after the initial bleeding, and the percentage decreased thereafter. And in another study, the risk of rebleeding during the first year was 17.9 percent. The risk of rebleeding may be even higher in the first year after a second bleed, with a reported rate of 25%. People who are 11 to 35 years old and have AVM malformation are more at risk of bleeding.

  Bleeding and pregnancy

  The risk of bleeding due to arteriovenous malformation during pregnancy usually increases after the first three months of pregnancy. This bleeding does not only occur during labor. It is believed that this happens due to increased blood circulation during pregnancy. Although not all AVMs bleed during pregnancy, it is recommended to delay pregnancy until the AVM has completely healed.

  Diagnosis

  

  It is possible that you or a loved one has been taken to the emergency room for a ruptured aneurysm or is undergoing treatment for a ruptured aneurysm. Checks family history and also performs physical examination. Diagnostic tests are used to help determine the location, size, type, and whether or not other parts are involved in the abnormality.

  CT scan

  Computed tomography (CT) scan A scan using X-rays and non-invasive (without entering a body cavity or penetrating the skin) to view anatomical structures inside the brain to detect blood in or around the brain. A newer technology called CT angiography involves injecting contrast into the bloodstream to view the arteries of the brain. This type of test provides the best images of blood vessels through angiography and body tissues through CT.

  Magnetic resonance imaging (MRI) is a non-invasive test that uses a magnetic field and radio waves to see brain tissues in detail. An MRI is a non-invasive study, with a contrast dye injected through an IV to make the blood vessels appear brighter.

  Angiography is an invasive procedure, in which a thin tube called a catheter is inserted into an artery and passed through the blood vessels to the brain. Once the catheter is inserted into the artery, contrast dye is injected into the bloodstream and X-ray images are taken.

  Treatment

  Surgery, endovascular, and radiosurgery can be used alone or in combination to treat AV. Endovascular embolization is often performed before surgery to reduce the size of the AVM and reduce the risk of surgical bleeding. Radiosurgery or embolization may be used after surgery to treat residual AVMs. A neurosurgeon will discuss all treatment options with you and prescribe the best treatment for you.

  Patient follow-up

  If there is no pre-existing bleeding, the doctor may decide to monitor the patient, and may prescribe the use of anticoagulants to prevent seizures and medication to lower blood pressure. If there are no symptoms, or the arteriovenous abnormality is in an area of ​​the brain that cannot be easily treated, conservative medical treatment may be indicated. If possible, a person with EVM should avoid activities that may raise blood pressure, including lifting heavy objects or straining themselves while doing tasks, and avoid blood thinners such as warfarin. A person with EVM should be regularly checked by a neurologist or neurosurgeon. Embolization is an invasive procedure that uses small catheters to enter blood vessels to transfer glue or other barrier materials to the EVM so that blood does not flow through the abnormality. This procedure is performed in the angiography suite of the radiology department. A small incision is made in the groin and the catheter is inserted into an artery and then passed through the blood vessels to the feeding arteries of the AVM. Blocking material, either tangles or acrylic glue, is delivered through the catheter to the EVM. The time to perform this procedure can be different and the patient will be observed in the hospital for several days. The advantage of this treatment method is that it is less invasive than surgery and can be used for deep or non-surgical treatments. Disadvantages of this method include the risk of cerebral embolism due to failure to remove the AVM with the catheter and stop bleeding, which may require multiple treatments.

  Surgery

  

  With the use of general anesthesia, the operation of opening the skull, which is known as the head bowl operation, is performed. The brain shrinks slowly, which may be due to an arteriovenous malformation. Using different methods such as laser and electrocautery, the AVM is reduced and separated from the normal brain tissue. The duration of hospitalization varies between 5 and 7 days with some rehabilitation. The type of surgery to remove the skull depends on the size and location of the AVM. The choice of surgery for EVM treatment also depends on the general health of the patient. The advantage of using surgery is that if the entire EVM is removed, the length of the treatment period is fast. Disadvantages when the AVM is destroyed include the risk of bleeding, damage to adjacent brain tissue, and stroke elsewhere in the brain.

  

  Radiotherapy

  The aim of radiotherapy is to radiate radiation to abnormal vessels. This method takes several hours of preparation and one hour of irradiation. The patient can go home the same day, and after 6 months to 2 years, the vessels are gradually closed and the wounded tissue heals. The advantage of this treatment is that it is painless. The disadvantages of this method are that it works better with smaller AVMs and may take a long time to work (there is a risk of bleeding during this long time). Recently, in a long and extensive study, 90% of patients had their AVM disappear 5 years after radiotherapy, and 4% of patients had recurrent bleeding during the waiting period. panel-widget-for-3447-0-1">

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