CNS Vascular Malformations

1 What are Central Nervous System Vascular Malformations?

Central nervous system vascular malformation is a rare disease which occurs due to abnormally arranged blood vessels in your brain or spinal cord and their membranes.

It is characterized by a wide range of neurological signs and symptoms that include

The different types of central nervous system vascular malformations are:

Arteriovenous malformations (AVMs)

It is characterized by abnormally connected arteries and veins, and “missing” capillaries.

Capillary telangiectasias

Capillary telangiectasias are enlarged capillaries in brain.

Cavernous malformations

Cavernous malformations are marked by formation of clusters of blood vessels in your brain or spinal cord that look like a mulberry.

Dural arteriovenous fistulas

Dural arteriovenous fistulas occur when arteries in the covering of brain or spinal cord called the dura, are abnormally connected to the veins that drain blood.

Spinal arteriovenous malformations

A spinal arteriovenous malformation is characterized by entangled blood vessels in your spinal cord.

Venous malformations

In venous malformations, the veins in your brain or spinal cord are abnormally large.

2 Symptoms

Symptoms of Central nervous system vascular malformations vary among different people. In some cases, they can be fatal.

Headaches

Headaches, as painful as migraine, can occur with varying intensity, duration, frequency among people. Either one side or both sides can be affected.

Seizures

Seizures can be confined to a particular part of brain (focal) or spread throughout the brain (widespread). Seizures are characterized by

  • loss of movement control,
  • changes in level of consciousness.

Neurological symptoms of AVMs can vary among people and depend on the location of the AVM.

The signs and symptoms include:

  • Lack of muscle strength or paralysis in one part of the body
  • Poor movement coordination (ataxia) causing an abnormal gait
  • Inability to make appropriate movements (apraxia)
  • Lower back pain (due to spinal AVM)
  • Lightheadedness
  • Vision problems such as loss of part of the visual field, uncontrolled eye movement, or inflammation of a segment of the optic nerve
  • Problem speaking, listening, reading, and writing (aphasia)
  • Numbness, tingling, or spontaneous pain
  • Memory problems
  • Confusion, hallucinations, or dementia

Find here some features of the signs and symptoms of Central Nervous System Vascular Malformations

  • The signs and symptoms may not be evident until 20’s or later. Once they appear, they start deteriorating as the time passes by.
  • The initial signs include slight difficulty in learning or behavioral disorders in some children or adolescents.
  • If you do not experience any symptoms of AVMs till 40’s or early 50’s, you are less likely to experience them later even though you carry the condition.
  • Pregnancy associated cardiovascular changes like increased blood volume and pressure may cause the symptoms to appear suddenly or worsen them.
  • Vein of Galen is an atypical symptom of severe AVMs in which abnormally connected arteries and veins are found in the deep regions of brain. It causes hydrocephalus (fluid buildup in certain spaces of the brain resulting in enlarged head), inflamed veins on the scalp, seizures, failure to thrive, and congestive heart failure. Children with this condition often have physical and mental disabilities.
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3 Causes

The exact cause of vascular malformation of the central nervous system is unknown. Malformation is believed to occur during fetal development.

In few cases, genetic mutation is the probable cause. Some types of vascular malformations are hereditary.

Few studies suggest acquired brain injury can also cause this condition. The formation and growth of blood vessels in fetus are controlled by endogenous chemicals called angiogenic factors.

Abnormal angiogenic factors may cause malformation of blood vessels. But it’s not clear what causes such structural changes in angiogenic factors. Mutation in chromosome 7 is found to cause a type of cavernous malformation with multiple lesion. This genetic mutation is more common in Hispanic Americans living in the Southwest.

Some other hereditary central nervous system vascular defects include

4 Making a Diagnosis

A distinct sign for making a diagnosis of Central nervous system vascular malformations is a bruit. Bruit is an abnormal sound caused by turbulent blood flow in blood vessels of an AVM.

Severe bruit is easily heard by individuals. Severe bruit can cause

  • reduced hearing ability,
  • sleep disturbance,
  • psychological distress.

Other different tests to diagnose AVMs are:

Cerebral angiography (cerebral arteriography)

In cerebral angiography, a contrast agent (dye) is injected into artery so that the structure of blood vessels can be seen on X-rays.

CT scans (computed axial tomography)

They utilize numerous X-rays to create cross-sectional image of the head, brain, or spinal cord and can detect hemorrhage.

MRI (magnetic resonance imaging)

It utilizes strong magnetic fields and radio waves to produce detailed images which can reveal even slight alteration of neurological tissues.

Magnetic resonance angiography (MRA)

It is used to record the pattern and flow rate of blood through vascular lesions as well as the flow of cerebrospinal fluid throughout the brain and spinal cord.

Transcranial Doppler ultrasound

It uses high frequency sound waves to determine the blood flow through the brain. It can be helpful in diagnosing medium-size to large AVMS as well as identify the presence and extent of hemorrhage.

5 Treatment

Treatment options for Central nervous system vascular malformations and other vascular lesions include surgery or focused radiation therapy.

Some medications can provide relief from symptoms, such as:

It is wise to evaluate the risk before starting any treatment for AVMs. Untreated AVM can cause hemorrhages that may lead to neurological deficits or death.

So surgery is recommended if the risk of hemorrhage and resultant neurological damage is high. Unfortunately, surgery is complex and can cause serious complications or death.

An AVM grading system can help your doctors assess the risk of surgery based on the size of the AVM, position in the brain and involvement of neighboring tissues, and any leakage. The surgical options for AVMs include

  • conventional surgery,
  • endovascular embolization,
  • radiosurgery.

The choice of the option depends largely on the size and location of an AVM. Endovascular embolization and radiosurgery are relatively safer for deep seated AVMs.

Conventional surgery

For smaller or superficial AVMs, surgery can remove the middle part of the AVM, including the fistula without damaging neighboring neurological structures. This option is not recommended for deep seated AVMs.

Endovascular embolization

A tiny flexible tube (catheter) is inserted into artery and guided to the AVM. As the catheter reaches the area of malformations, fast-drying glue-like substances, fibered titanium coils, and tiny balloon, is released into the area through the tube. This creates an artificial blood clot in middle of AVM which seals off the malformed blood vessel. It is used prior to surgery or radiosurgery to reduce the amount of blood flow through AVM.

Radiosurgery

It is a noninvasive approach used to treat small unruptured AVMs. A beam of radiation is focused on your AVM to damage the walls of the blood vessels. The blood vessels then slowly degenerate and ultimately close.

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