Definition and causes of Arterial malformations

Arterial malformations are malformations of the brain's blood vessels with abnormal connections between the arterial vessels (arteries which carry oxygenated blood) and the venous blood veins (veins, carrying un-oxygenated blood) in the brain. The most common deformity is that blood vessels form a dense network of small very thin walled tubes. The malformations are usually congenital and may vary greatly in size and design and occur more frequently in males than females.

Malformation of the brain's blood vessels gives symptoms either because blood cannot flow through the blood vessels, or because the blood runs the wrong way through the blood vessels starving some vessels from blood. Both situations result in part of the brain not getting enough oxygen and nutrients. The malformed veins are also more fragile than normal blood vessels with great risk that they might burst and cause bleeding into the brain tissue (see Stroke)

Symptoms of malformations of the brain's blood vessels

The symptoms usually occur in childhood or adolescence and may be as follows:

• Stroke as either a blood clot in the brain or brain haemorrhage occurs in around 50% of cases.
• Epilepsy.
• Headache resembling migraine
• Sensory disturbance or paralysis occurring as attacks lasting minutes or hours or as a slow gradual progression

Precautions and diagnosis

If you experience any of the above symptoms seek immediate medical attention and until examined by a doctor remain at rest. The medical examination and diagnosis typically involve a CT or MRI scanning performed with injection of contrast fluid into the veins. The scanning images will usually very clearly show the extent and location of any malformation.

Malformed blood vessels in the brain carry a high risk of brain haemorrhage and oxygen starvation in the brain which are very serious conditions calling for the removal of the malformed blood vessels. This can be done in the following ways:

• Operation: The deformed vessels are removed but this is not without risk to the surrounding brain tissue.
• Embolization: The procedure is carried out to cut off the blood supply to the malformed blood vessel and stop uncontrolled bleeding.
• Radiation: The malformed blood vessels are targeted very accurately and destroyed.

The choice of treatment depends on size, location and type of malformation and also depends on the ability of other blood vessels to take over in the affected area. Often a combination of the different methods is used.

Outlook

Many never experience any symptoms and therefore never realize that there is something wrong and that they are at risk as the deformities often give no symptoms before a sudden emergence of heamorrhage or a blood clot in the brain. This is a very serious condition where fast medical assistance is essential with many cases ending fatally or with lasting serious disabilities as the result.

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