What are the other types of cerebrovascular diseases?
Apart from ischemia and haemorrhages, there are three other types of cerebrovascular diseases. They include vascular malformations, hypertensive cerebrovascular disease and vasculitis. I’ll discuss vascular malformations here, and the others in the page Other C/V Diseases.
There are four different classifications of vascular malformations within the nervous system, and these classifications are based on the nature of the abnormal cells. These classifications include:
- AVM or arteriovenous malformations
- Cavernous angiomas
- Capillary telangiectasias
- Venous angiomas
AVMs tend to involve vessels within the subarachnoid space in the meninges as well as exclusively within the brain, and usually affects males between the ages of 10 and 30 years of age. It is twice as likely to affect men as it does women. It is the most dangerous type of vascular malformation due to the fact that AVMs often result in bleeding. AVMs often present with other symptoms such as seizures, haemorrhaging within the subarachnoid space or a intracerebral haemorrhage. These bleedings happen because the malformation results in the blood vessels becoming enlarged and having duplicated yet fragmented elastic lamina (as discussed in Brain Haemorrhage, this part of the blood vessel is responsible for it being flexible).
Cavernous haemangiomas often happen within the cerebellum, pons and regions below the cortex. A defining feature of cavernous haemangiomas is that they have large cavities or blood-filled spaces. They are often disfiguring and tend not to regress back into the body. Additionally, they can lead to ulcers (as discussed in Introduction to Acute Inflammation ) and haemorrhages.
Capillary telangiectasias are also known as spider veins, and they can occur anywhere in the body: in the brain they are most common within the pons. Unlike cavernous haemangiomas, capillary telangiectasias are surrounded by normal brain tissue.
Venous anginomas are more commonly known as varicose veins. They are basically collections of venous channels, and are mostly seen on the legs as shown on the picture alongside. Unlike normal veins, the valves separating sections of the vein do not close completely. Normal veins rely on these valves (as well as skeletal muscles) to hold blood in a certain section because they run against the pull of gravity. Because of the vein not being sealed, the blood can pool due to it leaking back in the previous section. They are unlikely to bleed or cause symptoms and in the brain, they are often seen as lesions.