In the previous post, we have discussed two most common reasons for intracerebral hemorrhages, namely hypertensive hemorrhages and amyloid angiopathy. 

In this post we will discuss less frequent reasons for intracerebral hemorrhage, such as AVMs, Cavernomas, venous angiomas and aneurysmal subarachnoid hemorrhage. 

 Intracerebral hemorrhages may also be caused by arteriovenous malformations of the brain. An arteriovenous malformation is an abnormal clump of vessels connecting arteries to veins directly. During our development, those connections are present in the brain, but they are typically replaced by separating arteries from veins with capillaries. This works as a buffer for high-pressure in the arterial structure compared to the venous structure. In arteriovenous malformations, the transfer of high-pressure in the arterial system to the venous system is direct. Veins are much thinner and cannot tolerate as much blood pressure which makes them prone to rupture.

Arteriovenous malformations may be present either with seizures or with severe headaches related to an intracerebral hemorrhage.

 
They may vary in size significantly from very small to extremely large. The treatment is commonly endovascular or open neurosurgery. Treatment options are dependent on the location of the malformation.

Another type of vascular malformation of the brain is called cavernous angioma or cavernoma. This is an abnormal clump of capillary vessels. They are typically very small but they may be found in multiple areas. About 5% of are familial. The bleeding related to cavernous angiomas is typically not severe but may be significantly symptomatic depending on the location of the angioma, especially if they are located in the brainstem. 

There are typically multiple episodes of bleeding, which causes cavernoma to grow in size.  Typically, cavernomas do not require surgical intervention. Surgical intervention is typically undertaken when cavernoma is very superficial or large in size.  However, they do tend to cause recurrent bleeding and symptoms. I use specific medication to prevent those recurrent bleedings.

A third type of vascular malformation is called venous angioma. These types of lesions are commonly asymptomatic and found by accident on an MRI. They rarely bleed and are typically considered to be benign.

The final type of bleeding in the brain is called a subarachnoid hemorrhage (SAH). These are typically related to a ruptured intracranial aneurysm. The most common cause of subarachnoid hemorrhages is related to trauma, but in patients who did not have trauma, cerebral aneurysms are more commonly seen. Patients typically will say they are having the worst headache of their life and they felt like somebody hit them in the head with a brick. This is an extremely dangerous type of bleeding in that it can be potentially fatal. 

Cerebral aneurysms are located deep on the major vessels inside of the brain and are related to inherent weakness in the vessel wall. They look like little balloons protruding from the vessel. They are thinner, weaker and more prone to rupture. The known causes of growth and rupture of those aneurysms are high blood pressure and smoking. Commonly, those aneurysms are discovered by accident during routine MRIs or MRAs. The size of the aneurysm may vary from less than 1 mm to over 2 cm.

Treatment of SAH typically required intensive care, very tight control of blood pressure, closure of the aneurysm and control in the intracranial pressure. 
 
Treatment of the aneurysms is typically endovascular. Sometimes, patients do require an open skull surgery by neurosurgeons. Previous studies showed that aneurysms less than 7 mm in size have a much smaller chance of rupture. In my experience, aneurysms with a size of 3-5 mm can also rupture, thus I typically recommend treatment with aneurysms which reach that size. Close monitoring is recommended for smaller aneurysms

Multiple aneurysm may be genetic and may occur in the families. It is strongly recommended that all first degree relatives are screened for aneurysms with MRA if the patient has multiple aneurysms. 

Good additional resources on SAH prepared by Mayo Clinic