Introduction to Brain AVMs
- Brain (cerebral) vascular malformations (VMs), are abnormal vessels with direct artery to vein connections in the brain.
- At least 10% of people with HHT (Hereditary Haemorrhagic Telangiectasia) have VMs in the brain (cerebral) blood vessels.
- They are generally thought to arise during embryonic or foetal development.
- Without treatment, brain VMs are a common cause of haemorrhagic stroke (bleeding in the brain) in HHT families. People are often unaware that they have brain VMs until they develop a life-threatening complication, such as stroke or seizure.
- With the right screening and treatment, these life-threatening complications can be prevented, however, there is no single ‘standard treatment’ that can be recommended for all brain VMs in HHT at the current time
Magnetic Resonance Imaging (MRI): The recommended test for identifying brain VMs. This test utilises strong magnetic fields to form images of the body. No radiation is used during this study. An IV will need to be started for contrast (dye) to be given. The scanner resembles a large tube and the patient is required to lie still during the actual MRI scanning. If the patient has claustrophobia, the doctor may prescribe an oral medication to take prior to the MRI. This typically requires sedation or anaesthesia in young children. Brain (cerebral) angiogram: May be recommended if a brain VM is identified on MRI. It is a minimally invasive procedure performed by a neuro-interventional radiologist in an angiography suite. The patient is given sedation or general anaesthesia for this procedure. A catheter (a small tube) is inserted into an artery in the top of the thigh and directed through the blood vessels in the body to arteries in the neck or the brain. After the procedure, the patient is observed for several hours or overnight before being discharged home. Screening should be performed at the time of initial clinical evaluation for HHT. Patients with brain VMs should be referred to a centre with neuro-vascular expertise to be considered for further testing and individualised management.
Brain (cerebral) embolization: A procedure performed to block the blood flow to the abnormal vessels. The patient is given sedation or general anesthesia for this procedure. In an angiography suite, a catheter (a small tube) is inserted into an artery in the top of the thigh and directed through the blood vessels in the body to arteries in the brain. An agent is then inserted to block off blood flow into the VM and lessen the risk of stroke. After the procedure, the patient is observed overnight before being discharged home. Surgical Removal: A surgical procedure to place a clip on the VM or to remove the VM. This procedure is fully curative, but has a higher complication rate than embolisation. Stereotactic Radio-surgery (Gamma Knife): A type of focused radiation that destroys the AVM tissue. This is often done after embolisation to ensure that the VM is cured. Oftentimes, treatment requires a combination of the above procedures. Treatment should be performed by a clinician with neuro-vascular expertise.
- Brain haemorrhage
Signs & Symptoms
- PERSISTENT HEADACHES
- NUMBNESS IN THE BODY
- VISION CHANGES
- SPEECH PROBLEMS
Facts to Remember
- At least 10% of people with HHT have brain VMs.
- Brain VMs can be life-threatening or disabling if they bleed.
- Since brain VMs often do not cause warning symptoms prior to bleeding, screening is recommended in all people with HHT, even infants.
- Brain VMs can be successfully treated in most cases