HHT (Hereditary Hemorrhagic Telangiectasia)
What is HHT (Hereditary Hemorrhagic Telangiectasia)?
Hereditary hemorrhagic telangiectasia (HHT) is a genetic disorder that causes multiple arteriovenous malformations (AVMs), potentially resulting in bleeding from the blood vessels (hemorrhaging). An AVM is an abnormal tangle of blood vessels in which arteries and veins connect directly to each other instead of being linked by smaller vessels called capillaries. AVMs may form underneath the skin, where they are visible as red markings called telangiectases. They can also occur in the brain, spinal cord, and various organs throughout the body.
Generally speaking, there are three ways an AVM can damage the brain or spinal cord:
- Blood vessels in AVM can rupture and bleed into the brain or spinal cord (hemorrhage)
- An AVM can reduce the amount of oxygen delivered to brain and spinal tissues, causing them to deteriorate and die
- An AVM can compress or displace parts of the brain or spinal cord
Symptoms of HHT (Hereditary Hemorrhagic Telangiectasia)
Symptoms of HHT can vary widely depending on the location of the blood vessel abnormalities. Symptoms of brain or spinal AVMs may include:
- Back pain or numbness
- Loss of feeling or function in an arm or leg
- Inability to control eye movement
- Memory deficits
- Mental confusion, hallucinations, or dementia
- Problems with balance and coordination (ataxia)
- Visual disturbances, such as loss of part of the visual field or double vision
Other symptoms of HHT may include:
- Bleeding in the gastrointestinal tract, including loss of blood in stool
- Exercise intolerance
- Frequent nosebleeds, which is the first symptom in many cases
- Migraine headaches
- Shortness of breath
- Telangiectases, most commonly found on the tongue, lips, face, ears, and fingers
If you are experiencing any symptoms, contact a medical professional for a proper diagnosis.
Treatments for HHT (Hereditary Hemorrhagic Telangiectasia)
While there is no known cure for HHT, treatments can help improve quality of life and prevent life-threatening complications, such as stroke. If you have brain or spinal AVMs due to hereditary hemorrhagic telangiectasia, we can help. Treatment for an AVM depends on its size and location.
Your doctor may recommend one or a combination of the following treatments:
- Conventional surgery – The neurosurgeon removes part of your skull to access the AVM and seals off the AVM with special clips before closing the skull.
- Endovascular embolization – In this minimally invasive alternative to open surgery, the neurosurgeon guides a catheter through the network of arteries using X-ray visualization until the thin tube reaches the site of the AVM. The neurosurgeon then inserts a material such as glue or a metal coil to reduce blood flow into the AVM.
- Radiosurgery – In this noninvasive procedure, focused beams of radiation are used to destroy the AVM. At Barrow, we offer Gamma Knife and Cyberknife radiosurgeries.
How common is HHT?
According to the National Institutes of Health (NIH), HHT is believed to affect between 1 in 5,000 and 1 in 10,000 people. However, the NIH says it is difficult to determine how many people have this disorder because the severity of symptoms can vary widely and some symptoms, such as frequent nosebleeds, are common in the general population.
Symptoms may also resemble other conditions, such as anemia, migraine, and asthma, which can result in misdiagnosis.
Who gets HHT?
HHT affects men and women equally, and symptoms can occur at any age. Scientists have identified four genes involved in HHT and more than 600 mutations in these genes. The disorder is inherited as an autosomal dominant trait, meaning a person only needs to inherit an abnormal gene from one parent to be affected.
How is HHT diagnosed?
Your doctor may use the following to diagnose HHT:
- Blood tests
- Family history
- Genetic testing to look for changes in the genes associated with HHT
- Imaging tests, such as magnetic resonance imaging (MRI) or computed tomography (CT), to look for AVMs inside the body
- Physical examination (which can detect telangiectases)