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Hereditary Hemorrhagic Telangiectasia
UT Southwestern Medical Center is one of 22 designated HHT Centers of Excellence in the United States, with experts in the diagnosis and treatment of hereditary hemorrhagic telangiectasia (HHT). Our Hereditary Hemorrhagic Telangiectasia Center is the leading source for HHT care in the region and the only HHT Center of Excellence in Texas.
Although there is no cure for HHT, effective treatment can help patients manage the disease and prevent its complications.
HHT is a hereditary disorder that affects blood vessel development, resulting in arteries and veins directly joining without the normal capillaries between them. These abnormalities range from small lesions to larger ones and can affect almost any part of the body. The nose, skin, lungs, gastrointestinal tract, and brain are most commonly affected.
HHT affects approximately 1 in 6,000 individuals in the United States. By comparison, cystic fibrosis occurs in roughly 1 in 2,500 live births. Men and women are equally affected by HHT.
The UT Southwestern Hereditary Hemorrhagic Telangiectasia Center is staffed by a team of experienced professionals assembled in response to a regional need for the highest quality HHT care. Consultations with various specialists can be arranged during the same visit to address specific problems such as severe nosebleeds, GI bleeding, or pulmonary or neurological symptoms.
Translating Research into Improved Testing
The genetic basis of HHT is becoming better understood through the efforts of clinicians and scientists. Genetic testing is now available, thanks to HHT Foundation International and individual leaders at several HHT centers.
HHT can result from many different mutations in at least three different genes, which means genetic testing is not perfect in identifying the responsible mutation in every family. The diagnosis of HHT should first be confirmed in at least one family member based on symptoms and family history. That individual should be tested to see if the genetic mutation causing HHT can be detected, and depending on the test result, a physician can determine whether testing blood or saliva samples from additional family members will be helpful. A UT Southwestern geneticist can help patients and their family members understand the various options.
Our medical screening protocol is aimed at detecting internal arteriovenous malformations (AVMs) – a hallmark of HHT – before they cause major medical problems. We encourage all direct relatives of a family with HHT to be screened.
Pulmonary AVMs can cause severe complications even if they show no symptoms, so we use a saline contrast echocardiogram (bubble echo) to screen for their presence. If bubbles go from the right to the left side of the heart, there are at least some abnormal blood vessels in the lungs. If positive, we follow with a computed tomography (CT) scan to localize the AVMs and plan treatment.
We screen for cerebral AVMs using cerebral magnetic resonance imaging (MRI). We also screen for anemia with a blood count, and screen for symptoms and signs of other organ involvement.
Treatments for HHT
At UT Southwestern, a number of treatment options are available for HHT and related conditions, such as:
- Anemia: Most often caused by iron deficiency, anemia usually responds to oral iron supplements and treatment of nose or GI bleeding. Some patients require iron given intravenously at intervals, which can be done in the patient’s hometown or at UT Southwestern. A small fraction of patients will require blood transfusions.
- Cerebral AVMs: Treatment of cerebral AVMs is individualized. Most small, asymptomatic AVMs will be monitored. For those that require treatment, options include surgery, catheter-guided therapy, and highly localized radiation therapy.
- Gastrointestinal (GI) bleeding: GI bleeding might respond to local treatment through an endoscope. A variety of medicines can help reduce bleeding. We anticipate participating in a multicenter clinical trial evaluating bevacizumab (Avastin®) to treat nose and GI bleeding.
- HHT in children: Children with HHT can be hard to diagnose because nosebleeds can be absent or minor, and skin lesions are often absent or inconspicuous. Our pediatric expert oversees all pediatric evaluations, and our medical geneticist can provide advice and arrange for genetic testing.
- Liver AVMs: Liver AVMs causing symptoms occur in a few patients and can also cause signs of heart failure (e.g., leg swelling or trouble breathing) or liver disease (e.g., abdominal swelling). Medical treatment is highly individualized, and a small number of patients might need liver transplantation.
- Nosebleeds: Patients with significant nosebleeds will be seen by our otolaryngologist. Therapy will be individualized, and mild nosebleeds can be managed with topical therapy, moisturization, and humidification. Patients with more severe nosebleeds have a complete range of options such as laser therapy, embolization therapy, and surgery.
- Pulmonary AVMs: Most pulmonary AVMs are treated with embolization therapy involving a catheter that enters through the leg; surgery is rarely needed. Most patients will need only one session and will be discharged after several hours. Others might require more than one procedure, and overnight hospitalization is occasionally required. Some AVMs are too small to embolize and will be followed at intervals with CT scans.