Rare Disorder Affecting Blood Vessels Requires Specialty Care

Karen Swanson, Mayo Clinic

DEAR MAYO CLINIC:

My twin brother has internal bleeding caused by hereditary hemorrhagic telangiectasia. Please explain this disease and how it can be diagnosed and treated. Should he be seeing a specialist for treatment or monitoring? Our mother died from this after numerous transfusions.

ANSWER:

Hereditary hemorrhagic telangiectasia (HHT) is an uncommon inherited disorder that affects blood vessels. A diagnosis of HHT is based on an assessment of symptoms, examination findings and genetic testing. Currently there's no cure, but in many cases the symptoms can be effectively managed.

HHT involves blood vessels that don't form properly. In people with the disorder, most of the body's blood vessels are normal. But some networks of blood vessels that join arteries to veins (capillaries) are either missing or poorly formed, so they can't do their job of filtering the blood that passes between arteries and veins. In small blood vessels, these malformations are called telangiectases. When they occur in larger vessels, they're called arteriovenous malformations (AVMs). Patients with HHT have both kinds of malformations.

Telangiectases and AVMs bleed easily, leading to a variety of symptoms that depend on where the blood vessel abnormality is located. Areas most often affected are the nose; skin of the face, hands and mouth; lining of the stomach and intestines; lungs, liver and brain. Recurrent nosebleeds are the most common HHT symptom. Many people with the disorder also develop small spots on their skin (external telangiectases), typically on the fingertips, lips and mouth.

Although HHT is not usually life-threatening, in some areas of the body -- especially the lungs, brain and liver -- these blood vessel abnormalities can be serious because they may result in undetected internal bleeding, infection or low oxygen levels. The severity of HHT often varies significantly from person to person, even within families.

The clinical criteria for an HHT diagnosis include: nosebleeds, a family history of nosebleeds or blood vessel abnormalities, AVMs in internal organs such as the brain, lungs, gastrointestinal tract or liver, and external telangiectases. Genetic testing is generally only helpful after HHT has first been confirmed in a family based on symptoms and physical exam findings. Thus, the first step in a diagnosis should be to work with a professional genetic counselor to review and assess a detailed family medical history. That assessment determines whether genetic testing may be helpful and, if so, which family members should be tested.

At this time, the vessel malformations of HHT cannot be prevented or cured. Current treatments are designed to stop or prevent the problems that telangiectases and AVMs can cause. HHT treatment depends on which part of the body is affected, and the problems that result. Although no cure exists, much can be done to treat the symptoms and avoid serious outcomes that may result from telangiectases and AVMs.

People who have HHT, like your brother, should seek treatment at a medical center familiar with this disorder. Because the disorder is uncommon, finding a specialist in HHT can be difficult. In the United States, 12 HHT treatment centers, including Mayo Clinic, are designated by the HHT Foundation International for their ability to diagnose and treat all aspects of the disorder. If possible, your brother should be evaluated at least once at one of these treatment centers. For locations and contact information, refer to the HHT Foundation International website at www.hht.org.

If your brother does not live near an HHT center and cannot find a local HHT expert for ongoing monitoring, he should work with a doctor who's willing to learn more about the disorder and to collaborate with an expert to provide the best possible care.

Karen Swanson, D.O., Pulmonary and Critical Care Medicine, Mayo Clinic, Rochester, Minn.

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