Did you know that June is HHT Awareness Month? You’re probably wondering, what is HHT? That’s because most people, including many doctors, have never heard of Hereditary Hemorrhagic Telangiectasia (HHT), a rare genetic blood vessel disorder. In fact, most people who have HHT don’t know that they have it! Which is precisely why awareness is so critical to identifying and treating people who have HHT. As someone with HHT and the author of Living with HHT, I’m happy to be part of this special month devoted to HHT awareness—and I hope my book will contribute to HHT awareness all year round.
In my last blog post, “When a Nosebleed is More than a Nosebleed: Understanding HHT,” I introduced you to HHT, describing its symptoms and complications and how to tell if you or your family should be tested for HHT. Today I’ll describe the primary screening tests recommended for people who are diagnosed with HHT (or are at risk for HHT) and give an overview of currently available treatments for common symptoms and complications of HHT.
- Why are Screening Tests Needed? As discussed in my prior post, many people with HHT have brain and/or lung AVMs (arteriovenous malformations). These are invisible and may cause no symptoms for a long time if ever—OR they may result in devastating complications such as stroke, brain abscess or sudden bleeding into the lungs or brain. Lung AVMs in HHT can cause problems in the brain—brain abscess (infection) and the type of stroke caused by a blocked blood vessel in the brain. This is because capillaries (the smallest blood vessels) that normally filter out debris and bacteria in the lungs are missing in the AVMs, increasing the risk that these materials will travel through the bloodstream and lodge in the brain. A brain AVM can cause another type of stroke if it ruptures and bleeds into the brain (brain hemorrhage or hemorrhagic stroke). Lung AVMs can also rupture, causing bleeding into the lungs, a dangerous and sometimes fatal complication; women with untreated lung AVMs are more at risk for this during pregnancy.
The only way to know whether these AVMs are present—and to prevent or reduce the risk of these complications, is to have screening tests.
- What Tests are Necessary? The basic screening tests include an MRI (magnetic resonance imaging) of the brain to look for brain AVMs and an echo bubble test (contrast echocardiogram) to look for lung AVMs. An MRI is a painless, non-invasive test that does NOT use any radiation. It takes pictures of the brain that can identify the presence of AVMs and other abnormalities in the brain. A person needs to be completely still during the test, so young children may need sedation to ensure good MRI images. The echo bubble test screens for lung AVMs by looking at whether tiny air bubbles (that should be filtered by capillaries in the lungs) are instead getting into the vessels that return blood to the brain. The test is done by shaking up a saline solution and injecting it into a vein, and then using ultrasound to take pictures of the heart. (During this test, a person with HHT can also be screened for pulmonary hypertension—high blood pressure in the lungs—which occurs in a small group of people with HHT). If the echo bubble is positive, follow up with a CT (computerized tomography) scan of the lungs may be recommended to determine the size and location of AVMs in the lungs, and decide whether treatment is warranted. While all adults diagnosed with HHT should have the echo bubble test, it is not recommended for children under 10 who have no symptoms. This is because children have a lower risk of complications from lung AVMs and because treatments are not as effective in younger children. An echo bubble test is usually recommended for children under 10 who experience symptoms such as low oxygen levels, shortness of breath or difficulty running or playing sports.
- Where Can I Get Tested? The best place to get screened is at one of the 27 HHT Centers of Excellence in North America (there are others around the world). For a list of these Centers, see Living with HHT or go to www.curehht.org. These specialty centers provide comprehensive screening for HHT, genetic testing and counseling, and treatments for all the various symptoms and complications of HHT. If you are unable to go to an HHT Center, you can get the necessary screening tests through your primary care doctor, but he or she may need to consult with an HHT Center or with Cure HHT to learn about what is required and/or to interpret the test results.
- What treatments are available for HHT? Nosebleed frequency can be reduced by moisturizing the nose with petroleum jelly or saline spray. More severe nosebleeds can be treated with laser therapy and with a variety of medications. Lung AVMs are treated with a procedure called embolization in which the blood vessel leading to the AVM is plugged; this is an outpatient procedure using X-ray images to guide a catheter into the vessel and can be done in adults without general anesthesia. Some brain AVMs can also be treated with this technique, but others require radiation or surgery. Anemia (low red blood cell count) can be treated with oral iron pills, iron infusions (IV iron), or in severe cases, blood transfusions. There are also various medications for reducing bleeding in the nose and gut, and several clinical studies are now underway to find more effective medicines with fewer side effects. In people with heart failure caused by AVMs in the liver, medications can help manage the symptoms and reduce the bleeding. Currently, liver transplantation is the only permanent, life-saving treatment for severe heart failure caused by liver AVMs. Current research is seeking to better understand the mechanisms of HHT and advance treatments with effective oral medications and gene therapies to shrink AVMs, reduce bleeding and make blood transfusions unnecessary. Living with HHT discusses treatment options in more detail and describes a range of research on medications and procedures for HHT.
Once you’ve been diagnosed with HHT—or if you are at risk because your parent, sibling or child was diagnosed with HHT—the first step in protecting your health is to get proper screening. The next step may be treatment, if you need it, monitoring your AVMs, or managing your nosebleeds. With proper medical care, most people with HHT can work, raise children and participate fully in life. Those limited by HHT related illness and disability can benefit from new treatments to reduce severe bleeding and associated heart failure. For more information on managing the medical, emotional and family aspects of HHT, read Living with HHT and visit www.curehht.org for HHT factsheets, webinars, and scientific updates.
Happy HHT Awareness Month!
Sara Palmer, PhD, is a psychologist and an assistant professor in the Department of Physical Medicine and Rehabilitation at Johns Hopkins University School of Medicine. She is the author of Living with HHT: Understanding and Managing Your Hereditary Hemorrhagic Telangiectasia, and the coauthor of Spinal Cord Injury: A Guide for Living; When Your Spouse Has a Stroke: Caring for Your Partner, Yourself, and Your Relationship; and Just One of the Kids: Raising a Resilient Family When One of Your Children Has a Physical Disability.