Clinical Focus: Hereditary Hemorrhagic Telangiectasia, The Forgotten Illness
As one of the world’s foremost experts in treating pediatric patients with hereditary hemorrhagic telangiectasia (HHT), Andrew White, MD, is often called upon to talk with physicians about this genetic disorder of the blood vessels. When he asks how many audience members have cared for children with cystic fibrosis, most raise their hands. When he asks the same question about HHT, rarely does anyone respond.
“HHT and cystic fibrosis have roughly the same incidence, around one in 5,000 people,” explains Dr. White, who, along with Murali Chakinala, MD, an adult pulmonologist, co-directs the HHT Center at Washington University School of Medicine (WUSM) and St. Louis Children’s Hospital (SLCH). “Although it is a common disease, we believe most cases of HHT go undiagnosed because the minor symptoms can be easily overlooked, and the major symptoms are clinically silent until they cause significant problems such as a stroke or coughing up blood.”
HHT is characterized by arteriovenous malformations (AVMs), abnormal connections between arteries and veins located in the lungs, brain and GI tract; and by nosebleeds and telangiectasia located on the skin of the face and/or hands.
“Most people have nosebleeds, so distinguishing between an abnormal nosebleed and a common one is complicated,” says Dr. White. “Some kids present with no or very few telangiectasia spots, which often go unnoticed. This is why a thorough family history is so important to diagnosing HHT. Nosebleeds and red spots on the hands and face may not cause suspicion, but combine that with a grandfather who had a brain abscess or a mother who had a stroke at a relatively early age, and those factors should raise some suspicion for HHT.”
A Center of Excellence for treating HHT
Founded nearly 20 years ago, the HHT Center at WUSM/SLCH has been accredited by the HHT Foundation International as a Center of Excellence. It is one of only 10 centers in North America treating the disorder, and patients are referred to it from throughout the United States.
“The most important factors for attaining accreditation are the number of experts in HHT involved in patients’ care and the additional resources available to ensure a multidisciplinary approach to treatment,” says Dr. White, who also serves as director of pediatric rheumatology and immunology at SLCH and as an attending physician in the hospital’s Diagnostic Center. “Our team includes specialists from pulmonology, pediatrics, otolaryngology, radiology, neurosurgery, genetics, cardiology, gastroenterology, hematology and dermatology.”
During their initial visit to the center, patients undergo a thorough screening that includes an in-depth family history, complete physical exam, SaO2 reading, and imaging studies that may include an MRI of the brain, CT angiogram of the chest, or echocardiogram with bubble contrast. The testing and consultation often can be completed within one to two days. After the evaluation, patients and their families will know whether or not they have symptoms consistent with possible or definite HHT.
Once a diagnosis is made, the goal is to identify problem areas, treat current symptoms and work to avoid future complications. AVMs in the brain and lung may be removed or embolized to block affected blood vessels and then reroute blood to healthy vessels. Medications may be prescribed to manage heart failure caused by liver AVMs; in severe cases, liver transplantation may be needed. Patients with frequent nosebleeds may need to use moisturizing sprays or creams, have abnormal vessels cauterized or undergo injection of a scarring agent to close vessels.
“If AVMs are not identified on the initial imaging studies, then patients return every two years to have the scans repeated,” says Dr. White. “There is disagreement in the literature about the initial occurrence of AVMs. Many believe that the brain AVMs are present at birth and lung AVMs show up at puberty, but I have clear examples that AVMs do crop up at other times.”
In addition, new findings indicate that more than 90 percent of pulmonary AVMs are linked to HHT. “Thirty years ago, pediatric pulmonologists concurred that the majority of AVMs in the lung were not tied to any other disease,” says Dr. White. “We know now that isolated pulmonary AVMs don’t really exist. If a pediatric pulmonologist, gastroenterologist, cardiologist or neurologist finds an AVM, they need to ask about nosebleeds and family history.”
A diagnosis for the entire family
Since HHT is an autosomal dominant disorder, diagnosing one child with the disease essentially is a diagnosis for the whole family. It means at least one parent has HHT, and each sibling has a 50/50 chance of having it. Grandparents, aunts, uncles, cousins—once one person is diagnosed with HHT, everyone in the family related by bloodlines is at risk.
“The broad implications for families of an HHT diagnosis is the reason we want to increase knowledge of the disease among physicians,” says Dr. White. “We want to diagnose people as early as possible so that they can receive care at an HHT treatment center throughout their lives.”
Unfortunately, HHT can never fully be cured because new artery-to-vein connections can manifest at any time. Because of its long-term nature, people diagnosed with HHT at age 10 will experience a radically different disease by the time they reach age 60.
“This is another reason for patients to receive treatment at an HHT Center of Excellence. Over time they learn more about their disease, and they can connect to an entire community of HHT patients,” says Dr. White. “They also benefit from the latest therapies available. Research is under way to develop treatments directed at preventing abnormal blood vessels from growing. Toward that end, some chemotherapy drugs are already under investigation.”
For more information about the HHT Center, call Children’s Direct at 800.678.HELP (4357).
