About 95% of people with the gene for HHT will eventually develop signs or symptoms of HHT, usually by the age of 40. However, just because a person reaches the age of 50 without symptoms of HHT does not mean that they are not affected. They may have subtle signs on physical exam and lab testing that only a doctor familiar with HHT might detect. The earliest symptom of HHT is usually nosebleeds, often developing in adolescence. Patients also start to develop small red spots, or telangiectasias, on the face, mouth, and fingers. other common symptoms include shortness of breath, exercise intolerance, fatigue, migraine headaches, seizures, abdominal pain, leg swelling, and intestinal bleeding.
Telangiectasias in the nose, along with the nosebleeds they cause, are the most common sign of HHT. About 90% of people with HHT will ultimately develop recurring nosebleeds by the time they reach their forties.The average age at which nosebleeds begin is 12, but they can begin as early as infancy, or as late as adulthood. The nosebleeds can be as infrequent as a few times a year or can occur daily. When a nosebleed occurs it can last anywhere from seconds to hours. The amount of blood lost may be one or two drops, or enough to require an emergency blood transfusion.
The Epistaxis Severity Score (ESS) is a way to monitor the severity of your nosebleeds and their response to treatment. This is a simple score that is calculated automati- cally when you answer six simple questions about your nosebleeds. You can access the ESS tool through the HHT Foundation website at www.hht.org.
Telangiectasias on the skin of the hands, face and mouth are also found in about 95% of all people with HHT. However, these often do not become apparent until the 30s or 40s. They appear as small red to purplish spots, usually pinpoint to pinhead size. In some individuals with HHT they become quite prominent by late adulthood; in others they are more subtle. These telangiectasias on the hands, face or in the mouth can bleed, but they are less likely to bleed than those in the nose. Both telangiectasias of the skin and nose have a tendency to become more numerous with increased age. However, not all red spots are telangiectasias. Red spots on the chest, belly or upper arms are common in people without HHT and are usually called cherry angiomas.
About 80% of those with HHT have telangiectasias in their stomach or intestines, but only 20% develop obvious gastrointestinal bleeding. Again, it can range from mild to severe. Telangiectasias can be found anywhere in the gastrointestinal system, including the esophagus,stomach, small intestines, and colon (large intestines), but most commonly, the stomach and the upper part of the small intestines are involved. Telangiectasias in the GI tract do not cause pain or discomfort. Symptoms of GI bleeding are black or bloody stools and/or anemia; often patients don’t notice any change in the stool but instead are found anemic through blood work. Anemia can cause fatigue, shortness of breath, chest pain or lightheaded feelings.
ARTERIOVENOUS MALFORMATIONS (AVMs)
Approximately 40% of people with HHT have AVMs in the lungs (pulmonary AVM or PAVM). People with HHT1 (ENG) are 5-10 times more likely to have PAVMs than people with HHT2 (ACVRL1). PAVMs, particularly during pregnancy, have a risk of rupturing when blood volume tends to increase. This can be life-threatening. However, there are additional concerns about untreated PAVMs. Normally, the lung arteries get smaller and smaller as they go deeper into the lungs, similar to the branches of a tree. At the ends of these artery branches, hair- like blood vessels called capillaries join the arteries and veins. These capillaries per- form many important functions including allowing passage of oxygen into the blood as well as filtering the blood of impurities (clots, bacteria, air bubbles) before the blood circulates to the brain. With a PAVM, these capillaries are missing and the artery connects directly to the vein. If the artery leading into the PAVM is larger than 2-3 mm in diameter, small blood clots can travel through the PAVM and go to the brain causing a stroke. Bacteria can travel through even smaller PAVMs and result in brain abscesses (a brain infection). Stroke and brain abscess can be life-threatening or disabling. Fortunately, PAVMs are almost always easily treatable.
Brain AVMs are found in about 5-20% of people with HHT and can also be successfully treated in most cases. They can be life-threatening or disabling if they bleed. Since they often do not cause warning symptoms prior to bleeding, we recommend screening for them in all people with HHT, even infants. Other types of brain vascular malformations may be seen in HHT patients, such as telan- giectasias and venous malformations. It is not clear if these malformations are seen any more commonly in HHT patients, but they are usually harmless and most do not require treatment.
Spinal AVMs are more rare, less than 1%, but can also be treated. They can cause pain in the area of the back over the spine, or loss of feeling or function in an arm or leg.
Liver AVMs are found in 32-74% of people with HHT, but only cause symptoms in an estimated 8%. AVMs in the liver occasionally cause heart failure, usually later in life. Heart failure can occur if the heart has been overworked for years, pumping extra blood through the low resistance pathway of a liver AVM (shunt), as well as through all the normal vessels of the body. There are several other even more rare and complex complications that can result when HHT affects the liver. Few physicians outside of clinics that specialize in HHT are familiar with these complications.