Signs and Symptoms
The location of telangiectases and /or AVMs in the body determines what problem(s) someone with HHT might have. In most locations, and at any size, a telangiectasia or AVM has a greater tendency to rupture and bleed than a normal blood vessel. In the nose, skin, GI tract (stomach and intestines), and brain the primary problem they can cause is bleeding. AVMs in the lungs or liver are less likely to rupture and bleed, but can cause other problems that are less obvious to doctors and patients who lack an in depth understanding of HHT. No one with HHT has all of the signs and symptoms listed below.
Symptoms of HHT vary greatly, even within a family. A parent may have horrible nosebleeds, but no AVM in an internal organ. Yet, the child may have a nosebleed only rarely, but have AVMs in one or more internal organs. We cannot predict how likely someone is to have one of the hidden, internal AVMs based on how many nosebleeds or skin telangiectases they have. In other words, the person with HHT who has minor/mild nosebleeds is as likely to have an AVM in their lung, as the person with HHT who gets severe nosebleeds daily.
Telangiectases in the nose, along with the nosebleeds they cause, are the most common symptom of HHT. About 90% of people with HHT have recurring nosebleeds by the time they reach middle age. The average age at which nosebleeds begin is 12, but they can begin as early as infancy, or as late as adulthood. Nosebleeds can be as infrequent as a couple per year or can occur daily. When a nosebleed occurs, it can last anywhere from a few seconds, up to several hours in some cases. The amount of blood lost may be a few drops, or enough to cause anemia (low blood count). As with most things that are variable in human beings (i.e. height and shoe size), the majority of people with HHT are in between the two extremes in terms of nosebleed frequency and severity.
Telangiectases in the skin of the hands, face and mouth are also found in about 95% of all people with HHT. These often do not become apparent until the age of 30s or 40s, however. They appear as small red to purplish spots. In some individuals with HHT they become quite prominent by late adulthood, in others they are subtle. The telangiectases on the skin and in the mouth can bleed also, but they are less likely to bleed than those in the nose. Both telangiectases of the skin and nosebleeds have a tendency to become more numerous with increasing age. But with this too, there are many variations and exceptions!
About 20-25% of those with HHT will develop symptoms of gastrointestinal (GI) bleeding. Again, it can range from mild to severe. Telangiectases can be found anywhere in the gastrointestinal system, including the esophagus (swallowing tube), the stomach, the small intestines, and the colon (large intestines), but most commonly, in the stomach and small intestines. Telangiectases in the GI tract look similar to telangiectasia on the skin. Telangiectases in the GI tract do not cause pain or discomfort. Symptoms of GI bleeding are black or bloody stools and/or anemia. The anemia (low blood count) can then cause fatigue, shortness of breath, chest pain or light-headed feelings.
Approximately 30-50% of people with HHT have one or more AVM in the lungs (pulmonary AVM or PAVM). AVMs in the lung are at risk of rupture, particularly during pregnancy when blood pressure and blood volume tend to increase. This can lead to life threatening bleeding. In addition people with lung AVMs are at risk for stroke (a clot in the brain blocking off blood flow) or brain abscess (a bacterial brain infection). Stroke and brain abscess can be life threatening or disabling. In the normal lung, the capillaries between an artery and vein act as a filter for impurities (clots, bacteria, air bubbles) in the blood, before the blood circulates to other parts of the body, including the brain. When lung AVMs are present, these particles can pass through the AVM, go to the left side of the heart and then on to the brain or other organs. Fortunately, lung AVMs are usually 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 causing a brain hemorrhage, we recommend screening for them in all people with HHT. Spinal AVMs are more rare but can also be treated. They can cause pain in the back over the spine or loss of feeling or function in the arms or legs.
Liver AVMs can also occur, are relatively common, but rarely cause sudden, severe medical complications like lung and brain AVMs can. Liver AVMs almost never bleed and most are not currently treated. Large AVMs in the liver occasionally cause heart and liver 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 an AVM (in this context an AVM is sometimes called a “Shunt”.