Most people affected by HHT experience two problems:
- the fragile blood vessels are prone to bleed, for example, in the nose causing nose bleeds, and less frequently in the gut. Generally, this bleeding settles down on its own, but if it leads to anaemia, it may need treatment with iron tablets, or with a blood transfusion if severe
- the abnormal blood vessels may become visible as blood spots, for example on the lips or fingertips.
A few people will have abnormal vessels elsewhere. The lungs are affected in 1 in 5 individuals with HHT and it is important that this is recognised (see below). For other sites, such as the liver and brain, it is not clear that any specific tests or treatment are needed if they are not causing problems already.
About 1 in 5 individuals with HHT develops abnormal vessels in the lungs. These are called pulmonary arteriovenous malformations (PAVMs). These malformations let blood bypass or 'shunt' past the lung airsacs. They are particularly important because individuals who have PAVMs are at risk of having a ministroke or brain abscess even if they feel well. In addition, a few women with PAVMs have complications during pregnancy. It is therefore important to check whether or not PAVMs are present and, if so, arrange for a simple treatment to close them off.