Medicines for Hereditary haemorrhagic telangiectasia

What it is

Hereditary haemorrhagic telangiectasia (HHT), also known as Osler-Weber-Rendu syndrome, is a genetic condition that affects the blood vessels, causing some of them to form abnormally. It is inherited (passed down in families), and is caused by changes in certain genes; a person with HHT has a chance of passing it on to their children. In HHT, some blood vessels do not form properly, resulting in abnormal connections and fragile vessels that can bleed. This produces the characteristic features of the condition. The most common and often earliest feature is recurrent nosebleeds (from fragile blood vessels in the nose), which can be frequent and sometimes troublesome. Another characteristic feature is small red or purplish spots (telangiectasias) on the skin and the lining of the mouth, lips, and fingers, which are clusters of small abnormal blood vessels near the surface. Beyond these, HHT can involve larger abnormal blood vessel connections (arteriovenous malformations, or AVMs) in internal organs — such as the lungs, liver, brain, and digestive system — which are present in some people with HHT and can, in some cases, cause problems or complications (for example, bleeding, or, with lung AVMs, other effects); bleeding in the digestive system can also occur and, along with recurrent nosebleeds, can lead to iron-deficiency anaemia over time. The features and severity of HHT vary between individuals, even within the same family. Because HHT can involve internal organs, and because some of its potential complications can be significant but are often preventable or treatable if identified, an important part of managing HHT is screening for and monitoring these internal involvements, and treating problems as needed, alongside managing the more visible features such as nosebleeds. With appropriate diagnosis, screening, monitoring, and treatment — often through specialist HHT services — HHT can be well managed, and complications reduced. The key messages are that HHT is a genetic blood vessel condition causing recurrent nosebleeds and red spots, and sometimes abnormal vessels in internal organs, and that it is managed with diagnosis, screening for internal involvement, monitoring, and treatment.

How it is treated

HHT is managed by diagnosing the condition, screening for and monitoring internal organ involvement, treating problems (such as nosebleeds and any complications) as needed, and providing genetic advice — often through specialist HHT services. Diagnosis is based on the characteristic features (such as recurrent nosebleeds, the typical red spots/telangiectasias, internal AVMs, and a family history), and can be supported by genetic testing; recognising the pattern is important, as the features can otherwise be attributed to other causes. Because HHT can affect internal organs, an important part of management is screening for and monitoring the potential internal involvements — for example, checking for abnormal blood vessel connections (AVMs) in the lungs, brain, liver, and digestive system, as recommended, since some of these can be significant but are often treatable or preventable if identified; this screening (with appropriate scans and tests, guided by specialist services) allows problems to be found and managed before they cause complications. Managing the specific features and any problems is then tailored to the individual: recurrent nosebleeds, which are often the most troublesome day-to-day feature, are managed with a range of measures (such as keeping the nasal lining moist, measures to reduce and treat bleeding, and, for more severe cases, various treatments and procedures available through specialists); iron-deficiency anaemia from recurrent bleeding is treated (for example with iron replacement, and by managing the source of bleeding); and any AVMs in internal organs that need treatment are managed by specialists — for example, treating lung AVMs (which is important, as they can cause specific problems) with procedures to close them off, and managing others as appropriate. Being aware of and promptly assessing any new or concerning symptoms (such as significant bleeding, neurological symptoms, or breathlessness) is important. Because HHT is genetic, genetic counselling is offered to discuss the condition, its inheritance, testing, and implications for family members (who may be offered assessment), and family planning. Care is often best coordinated through specialist HHT centres, which have expertise in the condition and its various aspects. With diagnosis, screening, monitoring, and treatment, many people with HHT are well managed, and potentially serious complications can be prevented or treated. The reassuring messages are that HHT, although a lifelong genetic condition, is manageable — with treatment for nosebleeds and anaemia, and, importantly, screening for and treatment of internal AVMs to prevent or manage complications — and that specialist services and genetic advice support people and their families; so diagnosis, appropriate screening, and specialist care are the keys to managing it well.