HHT (Hereditary Haemorrhagic Telangiectasia)

Hereditary haemorrhagic telangiectasia (HHT), also known as Osler-Weber-Rendu syndrome, is a rare genetic disorder that affects the blood vessels. It is characterised by the formation of fragile blood vessels, known as telangiectasias, which can lead to frequent bleeding. In some cases, these abnormalities extend to larger blood vessels, forming arteriovenous malformations (AVMs) that can disrupt normal blood flow and oxygen delivery.

The condition is genetic, meaning it is passed down through families. A mutation in one of several specific genes, most commonly ENG, ACVRL1, or SMAD4, is responsible for HHT. If one parent carries the faulty gene, there is a 50% chance of passing it to their children.

 

 

How does HHT affect the body?

The effects of HHT can vary widely among individuals. The hallmark of the condition is the presence of telangiectasias on the skin and mucous membranes, particularly on the face, hands, and inside the nose and mouth. These fragile vessels can rupture easily, leading to recurrent nosebleeds, which are one of the most common symptoms.

More severe manifestations include arteriovenous malformations, which can occur in critical organs such as the lungs, liver, and brain. These AVMs may cause complications like strokes, heart failure, or life-threatening bleeding if left untreated.

In addition to physical symptoms, HHT can have a significant psychological and emotional impact due to its chronic nature and potential complications. Many patients experience anxiety about sudden bleeding episodes or the possibility of severe organ involvement.

How is HHT diagnosed?

Diagnosing HHT can be challenging because its symptoms often overlap with other conditions. However, doctors typically rely on the following criteria, known as the Curaçao Criteria:

Recurrent nosebleeds: Spontaneous and frequent bleeding episodes are a strong indicator. Telangiectasias: Visible tiny red spots on the skin or mucous membranes. Arteriovenous malformations: Detected in internal organs using imaging techniques like CT scans, MRIs, or ultrasounds. Family history: A close relative with HHT supports the diagnosis.

Genetic testing can confirm the presence of mutations associated with the condition, providing definitive evidence.

How is HHT treated?

While there is currently no cure for HHT, various treatments are available to manage its symptoms and complications effectively. Treatment plans are tailored to the individual, depending on the severity of the condition and the organs involved.

For recurrent nosebleeds, treatments may include:

Nasal cauterisation to seal bleeding vessels. Topical ointments or sprays to reduce dryness and irritation. Laser therapy to minimise bleeding risk.

If arteriovenous malformations are present in the lungs, brain, or liver, intervention may be necessary to prevent complications. Procedures like embolisation, where the abnormal blood vessels are blocked off, or surgical removal of AVMs may be performed. In some cases, medications like anti-angiogenic drugs are prescribed to reduce the formation of new blood vessels.

Patients with HHT are also advised to avoid medications that increase bleeding risk, such as aspirin, and to monitor their condition regularly through medical check-ups.

Why is early detection important?

Early detection of HHT is critical to prevent serious complications. Since the disorder can affect multiple organs, undiagnosed cases may lead to life-threatening conditions like stroke, heart failure, or severe haemorrhage. By identifying HHT early, doctors can monitor for AVMs and treat them proactively.

Family members of individuals diagnosed with HHT are encouraged to undergo screening, even if they do not show symptoms. This ensures that any abnormalities are detected and managed promptly.

Living with HHT

Managing HHT requires a proactive approach. Patients are encouraged to maintain regular consultations with healthcare providers familiar with the condition. Support from specialised centres, such as HHT clinics, can be invaluable in coordinating care and accessing the latest treatments.

Dietary adjustments, like staying hydrated and eating iron-rich foods, can help combat anaemia caused by chronic blood loss. Emotional support, whether through counselling or patient support groups, also plays a vital role in coping with the challenges of living with a chronic condition.