What is Hereditary Hemorrhagic Telangiectasia (HHT)?

From the Guidelines

Teleangectasia emorragica ereditaria, also known as Hereditary Hemorrhagic Telangiectasia (HHT), is a genetic disorder that requires a comprehensive management approach to prevent morbidity, mortality, and improve quality of life, as recommended by the Second International Guidelines for the Diagnosis and Management of Hereditary Hemorrhagic Telangiectasia 1.

Key Considerations

• HHT is characterized by the presence of vascular malformations, leading to chronic bleeding, acute hemorrhage, and complications from shunting through these malformations.
• The condition is inherited in an autosomal dominant pattern, with common symptoms including recurrent nosebleeds, visible red spots on the skin and mucous membranes, gastrointestinal bleeding, and potential complications from arteriovenous malformations (AVMs) in major organs.
• Treatment focuses on managing symptoms and preventing complications, with options for nosebleeds including moisturizing nasal sprays, topical treatments like tranexamic acid, laser therapy, or in severe cases, surgical interventions.
• For gastrointestinal bleeding, endoscopic treatments or medications like iron supplements for resulting anemia may be needed.
• Screening for AVMs is essential, particularly in the lungs and brain, as these can cause serious complications if left untreated.
• Genetic testing can confirm the diagnosis and help identify at-risk family members.

Management Recommendations

• Patients with HHT should be managed by a multidisciplinary team familiar with this rare disorder to ensure comprehensive care.
• The use of systemic therapies, including antiangiogenics and antifibrinolytics, is now recommended as standard treatment options for bleeding in HHT patients, as highlighted in recent clinical recommendations 1.
• Topical medications, such as thalidomide and tranexamic acid, have shown promise in reducing the severity and frequency of nosebleeds in HHT patients, and their use should be considered as part of the treatment plan 1.

Conclusion is not allowed, so the answer will continue with more details about the management of the condition.

Additional Considerations

• The clinician should assess, or refer to a specialist who can assess, the presence of nasal telangiectasias and/or oral mucosal telangiectasias in patients with a history of recurrent bilateral nosebleeds or a family history of recurrent nosebleeds to diagnose HHT.
• A comprehensive approach to managing HHT includes not only treating the symptoms but also preventing complications and improving the patient's quality of life.
• The latest guidelines and research should be consulted to ensure that patients receive the most up-to-date and effective care for their condition.

From the Research

Definition and Prevalence

• Hereditary hemorrhagic telangiectasia (HHT) is an autosomal dominant disorder of the blood vessels that leads to the formation of telangiectasias and arteriovenous malformations (AVMs) 2.
• HHT affects approximately 1/5,000 people, but this varies significantly by geography and ancestry 2.

Diagnostic Criteria

• The Curaçao criteria for HHT consist of four diagnostic criteria: spontaneous epistaxis, first-degree relative with HHT, AVMs in characteristic location (liver, lung, brain), and telangiectasias 2, 3.
• Fulfillment of 3 or more criteria provides a definite diagnosis of HHT, whereas 2 criteria constitute a possible diagnosis of HHT 3.

Clinical Manifestations

• Clinical manifestations of HHT include vascular malformations of the skin, nasal mucosa, gastrointestinal tract, lungs, liver, and central nervous system 4.
• Telangiectases in the nasal and gastrointestinal mucosa and brain arteriovenous malformations generally present with hemorrhage 5.
• Complications of arteriovenous malformations in the lungs and liver are generally the consequence of blood shunting through these abnormal blood vessels 5.

Management and Treatment

• HHT patients are best cared for by a multidisciplinary team, ideally all with HHT-specific experience 2.
• The management of HHT can involve interventional radiology techniques, particularly for patients with pulmonary arteriovenous malformations 6.
• Medical management of vascular complications may include oral tranexamic acid and IV bevacizumab 4.
• Endovascular and surgical treatments are clinically indicated when the benefits outweigh the risks of the interventions 4.