What is Osler-Weber-Rendu syndrome?

From the Guidelines

Osler-Weber-Rendu Syndrome

Osler-Weber-Rendu syndrome, also known as hereditary hemorrhagic telangiectasia (HHT), is a rare genetic disorder characterized by the presence of vascular malformations that can lead to bleeding complications 1.

Key Characteristics

The primary concern in patients with Osler-Weber-Rendu syndrome is the risk of bleeding from these vascular malformations.

• The disorder is autosomal dominant and affects approximately 1 in 5,000 people worldwide 1.
• It is associated with telangiectasias and larger vascular malformations (VMs) in various organs, including the skin, mucosa, and viscera 1.
• The clinical presentation varies widely based on the number, type, and location of these malformations.

Management Considerations

For patients with Osler-Weber-Rendu syndrome:

• It is recommended to avoid antiplatelet and anticoagulant medications, such as aspirin and warfarin, due to the increased risk of bleeding.
• Bevacizumab, a vascular endothelial growth factor inhibitor, may be considered for the treatment of severe epistaxis or other bleeding complications, at a dose of 5-10 mg/kg intravenously every 2-4 weeks.
• Iron supplementation, such as ferrous sulfate 325 mg orally three times a day, may be necessary to manage iron deficiency anemia resulting from chronic bleeding.
• Regular monitoring of hemoglobin and hematocrit levels is essential to assess the severity of anemia and guide treatment.

Associated Conditions

Osler-Weber-Rendu syndrome is also associated with pulmonary arteriovenous malformations (PAVMs), which can lead to complications such as paradoxical embolization, brain abscess, and rupture 1.

• Transcatheter occlusion is recommended for symptomatic patients and for asymptomatic patients with discrete lesions to prevent neurological complications and progressive cyanosis 1.

From the Research

Definition and Characteristics of Osler-Weber-Rendu Syndrome

• Osler-Weber-Rendu syndrome, also known as Hereditary Hemorrhagic Telangiectasia (HHT), is a rare autosomal dominant genetic disorder that leads to abnormal blood vessel formation in the skin, mucus membranes, and organs such as the lung, liver, and brain 2, 3, 4, 5, 6.
• The disorder is characterized by the presence of telangiectasias and arteriovenous malformations (AVMs) in various organs, which can cause bleeding, anemia, iron deficiency, and other complications 2, 3, 4, 5, 6.

Symptoms and Diagnosis

• The most common symptom of HHT is recurring nosebleed (epistaxis), which begins in childhood and affects about 90-95% of people with HHT 2.
• Other common signs and symptoms include punctate, linear, or splinter-like telangiectasias on the upper body, oral mucosa, or nail beds, gastrointestinal bleeding, and iron deficiency anemia 2, 3, 4, 5.
• The diagnostic criteria currently in use are the Curaçao criteria, which include epistaxis, telangiectasias, visceral involvement, and a family history of HHT in a first-degree relative 2, 3, 5.
• Diagnosis is made by clinical screening, baseline investigations, genetic testing, and detailed medical imaging to detect visceral AVMs 2, 3.

Management and Treatment

• Management of HHT includes intravenous iron therapy or blood transfusion, antifibrinolytics, ablation therapies, and systemic anti-angiogenic agents 2, 3, 4, 6.
• A multidisciplinary approach is recommended for optimal treatment, with appropriate diagnosis, screening, and local and/or systemic management of lesions 3, 6.
• Early detection and intervention through screening can extend the life expectancy of patients with HHT to levels comparable with that of the general population 6.