From the Guidelines
Osler-Weber-Rendu syndrome, also known as hereditary hemorrhagic telangiectasia (HHT), is a genetic disorder that requires management focusing on controlling bleeding and preventing complications from arteriovenous malformations (AVMs) in various organs, as recommended by the Second International HHT Guidelines 1.
Key Management Strategies
- For recurrent nosebleeds, treatments include humidification, nasal moisturizers, and topical treatments like tranexamic acid applied locally.
- Systemic medications for severe cases include oral tranexamic acid (500-1000 mg three times daily) or hormonal therapy such as estrogen-progesterone combinations.
- Iron supplementation (ferrous sulfate 325 mg daily) and sometimes intravenous iron are needed for iron deficiency anemia from chronic bleeding.
Screening and Intervention
- Patients should undergo screening for pulmonary, cerebral, and hepatic AVMs, typically with contrast echocardiography for pulmonary AVMs and MRI for brain AVMs, as outlined in the guidelines 1.
- Large AVMs may require embolization or surgical intervention to prevent serious complications like stroke or hemorrhage.
Genetic Basis
- This condition is autosomal dominant, most commonly involving mutations in the ENG, ALK1, or SMAD4 genes, which affect blood vessel wall integrity and explain the tendency for abnormal vessel formation and bleeding, as discussed in the guidelines 1.
Clinical Recommendations
- The Second International HHT Guidelines provide evidence-informed consensus guidelines regarding the diagnosis of HHT, prevention of HHT-related complications, and treatment of symptomatic disease in areas not previously addressed by guidelines and those where significant new literature had been published 1.
- The guidelines highlight new evidence in existing topics from the first International HHT Guidelines and provide guidance in 3 new areas: anemia, pediatrics, and pregnancy and delivery 1.
From the Research
Definition and Prevalence of Osler-Weber-Rendu
- Osler-Weber-Rendu, also known as Hereditary Hemorrhagic Telangiectasia (HHT), is an autosomal dominant disorder that causes abnormal blood vessel formation 2.
- The prevalence of HHT is estimated to be around 1 in 5000 persons, making it the second most common inherited bleeding disorder worldwide 3.
- HHT is characterized by multiple arteriovenous malformations (AVMs) involving the skin, mucosal surfaces, and internal organs 4.
Clinical Manifestations
- Common clinical manifestations of HHT include epistaxis, telangiectasia, and visceral arteriovenous malformations 5, 4.
- Patients with HHT may experience bleeding, anemia, iron deficiency, and high-output heart failure due to the abnormal blood vessel formation 2.
- Pulmonary vascular malformations can cause dyspnea, cardiac failure, and ischemic stroke, while brain vascular malformations can cause hemorrhagic stroke and seizures 5, 6.
Diagnosis and Management
- The diagnosis of HHT is clinical, based on the Curaçao criteria, and can be confirmed by genetic testing 2, 5.
- Management of HHT requires a multidisciplinary approach, including screening and local and/or systemic management of lesions 2, 5.
- Anti-angiogenic agents, such as bevacizumab, have emerged as a promising systemic therapy in reducing bleeding complications, while antifibrinolytics and hormonal treatment may also be used 2, 3.
- Iron supplementation is often necessary to manage iron deficiency anemia, a common complication of HHT 3.