[Osler-Weber-Rendu--a life-threatening disease in adults and children]

Osler-Weber-Rendu Syndrome or Hereditary Hemorrhagic Telangiectasia (HHT) is an autosomal dominant inherited disease. It is more common than previously estimated, with a prevalence of 1:5,000-10,000. It was described mainly in adults, however recent studies suggest a similar presentation in children. The clinical characteristics include epistaxis, skin and mucosal telangiectases and visceral arteriovenous malformations (AVMs), and diagnostic criteria for this disease have been established. Epistaxis and telangiectases appear in most patients. Epistaxis can be massive and difficult to treat. Pulmonary AVMs are present in 30% of patients and can result in right to left shunt, with dyspnea, cyanosis and polycythemia. The shunt, bypassing the pulmonary capillary bed, can also result in paradoxical emboli to the brain, strokes and brain abscesses. Different screening methods have been suggested for pulmonary AVMs, preferably high resolution chest CT and bubble echocardiography. Definite diagnosis is made by pulmonary angiography. The recommended treatment is pulmonary embolization and recent studies show excellent results in adults and children. Cerebral AVMs appear in 5% of patients and can result in cerebral hemorrhage. MRI is the recommended screening test. There is a debate as to whether to treat asymptomatic patients with cerebral AVMs. Mutations in two genes have been shown to cause 2 types of this disease. Both genes encode proteins, endoglin and ALK-1, which are components of the TGF-beta receptor. Mutations in these genes cause HHT1 and HHT2, respectively. Screening family members of patients for pulmonary AVMs is recommended, and children should probably be included.