A rare genetic disorder characterized by nosebleeds and multiple telangiectases that can occur on the skin, mucosal lining and internal organs. The occurrence of pulmonary arteriovenus fistulas in type 3 is greater than type 2 but less than in type 1. It has a different genetic origin to type 1 and 3 (defect on chromosome 5q31.3-q32).
* Pulmonary arteriovenous malformations * Cerebral arteriovenous malformations * Spinal arteriovenous malformations * Liver arteriovenous malformations * Nosebleeds
Hereditary hemorrhagic telangiectasia is transmitted by autosomal dominant inheritance. It seldom skips generations. In its homozygous state, it may be lethal.
Diagnosis is based principally on an established familial pattern of bleeding disorders and on clinical evidence of telangiectasia and hemorrhage. Bone marrow aspiration demonstrating depleted iron stores confirms secondary iron deficiency anemia. Hypochromic, microcytic anemia is common; abnormal platelet function may also be found. Coagulation tests are essentially irrelevant, however, because hemorrhage in telangiectasia results from weakness in the vascular wall.
Supportive therapy includes blood transfusions for acute hemorrhage and supplemental iron administration to replace iron lost in repeated mucosal bleeding. Ancillary treatments consist of applying pressure and topical hemostatic agents to bleeding sites, cauterizing bleeding sites not readily accessible, and protecting the patient from trauma and unnecessary bleeding. An interventional radiologist may clot off large collections of abnormal blood vessels in the lungs, called arteriovenous malformations, by using a coiling procedure. Parenteral administration of supplemental iron enhances absorption to maintain adequate iron stores and prevents gastric irritation. Administering antipyretics or antihistamines before blood transfusions, and using saline-washed cells, frozen blood, or other types of leukocyte-poor blood instead of whole blood may prevent febrile transfusion reactions. The administration of estrogen has proved effective in some patients, especially when used to control epistaxis.