Common bleeding disorders affecting individuals with Hereditary Hemorrhagic Telangiectasia
Hereditary Hemorrhagic Telangiectasia (HHT) is an autosomal dominant disorder affecting vasculature in different organ systems; seen at a rate of approximately 1:5000 in North America. Complications, with significant increases in health service utilization, arise from bleeding and shunts, and are particularly problematic in the lung and liver. Although these patients tend to chronically bleed from the GI tract and nasal cavities, a single bleed from arterio-venous malformations in the lungs or brain can have serious health implications and may be fatal. Bleeding due to vascular wall fragility in HHT patients can be further complicated with a concomitant bleeding disorder. The proportion of adult patients seen in the Edmonton HHT center with a concomitant bleeding disorder, as assessed by blood test results for Factor VIII and related factors (Ristocetin Cofactor), Factor IX and Factor XI, was determined in a retrospective, single centre study. Of 77 individuals with HHT, four had below normal values of von Willebrand Factor, Ristocetin Cofactor or Factor VIII. Two patients had laboratory parameters diagnostic of a bleeding disorder, accounting for 2.6% of confirmed HHT subjects. These results indicate that establishing screening for bleeding disorders in HHT centers is important in managing bleeding symptomatology. In individuals with HHT, the presence of a second bleeding disorder can have significant clinical implications on patient management and health care utilizations. This paper highlights areas that need to be reviewed with respect to best practice protocols for the management of HHT patients.