The four diagnostic criteria for HHT are listed below. A person has definite HHT if they meet at least three criteria and possible HHT if they meet two. Persons with less than two criteria are unlikely to have HHT.
Recurrent and spontaneous nosebleeds (epistaxis), which may be mild to severe.
Multiple telangiectasias on the skin of the hands, lips or face, or inside of the nose or mouth. Telangiectasias are small red spots that disappear when pushed on.
Arteriovenous malformations (AVMs) or telangiectasias in the internal organs including the lungs, brain, liver, intestines, stomach, and spinal cord.
A family history (i.e., first-degree relative such as brother, sister, parent or child) who meets these same criteria for definite HHT or has been genetically diagnosed.
There will be cases where a person has some signs of HHT, but their physician is not able to make a definitive diagnosis. In cases like this, a positive test might confirm that someone does have the condition, but a negative test will not rule it out.
Several features of these diagnostic criteria should be noted.
- The criteria spell out in detail exactly what is required for each manifestation of HHT. For example, as there is no agreement among doctors as to the precise number of episodes or severity of nosebleeds needed to satisfy a diagnosis of HHT, the criteria merely highlight that nosebleeds should occur spontaneously on more than one occasion, with night-time bleeds being particularly suspicious.
- The criteria emphasizes the importance of taking a detailed, targeted, family history in order to establish the diagnosis of this highly penetrant, but extremely variable, dominant genetic disorder in an individual. Also, these criteria allow us to distinguish between individuals who definitely have HHT, and those in whom it is suspected, and allow each label to be added to medical records to ensure appropriate follow-up and medical management.
- The criteria emphasizes that all offspring of an individual with HHT are at risk of having the disease since HHT may not manifest until late in life. We recommend that if there is any concern regarding the presence or absence of physical signs, a physician experienced with HHT should be consulted.
These consensus criteria summarized below were published in the American Journal of Medical Genetics in 2000.
My Family Health Portrait
The Surgeon General launched a national initiative to encourage all American families to learn more about their family health histories. Knowing your family's medical history can save your life.
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