Diagnosis, Testing, and Screening

Commonly Asked Questions

Cure HHT does not provide medical advice, nor does the printing of these answers constitute medical advice. For professional advice consult your medical caregiver.

Is there a blood test or DNA test available to diagnose HHT?

Yes, but it is important that a family member with confirmed HHT (based on clinical symptoms) be the first in their family to be genetically tested for HHT. Then once the specific gene mutation has been identified, other family members can be tested for that mutation.  In order to decide whether genetic testing will be helpful in your family, it is usually necessary to be seen either at an HHT Center or a genetics clinic/department in your area.

Should children be screened for AVMs?

There are currently no standard guidelines for the screening and treatment of lung AVMs in children. Based on the fact that some children have had complications from lung AVMs, we do advocate screening for all children of a parent with HHT. This screening should start as a baby with pulse oximetry every two or three years. Though oximetry will not detect mildly or moderately decreased oxygen levels, it will detect severely decreased oxygen levels. It seems to be the children who have severely decreased oxygen levels who are at risk for complications. Also, if a child is complaining of shortness of breath when exercising, or is having a hard time keeping up in sports, they should additional testing for lung AVMs depending on their age. At the age of 12, all children with HHT should have the same screening for lung AVMs recommended for adults. Children can be safely treated with embolization.

What is the best treatment for an HHT patient diagnosed with atrial fibrillation? Is there a procedure that does not require blood thinners?

Dr. James Gossage, Director of Augusta HHT Center: Atrial fibrillation in HHT is a complex issue that would be best managed with an HHT specialist alongside your cardiologist. There are other options such as the Watchman procedure which closes the atrial appendage and decreases the chance of blood clots and strokes, and blood thinner use is minimal if at all.

What are common symptoms of pulmonary AVMs and how can they lead to a misdiagnosis?

Dr. James Gossage, Director of Augusta HHT Center: Pulmonary AVMs (PAVM) are the most common serious problem in patients with HHT and are seen in 30% to 40% of patients. Common symptoms of PAVM include shortness of breath, low oxygen levels when checked by finger oximetry and hemoptysis (coughing up blood). Shortness of breath and low oxygen levels are often misdiagnosed as other problems such as asthma and heart disease because the standard chest X-ray may be normal, especially if the PAVM are microscopic. Hemoptysis is less likely to be misdiagnosed because this symptom usually results in checking a CT scan of the chest, which usually finds the PAVM.

In any case, the best first test for finding PAVM is a contrast (“bubble”) echocardiogram which shows shunting in the lungs – a characteristic finding of PAVM. Less common symptoms of PAVM include stroke and brain abscess (infection on the brain). These may also be misdiagnosed because physicians do not usually look at the lungs in case of these symptoms. Again, a contrast echo should find the PAVM. Bottom line, if you have any of these symptoms and they are eluding diagnosis or not getting better, please ask your physician to consider PAVM and ordering a contrast echocardiogram.

Why should a family member of an HHT patient be screened even if no symptoms have appeared?

Dr. Jeffrey Pollak, Medical Director of Yale University HHT Center:People with a family history of HHT, even those without symptoms, are potentially at-risk for having the condition and associated internal AVMs. Anyone with a parent, sibling or child with HHT is considered at-risk. Features leading to a suspicion of HHT, like nosebleeds and telangiectasia, often do not appear until adolescence or later, and sometimes never appear. Approximately 10% of adults with HHT do not have nosebleeds and skin telangiectasia can be subtle, so the absence of these signs does not exclude the condition. Lung and brain AVMs often don't cause symptoms, but if it is of a significant size, it can increase the risk for stroke, brain abscess and hemorrhage. Indeed, these serious complications can be the first evidence of the presence of AVMs, for which preventive therapy is available.
The most accurate way to determine who in a family has HHT is through genetic testing. A family member with definite HHT, based on clinical findings, is first tested to determine the family’s mutation, which is possible in 85% to 90% of families with HHT. Testing for this known mutation can then be done on at-risk family members with no or minimal symptoms. Only those with the family’s mutation would need HHT evaluation and AVM screening. Since the potentially life-threatening complications associated with HHT are preventable with appropriate treatment and follow-up, we recommend genetic testing and/or screening at-risk family members, even in the absence of symptoms.

How can a person can lose two units of blood in one week? Very minor nose bleeds not every day and also not physically seeing any blood in the stool.

Dr. James Gossage, Director of Augusta HHT Center: It is not uncommon to lose blood in the stool and not be able to see it.  It is also possible to underestimate blood lost during nosebleeds.  If you are iron deficient from slow bleeding you will not replace the blood which will further exacerbate the losses.  There may also be variability in the hemoglobin test that may make the loss look worse than it really was.

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Genetics/Inheritance of HHT

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Commonly Asked Questions