Signs and symptoms of telangiectases and arteriovenous malformations (AVMs) include nosebleeds, red or purple spots, lacy red vessels, shortness of breath, migraine headaches, iron deficiency anemia, fatigue, and blood in the stool.
A clinical diagnosis of HHT can be made if you have at least three of these four criteria:
- Recurrent nosebleeds that seem to start for no reason
- Visible telangiectases on your lips, mouth, fingers, nose and the inside of your mouth
- Internal telangiectases or AVMs in your lungs, brain, spine, digestive tract or liver
- Family history of a parent, sibling or child with HHT
Your doctor may diagnose HHT based on a physical examination, results of imaging tests and a family history. But some symptoms may not yet be apparent in children or young adults. Your doctor may also suggest you undergo genetic testing for HHT, which may confirm a suspected diagnosis.
Your doctor can refer you to a certified genetic counselor or medical geneticist, who can talk with you about how genetic testing for HHT may be useful for you and your family. HHT is a disorder you inherit from one of your parents. It's called an autosomal dominant disorder, which means that if one of your parents has HHT, you have a 50-50 chance of inheriting the dominant gene responsible for HHT. If you inherit this gene, you will have HHT.
As part of determining a diagnosis, your doctor will likely have you under one or a combination of the following imaging tests:
- Chest X-ray. A chest X-ray can help your doctor see the size, shape and structure of your lungs. It can also give clues about the location and severity of any arteriovenous malformations (AVMs).
- Ultrasound imaging. This technique is sometimes used to determine whether the liver is affected by AVMs.
- Magnetic resonance imaging (MRI). Your doctor may order an MRI scan to check your brain for any blood vessel abnormalities.
- Bubble study. To screen for any abnormal blood flow caused by an AVM in your lung, your doctor may recommend a contrast echocardiography, also called a bubble study. It uses sound waves to examine the blood flow through your vessels. With bubble echocardiography, you'll receive an injection of saline solution that has air bubbles in it, making it easier for your doctor to see vessel malformations and blood flow.
- Computerized tomography (CT) scan. This imaging test combines a series of X-ray views taken from many different angles and computer processing to create cross-sectional images of the bones and soft tissues inside your body. If a bubble echocardiogram reveals you may have a lung AVM, your doctor may order a CT scan of your lungs to confirm the diagnosis and assess whether you need surgery.
- Colonosocopy and upper endoscopy. People with HHT due to mutations in the SMAD4 gene may be at increased risk for polyps. If this relates to you, your doctor may recommend screening including a colonoscopy and upper endoscopy.