Screenings for people with HHT

The main guidance

The Second International HHT Guidelines were published in 2020 by an expert panel from 15 countries that included people with HHT. They made 36 recommendations in 6 areas: nosebleeds, stomach and bowel bleeding, anaemia and iron deficiency, liver vascular malformations, care of children, and pregnancy and delivery. (Second International HHT Guidelines, 2020) The European Hematology Association, which endorsed them in 2021, notes that brain and lung AVMs were not reassessed, so the recommendations of the first international guidelines still apply there, and that the new guidelines add screening advice for people without symptoms, especially children. (EHA endorsement, 2021) The first guidelines were published in 2011. (Hammill et al, 2021) A 2024 review says only a combination of screening and treatment brings the shorter life expectancy seen in HHT back to normal. (Geisthoff et al, 2024)

Checks the guidance lists

Check	When	Source
Bubble contrast echocardiogram for lung AVMs	Everyone with confirmed or suspected HHT	(Geisthoff et al, 2024)
Repeat lung AVM screen after a negative result	Every 5 years in children; every 5 to 10 years in adults	(Hammill et al, 2021)
Haemoglobin (blood count)	At least once a year	(Geisthoff et al, 2024)
Screening for iron deficiency anaemia	All adults, and children with symptoms	(Kasthuri et al, 2025)
Brain MRI	Discuss with your healthcare provider; disputed for adults without symptoms	(VASCERN, 2020)
Liver vascular malformations	Screening to be considered; little guidance on how	(Kasthuri et al, 2025)
Spine vascular malformations	Screening not recommended	(Geisthoff et al, 2024)
Colonoscopy and upper endoscopy (SMAD4 gene change, juvenile polyposis)	Starting between ages 12 and 15	(NCI PDQ, 2025)
Lung AVM screen before pregnancy	Women who plan to become pregnant	(Geisthoff et al, 2024)

Lung AVMs: bubble echo and when to repeat it

Lung AVMs can cause no symptoms, or tiredness, shortness of breath, low oxygen, migraine, or serious events such as stroke, a mini-stroke or a brain abscess. (Hammill et al, 2021) International guidelines recommend lung AVM screening for everyone with confirmed or suspected HHT. A 2024 review says the method of choice is a bubble contrast echocardiogram: a heart ultrasound after a small injection of tiny bubbles, which normally stay on the right side of the heart but reach the left side when there is a shunt through the lungs. It says chest CT is an alternative but involves radiation and misses very small shunts, so it is often used only to plan next steps, that a plain chest X-ray is not enough for screening, and that repeating the screen after about 5 years is currently recommended. (Geisthoff et al, 2024) A 2021 practical guide says a negative first screen should be repeated every 5 years in children and every 5 to 10 years in adults. (Hammill et al, 2021) Lung cancer screening with low-dose CT is a separate check; see low-dose CT lung scan: what to expect.

Blood count and anaemia

A 2024 review says people with HHT often get used to dark stools and anaemia from swallowed nosebleed blood, so even heavy bleeding in the gut can go unnoticed, and advises a haemoglobin check at least once a year. It says adults, and children with bleeding or signs of anaemia, should be tested for anaemia and iron deficiency. (Geisthoff et al, 2024) A 2025 review says the HHT guidelines recommend that all adults and children with symptoms are screened for iron deficiency anaemia. (Kasthuri et al, 2025) See complete blood count results and iron test results: ferritin.

Brain MRI

The European Reference Network for rare vascular diseases (VASCERN) says about 10% of people with HHT have brain vascular malformations. Its 2020 position statement says brain symptoms that could mean an AVM should be checked as in normal neurological and emergency care, separate from screening; that current evidence does not support widespread brain screening of people with HHT who have no symptoms; and that every person with HHT should have the chance to discuss brain screening with their healthcare provider, including the possible harm of finding something that would never have caused a problem. It reports that only one of its eight HHT centres routinely screens adults without symptoms with brain MRI. (VASCERN, 2020) The European Hematology Association notes that input from patients in the Second International Guidelines led to proposing brain MRI in children. (EHA endorsement, 2021) Self-pay whole-body MRI for people without a condition like HHT is a different thing; see full-body MRI screening.

Liver and bowel

Liver AVMs are the most common AVMs in HHT and often cause no symptoms; the updated guidelines recommend screening because it may pick up their effects, such as strain on the heart, earlier. (Hammill et al, 2021) A 2025 review says the guidelines recommend considering liver screening but give little guidance on how. (Kasthuri et al, 2025) See liver function test results.

A 2024 review says telangiectases in the stomach and bowel are found in up to 91% of people with HHT but bleed in only 30%, rarely before age 40. (Geisthoff et al, 2024) A 2021 practical guide says stool blood tests are not reliable while nosebleeds are ongoing. (Hammill et al, 2021) MedlinePlus Genetics says HHT caused by a SMAD4 gene change comes with juvenile polyposis, a tendency to grow polyps in the gut, while the other HHT types do not appear to raise the chance of polyps. (MedlinePlus Genetics) The NCI says the NCCN and the US Multi-Society Task Force on Colorectal Cancer recommend colonoscopy and upper endoscopy for juvenile polyposis beginning between ages 12 and 15, and that guidelines recommend people with juvenile polyposis and a SMAD4 gene change are screened for signs of HHT. (NCI PDQ, 2025) See screening colonoscopy: what to expect.

Before and during pregnancy

A 2024 review says lung AVMs can rarely bleed, somewhat more often in pregnancy, so women who plan to become pregnant should be screened and told the warning signs. If untreated brain or lung AVMs are present, or lung AVMs have not been ruled out recently, it says the pregnancy is treated as high risk and cared for by an experienced team at a specialist centre. (Geisthoff et al, 2024) See pregnancy screenings by week.

Checks for relatives

MedlinePlus Genetics says HHT is inherited in an autosomal dominant pattern, meaning one changed copy of the gene is enough to cause it. (MedlinePlus Genetics) A 2021 practical guide says genetic testing can find the gene change in a family with HHT and confirm the diagnosis in relatives, including young children with few or no symptoms. It says children need screening as well as adults, because they can have AVMs before nosebleeds or skin spots appear, and that genetic counselling is recommended before pregnancy. (Hammill et al, 2021) See family history and screening and how to collect your family health history.

Routine age-based screening

The USPSTF recommends colorectal cancer screening for adults aged 45 to 75. (USPSTF colorectal, 2021) The other routine screenings for your age and sex still apply; see screenings by age and gender and colorectal cancer screening tests compared.

Where they differ:

Repeat lung screen. A 2021 practical guide says every 5 to 10 years in adults after a negative screen, (Hammill et al, 2021) while a 2024 review says repeating after about 5 years is currently recommended. (Geisthoff et al, 2024)
Brain MRI. VASCERN says the evidence does not support widespread brain screening of people without symptoms and favours an informed discussion, (VASCERN, 2020) while the Second International Guidelines propose brain MRI in children, an approach the European Hematology Association says was favoured more by patients than by medical experts. (EHA endorsement, 2021)
Liver screening. The updated guidelines recommend considering it, (Kasthuri et al, 2025) while a 2024 review says it is disputed whether screening should be recommended. (Geisthoff et al, 2024)
Anaemia checks in children. A 2025 review says children with symptoms, (Kasthuri et al, 2025) and a 2024 review says children with bleeding or signs of anaemia. (Geisthoff et al, 2024)

Your doctor decides what your result means for you.

Questions people ask

How are people with HHT checked for lung AVMs?

International guidelines recommend screening for lung arteriovenous malformations (AVMs) in everyone with confirmed or suspected HHT. A 2024 review says the method of choice is a bubble contrast echocardiogram, that a plain chest X-ray is not enough, and that chest CT is often used only after a positive result. A 2021 practical guide says that if the first screen is negative, it should be repeated every 5 years in children and every 5 to 10 years in adults. (Geisthoff et al, 2024) (Hammill et al, 2021)

How often do people with HHT need a blood count?

A 2024 review says people with HHT are advised to have their haemoglobin checked at least once a year, because bleeding in the stomach or bowel can go unnoticed. A 2025 review says the HHT guidelines recommend that all adults and children with symptoms are screened for iron deficiency anaemia. (Geisthoff et al, 2024) (Kasthuri et al, 2025)

Should adults with HHT have a brain MRI?

Sources differ. The European Reference Network for rare vascular diseases (VASCERN) says the evidence does not support widespread brain screening of people with HHT who have no symptoms, and suggests every person with HHT should be able to discuss brain screening with their healthcare provider. Symptoms that could mean a brain AVM should be checked as in normal neurological care, which is separate from screening. (VASCERN, 2020)

Do people with HHT need bowel checks?

A 2024 review says telangiectases in the stomach and bowel are found in up to 91% of people with HHT but bleed in only 30%, rarely before age 40. People with HHT caused by a SMAD4 gene change also have juvenile polyposis; the NCI says national guidelines recommend colonoscopy and upper endoscopy for juvenile polyposis starting between ages 12 and 15. (Geisthoff et al, 2024) (NCI PDQ, 2025)

Should relatives of someone with HHT be checked?

A 2021 practical guide says genetic testing can find the gene change in a family with HHT and confirm the diagnosis in relatives, including young children who have few or no symptoms, and that children need screening as well as adults because they can have AVMs before any nosebleeds or skin spots appear. (Hammill et al, 2021)

Screenings for people with hereditary hemorrhagic telangiectasia (HHT)