Pediatric hereditary hemorrhagic telangiectasia (HHT) or Osler-Weber-Rendu syndrome

What is pediatric hereditary hemorrhagic telangiectasia (HHT) or Osler-Weber-Rendu syndrome?

Hereditary hemorrhagic telangiectasia (HHT) affects blood vessels and can lead to bleeding when abnormally structured blood vessels rupture. It’s also known as Osler-Weber-Rendu syndrome. 

HHT can affect many organs. However, the first sign is often unpredictable, severe nosebleeds. 

Normally, blood circulates from the heart to arteries and then to smaller vessels called arterioles and capillaries. From there, the blood should move to veins and then return to the heart. For people with HHT, some blood flows directly to the veins from the arteries. As a result, higher blood pressure builds up in veins, which have thinner and less elastic walls and can burst. This bleeding is known as hemorrhaging. 

When capillaries burst in smaller vessels near the skin or inside the nose, the condition is called telangiectases (singular telangiectasia). This looks like red or purple pin pricks on the skin. 

Arteriovenous malformations (AVMs) are large vascular malformations that can occur elsewhere in the body, including the lungs, liver, brain and spine. Serious problems can occur from AVMs in these organs. AVMs in the brain can cause critical, life-threatening complications. AVMs in the lungs can cause blood oxygen levels to be low.

What are the different types of pediatric hereditary hemorrhagic telangiectasia (HHT) or Osler-Weber-Rendu syndrome?

The types are differentiated primarily by the genetic cause, signs and symptoms.

Type 1

• Symptoms develop earlier

• Higher risk of blood vessel malformation in lungs and brain

• Women are at a higher risk for type 1

Type 2

• Symptoms develop later than type 1

• Higher risk of blood vessel malformation in liver

• Women are at a higher risk for type 2

Type 3

• Higher risk of blood vessel malformation in liver

Juvenile polyposis/hereditary hemorrhagic telangiectasia syndrome

• AVMs

• Growths or polyps in the GI tract

• HHT types 1, 2 and 3 don't increase the likelihood of polyps

What are the signs and symptoms of pediatric hereditary hemorrhagic telangiectasia (HHT) or Osler-Weber-Rendu syndrome?

HHT is sometimes referred to as the "great masquerader" because children may not exhibit any symptoms. If they do, it can be disguised as migraines, anemia, shortness of breath, stroke, congestive heart failure or even liver cirrhosis. Sometimes HHT isn’t correctly diagnosed until people are in their 40s and 50s.

• Anemia (iron deficiency)

• Arteriovenous malformations (AVMs), which are diagnosed through imaging

• Back pain

• Blood in the stool

• Exercise intolerance

• Fatigue

• GI bleeding

• Lacy red vessels, particularly on the lips and in the mouth

• Low oxygen saturation in the blood

• Migraines

• Nose bleeds

• Pulmonary hypertension – high blood pressure in arteries leading to the lungs

• Seizures

• Shortness of breath

How is pediatric hereditary hemorrhagic telangiectasia (HHT) or Osler-Weber-Rendu syndrome diagnosed?

Children’s Health and UT Southwestern offer the only pediatric HHT screening program in North Texas and the region. This screening can identify vascular abnormalities. Parents who are being treated for HHT will often seek screening for their children.

If children screen positive for vascular abnormalities, further testing will be ordered. If they test negative, they will still undergo screening every three to five years. Children’s Health can give your child’s pediatrician a checklist of symptoms to watch for as they continue normal checkups.

Children’s Health offers a pediatric HHT clinic to meet with families to discuss testing, symptoms and treatments.

Three out of four of the following criteria must be met before doctors will make a clinical diagnosis of HHT:

• Family history of a parent, sibling or child with HHT

• Recurrent nosebleeds

• Visible telangiectases on the mouth, lips, fingers and nose

• AVMs in the lungs, spine, brain, digestive tract or liver

Other tests include:

• Colonoscopy - Looks for abnormalities in the large intestine and rectum.

• Bubble study or contrast echocardiography - Used to screen for abnormal blood flow caused by AVMs in the lungs. Patients will receive an injection of saline solution that has air bubbles in it. If bubbles go from the right to the left side of the heart, that means there might be at least some abnormal blood vessels in the lungs.

• Genetic testing - Looks for a genetic mutation

• Imaging tests - Chest X-ray, ultrasound, CT and MRI looks for malformations.

• Upper endoscopy - Looks at the upper GI tract (esophagus, stomach and first part of the small intestine, called the duodenum).

What are the causes of pediatric hereditary hemorrhagic telangiectasia (HHT) or Osler-Weber-Rendu syndrome?

HHT is an autosomal dominant genetic disorder. If a parent has HHT, his or her children have a 50 percent chance of being diagnosed with it

How is pediatric hereditary hemorrhagic telangiectasia (HHT) or Osler-Weber-Rendu syndrome treated?

Overall, treatment for HHT depends on which parts of the body are affected. No cure exists, but treatment can help a patient avoid serious complications.

• Anemia, caused by nose or GI bleeding, is most often caused by iron deficiency. It can be treated with iron supplements and by addressing nose or GI bleeding. Some patients may receive iron intravenously at intervals. Some will require blood transfusions.

• Brain - AVMs of the brain are usually treated surgically by removing them, through embolization or with radiation to the affected area. With catheter embolization, medications or synthetic materials called embolic agents are inserted through a catheter into a blood vessel to block blood flow.

• Liver - AVMs in the liver are treated if the patient is in heart failure. Treatment is highly individualized based on symptoms.

• Lung - Most pulmonary AVMs are treated with embolization therapy with a catheter that enters through the leg. Treatment for pulmonary AVMs is also dependent on symptoms.

• Nose - Ablation, embolization and hormone therapy can be used to treat serious nose bleeds. With ablation, laser light or radiofrequency is used to shrink tissue in the nose. Home remedies, such as humidifiers, nose sprays and avoiding strong nose blowing can help with minor nosebleeds. Surgical remedies may also be considered.

• Skin - Laser therapy can be used to destroy the discolored tissue.

• Stomach and intestines - Treating telangiectases in the GI tract is difficult because of how widespread they can be. Laser therapy, a heater probe or hormone therapy are possible treatment plans.