Definition:
Osler-Weber-Rendu syndrome is an inherited disorder of the blood vessels, which can cause excessive bleeding.

Alternative Names:
Hereditary hemorrhagic telangiectasia

Causes, incidence, and risk factors:
Hereditary hemorrhagic telangiectasia, also known as HHT or Osler-Weber-Rendu syndrome, is inherited as an autosomal dominant trait. Affected children develop red or reddish-purple collections of abnormal blood vessels called telangiectases (spider-like, macular, or papular spots).

The telangiectases can be seen on the lips and tongue and the nasal mucosa. Other areas such as the face and ears may be involved and internal vascular abnormalities can occur in the brain, lungs, throat and larynx, gastrointestinal tract, liver, bladder, and vagina.

Frequent nosebleeds in children may be an early sign but the easily visible, characteristic vascular lesions (telangiectases) on the tongue and lips may not appear until puberty. The telangiectases bleed easily. Bleeding into the head (brain hemorrhage, stroke) may cause varied neurological symptoms such as seizures. If severe, this brain hemorrhage may be fatal.

Some patients only discover that they have this condition when they cough up blood and a chest X-ray shows an abnormality called an arterio-venous malformation. Some patients have enough large or multiple arterio-venous malformations in the lungs to cause shortness of breath.

Symptoms:

 
• frequent nosebleeds in a child  
• GI bleeding - i.e., loss of blood in stool or dark black stool (melena)  
• shortness of breath  
• the appearance of vascular lesions (telangiectases) during late childhood or early adolescence on the:
  • tongue      
  • lips      
  • whites of the eyes      
  • ears      
  • finger tips and nail beds      
  • skin

   

• coughing up blood, passing blood in the stool or unusually dark stool
   

• port wine stain (occasionally present)
   

• unexplained or multiple small strokes

Signs and tests:
An experienced physician can find telangiectases on physical examination. There is often a family history of hereditary hemorrhagic telangiectasia.

Other signs include:

 
• Chest X-ray may show a “spot on the lung” (Arteriovenous malformation)  
• Echocardiogram may show “high-output” heart failure  
• iron deficiency anemia may result from repeated blood loss  
• specialized blood gas tests may show decreased levels of oxygen in blood  
• endoscopy may show numerous abnormal blood vessels that bleed easily(Arteriovenous malformations) lining the throat, bowels, or airways  
• hepatomegaly  
• genetic testing may be available for mutations in the endoglin or ALK1 genes

Treatment:
Bleeding in vital areas must be corrected surgically. Frequent or heavy nosebleeds (epistaxis) may be treated with electrocautery or laser surgery. Large collections of abnormal blood vessels (arterio-venous malformations) in the lungs may be deliberately “clotted off” in a procedure called “coiling” which is performed by an Interventional Radiologist. Some patients respond to estrogen therapy, which can reduce bleeding episodes.

Support Groups:
HHT Foundation International, Inc. [url=http://www.hht.org;]http://www.hht.org;[/url] 800-448-6389

Expectations (prognosis):
Barring a fatal intracranial hemorrhage, this syndrome is compatible with a normal lifespan. Many patients do not know that they have this condition until a family member is diagnosed with it.

Complications:

 
• internal hemorrhaging  
• marked increased risk for nose bleeds  
• coughing up blood  
• increased risk for strokes and infections of the brain  
• heart failure  
• shortness of breath  
• high blood pressure in the lungs (pulmonary hypertension)

Calling your health care provider:
Call your health care provider if your child has frequent nose bleeds or other signs of this disease.

Prevention:
Genetic counseling is recommended for prospective parents with a family history of hereditary hemorrhagic telangiectasia. Some strokes and high output heart failure can be prevented by clotting off the abnormal blood vessels in the lung (see above).

Diseases and Conditions Center

All ArmMed Media material is provided for information only and is neither advice nor a substitute for proper medical care. Consult a qualified healthcare professional who understands your particular history for individual concerns.