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.
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) Shortness of breath 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 GI bleeding -- i.e., loss of blood in stool or dark black stool (melena) 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. www.hht.org ; 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.
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).