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Hereditary Hemorrhagic Telangiectasia
Also Known As: Osler-Weber-Rendu syndrome,[1] is an autosomal dominant genetic disorder that leads to vascular malformations
Condition / disease reference page from the Everyone Healthy database.
Connected health information
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Condition overview
Attributes
Commonalityis rare
Linked signs and symptoms
0No related signs or symptoms are listed yet.
Linked drugs / medications
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Treatments, therapies and supportive options
0Grouped by treatment type. These are educational database links, not personal treatment recommendations. Evidence labels are shown only where stored in the EH database.
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Linked diagnostic tests and investigations
5These are pulled from both EH diagnostic-test link tables, including the older large test-link table.
Biological and test markers
5This visual map uses existing EH database links to show biological agents and lab markers reported as increased, decreased, or associated with this condition. These are educational relationships only; test results must be interpreted by a qualified clinician because ranges vary by lab, method, age, sex and clinical context.
Often decreased
3- Hemoglobin (Hb)Reference range exampleFemale: 78–100 gm/dL; Male: 76–100 gm/dLLinked diagnostic tests3Hemoglobin (Hb) Concentration, Mean Corpuscular Hemoglobin (MCH) Weight Test
- RBC MassReference range exampleFemale: 36–48 %; Male: 42–52 %Linked diagnostic tests1Heamatocrit (Hct)
- Red Blood Cells (RBC)Reference range exampleAdult ( > 16y), Female: 3.6–5 106/mm3; Adult ( > 16y), Male: 4.2–5.4 106/mm3Linked diagnostic tests1Red Blood Cell (RBC) Count
Other associated markers
0No markers in this group.
Introduction / full article
Hereditary Hemorrhagic Telangiectasia
Hereditary hemorrhagic telangiectasia
In medicine, hereditary hemorrhagic telangiectasia (HHT), also known as Osler-Weber-Rendu syndrome,[1] is an autosomal dominant genetic disorder that leads to vascular malformations.
Signs and symptoms
HHT is characterised by telangiectasia (small vascular malformations) on the skin and mucosal linings, epistaxis (nosebleeds), and arteriovenous malformations (AVMs) in various internal organs. Skin and mucosa telangiectasias are most remarkable on the tongue, hands/fingers, nose, lips, mouth/throat and conjunctiva.
The internal organs that can harbor AVMs often include the brain and lungs. In both, bleeding can seriously endanger life. Anemia may occur due to bleeding from digestive tract AVMs. Congestive cardiac failure (high-output heart failure) may develop in the presence of marked shunting arterial blood to the venous circulation, e.g. when AVMs are present in the liver.
Diagnosis
There are four diagnostic criteria.[2] If three or four are met, a patient has definite HHT, while two gives a possible diagnosis:
- Spontaneous recurrent epistaxis
- Multiple teleangiectasias on typical locations (see above)
- Proven visceral AVM (lung, liver, brain, spine)
- First-degree family member with HHT
When HHT is suspected, physical examination focuses on inspecting the whole skin for teleangiectasias, auscultation of the lungs and liver, and neurological examination.
Pulmonary AVMs can be anticipated by measuring oxygen levels and performing arterial blood gas (ABG) sampling. An X-ray of the chest can show susceptible lesions; in addition, low oxygen tension (<96% or a 2% decrease upon standing) or low blood oxygen levels on ABG are required for a diagnosis.
Pathophysiology
The mechanism underlying the formation of vascular malformations is not completely understood, but signalling of transforming growth factor-β1 is most likely to be involved. Possibly, connective tissue is required to support and guide proliferating blood vessels during angiogenesis, and defects in TGF-β signalling adversely affect connective tissue and matrix production.
Treatment
There is no specific treatment for the condition. Anemia due to bleeding from digestive tract AVMs often necessitates repeated blood transfusions. AVMs in critical organs often necessitates surgery. If major AVMs are all the patient has in terms of long-term problems, the surgery performed will block the malformed arteries, ruling out the risk for stroke and blood-clots. This surgery will hopefully lead to a normal life for the patient, and also help doctors diagnose patients with HHT more easily around the globe.