Hereditary Hemorrhagic Telangiectasia

1. Definition
   1. Autosomal Dominant disorder of abnormal blood vessel formation
2. Epidemiology
   1. Prevalence: one in 5000 to 8000 persons
3. Pathophysiology
   1. Autosomal Dominant inheritance
   2. Profuse Telangiectasias form throughout the body
      1. Number of lesions increases with age
4. Symptoms
   1. Profuse Hemorrhages
   2. Frequent Epistaxis (presenting concern in 90% of patients)
5. Signs: Telangiectasias
   1. Bright red elevated Telangiectasias on skin and nose and Gastrointestinal Tract
      1. Blanch with pressure
   2. Distribution
      1. Most common on face (esp. lips and Tongue), chest and hands
6. Labs
   1. Coagulation Factors
      1. Normal
   2. Complete Blood Count
      1. Iron Deficiency Anemia
      2. Start screening by age 35 years
   3. Consider Genetic Testing in those with Family History
      1. First test the known case patient in family to determine if they carry an identified genetic marker
      2. Negative testing for the family members specific genetic defect excludes the condition and requires no further testing
7. Imaging
   1. MRI Brain
      1. Evaluate for intracranial Arteriovenous Malformation
   2. Contrast Echocardiography (bubble Echocardiography)
      1. Evaluate for intracranial Arteriovenous Malformation
      2. If positive screening, pursue CT Angiogram to localize the AV Malformations
      3. Rescreen every 3-5 years
   3. Consider Abdominal MRI, CT or RQ Ultrasound
      1. Screen only for those with Gastrointestinal Bleeding or other signs suggesting possible hepatic involvement
      2. Evaluate for hepatic Arteriovenous Malformation or focal nodular hyperplasia
8. Associated Conditions
   1. Juvenile polyposis syndrome
   2. Primary Pulmonary Hypertension
9. Complications
   1. Pulmonary Arteriovenous Malformation (15-30% of patients)
      1. Risk of right to left shunt with risk of Hypoxemia
      2. High risk of Pulmonary Hemorrhage during pregnancy
   2. Intracranial Arteriovenous Malformation (10% of patients)
      1. Associated with Seizures, Headaches and Intracranial Hemorrhage
   3. Hepatic Arteriovenous Malformation
      1. Associated risk of Portal Hypertension, high output cardiac failure and biliary disease
10. Diagnosis: Requires 3 of 4 criteria
    1. Epistaxis
    2. Telangiectasias
    3. Visceral Arteriovenous Malformation
    4. Family History of Hereditary Hemorrhagic Telangiectasia
11. Management:
    1. Iron Deficiency Anemia management
    2. Recurrent Epistaxis management
       1. See Epistaxis
       2. Topical Estrogen
       3. Laser coagulation of Telangiectasia
       4. Septal dermoplasty
       5. Complete nasal closure (Youngs procedure)
       6. Embolization for acute, severe and refractory Epistaxis
       7. Experimental use of Vascular Endothelial Growth Factor
    3. Pulmonary Arteriovenous Malformation
       1. Antibiotic prophylaxis in dental work, endoscopy or procedures
          1. Indicated in known Pulmonary AVM (or unscreened patients)
       2. Embolization with coils
          1. Indicated for AVM of 3 mm or greater
       3. Intravenous lines should always have air filters
       4. No Scuba Diving
    4. Gastrointestinal Bleeding
       1. Laser therapy with endoscopy
       2. Experimental use of thalidomide
    5. Cerebral Arteriovenous Malformation
       1. Embolization or neurosurgery
12. References
    1. Olitsky (2010) Am Fam Physician 82(7): 785-90 [PubMed]