Hereditary hemorrhagic telangiectasia

Published on 18/03/2015 by admin

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Hereditary hemorrhagic telangiectasia

Mitchell S. Cappell and Oscar Lebwohl

Evidence Levels:  A Double-blind study  B Clinical trial ≥ 20 subjects  C Clinical trial < 20 subjects  D Series ≥ 5 subjects  E Anecdotal case reports

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Hereditary hemorrhagic telangiectasia (HHT, or Osler–Weber–Rendu syndrome), an autosomal dominant disease, produces a syndrome of multiple orocutaneous telangiectasias, especially on the face, lips, tongue, oral mucosa, and fingertips, together with multiple internal telangiectasias, especially on the mucosa in the nose and gastrointestinal tract. Cutaneous or mucosal lesions typically are 3–10 mm wide, macular, bright red, non-pulsatile, and spidery or punctate in shape with a fine reticular internal structure. They tend to blanch under pressure (with diascopy), and to slowly increase in size and number with age. Although the dermatologic lesions are usually only a minor, cosmetic problem, the nasal and gastrointestinal telangiectasias often bleed significantly and repeatedly. Chronic blood loss may result in iron-deficiency anemia, whereas acute blood loss may cause hypovolemia and systemic hypotension. Internal shunts created by direct arteriovenous communications in HHT infrequently cause clinical manifestations, including hypoxia from pulmonary arteriovenous shunts; cerebral ischemia, hemorrhage, or abscesses from intracerebral shunts; and portal hypertension, biliary tract disease, or high-output cardiac failure from intrahepatic shunts.

The prevalence of HHT is estimated at 1 per 6000 individuals. The basic lesion in HHT is a defect in the wall of small vessels that leads to direct arteriovenous communications without intervening capillaries. Most cases of HHT are due to underlying genetic mutations.

Management strategy

HHT is reliably diagnosed by the presence of three or more findings among the following clinical tetrad: recurrent, spontaneous epistaxis; mucocutaneous telangiectasias; gastrointestinal telangiectasias or visceral arteriovenous malformations; and a first-degree relative with HHT (Curacao criteria). HHT is highly unlikely in adult patients satisfying only one or none of these criteria. The diagnosis may be confirmed by genetic tests for the individual underlying mutations, but such tests are generally not required for diagnosis or clinical management. Patients may have telangiectasias solely on the face with rosacea or lupus erythematosus, but lack other manifestations of HHT. Patients with sporadic gastrointestinal angiodysplasia are differentiated from patients with HHT by clinical presentation in old age, a paucity of the characteristic lesions, a negative family history, and by exclusively gastrointestinal involvement without epistaxis or intranasal telangiectasia.

For epistaxis, the bleeding severity is determined by inspection, vital signs, and laboratory tests. The bleeding site is precisely localized by nasal examination using bright, shadow-free illumination, with a headlight or head mirror, and spot suction, using a fine-caliber rigid tube. For gastrointestinal bleeding, the bleeding severity is indicated by patient history, vital signs, physical findings, rectal examination, nasogastric aspiration, and transfusion requirements. The bleeding site and source are conclusively diagnosed by gastrointestinal endoscopy.

Choice of therapy depends on the bleeding site, severity, and chronicity as well as individual physician expertise. Significant acute blood loss is treated with intravenous fluid resuscitation and transfusion of packed erythrocytes as needed. Chronic blood loss is treated with iron supplementation as needed. Epistaxis is initially treated by non-specific local therapy such as nasal packing to tamponade the bleeding, and topical vasoconstrictors to reduce local blood flow. Estrogen with progesterone is used to prevent or arrest chronic epistaxis by promoting vascular integrity. Significant, refractory, chronic epistaxis is definitively treated by septal dermoplasty. Actively bleeding gastrointestinal telangiectasias are ablated at endoscopy by argon plasma coagulation, thermocoagulation, electrocoagulation, or photocoagulation. Chronically bleeding gastrointestinal telangiectasias may be treated with estrogen and progesterone. Surgical resection is reserved for well-localized, active bleeding from gastrointestinal telangiectasias refractory to other therapy, because patients tend to subsequently rebleed from telangiectasias at other gastrointestinal sites. Where available, angiographic embolization can obviate the need for gastrointestinal surgery.

Specific investigations

Serial hematocrit determinations are important, particularly for acute bleeding, to determine the need for transfusions of packed erythrocytes. Serum levels of iron, total iron-binding capacity (TIBC), and ferritin are important, particularly for chronic bleeding, to determine the need for iron replacement therapy. Upper gastrointestinal bleeding, usually manifested by hematemesis or melena, should be investigated by esophagogastroduodenoscopy. Lower gastrointestinal bleeding, usually manifested by hematochezia or fecal occult blood, and occasionally manifested by melena, should be investigated by colonoscopy. Barium contrast radiography or virtual colonoscopy should not be performed to evaluate lower gastrointestinal bleeding in patients with HHT because the telangiectasias are mucosal and macular, and not visualized with barium contrast. Small intestinal bleeding, usually manifested by hematochezia, melena, or fecal occult blood, can be investigated by capsule endoscopy after exclusion of upper and lower gastrointestinal bleeding by the aforementioned endoscopic tests. Double-balloon enteroscopy is being increasingly used instead of capsule endoscopy for small intestinal bleeding because of its greater diagnostic sensitivity and therapeutic capabilities despite its greater costs.

At endoscopy, the gastrointestinal lesions resemble the cutaneous telangiectasias in size and shape. Angiography is indicated for active gastrointestinal bleeding if colonoscopy and esophagogastroduodenoscopy failed to diagnose the source of bleeding. Telangiectasias bleed only intermittently, and extravasation of contrast material from telangiectasias is infrequently detected at angiography.

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