Wallach's Interpretation of Diagnostic Tests: Pathways to Arriving at a Clinical Diagnosis (404 page)

   Other recommendations have been published by the International Society on Thrombosis and Haemostasis in 2003 and reviewed in 2007 and by the Japanese Ministry of Health and Welfare in 1987.

Suggested Readings

Takemitsu T, Wada H, Hatada T, et al. Prospective evaluation of three diagnostic criteria for disseminated intravascular coagulation.
J Thromb Haemost.
2011;105:40–44.

Yu M, Nardella A, Pechet L. Screening tests of disseminated intravascular coagulation: guidelines for rapid and specific laboratory diagnosis.
Crit Care Med.
2000;28:1777–1780.

HEREDITARY HEMORRHAGIC TELANGIECTASIA (HHT)

   Definition

HHT is an autosomal vascular disease manifested by epistaxis, mucocutaneous and gastrointestinal telangiectasias, and arteriovenous malformations in the pulmonary, cerebral, or hepatic circulation. It was previously described under the acronym Osler-Weber-Rendu disease. This rare disease is the result of abnormal angiogenesis due mostly to two mutations: endoglin (ENG) and ACVLR1 (ALK1) genes leading to HHT1 and HHT2, respectively. In addition, rare cases present with a mutation in the MADH4 gene encoding the transcription factor SMAD4.

   Who Should Be suspected?

   Patients who present with three out of the following four criteria:

   Spontaneous, recurrent epistaxis

   Multiple telangiectasias (lips, oral cavity, fingers, nose)

   Family history in first-degree relative(s)

   Visceral lesions with telangiectasias or arteriovenous fistulas

   Laboratory Findings

   
Molecular testing
: Genetic tests are available for the endoglin, ACVRL1, and SMAD4 genes. One of these mutations is found in 90% of patients with the clinical diagnosis of HHT. Molecular diagnosis is recommended also for screening suspected first-degree relatives.

   
CBC and serum iron studies
will detect iron deficiency anemia in most patients with recurrent bleeding manifestations.

   A definitive diagnosis is imperative since antiangiogenic treatments are being developed.