Congenital thrombocytopenias.

Congenital thrombocytopenias are rare bleeding disorders but must be included in the differential diagnosis when investigating a young infant with chronic thrombocytopenia. Several of these syndromes have associated defects of immune, renal, or skeletal systems in addition to thrombocytopenia. These can be categorized into two groups depending on the presence or absence of bone marrow hypoplasia. The majority of these disorders are associated with a mild bleeding tendency and thus may be missed until the affected individuals experience excessive postoperative or posttraumatic hemorrhage. In adults, this entity must be considered when evaluating a patient with thrombocytopenia who is unresponsive to the medical management of immune thrombocytopenia. Other than platelet transfusion, no specific therapy is available for these disorders. A test dose of desmopressin may be attempted in a nonbleeding patient (to see if it will shorten the bleeding time) prior to using it for treatment of a bleeding episode or surgical prophylaxis. Bone marrow transplantation may prove curative in a select group of thrombocytopenic syndromes.