The patient most likely has immune thrombocytopenic purpura (ITP) and should have another complete blood count performed in 1 week. Although ITP is a diagnosis of exclusion, supportive clinical findings include an otherwise normal blood count and the absence of additional organ dysfunction. Platelets on the peripheral blood smear are large because they typically have been recently released from the marrow, and the enhanced hemostatic function of these young platelets may account for less severe bleeding symptoms than those associated with other diseases with a similar platelet count. Not all patients with ITP require therapy, and monitoring for signs of bleeding or further declines in platelet counts may be appropriate. Asymptomatic patients without evidence of bleeding and platelet counts greater than 30,000 to 40,000/µL (30-40 × 109/L) have less than a 15% chance of developing more severe thrombocytopenia requiring treatment. In such patients, the most appropriate course of action is to provide counseling on potential bleeding symptoms and repeat the complete blood count at a designated interval, generally 1 to 2 weeks, until the course of the illness is determined.
In adults with ITP, therapy may be required for patients with platelet counts lower than 30,000 to 40,000/µL (30-40 × 109/L) or with bleeding. Initial therapy consists of glucocorticoids. Patients who do not respond to glucocorticoid therapy should be treated with an additional agent such as intravenous immune globulin or anti-D immune globulin or rituximab.
Splenectomy leads to a sustained remission in 75% of patients. Because of this patient's lack of symptoms and platelet count greater than 30,000/µL (30 × 109/L), therapy is unnecessary at this time, and the patient may be safely observed.
