A 35-year-old female is hospitalized for knee replacement surgery. Preoperative blood tests reveal a platelet count of 64 × 10⁹/L. The surgery is postponed, and the platelet count is repeated two days later when it is 48 × 10⁹/L. All other labs appear normal and the platelet estimate on the peripheral smear correlates with the decreased platelet count. Based on this information, what is the most likely diagnosis?

Question

Quizplus · Accepted Answer

Chronic Immune Thrombocytopenic Purpura (ITP) is the most likely diagnosis given the isolated thrombocytopenia (low platelet count) with normal other lab values and a gradual decrease in platelet count without an acute onset, which is more indicative of a chronic process. Acute ITP typically presents more suddenly, often in children following a viral infection. TTP and HUS usually present with a combination of symptoms and lab abnormalities, including anemia, renal dysfunction, and neurological symptoms, which are not mentioned in this scenario.

A 35-Year-Old Female Is Hospitalized for Knee Replacement Surgery