Review Question - QID 106575

This patient is suffering from thrombotic thrombocytopenic purpura (TTP). TTP shows reduced platelet count and moderate-to-severe schistocytosis on peripheral blood smear.

Thrombotic thrombocytopenic purpura (TTP) is a relatively rare but severe bleeding disorder that presents with the five following findings/symptoms: 1) fever, 2) microangiopathic hemolytic anemia, 3) thrombocytopenia leading to abnormal bleeding/bruising, 4) renal failure, and 5) neurologic abnormalities and/or a change in mental status. TTP usually occurs in patients under 50 years of age, and risk factors for the disease include: pregnancy, oral contraceptive pill use, or HIV. Of note, hemolytic uremic syndrome (HUS) is characterized by all of the symptoms/findings of TTP except without the fever or neurologic symptoms.

Illustration A shows a blood smear from a patient with TTP; the arrows indicate schistocytes. Illustration B shows the rash seen with TTP; note that the purpura do not blanch with pressure from the overlying slide.

Incorrect Answers:
Answer 1: Ovalocytes are seen in hereditary elliptocytosis.
Answer 2: Spherocytes suggest the diagnosis of hereditary spherocytois or autoimmune hemolytic anemia.
Answer 3: Atypical lymphocytes are seen following viral infections, particularly infectious mononucleosis.
Answer 5: Rouleaux formation (stack of coins/poker chips) is seen most commonly in multiple myeloma.