Based on the clinical hematologist's findings, he confirmed the presence of blood in the urine (hematuria), fragmented red blood cells (schistocytes), decreased hemoglobin, elevated lactate dehydrogenase (LDH), and low platelets (thrombocytopenia). All of these findings are consistent with a hemolytic episode. The differential diagnoses includes:
Immune thrombocytopenia purpura generally lacks anemia and is dominated by petechial lesions and mucosal hemorrhage. The Coombs test is positive in autoimmune hemolytic anemia and is also frequently positive in SLE. In addition, leukopenia is commonly seen in SLE. Characteristic laboratory findings in PNH are anemia, leukopenia, and thrombocytopenia, also known as pancytopenia. The PT/APTT are increased in DIC. Also, in DIC the fibrinogen is usually decreased. It should be pointed out that no single test is diagnostic of DIC; however, in the appropriate clinical setting, patient history and type of bleeding, and laboratory data can ensure a diagnosis of DIC.
Some tests that may help exclude DIC are:
Hemolytic uremic syndrome was also ruled out (Table 4).
|Age||Peak incidence at 40 years||Childhood|
|Link to E. coli 0157:H7||Occasional||Yes|
|Thrombocytopenia||Severe||Moderate to severe|
|Organ involvement||Multiple||Limited to the kidney|
Modified from Harmening DH. Clinical hematology and fundamentals of hemostasis. 3rd ed. Philadelphia: F. A. Davis; 1997, 519.
A diagnosis of TTP was made based on the patient's clinical presentation and the supportive laboratory data. Patients with TTP initially present with nonspecific symptoms of malaise, weakness, and fatigue. TTP patients usually present with fever, abdominal pain and bleeding as a result of severe thrombocytopenia. Hemolysis is associated with an increase in serum LDH, total bilirubin, reticulocytosis, and the presence of spherocytes and fragmented red cells on the smear. Prothrombin time (PT), activated partial thromboplastin time (APTT), and fibrinogen levels are usually normal in patients with TTP, although FDPs may be slightly elevated.