Case 145 | Clinical Pathology Unknown Conference

1. Presented by: Chinelo P. Onyenekwu, MD and reviewed by: Lorraine Blagg, EdD, MA, MLS(ASCP)^CMSBB, AHI(AMT)

Clinical Vignette:
The blood bank is experiencing a low platelet inventory and is triaging all platelet requests. There is a platelet transfusion request for a patient with complaints of headache, paresthesia, and vomiting of two days duration. The patient had hematuria on admission, with easy bruising. They require central venous catheter placement, and the Interventional Radiologist requests transfusion of one platelet product prior to the placement of the catheter. Your review of the chart shows the following laboratory results:

CBC:
White blood cell count: 10.61 K/cu mm (4.50-11.00)
Hemoglobin: 8.2 g/dL (12.0-15.0)
Hematocrit: 26.2% (36.0-46.0)
Platelet count: 6 K/cu mm (150-350)
Immature platelet fraction: 13.8% (0.1-6.3)

Peripheral blood smear (Outside Institution’s Review): Schistocytes and thrombocytopenia

ADAMTS13 Activity: <5% (70-150)
ADAMTS13 Inhibitor: 63.1% (0-44)

Question: What is the most likely diagnosis and the best way to handle the request for a unit of platelets?

A. Microangiopathic hemolytic anemia. Since the patient is anemic with evidence of blood loss, it is best to transfuse RBCs prior to administering platelets.

B. Thrombotic thrombocytopenic purpura. Since there is a shortage of platelets and the patient’s bleeding is not life threatening, do not approve the request for platelets.

C. Microangiopathic hemolytic anemia. Approve the platelet request as transfusion of platelets will increase the patient’s platelet counts and prevent continued subcutaneous or mucosal bleeding.

D. Thrombotic thrombocytopenic purpura. Recommend avoiding platelet transfusions and encourage urgent placement of central venous catheter placement and immediate commencement of therapeutic plasma exchange (TPE).