Question 15

Question:

A 49-year-old male is being treated for a pulmonary embolism. On the 6th day of hospitalization, he is found to have a platelet count of 65,000. Heparin therapy is stopped immediately to prevent which of the following complications?

Correct Answer: A. Arterial thrombosis

This patient likely has heparin-induced thrombocytopenia (HIT). Even though the platelet absolute count is lowered, HIT paradoxically causes more thrombosis than bleeding. HIT occurs when antibodies form to the heparin and platelet factor IV complex. The antibody reacts by attaching to the receptors, which in turn causes platelet activation. The typical presentation of HIT is a drop in platelet counts more than 30% in 5-10 days after initiation of heparin. The patient may present with widespread ischemic features. Patients with HIT require immediate treatment starting with the discontinuation of heparin.