Cardiac-Vascular Nursing (CVRN) Practice Exam

What is the major characteristic associated with heparin-induced thrombocytopenia (HIT)?

1. Gastrointestinal distress

2. Abrupt drop in platelet count to less than 50% of baseline

3. Thrombophlebitis

4. Elevated activated partial thromboplastin time (aPTT)

The correct answer is: Abrupt drop in platelet count to less than 50% of baseline

Heparin-induced thrombocytopenia (HIT) is primarily characterized by an abrupt drop in platelet count, typically to less than 50% of the baseline level. This decrease generally occurs about 5 to 14 days after the initiation of heparin therapy and can occur more quickly if the patient has been previously exposed to heparin. The pathophysiology of HIT involves the formation of antibodies against complexes of heparin and platelet factor 4, leading to platelet activation, increased risk of thrombosis, and ultimately a significant reduction in platelet counts. This abrupt drop in platelets can lead to a paradoxical increase in thrombotic events, which is why monitoring platelet counts in patients receiving heparin is crucial. Recognizing this key feature of HIT is essential for timely diagnosis and management, including the cessation of heparin and the use of alternative anticoagulants. The other options do not directly reflect the hallmark of HIT; gastrointestinal distress can occur for various reasons and is not central to HIT, thrombophlebitis might indicate inflammation but isn't specific to the condition, and while elevated aPTT can occur with heparin therapy, it is not diagnostic for HIT and does not reflect the key change in