A 46 year old male who has never been hospitalized is admitted for e. coli bacteremia treatment. On hospital day 4 you note this non-blanchable rash. He's been getting heparin 5000 IU TID and has never taken any medications. Platelets today are 120. On admission they were 205.
What should you do next:
A. Stop heparin, start direct thrombin inhibitor
B. Stop heparin only
C. Order HIT Antibody
D. Leave heparin, don't order any HIT tests
The best answer here is D. HIT is a clinical diagnosis based on the timing, platelet drop, presence of clots and whether there are other causes of thrombocytopenia.
The best answer here is D. HIT is a clinical diagnosis based on the timing, platelet drop, presence of clots and whether there are other causes of thrombocytopenia.
Our patient has a platelet drop of between 30-50% but this occurred under 5 days. There was no mention of clots. Moreover, the patient is being treated for bacteremia. While not mentioned what antibiotic he is on, many are known to cause thrombocytopenia. Testing for HIT with serology in patients with low clinical probability of HIT is not indicated and may cause unneeded treatment if falsely positive.
In patients who are high or intermediate probability, then heparin (or LMWH) should be stopped, and another form of anticoagulation (such as a direct thrombin inhibitor) should be started until more data from serology can be obtained.
Of note, even if patient does not have HIT, the heparin may need to be stopped if the platelets continue to lower or there is any concern for bleeding.
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