thrombocytopenia

one of my patients the last couple of nights was a 79 year old lady who came into our unit after a small bowel resect., hypotensive, septic, had an MI, on the vent for 5 days. She's been off vasopressors for 12hours, BP increased to normal, making plenty of urine, responding appropriately. now she's just on tpn, NS, and a fentanyl gtt for pain. She was on CPAP last night and about to be extubated this day shift.

My question is about her platelets. They were at about 200 on admission 9/28, then steadily they've dropped. 54, 33, then 16 today. Her Hgb has stayed above 10. She was on lovenox since 9/29 30mg per day, now dc'd. We sent out a HIT panel yesterday (our lab can't do it) and it apparently won't be back until Friday. This morning I started a unti of platelets with 2 ordered.

Now this is where I'm confused. After reading up on this a little, it sounds like HIT is rare. So a more likely explanation for her thrombocytopenia is sepsis, right? And where the problem with HIT is increased thrombus formation, the problem with sepsis related thrombocytopenia is increased bleeding risk?

There's really no way to guess. Pt will need a work-up. HIT is a possibility, sepsis (of course), several antibiotics can cause the drop, etc., etc. It's hard to even attempt a guess because there're so many possibilities. If patient was on Lovenox (low molecular weight-heparin), HIT is less likely to develop...but certainly still can. But you'reright, true HIT is associated with increased thrombus formation, and ANY thrombocytopenia can cause bleeding. However, even with a platelet count s low as 16,000, your patient may not exhibit any overt signs of bleeding (or thromus formation).

Best bet is to pick the brain of the hematologist on the case...or if one is not, they should get one.

Hi Hiji,

LMWH is more commonly used now a days due to the associated problems with UFH (Unfractionated Heparin) which had a direct impact on platelet counts usually within 6 to 14 days of administering. That withstanding, LMWH can also have the same associated side effect in some patients. The question I have is was there a PT, aPPT or normalized ratio prior to administering the lovenox. Many facilities will start an initial IV regimen of UFH then switch to LWMH afterwards. That might be a direction to look as well. Does your patient exhibit any signs of occult blood, ecchymosis or petechiae or gingival bleeding?

And yes sepsis can be the cause of thrombocypenia but I think you'd see a direct correlation with that on WBC panel. I'm curious as to her ph since sepsis can cause acidosis which can cause a depletion of platelets as well. Like Dinith88 said there are many causes that can affect platelets count and aggregation. But follow the logic from the test and I'm sure you'll at least be in the ballpark.