Etiology

Description

Consumption

Seen in larger blood loss surgeries

Occurs immediately after surgery

Returns toward normal within 2–3 days

Thrombocytopenia due to infection

Associated with both viral and bacterial infections

Can be seen as part of disseminated intravascular coagulation (DIC) process

Other mechanisms less well understood [1]

Pseudo-thrombocytopenia

Artifact due to EDTA in CBC tube. Clumping present on smear. Redraw platelet count in tube containing citrate instead of EDTA

Heparin-induced thrombocytopenia

Platelet count usually falls >50 % of baseline but nadirs >20,000/μL

Can cause skin necrosis, DVT, pulmonary embolism, venous sinus thrombosis, and stroke (see Chap. 21)

Dilution of platelets after transfusion

Occurs soon after transfusion (may be soon after surgery if transfusions are given during case)

Severity tends to be proportional to the volume of blood administered and usually seen in large volume resuscitations

Clinical course usually benign

Platelet count usually returns to normal within 3–5 days after blood transfusion [1]

Non-HIT drug-induced immune thrombocytopenia

Quinidine, digoxin, valproic acid, alpha-methyldopa, penicillin class drugs, thiazides, trimethoprim/sulfamethoxazole, cimetidine, famotidine