| Mechanism of Thrombocytopenia | Differential Diagnosis | Comments |
|---|---|---|
| Impaired production | Hematologic malignancies20 | Often accompanied by abnormalities in other marrow cell lines (ie, red and white blood cells) |
| Aplastic anemia41 | Other marrow cell lines affected as well | |
| Myelodysplasia20 | May be accompanied by abnormalities in other marrow cell lines; bleeding may occur at higher platelet counts than expected | |
| Drugs/toxins41,42 | For example, alcohol, chemotherapeutic agents, radiation | |
| Viral marrow suppression or damage42 | For example, because of EBV, parvovirus, HCV, or HIV | |
| Gestational thrombocytopenia43 | Generally mild [ie, platelet count >70,000/mL] and self-limited, resolving after delivery; exact mechanism of thrombocytopenia unknown—hemodilution and increased platelet turnover may also contribute | |
| Liver disease42 | Because of reduced levels of thrombopoietin, which is produced by the liver | |
| Nutritional deficiencies42 | For example, folate, vitamin B12 | |
| Inherited thrombocytopenias16,17,19,41 | Often present with incidental thrombocytopenia in adulthood; may have family history of thrombocytopenia or personal history of low platelet counts | |
| Destruction or consumption | Immune | |
| Medication, including heparin (most common), various antimicrobial, antiarrhythmic, anticonvulsant, and antifungal agents, and H2 receptor antagonists41 | ||
| ITP | Along with drug-induced thrombocytopenia, accounts for majority of isolated thrombocytopenia in adults16; typically chronic in adults41; may occasionally be accompanied by Coombs positive hemolytic anemia [Evans syndrome]41 | |
| Autoimmune disease41 | ||
| Infection41,45 | For example, HIV | |
| TTP in presence of ADAMTS13 autoantibodies41,46 | Coombs-negative hemolytic anemia and thrombocytopenia; may or may not have associated renal insufficiency, fever, and mental status changes; neurological symptoms vary, ranging from headache and confusion to seizures and stroke-like symptoms | |
| Nonimmune | ||
| HUS | Relatively uncommon but life-threatening cause of thrombocytopenia; classic form consists of microangiopathic hemolytic anemia, thrombocytopenia, and renal failure | |
| DIC41 | Other hallmark laboratory findings include decreased fibrinogen, elevated fibrin degradation products, and a positive D-dimer | |
| Sepsis42 | ||
| HELLP syndrome44 | Serious intrapartum condition characterized by hemolysis and elevated liver enzymes in addition to thrombocytopenia; frequently coexists with preeclampsia; may recur in subsequent pregnancies | |
| Physical destruction41,42 | For example, valvular disease, cardiopulmonary bypass, cavernous hemangiomas (eg, in Kassabach-Merritt syndrome) | |
| Sequestration | Splenomegaly41,42 |
ADAMTS, a disintegrin and metalloproteinase with thrombospondin type 1 motives; DIC, disseminated intravascular coagulation; EBV, Epstein-Barr virus; HCV, hepatitis C virus; HELLP, hemolysis, elevated liver enzymes, and low platelets; HIV, human immunodeficiency virus; HUS, hemolytic uremic syndrome; ITP, idiopathic thrombocytopenic purpura; TTP, thrombotic thrombocytopenic purpura.