Differential Diagnosis

Splenomegaly with platelet sequestration

Increased platelet destruction by an immune mechanism; can occur as a result of:

  • Heparin-induced thrombocytopenia (HIT)

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  • Idiopathic or immune thrombocytopenic purpura (ITP)

  • Drug (other than heparin)-induced thrombocytopenia

  • Post-transfusion purpura (PTP)

Increased platelet destruction by non-immune mechanisms, as caused by:

  • DIC

  • Hemolytic uremic syndrome (HUS)

  • Thrombotic thrombocytopenic purpura (TTP)

Decreased platelet production most often occurs after exposure to drugs (e.g., chemotherapeutic agents) that suppress synthesis of new platelets or by infiltration of the marrow by tumor or other structures.

Suggested Additional Lab Testing

Platelet count establishes presence or absence of thrombocytopenia; 100,000 functional platelets/µL is usually considered adequate for any challenge to hemostasis.

Workup for DIC:

  • PT

  • D-dimer or FDP

  • Fibrinogen

  • Peripheral blood smear to check for schistocytes

Test for HIT:

  • Most often available is ELISA for antibody to platelet factor 4/heparin complex

  • ITP is a diagnosis of exclusion.