Myeloproliferative disorders: a paradox of in-vivo and in-vitro platelet function.

A patient with features of a myeloproliferative disorder developed an acute multisystems illness and died. In-vitro platelet aggregation was imparied, but necropsy revealed widespread platelet-rich thromboemboli and multiple organ infarctions. It is suggested that platelets are damaged during disseminated intravascular platelet aggregation (DIPA) and that disaggregation of platelet thrombi and recirculation of platelets give rise to their subsequent hypofunction when tested in vitro.