Hemostatic alterations accompanying sickle cell pain crises.

Three patients with sickle-cell disease (SSD) were followed, weekly, for 1 1/2 to 2 years, during which time they experienced one or more episodes of crisis. Crisis was associated with reproducible sequential hemostatic alterations indicating intravascular fibrin formation and a marked disturbance in platelet economy. With crisis onset, or possibly before, there was an increase in plasma high-molecular-weight fibrinogen complexes and a transient fall in platelet count, with a subsequent rise in both fibrinogen concentration and platelet count; plasma fibrinogen peaked 1 week after crisis onset and platelet count approximately 2 weeks after onset. Subsidence of crisis was associated with a fall in high-molecular-weight fibrinogen complexes and a subsequent increase in fibrinogen first derivative, an early fibrinogen breakdown product. Hemostatic findings and patient clinical status were generally correlated, the findings during asymptomatic periods being essentially normal. Agents affecting platelet function (aspirin alone or in combination with dipyridamole) appeared to reduce the extent of laboratory abnormality, suggesting potential clinical usefulness in this disorder.