A typical profile of the events that develop during the evolution of a severe sickle cell painful crisis in an adult in the absence of overt infection or other complications. Such events are usually treated in the hospital with an average length of hospital stay of 9–11 days in adults. Pain becomes most severe by day 3 of the crisis and starts decreasing by day 6 or 7. The Roman numerals refer to the phase of the crisis: I. Prodromal Phase; II. Initial Phase; III. Established Phase; and IV. Resolving Phase. Changes that may occur during the crisis are indicated by dots: their location on the X-axis indicates the time when they become apparent and their location on the Y-axis indicates their relative value in comparison to that of the steady state indicated by the horizontal dashed line. Arrows indicate the time when certain clinical signs and symptoms may become apparent.

Abbreviations: ISC, irreversibly sickled cells; RDW, red cell distribution width; HDW, Hb distribution width; RBC DI, red cell deformability index; CRP, C-reactive protein; SAA, serum amyloid A; LDH, lactate dehydrogenase; CPK, creatinine phosphokinase; ESR, erythrocyte sedimentation rate.

Reprinted with permission from Ballas SK.²⁷