Sickle cell crisis as evaluated from measurements of hydroxybutyrate dehydrogenase and myoglobin in plasma.

Data on plasma hydroxybutyrate dehydrogenase activity (I) and myoglobin concentration were used to evaluate painful sickle cell crises. I was increased during non-crisis steady state in patients with sickle cell disease as compared to normal values (232, SD 79.7 vs 85, SD 33 Sigma units/mL). During crisis, the mean value for I increased further to 379 (SD 139) Sigma units/mL. For 12 patients evaluated both during steady state and crisis, there was a mean increase in plasma I of 131% (SD 76%). Repeated determinations of I in sickle cell disease patients during several months while they were in steady state showed that baseline I varied by no more than 20% from the mean. Plasma myoglobin in patients with sickle cell disease was not above normal, but during crisis 21 of 39 patients tested had increased plasma myoglobin concentrations. Our data suggest that I may be a useful indicator of sickle cell crisis when the patient's own baseline value is available for comparison. Plasma myoglobin measurements give evidence of muscle damage during crisis with high specificity but low sensitivity.