EFFECT OF CLASSIC HEATSTROKE ON SERUM PROCALCITONIN

Objective: Procalcitonin, the precursor peptide of calcitonin, has bee n shown to be a serum marker of the severity and mortality of several systemic inflammatory response syndromes, This study addressed the cor relation of serum procalcitonin with the course of classic (nonexertio nal) heatstroke. Design: Serum samples were collected prospectively ev ery 6 hrs for 24 hrs. Setting: Heatstroke treatment unit, Makkah, Saud i Arabia. Patients: A total of 25 patients were admitted during the an nual Hajj pilgrimage in 1994, Ten patients evaluated in the same treat ment center with minor illnesses and without pyrexia served as control s. Interventions: Patients were cooled according to an established eva poration method. Measurements and Main Results: Standard critical care parameters including continuous rectal temperature, A rapid immunoche mical assay for serum procalcitonin was utilized. The mean serum proca lcitonin was elevated 20-fold on admission in patients with heatstroke compared with controls (p <.011), The procalcitonin concentration sub sequently increased to a pla teau by 6 hrs and remained increased at 2 4 hrs, compared with the admission level (p <.0001), In this study, 77 % of the patients with heatstroke survived, A subgroup analysis demons trated that the patients who survived had a significantly higher proca lcitonin concentration than those patients who died of heatstroke; a p rocalcitonin concentration of >0.5 ng/mL (>0.15 nmol/L) at 6 hrs predi cted survival (p =.02). Conclusion: Classic heatstroke is associated w ith increased concentrations of serum procalcitonin, particularly amon g survivors, Further studies are required to elucidate the source and action(s) of procalcitonin as well as its relationship to cytokine act ivation.