Adrenal status in children with septic shock using low-dose stimulation test.

OBJECTIVES: There is paucity of data on the magnitude of absolute or relative adrenal insufficiency in septic shock, especially in children. We conducted a prospective study to determine the prevalence of adrenal insufficiency in children with septic shock using a low-dose Synacthen (1 microg) stimulation test.
DESIGN: Cross-sectional study.
SETTING: Pediatric intensive care unit in a tertiary care hospital in northern India. PATIENTS: Children with septic shock.
INTERVENTIONS: None.
MEASUREMENTS AND MAIN RESULTS: We performed cortisol estimation at baseline and after low-dose Synacthen (1 microg) stimulation at 30 and 60 mins in children with fluid refractory septic shock admitted to our pediatric intensive care unit. Basal cortisol levels <7 microg/dL and peak cortisol level <18 microg/dL were used to define adrenal insufficiency. An increment of <9 microg/dL after stimulation was used to diagnose relative adrenal insufficiency. As there is lack of consensus on the cutoffs for defining relative adrenal insufficiency using the low-dose adrenocorticotropic hormone test, we evaluated different cutoff values (increment at 30 mins, increment at 60 mins, greater of the two increments) and evaluated their association with the incidence of catecholamine refractory shock and outcomes. Children with sepsis but without septic shock were sampled for baseline cortisol levels as a comparison. Thirty children (15 girls) with septic shock were included; median age (95% confidence interval) was 36.5 (9.39- 58.45) months. Median Pediatric Risk of Mortality score was 22.5 (14.13-24.87). Fifteen (50%) children survived. The median (95% confidence interval) cortisol values at baseline and 30 mins and 60 mins after stimulation were 71 (48.74-120.23) microg/dL, 78.1 (56.9-138.15) microg/dL, and 91 (56.17-166.44) microg/dL, respectively. The median baseline cortisol value in age- and gender-matched children with sepsis was 11.5 microg/dL. None of the children with septic shock fulfilled the criteria for absolute adrenal insufficiency. However, nine (30%) patients had relative adrenal insufficiency (increment in cortisol <9 microg/dL). Of these nine patients, five (56%) died; of the 21 patients with a greater increment in cortisol after stimulation, ten died (p = .69). Compared with patients in septic shock with normal adrenal reserve, those with relative adrenal insufficiency had a higher incidence of catecholamine refractory shock (p = .019) but no difference in mortality rate (p = .69). On the sensitivity and specificity analysis using various cutoffs of increment, the best discrimination for catecholamine refractory shock was obtained with a peak increment <6 microg/dL.
CONCLUSIONS: Relative adrenal insufficiency is common in children with septic shock and is associated with catecholamine refractory shock.