Assessment of Cortisol Levels in Critically-ill Patients |
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An increase in tissue corticosteroid levels is an important protective response during acute illness. Cortisol production increases as much as six-fold in response to severe infection, trauma, burns, illness or surgery. Corticosteroid binding globulin decreases rapidly during these situations, resulting in increased levels of circulating free corticosteroids, which is the biologically active fraction. However, during severe illness, many factors can impair the normal corticosteroid response. These factors include pituitary apoplexy, CNS disease, inflammatory cytokines, anti-infective drugs, hemorrhage, exogenous corticosteroids and HIV infection.
Recognizing the clinical manifestations of adrenal insufficiency in a critically ill patient is extremely difficult. Therefore, measurement of cortisol levels as either random cortisol levels or the corticotropin (ACTH, Cosyntropin, Cortrosyn) stimulation test has been recommended. Interpretation of results is depicted in the following flow chart.
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