Critical illness–related corticosteroid insufficiency

Critical illness–related corticosteroid insufficiency is a form of adrenal insufficiency in critically ill patients who have blood corticosteroid levels which are inadequate for the severe stress response they experience. Combined with decreased glucocorticoid receptor sensitivity and tissue response to corticosteroids, this adrenal insufficiency constitutes a negative prognostic factor for intensive care patients. The hypothalamic-pituitary-adrenal axis (HPA axis), in which the hypothalamus and pituitary gland control adrenal secretions, undergoes profound changes during critical illness. Both very high and very low levels of cortisol have been linked to a poor outcome in intensive care patients. It has been suggested that high levels could represent severe stress, whereas low levels are due to blunted cortisol production and response. CIRCI can be suspected in patients with low blood pressure despite resuscitation with intravenous fluids and vasopressor drugs. The Surviving Sepsis Campaign guidelines advocate intravenous hydrocortisone only in adults with septic shock and refractory hypotension. The exact definition of this condition, the best ways to test for corticoid insufficiency in critically ill patients, and the therapeutic use of (usually low doses) of corticosteroids remains a subject of debate. The best known feature that suggests a possible underlying adrenal insufficiency is low blood pressure despite resuscitation with intravenous fluids, requiring vasopressor drugs. These patients typically display tachycardia and other signs of hyperdynamic shock. Other symptoms include fever, purpura fulminans, and gastrointestinal or neurological disturbances. All these features are relatively non-specific in intensive care patients. In some patients a specific reason for adrenal insufficiency can be suspected, such as prior intake of corticosteroids that suppressed the HPA axis, or use of enzyme inducing drugs such as phenytoin.