Critical illness is any illness, sickness or a disease or a corrective measure or situation which is life threatening or potentially life threatening. During critical illness, the state of stress results in increased energy expenditure, hypermetabolism, hyperglycemia and muscle loss.(1, 2) The mechanisms of these successive adaptive changes are increasingly understood and are now gathered into a general theory of the metabolic response to stress. Some of the specific endocrine changes which occur as a part of the stress response are as follows