Despite their excellent anti-inflammatory efficacy, the use of GCs as therapeutics is often restrained due to two major drawbacks. First, long-term treatment with GCs is often accompanied by severe side effects, such as diabetes, increased risk of infection, osteoporosis, hypertension, and so forth [ 25 , 26 ]. Occurrence of GCs resistance also restricts many GC-based therapies. Second reason, under normal condition hypothalamic-pituitary-adrenal (HPA) axis regulates the secretion GCs, suppression of HPA axis and adrenal failure may result in inadequate GCs activity to down regulate inflammatory response in severe illness patients. Few studies investigated the relationship between adrenal function and severity of pneumonia. Increased serum cortisol concentration was reported and shown to be linked with severity and mortality in CAP [ 27 , 28 ].