Cushing-like syndrome

The common side effects of long-term corticosteroid therapy are summarized in Figure 27.13. [Note Increased appetite is not necessarily an adverse effect, since it is one of the reasons for the use of prednisone in cancer chemotherapy.] The classic Cushing-like syndrome—redistribution of body fat, puffy face, increased body hair growth, acne, insomnia and increased appetite—are observed when excess corticosteroids are present. Increased frequency of... 

The authors thought it likely that inhibition of cytochrome P-450 by ritonavir increased the systemic availability of fluticasone and thus caused Cushing s syndrome in this patient. 

In addition to systemic steroids causing iatrogenic Cushing s syndrome, they also can lead to increased susceptibility to infection, osteoporosis, sodium retention with resultant edema, hypokalemia, hypomagnesemia, cataracts, peptic ulcer disease, seizures, and gen-erahzed suppression of the HPA-axis. Long-term comphcations tend to be insidious and less likely to respond to steroid withdrawal. 

Rare examples of serotonin-producing endocrine tumors may occur within the pancreas. Other tumors occurring as primary pancreatic endocrine tumors may produce growth hormone-releasing hormone (acromegaly), ACTH (Cushing s syndrome), and PTH or PTH-like peptide (hypercalcemia). Nonfunctional pancreatic endocrine tumors may contain scattered cells positive for a variety of hormones, most commonly PP and glucagon (Fig. 10.40). 

Cushing s syndrome is the most likely diagnosis in this case. One can be confident of the diagnosis in view of the increased urinary cortisohcreatinine ratio, the absent diurnal rhythm, failure to suppress with low-dose dexamethasone and the failure of the insulin-induced hypoglycaemia to stimulate cortisol secretion. 

Benign tumors in the pituitary or adrenal glands can lead to excess release of ACTH or cortisol into the blood, causing the symptoms of Cushing syndrome. Typically, excess levels of endogenous cortisol— not synthetic forms of cortisol—can cause hypertension, most likely because of its weak binding capacity with mineralocorticoid receptors (i.e., aldosterone receptors). 

If hormone imbalance is present, treatment centers around restoring hormone status. For example, in hyperaldosteronism, the offending tumor or tissue is removed, and in Cushing syndrome (with corticosteroids that behave like aldosterone causing absorption of sodium), treatment centers on decreasing the excess aldosterone or corticosteroids. If the level of aldosterone or corticosteroids is severely limited in the body, a deficiency of either hormone could occur, resulting in hyponatremia. 6 In diabetes insipidus (i.e., decreased ADH secretion), supplemental ADH is provided. Care must be taken during treatment with supplement to avoid excess ADH intake, which will cause retention of water and potential for dilutional hyponatremia. 6... 

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