Pituitary tumor can be accompanied with various pituitary hormone abnormalities. Pituitary tumors can be divided into functioning or nonfunctioning tumors. A functioning pituitary tumor, via the oversecretion of pituitary hormones, causes diverse clinical features. A nonfunctioning pituitary tumor can be accompanied with pituitary dysfunction and this may be due to compression or destruction of normal pituitary tissue, suppression of the pituitary portal system or direct damage to the hypothalamus. Corticotropin-releasing hormone (CRH) deficiency, which is caused by defects in the synthesis or release of CRH, is a cause of secondary adrenocortical insufficiency. The clinical presentations are hypoglycemia, weight loss, anemia, weakness, nausea, vomiting and hyponatremia. Acquired CRH deficiency has also been suggested to occur based on a lack of adrenocorticotropic hormone (ACTH) response to insulin-induced hypoglycemia, but there is a normal ACTH response to exogenous CRH. We experienced a case of a woman with pituitary macroadenoma accompanied with CRH deficiency. We report here on this case with the review of the literature.
BACKGROUND Determination of the adequate dose of glucocorticoid replacement therapy, in patients with secondary adrenal insufficiency, is of great importance to avoid the consequences of under or over treatment. The aims of this study were: 1) to assess the value of adrenal cortical function tests in determining whether glucocorticoid replacement should be given, and 2) to investigate the adequate maintenance dose of glucocorticoid in patients with secondary adrenal insufficiency. METHODS: Forty patients, with secondary adrenal insufficiency, confirmed by the insulin-induced hypoglycemia test (IHT), were studied. All subjects underwent basal serum cortisol measurement, IHT and 250 g rapid ACTH stimulation tests (AST). The clinical usefulness of these tests, for the determination of glucocorticoid replacement therapy, was evaluated in patients with secondary adrenal insufficiency. 26 of the 40 patients had received prednisolone (Pd) (5 mg per day) replacement due to symptoms from adrenal insufficiency. The dose of Pd was serially changed from 5 to 3.75, and then to 6.25 mg per day, every 3 month. The measured lipid parameters, serum osteocalcin and urinary N-telopeptide were measured and the quality of life evaluated by the administration of an Addisonian questionnaire, both before and after the dose changes. RESULTS: 1) For all tests, cut-offs were selected that would provide adequate specificity and sensitivity. When the cut-offs were set to provide 95% specificity, the corresponding sensitivitycut-off values, obtained with basal serum cortisol, peak serum cortisol in IHT and AST were: 88.4% <5 microgram/dL, 80.7% <11 microgram/dL and 76.9% <16 microgram/dL. 2) The urinary type I collagen N-telopeptide, total cholesterol, HDL- and LDL-cholesterol levels were significantly increased, and the serum osteocalcin levels significantly decreased when the daily dose of Pd was increased to 6.25 from 3.75 or 5 mg. The LDL-cholesterol levels especially, were significantly increased, even though the change in the Pd from 3.75 to 5 mg per day was subtle. CONCLUSION: The basal cortisol levels, HPA axis tests and the symptoms of patients may be helpful to determine whether prednisolone replacement therapy should be given. It is suggest that an adequate dose of glucocorticoid replacement therapy should be not exceed Pd 5mg per day, so as not to have adverse effects on the bone and lipid metabolisms.
BACKGROUND Although insulin induced hypoglycemia test is a standard diagnostic method in assessment of hypothalamo-pituitary-adrenal axis, rapid ACTH stimulation test using 250microgram has been used as a first line diagnostic test especially in secondary adrenal insufficiency due to iatrogenic Cushing syndrome because it is easy and safe. However, it was suggested that a maximal cortisol response can be achieved with a much lower ACTH dose and 1microgram ACTH enhances the sensitivity without decreasing specificity of test. Also recently, there was a report that midnight to morning urine cortisol increment is more accurate, noninvasive method can be used for measurement of hypothalmo-pituitary-adrenal axis. In this study, we compared the 1microgram ACTH stimulation test with midnight to morning urinary free cortisol increment in secondary adrenal insufficiency due to iatrogenic Cushing syndrome to study the agreement of two test and accuracy of increment of urinary free cortisol in diagnosis of adrenal insufficiency. METHODS: Double voided urine sample were collected at midnight and 8 A.M. in 12 patients who have Cushing-like feature and history of taking glucocorticoids and in 12 normal controls. Urinary free cortisol was measured and cortisol increment was defined as the morning urine free cortisol minus the midnight urine free cortisol. The 1microgram ACTH stimulation test was performed in 12 iatrogenic Cushing syndrome patients at the same day and compard with the result of cortisol increment. RESULTS: Using the results of 12 controls, normal urine free cortisol increment was defined as greater than 165.5nmol/L(6.0microgram/dL). Subnormal cortisol response in 1microgram ACTH stimulation test was noted in 8 out of 12 patients group and urinary free cortisol increment was not observed in 7 out of 8 subnormal response group. Normal cortisol response in 1microgram ACTH stimulation test was noted in 4 out of 12 patients group and urinary free cortisol increment was observed in 3 out of 4 normal response group. So 83% of concordance rate between 1microgram ACTH stimulation test and urine free cortisol increment was recorded. CONCLUSION: Urinary free cortisol increment has high concordance rate with 1microgram ACTH stimulation test and simple, easy test in diagnosing secondary adrenal insufficiency due to iatrogenic Cushing syndrome. Further study including more patients will be helpful to know the adequacy and reliability of test in evaluation of hypothalamo-pituitary-adrenal axis.