Low Diagnostic Utility of Overnight High-Dose Dexamethasone Suppression Test in ACTH-Dependent Cushing's Syndrome

Bowel perforation associated with Cushing's disease: a case report with literature review

Although rare, endogenous hypercortisolemia, including Cushing's disease (CD), is known to cause bowel perforation and to mask typical symptoms of bowel perforation, leading to delayed diagnosis. Additionally, elderly patients with CD are considered to be at a higher risk for bowel perforation because intestinal tissue fragility tends to increase in the elderly. Herein, we describe a rare case in which a young adult patient with CD was diagnosed with bowel perforation associated with CD following severe abdominal pain. A 24-year-old Japanese man was admitted to the hospital for the evaluation of ACTH-dependent Cushing's syndrome. He suddenly complained of severe abdominal pain on the 8th day of hospitalization. Computed tomography revealed free air around the sigmoid colon. The patient was diagnosed with bowel perforation, underwent emergency surgery, and was saved. He was subsequently diagnosed with CD, and the pituitary adenoma was resected transsphenoidally. To date, eight cases of bowel perforation due to CD had been reported, with a median age of 61 years at the time of bowel perforation. Hypokalemia was detected in half of the patients, and all had a history of diverticular disease. Nevertheless, not many patients complained of peritoneal irritation. In conclusion, this is the youngest reported case with bowel perforation due to CD and the first report of bowel perforation in a patient without a history of diverticular disease. Bowel perforation may occur in patients with CD, irrespective of age and the presence of hypokalemia, diverticular disease, or peritoneal irritation.

Sensitivity of Different ACTH and Cortisol Concentration Values in Corticotropin-Releasing Hormone Based Tests in Cushing's Disease

PURPOSE

In Cushing's disease (CD) patients, the aim of the present study is to confirm sensitivity of several ACTH and cortisol concentration values in different time points, during corticotropin-releasing hormone (CRH) stimulation test and during CRH stimulation following dexamethasone suppression (DEX-CRH) test.

METHODS

We retrospectively analyzed cortisol and ACTH concentration increment during CRH and DEX-CRH tests in 23 patients with confirmed CD. Cortisol and ACTH concentrations were determined immediately before, 15 min and 30 min after CRH stimulation. We evaluated the sensitivity of different cutoff values including those reported in previous studies, in the diagnosis of CD.

RESULTS

During DEX-CRH test, 15 min serum cortisol concentration of 1.4 μg/dl (38 nmol/L) had a sensitivity of 90.9%, and serum cortisol concentration ≥1.27 μg/dl (35 nmol/L) had a sensitivity of 100%. For plasma ACTH, sensitivity of 100% was obtained using ACTH ≥3.5pmol/L (16 pg/ml) at 30 min. During CRH test, 35% increase from baseline in ACTH concentration had a sensitivity of 72.7%. Twenty percent increase in cortisol 30 minutes after stimulation yielded a sensitivity of 85.7%. The best sensitivity of ACTH and cortisol increment was obtained 15 min after stimulation, using 19% and 9% increase, respectively (sensitivity of 100% and 92.8%, respectively).

CONCLUSION

During CRH and DEX-CRH tests, the study findings agree with the good sensitivity of ACTH and cortisol cutoff values suggested in previous studies; yet, other cutoff values may give a higher diagnostic sensitivity.

Endogenous Cushing's syndrome during pregnancy

Endogenous Cushing's syndrome (CS) is rare during pregnancy, probably because hypercortisolism induces anovulation and infertility. To date, slightly above 200 cases have been reported in the literature. The most frequent etiology of CS diagnosed during gestation is from primary adrenal causes, namely adrenal adenomas and an entity called pregnancy-induced CS. The latter can be secondary to the aberrant adrenal expression of luteinizing hormone/human chorionic gonadotropin receptor (LHCGR) in the adrenal lesions. Diagnosis of CS during pregnancy is extremely challenging, as a consequence of the physiologic hypercortisolism normally present during pregnancy. Assessment of excess cortisol production tests should be interpreted cautiously using adapted upper limits of normal criteria for pregnant patients and a high index of suspicion is required for diagnosis. Imaging is also limited due to high risk of radiation exposure with computed tomography and teratogenicity with contrast agents. The optimal treatment strategy is surgical resection of adrenal adenoma or pituitary adenoma, ideally before 24 weeks of gestation to reduce the risk of maternal and fetal complications. In mild cases, surgery can be postponed until after delivery and treatment should focus on controlling metabolic complications of hypercortisolism, such as hypertension and dysglycemia. Maternal and fetal outcomes of excess cortisol exposure, except fetal loss, are not readily improved by successful treatment of hypercortisolism.