8130 A Case of Cushing’s Disease Presenting with Posterior Reversible Encephalopathy Syndrome

Abstract Disclosure: A.H. Chincholi: None. M.D. Goldberg: None. Introduction: Posterior reversible encephalopathy syndrome (PRES) is characterized by headaches, altered mental status, vision changes, and seizures, along with characteristic imaging findings of bilateral white matteredema in the posterior cerebral hemispheres. The syndrome often occurs in the context of severe hypertension, and has previously been reported in 6 patients with Cushing’s syndrome (CS) - 4 with ectopic sources of ACTH, 1 with micronodular adrenal hyperplasia and 1 pediatric case with Cushing’s disease. Clinical Case: An 18-year-old-man was admitted to our hospital after experiencing a second seizure at home. His presentation was significant for lethargy, hypertension, facial plethora, acne, proximal muscle weakness,central obesity, extensive purple striae, hyperglycemia, and hypokalemia. Two months prior, a diagnosis of ACTH-dependent CS had been made at an outside facility when he presented with a hypertensive emergency and new-onset diabetes. One month prior, he had been hospitalized with pneumonia complicated by acute kidney injury requiring temporary hemodialysis, and his first seizure. Brain MRI had shown extensive T2/FLAIR hyperintensities in the temporal lobes and cerebellum,consistent with PRES. On this admission, morning serum cortisol was 56.1 mcg/dL, and then 57.9 mcg/dL following 10 mg dexamethasone at night; ACTH was 120 pg/mL, and 24-hour UFC was 2,204 mcg. Ketoconazole and spironolactone were added, with no appreciable improvement in his cortisol levels but normalization of blood pressure. He required up to 150 units of insulin per day to manage his hyperglycemia. PituitaryMRI revealed a 0.6 cm adenoma, along with the T2/FLAIR hyperintensities. Chest CT showed no masses. A 10 mcg IV desmopressin stimulation test resulted in a 248% increase in ACTH and 32% increase in cortisol, and a second MRI with a 3T scanner measured the pituitary adenoma to be 1.0 cm. It was concluded that he had Cushing’s disease, and he underwent transsphenoidal resection of the pituitary adenoma. The surgery was curative, as reflected by postoperative central adrenal insufficiency. The patient was discharged on postoperative day 3 with oral hydrocortisone. Two weeks later, he was euglycemic off insulin and his blood pressure had normalized off spironolactone. Three months later, his muscle weakness and his headaches had completely resolved. Brain MRI showed complete resection of the pituitary adenoma and resolution of the white matter changes. Conclusion: To our knowledge, this is the first report of PRES associated with CS due to an ACTH-secreting pituitary adenoma in an adult. We suspect that this patient’s marked secondary hypertension triggered the reversible encephalopathy. Providers should be aware of this potential complication of hypercortisolism. This case also highlights the utility of desmopressin stimulation test in defining the cause of ACTH-dependent CS. Presentation: 6/3/2024