8233 Cushing Disease Presenting As Severe Persistent Hypokalemia

Abstract Disclosure: G. Palaguachi: None. A. Randhawa: None. M. Sattar: None. G. Mahajan: None. J. Karam: None. Introduction: The clinical presentation of Cushing Disease represents a wide spectrum of clinical and laboratory findings, including electrolyte derangements such as hypokalemia. In this case report, we describe a patient in whom the admission for severe persistent hypokalemia prompted the diagnosis of Cushing Disease. Clinical Case: A 35-year-old woman with history of type 2 diabetes, hypertension, and hyperlipidemia, presented to the Emergency Department with worsening bilateral lower extremities swelling, impairing her ability to walk, found to have severe hypokalemia with K level of 2.8 (3.4-4.8 mmol/L), in additional to right pubic rami fracture, left breast abscess, oral thrush, and severe hyperglycemia with HbA1C of 15.4%. Additional history was relevant for hirsutism, scalp hair thinning, weight gain, and amenorrhea of few months duration. Physical examination was significant for round face, thin scalp hair, oral thrush, facial hirsutism, central obesity, wide abdominal striae, onychomycosis, thin skin with multiple ecchymoses, bilateral lower extremity edema, and thin extremities. Her hypokalemia was resistant to therapy and K level remained in 3.2-3.5 mmol/L range on the third week of admission despite oral and intravenous potassium replacements and spironolactone high dose therapy at 100mg twice a day. Additional laboratory testing showed Cortisol 25.0 (6.70 - 27.60 ug/dL) and normal Aldosterone and renin levels. Given absence of otherwise clear etiology of hypokalemia, and presence of multiple features of Cushing’s syndrome, further inpatient evaluation included 24-hour Urine Free Cortisol level that came back at 2754 (3.5 - 45.0 mcg/24hour), 1 mg Dexamethasone Suppression Test Cortisol of 24.9 (6.70 - 27.60 ug/dL), ACTH of 151.0 (7.2 - 63.3 pg/mL), and 8 mg Dexamethasone Suppression Test Cortisol of 14.2 (6.70 - 27.60 ug/dL). MRI Pituitary showed a pituitary adenoma (0.7 x 0.3 cm) with cavernous sinus involvement. A diagnosis of Cushing disease was made and the patient underwent transsphenoidal surgery on the fourth week of hospital stay with diffuse ACTH staining of the tumor. Postoperatively, cortisol levels were not suppressed suggesting persistent disease, but hypokalemia resolved while on Spironolactone. Conclusion: This patient had several classical features of hypercortisolemia with associated hyperglycemia, recurrent infections, and bone fractures, however the finding that connected the dots and prompted establishing her diagnosis was her severe refractory hypokalemia. Although not a defining feature of Cushing Disease, and usually more pronounced with ectopic ACTH secretion, severe and/or persistent hypokalemia can be part of the presenting symptoms. This case demonstrates the importance of including Cushing Disease as part of the differential diagnosis of persistent hypokalemia in correlation with other clinical signs and diagnostics. Presentation: 6/2/2024