A Case of Incidentally Discovered Subclinical Cushing Syndrome in a Patient with Chronic Fatigue and Anxiety
A 51-year-old woman visited the department of family medicine, Pusan National University Yangsan Hospital, Yangsan, Korea, complaining of a 2-year history of anxiety and fatigue. She had previously visited a cardiologist and was diagnosed with early-stage diabetes with known hypertension, and prescribed alprazolam and lorazepam. However, her symptoms were not alleviated, and fatigue, weakness, and dizziness developed. She also visited a neurologist and rehabilitation specialists, but these symptoms persisted. Her underlying diseases included 10 years of hypertension, 2 years of diabetes, and lumbar neuropathy following surgery for spinal stenosis 2 years ago. She was also a chronic hepatitis B carrier. Her family history did not yield any remarkable findings, and she had no history of smoking or drinking. On physical examination, her blood pressure was 149/91 mm Hg; pulse, 74 beats/min; temperature, 36.5℃; and respiratory rate, 20 breaths/min. Her weight was 47.9 kg, and her body mass index was 19.8 kg/m2. The patient was in good condition and her chest and abdomen were normal. There was no peripheral edema. The results of her neurological examination were normal.\nThe results of routine laboratory blood tests and thyroid function tests were normal. Routine urine analysis revealed microscopic hematuria (red blood cell [RBC] > 30/HPF) and rechecked value was RBC 3-5/HPF. Abdominal ultrasonography revealed no specific findings except for mild fatty liver. Computed tomography (CT) was performed for the unexplained hypertension and differential diagnosis of hematuria. CT showed a right renal stone, and a well-circumscribed and homogeneous 2.7 cm-sized mass containing a fatty component in the left adrenal gland on a non-contrast-enhanced CT, suggesting adrenal adenoma (). There was no specific finding on endoscopy except for erosive gastritis. Dual-energy X-ray absorptiometry revealed osteopenia.\nThe patient received endocrine evaluation for the differential diagnosis of adrenal incidentaloma. Baseline serum cortisol at 8:00 a.m. (17.17 µg/dL) was normal but the 24-hour excretion of urinary free cortisol (UFF) (100.54 µg) and serum basal 17-hydroxyprogesterone (19.0 mg/d) were elevated. A low-dose dexamethasone suppression test (DST) (0.5 mg orally, 4 times a day for 2 days, with measurement of serum cortisol and other steroids at 8:00 a.m. the following morning, and determination of UFF) failed to suppress the serum cortisol level (14.78 µg/dL) and the 24-hour UFF (282.56 µg). High-dose DST (2 mg, 4 times a day for 2 days) also failed to suppress the serum cortisol level (16.82 µg/dL) and the 24-hour UFF (186.62 µg). The 24-hour urinary excretion of catecholamines and metanephrine, measured to rule out pheochromocytoma, showed normal results (epinephrine 1.0 µg/d, norepinephrine 54.5 µg/d, and metanephrine 0.672 mg/d). Renin plasma activity was 0.26 ng/mL/h, aldosterone was 9.63 pg/mL, and the aldosterone renin activity ratio was normal (0.96), excluding an aldosterone-producing adenoma. Therefore, the adrenal mass on CT was diagnosed as a cortisol-producing tumor. The tumor was surgically removed by left laparoscopic adrenalectomy. The pathological diagnosis was adrenocortical adenoma, 3 × 2 cm in size, without any evidence of malignancy.\nAfter the resection of the adrenal adenoma, the patient's general condition improved and self-reported anxiety and dizziness disappeared. Her blood pressure stabilized with fewer antihypertensive medications, and her hemoglobin A1c level decreased to 5.3% after 5 months. She was followed up with supplemental prednisolone 5 mg/d to treat a suppressed hypothalamic pituitary axis (baseline serum cortisol at 8:00 a.m., 2.78 µg/dL; adrenocorticotropic hormone, 11.1 pg/mL).