A Rare Cause of Fever of Unknown Origin: A Case of Secondary Adrenal Insufficiency

Abstract

Abstract

Fever is one of the most common symptoms observed in infecXous diseases.However, non-infecXous causes should also be considered in the differenXal diagnosis.In paXents presenXng with a common symptom such as fever, it is important to keep adrenal insufficiency in mind as a rare but possible underlying cause.A 54-year-old woman with a history of coronary artery disease, hypertension, and hypothyroidism presented with complaints of faXgue, weakness, nausea, vomiXng, abdominal pain, headache, and fever.Her past medical history was notable for a previous pituitary adenoma surgery.Laboratory tests revealed elevated C-reacXve protein (65 mg/L) and procalcitonin levels (33.2 ng/mL).To invesXgate a possible infecXous eXology, neck, thoracic, and abdominal computed tomography, transthoracic echocardiography, blood and urine cultures, and other infecXous disease workups were performed, but no pathology was idenXfied.Pituitary magneXc resonance imaging revealed a macroadenoma.Laboratory findings showed hyponatremia and decreased early morning corXsol levels (1.82 μg/dL), while adrenocorXcotropic hormone (ACTH) levels were within the normal range.A high-dose ACTH sXmulaXon test confirmed the diagnosis of secondary adrenal insufficiency.The paXent showed a dramaXc clinical improvement aner glucocorXcoid replacement therapy and was discharged with an appropriate treatment plan.When invesXgaXng the cause of fever, a thorough medical history, repeated physical examinaXons, and appropriate use of laboratory and imaging studies are essenXal.Common eXologies should be considered first, and if no diagnosis is established, rare causes must be carefully evaluated.