MON-480 Secondary Adrenal Insufficiency due to Inhaled Fluticasone Use Alone

Abstract Disclosure: N. Raja: None. M. Romanovschi: None. Y. Hu: None. Introduction: Secondary adrenal insufficiency (SAI) is a rare but clinically significant disorder characterized by impaired cortisol production due to decreased stimulation of the adrenal glands by adrenocorticotropic hormone (ACTH). It has a myriad of pathological causes but has rarely been demonstrated due to suppression of the hormone from inhaled and/or intranasal corticosteroid use alone. Case: This is the case of a 46-year-old female with a past medical history of asthma who presented with concern of adrenal insufficiency. The patient was noted to have low 24-hr urinary cortisol of 1.1 ng/mg (65-200 ng/mg) and low DHEA level of 1.0 ng/mg (20-750 ng/mg) , low AM cortisol of <0.1 ng/mg (30-130 ng/mg). Repeat lab work confirmed low ACTH of <5 pg/mL (6-50 pg/mL) and low AM cortisol <0.5 mcg/dL (4.0-22.0 mcg/dL). She endorsed associated symptoms of lightheadedness, weight loss and fatigue. Her life-long history of asthma was controlled on daily fluticasone propionate/salmeterol and albuterol as needed. She also suffered from intermittent asthma flares which required steroid courses with most recent prednisone course a year prior to presentation. She had been on fluticasone propionate/salmeterol for years with recent increase in dose to two puffs a day in the last six months. Her decreased AM cortisol level and symptoms suggested a diagnosis of adrenal insufficiency. Low ACTH suggested a secondary cause. Pituitary MRI was performed confirming no pituitary abnormalities. CT abdomen performed without any acute abnormality noted on adrenal glands. Her secondary AI was likely caused by her fluticasone use. She was recommended to start on hydrocortisone replacement however instead, she slowly tapered off her inhaled steroid over the course of three months. Her HPA axis function slowly recovered along with her fatigue and weight loss. Repeat AM cortisol after three months went back to 10.2 mcg/dL (4.0-22.0 mcg/dL). Discussion: This case presents secondary adrenal insufficiency arising from chronic inhaled corticosteroid use alone. It is well known that SAI may result from prolonged use of systemic exogenous glucocorticoid use by suppressing the hypothalamic-pituitary-adrenal (HPA) axis, leading to adrenal atrophy. The effects of inhaled or intranasal steroids were thought to be less significant. It has been better recognized that concomitant use of CYP3A4 inhibitor can cause AI such as seen in ritonavir with inhaled fluticasone or itraconazole and inhaled budesonide. It is rare to see inhaled steroids alone cause secondary AI. Through this report, we aim to raise awareness about the potential risk of SAI associated with inhaled steroid use alone. We would like to emphasize the importance of careful clinical evaluation in those receiving long-term corticosteroid therapy regardless of formulation, and prompt recognition and treatment to prevent adrenal crisis and improve patient outcomes. Presentation: Monday, July 14, 2025