FRI215 Rifampin Induced Adrenal Insufficiency

Disclosure: S.R. Campbell: None. R.M. Tierney: None. J. Lim: None. Introduction: Rifampin is a main component of antimycobacterial therapy in active tuberculosis disease. Although adrenal insufficiency can be caused by infiltration of the pituitary or adrenal glands by Mycobacterium tuberculosis, rifampin has also been suggested as a potential causative agent. This case shows a rare example of rifampin-induced adrenal insufficiency in the setting of active tuberculosis disease. Case Presentation: A 42-year-old man with a history of gout and anemia presented with fevers, chills, unintentional weight loss, and productive cough for two weeks. He immigrated from Guatemala 20 years prior and was treated for tuberculosis disease as a child. Upon presentation, he was borderline hypertensive with chest CT showing bilateral nodular opacities in a pattern suggestive of atypical pneumonia. Acid fast bacilli stains were positive and cultures grew Mycobacterium tuberculosis. The patient was started on rifampin, isoniazid, pyrazinamide, and ethambutol (RIPE) therapy. Serum cortisol levels on day 4 of RIPE therapy were appropriate in the setting of acute illness (>20 mcg/dl). On day 6 of RIPE therapy, the patient became hypotensive requiring vasopressor support. Labs at that time showed hyponatremia, hypokalemia, and inappropriately low cortisol levels (<20 mcg/dl). ACTH stimulation testing was performed and was blunted with values of 14.50 mcg/dL at 30 minutes and 16.32 mcg/dl at 60 minutes. CT abdomen was also performed and showed no evidence of infiltration. He was started on IV hydrocortisone 50 mg every 6 hours with plans to taper after shock resolved. Following steroid taper, the patient again became hypotensive requiring vasopressors. IV hydrocortisone was resumed, and RIPE therapy was held. He was restarted on PO hydrocortisone 40 mg every 12 hours. Isoniazid, ethambutol, pyrazinamide, and rifampin were sequentially resumed. Pyrazinamide was replaced with moxifloxacin due to recurrent gout flares. The reintroduction of rifampin and rifabutin both resulted in fevers leading to the stoppage of rifamycin therapy. The patient was discharged with stable vital signs on isoniazid 300 mg daily, ethambutol 800 mg daily, moxifloxacin 400 mg daily, and hydrocortisone 30 mg every 12 hours with plans to follow-up with the State Department of Health, internal medicine, and endocrinology. Conclusion: Many drugs are known to cause adrenal insufficiency. There are a few examples in which rifampin has been suggested as a potential cause of adrenal insufficiency. Classically, adrenal insufficiency has been associated with infiltration of the adrenal glands or pituitary gland with Mycobacterium tuberculosis. This case, however, shows further clinical evidence of adrenal insufficiency caused by rifampin therapy and highlights the need for further research to be done to study this adverse effect. Presentation: Friday, June 16, 2023