Suspected Levonorgestrel-Releasing Intrauterine System (LNG-IUS)-Induced Secondary Adrenal Insufficiency: A Case Report

Central adrenal insufficiency (CAI) is a rare endocrine disorder characterized by insufficient secretion of adrenocorticotropic hormone (ACTH) from the pituitary gland, resulting in decreased cortisol production. Here, we present the case of a 19-year-old female with suspected iatrogenic CAI possibly induced by a levonorgestrel-releasing intrauterine system (LNG-IUS). The patient presented with syncopal events, fatigue, and hypotension, prompting admission to the emergency department. Initial investigations revealed low morning cortisol levels and an inadequate cortisol response to ACTH stimulation, supporting the diagnosis of CAI. Treatment with glucocorticoid replacement therapy led to clinical improvement. Removal of the LNG-IUS led to the recovery of the hypothalamic-pituitary axis. Despite the absence of documented cases of LNG-IUS-induced CAI in literature, similarities with other progestin formulations suggest a potential mechanism involving interaction with glucocorticoid receptors. Further research is needed to elucidate the exact pathophysiology and evaluate the safety of LNG-IUS in relation to the hypothalamic-pituitary-adrenal (HPA) axis. This case underscores the importance of considering hormonal contraceptives as potential triggers of CAI in clinical practice.