# Blood glucose variability in early-onset adrenocorticotropic hormone deficiency induced by immune checkpoint inhibitor therapy with continuous blood glucose monitoring: a case report

## TL;DR

This case report shows how blood glucose monitoring helped detect early-onset hormone deficiency in a diabetic patient undergoing cancer treatment.

## Contribution

Demonstrates the use of continuous glucose monitoring to identify endocrine issues caused by immune checkpoint inhibitors in diabetic patients.

## Key findings

- The patient experienced unstable blood glucose levels after ICI treatment, with nocturnal hypoglycemia detected via CGM.
- Endocrine testing revealed hypopituitarism, highlighting the need for monitoring hormone function in such cases.
- CGM proved valuable in detecting subtle glucose fluctuations and guiding treatment adjustments.

## Abstract

Early diagnosis and treatment of immune-related adverse events (irAEs) associated with immune checkpoint inhibitors (ICIs) are essential because they directly impact patient quality of life. This report describes the case of an 85-year-old woman with type 2 diabetes on insulin therapy, whose glycemic fluctuations became highly unstable following irAE development. During treatment for refractory hepatocellular carcinoma with tremelimumab and durvalumab, she developed hyperglycemia and was hospitalized. Endogenous insulin secretion remained intact, and hyperglycemia improved after admission. Continuous glucose monitoring (CGM) revealed nocturnal and early-morning hypoglycemia from the fourth day of admission. Insulin requirements were tapered off; however, persistent anorexia and dyspnea led to the diagnosis of hypopituitarism through endocrine testing. For patients with diabetes who experience abnormal blood glucose fluctuations after ICI therapy, clinicians should monitor changes in endogenous insulin secretion and consider the possibility of hypoadrenocorticism. CGM may be valuable for detecting these endocrine abnormalities.