SHM Converge Scientific Abstract ePoster Gallery-Pituitary Pandemonium: A Case of Autoimmune Hypophysitis

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This case report describes a 43-year-old woman with triple-negative breast cancer treated with carboplatin, paclitaxel, and pembrolizumab, a PD-1 immune checkpoint inhibitor. Several months after treatment, she developed progressive lightheadedness, fatigue, weight loss, recurrent hypoglycemia, and hypotension. Because her symptoms could be mistaken for chemotherapy side effects and malnutrition, the diagnosis was initially not obvious.<br /><br />During hospitalization, she had repeated low blood sugar episodes and episodes of low blood pressure that improved with fluids. CT imaging of the chest, abdomen, and pelvis was unrevealing. Endocrine evaluation showed an undetectable morning cortisol and undetectable ACTH, consistent with secondary adrenal insufficiency due to autoimmune hypophysitis, an immune-related adverse event from pembrolizumab. MRI of the pituitary region showed an enhancing soft tissue mass involving the pituitary gland, supporting the diagnosis.<br /><br />She improved rapidly after treatment with IV hydrocortisone and was transitioned to oral hydrocortisone before discharge. The case emphasizes that immune checkpoint inhibitors can cause serious endocrine toxicities, including hypophysitis, which may present with nonspecific symptoms such as fatigue, headache, lightheadedness, hypotension, and hypoglycemia. Because these symptoms overlap with common cancer-treatment effects, clinicians must maintain a high index of suspicion.<br /><br />The report concludes that prompt recognition of immune-related adverse events, early hormone testing, steroid treatment, and multidisciplinary coordination are essential to reduce morbidity and improve outcomes in patients receiving immune checkpoint inhibitors.

Asset Subtitle

Brandon D. Muckley

Meta Tag

Author List Brandon D. Muckley, Brandon Davis, Richard White

Category Clinical Vignettes

Concept Immune Checkpoint Inhibitor Therapy

Concept Immune-Related Adverse Event

Concept Hypophysitis

Concept Adrenal Insufficiency

Concept ACTH

Distinguished Non-Finalist

Presenter Organization Emory School of Medicine Division of Hospital Medicine

Presenting Author Brandon D. Muckley

Track Adult

Keywords

triple-negative breast cancer

pembrolizumab

immune checkpoint inhibitor

autoimmune hypophysitis

secondary adrenal insufficiency

hypoglycemia

hypotension

pituitary MRI

hydrocortisone

immune-related adverse event

Immune Checkpoint Inhibitor Therapy

Immune-Related Adverse Event

Hypophysitis

Adrenal Insufficiency

ACTH