SHM Converge Scientific Abstract ePoster Gallery-Severe Hypercalcemia and Adrenal Crisis: Unmasking Late-Onset Adrenal Insufficiency After Immune Checkpoint Inhibition

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This case describes a 45-year-old woman with stage IA triple-negative breast cancer treated with pembrolizumab-based neoadjuvant chemotherapy who later developed delayed immune-related adrenal insufficiency (AI) after immune checkpoint inhibitor (ICI) therapy. She presented with two months of worsening nausea and vomiting, followed by confusion. Initial workup showed severe hypercalcemia (corrected calcium 15.8 mg/dL), low PTH, low 1,25-vitamin D, and mild eosinophilia, without evidence of metastatic disease, brain pathology, pituitary lesion, or bone involvement.<br /><br />Her clinical course progressed over several months from nonspecific symptoms such as nausea, vomiting, constipation, and borderline hypercalcemia to shock requiring ICU care, vasopressors, IV fluids, hydrocortisone, and broad-spectrum antibiotics. Endocrine testing confirmed adrenal insufficiency with very low morning cortisol and an abnormal ACTH stimulation test, consistent with ICI-related AI. She also developed hypothyroidism (rising TSH), supporting immune-mediated endocrinopathy.<br /><br />The presentation highlights several important points: immune-related adverse events can occur months after ICI exposure; AI is rare but potentially life-threatening; and symptoms may mimic cancer progression or treatment side effects, delaying diagnosis. Although hyponatremia and hyperkalemia are classic findings in AI, they may be absent in patients with vomiting or dehydration. Hypercalcemia, while uncommon, can occur in adrenal insufficiency due to decreased renal calcium excretion, increased bone resorption, and enhanced intestinal absorption mediated by increased renal 1α-hydroxylase activity.<br /><br />The key message is that in patients previously treated with ICIs who develop unexplained nausea, vomiting, weakness, hypotension, eosinophilia, or hypercalcemia, clinicians should promptly consider adrenal insufficiency. Early recognition and glucocorticoid replacement can be life-saving.

Asset Subtitle

Tajana Juranovic

Meta Tag

Author List Harshani Yarlagadda, Mark Ayoub, Tajana Juranovic

Category Clinical Vignettes

Concept Immune Checkpoint Inhibitor Therapy

Concept Adrenal Insufficiency

Concept Immune-Related Adverse Event

Concept Adrenal Crisis

Concept Hypercalcemia

Distinguished Non-Finalist

Presenter Organization Charleston Area Medical Center, Department of Internal Medicine

Presenting Author Tajana Juranovic

Track Adult

Keywords

triple-negative breast cancer

pembrolizumab

immune checkpoint inhibitor

adrenal insufficiency

immune-related endocrinopathy

hypercalcemia

nausea and vomiting

hypotension

eosinophilia

hydrocortisone

Immune Checkpoint Inhibitor Therapy

Adrenal Insufficiency

Immune-Related Adverse Event

Adrenal Crisis

Hypercalcemia