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Thyroid

(21.05) Simultaneous Hypophysitis with Adrenal Crisis and Thyroiditis due to Immunotherapy: A Case Report

Saturday, May 11, 2024
12:30 PM – 12:45 PM CDT
Location: ePoster Showcase, Empire Ballroom Foyer, Level 2
Introduction : Therapy with immune checkpoint inhibitors (ICI) have significantly increased the survival of various cancers. However, ICI frequently cause immune-related adverse events (irAEs), of which, endocrinologic irAEs are common. Symptoms of endocrinologic irAEs can be nonspecific and require a high level of suspicion to diagnose. We describe a case of secondary adrenal insufficiency (AI) with concurrent thyroiditis in a patient on combination ICI therapy.

Case(s) Description : A 68-year-old woman with history of metastatic melanoma on combination nivolumab and ipilimumab for 3 months presented for one week of recurrent fevers, fatigue, vomiting, and altered mentation. On physical examination, she was mildly ill-appearing and lethargic. Her vital signs showed blood pressure 83/55 mmHg, heart rate 127 bpm, and temperature 38.1°C. Initial sodium level was 124 mEq/L. She underwent infectious evaluation, which was negative. She had recurrent fevers and tachycardia. Further evaluation showed low morning cortisol (0.9 ug/dL), low ACTH (< 5 pg/mL), suppressed TSH (0.05 uIU/mL), and elevated free T4 (7.26 ng/dL). She was started on stress dose hydrocortisone with rapid clinical improvement. She was initially given methimazole for thyrotoxicosis, but stopped after her thyroid ultrasound and antibody testing returned negative. She developed hypothyroidism one month later consistent with diagnosis of thyroiditis and was started on levothyroxine. She continued physiologic replacement of hydrocortisone and the decision was made by her oncology team to continue her current ICI therapy.

Discussion :

ICI are effective cancer treatments which target key regulators of the immune system preventing oncogenic immune evasion, however, this also leads to autoimmunity and development of endocrinologic irAEs. Endocrinopathies occur most commonly in combination ICI therapy with an incidence of 40%. In combination ipilimumab and nivolumab, the highest endocrinologic irAE is hypothyroidism, with an incidence of 16%, while thyroiditis and hypophysitis are less common at 3.6% and 8.8%, respectively. Our patient presented with AI with simultaneous thyroiditis leading to a mixed clinical picture. Despite presenting with classic findings for AI, she had recurrent fevers due to thyroiditis, so infectious work-up was prioritized. Additionally, she presented critically ill with hypotension, hyponatremia, and very low cortisol levels which may have been exacerbated by thyrotoxicosis as this has been shown to increase glucocorticoid metabolism. This case illustrates the possibility of multiple endocrinologic irAEs and should be considered in these patients for timely diagnosis.