Refractory hypotension due to Nivolumab-induced adrenal insufficiency.

Nivolumab, a new immune checkpoint inhibitor that has been found to improve outcomes for patients with some advanced cancers, is being increasingly used. Immune checkpoint inhibitors can cause immune-related adverse events, including dermatitis, enterocolitis, hepatitis and hypophysitis, but adrenal insufficiency rarely occurs. We present a case of Nivolumab-induced adrenal insufficiency in a man who complained of refractory hypotension. A 52-year-old man with non-small cell lung cancer visited our emergency department complaining of fatigue and diarrhea. He had received Nivolumab every 2 weeks as third-line therapy for a total of 10 times. On arrival, his vital signs revealed shock: blood pressure, 68/48 mmHg; heart rate, 141 beats per minutes. Laboratory examination showed severe hemoconcentration with a hemoglobin level of 19.9 g/dL, normal electrolyte levels and hyperglycemia. We started intravenous infusion of 4.5 L of extracellular fluid, but his vital signs remained unstable. After admission, endocrine examination revealed abnormally low values of serum cortisol (4.86 μg/dL) and ACTH (<1.0 pg/mL), which had been normal at 2 months before admission (21.14 μg/dL and 20.1 pg/mL, respectively). We therefore made a diagnosis of adrenal insufficiency induced by Nivolumab and administered 100 mg hydrocortisone succinate sodium intravenously. He recovered soon after hydrocortisone replacement therapy. Nivolumab is a new immune checkpoint inhibitor and general physicians are not familiar with it. However, adverse events caused by Nivolumab, especially adrenal insufficiency, can lead to serious adverse outcomes if overlooked. We should recognize Nivolumab-induced adrenal insufficiency and administer a glucocorticoid immediately in cancer patients treated with immune checkpoint inhibitors.