Endocrine Abstracts

Lung cancer is the second most common cancer in the world with the leading position as a cause of oncological fatality. The immunotherapy is applied as the second line of chemotherapy, and seems a breakthrough therapy, promising a better quality of life to patients in the late stages of cancer. Pembrolizumab (also, known as MK-3475 or Keyruda) is a humanised antibody PD-1 receptor or antibody to programmed death ligand one. Side effects considered as acceptable and mostly presented with fatigue, pruritus, and decreased appetite. Primary adrenal insufficiency was reported in less than in one per cent of patients treated with Pembrolizumab. Nevertheless, this is rare but still seen presentation, which could lead to the development of adrenal crisis - a medical emergency. Misdiagnosis of a life-threatening condition might lead to an enormous physical and emotional impact with an already compromised quality of life. We report a case of a 72-year- old female patient, who developed acute adrenal insufficiency following a course of immunotherapy with Pembrolizumab for advanced lung cancer. The patient presented with nausea, vomiting, loose stools, dizziness, two weeks after her fourth cycle with Pembrolizumab, which initially was seen as usual complains followed a session of chemotherapy. On the other hand, the examination on the admission revealed significant hypotension in a patient known for long-term hypertension. She was dehydrated with mild tachycardia. In the Emergency Department, she was noted to have a severely low cortisol level on 33 mmol/l from an earlier investigation, and intravenous hydrocortisone was started. Oral hydrocortisone was continued on discharge to ensure metabolic and hemodynamic stability. This case report demonstrates the rare but possible endocrine complications of the immunotherapy that raised the possibility of the required differential diagnosis with possible development of life-treating Hypophysitis and raised the awareness of the potential development of the acute adrenal inefficiency in patients on immunotherapy for advanced cancer.

Discussion: This case illustrates the prompt and accurate diagnosis of acute adrenal insufficiency leading to optimal patient outcome.