[Unexplained reduction in the general condition of a female lung cancer patient]

A 63-year-old female patient with lung cancer presented to our emergency room for the first time with a sudden reduction in general condition, vomiting and severe weakness. She stated that she was receiving chemotherapy for the lung cancer and reported that she had no other relevant previous illnesses. Our initial suspected diagnosis was cytostatic-induced nausea and vomiting. Contrary to this suspected diagnosis, diagnostics carried out in the emergency room revealed the findings of ketoacidosis on the basis of an initial manifestation of diabetes mellitus with hyperglycemic decompensation as well as severe, manifest hypothyroidism. After obtaining the preliminary findings, it became evident that the patient was not receiving chemotherapy, but rather immune checkpoint therapy using durvalumab. The initial manifestations described were therefore to be viewed as immune reactions associated with durvalumab. After initiating diabetic recompensation therapy and substitution with L‑thyroxine, a rapid improvement in the patient's general condition was achieved.