Hepatic encephalopathy (HE) is a frequent and debilitating complication of liver disease and is oftentimes associated with hyperammonaemia. However, hyperammonaemia may occur in underlying conditions other than acute or chronic liver failure and clinical awareness is needed in order to be recognized and treated properly. A 24-year-old woman presented herself to our emergency department with acute confusion and altered mental state due to severe hyperammonaemia. The patient was diagnosed in the age of 14 with ornithine transcarbamylase (OTC) deficiency and was incompliant regarding her diet and suggested medication to treat this disorder. She was treated with sodium benzoate 250 mg/kg i.v., sodium phenylbutyrate/sodium phenylacetate 250 mg/kg i.v., L-arginine 250 mg/kg i.v., and received continuous hemofiltration. Under simultaneous medical treatment and haemodialysis, ammonia levels dropped to normal within 24 h and symptomatic encephalopathy ceased completely. OTC deficiency is rare in adults, and the majority of patients are diagnosed in childhood. It can lead to death if not diagnosed and treated properly. Our case underlines the importance of considering causes of HE other than liver cirrhosis.

Immune checkpoint inhibitors are increasingly used in advanced malignant diseases and are well-known for their good results. With the blockade of immune checkpoints, the probability of immune-related adverse events is also increased.We present a 54-year-old female patient with advanced NSCLC. She was treated with pembrolizumab and developed a stable disease under therapy. After six cycles, she presented with massive epigastric pain to our emergency department. Gastroscopy showed severe erosive-fibrinous pangastritis without the involvement of the esophagus, duodenum, or other immune-related adverse effects. Histology showed the complete destruction of the gastric mucosa. We concluded an immune-mediated gastritis by pembrolizumab, after the exclusion of other differential diagnoses.Despite treatment with prednisolone and marked improvement of her symptoms, the mucosa was never fully reconstituted into a healthy mucosa.Furthermore, we collected published reports of similar cases and conducted a comparison with features of a typical, endogenous type A gastritis to highlight similarities and differences.