A late-onset hyperammonemia syndrome caused by infection after kidney transplantation.

Hyperammonemia syndrome has a high mortality rate in the immunosuppressed population due to its association with mental status changes. Recently studies have shown that organisms' infection can lead to hyperammonemia in post-transplant patients. Symptoms typically occur within 30 days postoperatively. However, the late-onset hyperammonemia caused by infection after kidney transplantation has never been reported. In this case study, a 64-year-old Chinese male presented with symptoms such as nausea, vomiting, trouble sleeping, and deteriorating mental status 81 days after kidney transplantation. His plasma ammonia level was significantly elevated, and there was no evidence of liver synthetic dysfunction. Although common methods for ammonia clearance, such as haemodialysis and oral lactulose were initiated, his serum ammonia levels remained high. Metagenomic sequencing of serum determined infection. Levofloxacin and minocycline were administered respectively, which resulted in a decrease in ammonia levels, but normalization was not achieved. The computed tomographic scan revealed the presence of cerebral edema. Unfortunately, the patient eventually became brain dead with multiple organ failure. This case highlights that can cause late-onset hyperammonemia in kidney transplant patients. Once the mental status changes are identified, immediate empiric treatments should be initiated without waiting for a confirmed diagnosis of spp. infection.