Ureaplasma parvum causes hyperammonemia presenting as refractory status epilepticus after kidney transplant

•Intensivits should be aware of the possibility of hyperammonemia due to Ureaplasma infections in immunosuppressed patients.•The diagnosis should be evoked in the presence of a severe neurological symptom, in a post-transplant context, including remotely.•Early MRI and CSF examination are often normal. The diagnosis of hyperammonemia is based on EEG, and serum ammonia dosage.•Ureaplasma infection is suspected in cases of absence of liver disorder associated with hyperammonemia.•Diagnostic of Ureaplasma infection is based on PCR technique on serum and urine samples in a specialized laboratory.•Treatment of hyperammonemia is urgent. It relies on ammonemia lowering agents (sodium benzoate, sodium phenylbutyrate).•Treatment of Ureaplasma infection relies on antibiotics active on intracellular germs.•Because of the risk of irreversible neural damage, the prognosis is poor.