Pearls & Oy-sters: Status Epilepticus and Cerebral Edema From Hyperammonemia Due to Disseminated Ureaplasma and Mycoplasma Species

Non-hepatic hyperammonemia syndrome is a rare cause of neurologic dysfunction and cerebral edema and has most commonly been reported in post-transplant patients. Only recently has opportunistic infection with Ureaplasma species and Mycloplasma hominis been found to be key to the pathogenesis. We describe the cases of three immunosuppressed patients who developed hyperammonemia syndrome with new onset refractory status epilepticus and diffuse cerebral edema. PCR was positive for Mycloplasma hominis in one patient and Ureaplasma parvum in the other two. Despite of early diagnostic suspicion and aggressive management with empirical antibiotics, seizure control, hypertonic saline, and ammonia elimination, none of our patients survived this life-threatening infection. Non-hepatic hyperammonemia and new onset seizures can be presenting features of disseminated Ureaplasma species and Mycoplasma hominis infections in post-transplant patients. Immunosuppression in the absence of organ transplantation is likely sufficient to trigger this entity, as was the case in our third patient. When suspected, empiric combination antibiotics should be used due to high likelihood of resistance. The diagnostic test of choice is PCR. Patients with hyperammonemia syndrome associated with these infections typically have a poor prognosis. Early recognition and aggressive multimodal interventions may be key to ameliorating the high mortality and severe neurologic sequelae from this entity.