New-onset super-refractory status epilepticus (NOSRSE) is a rare clinical presentation of status epilepticus in an individual with no prior seizure history and no identifiable cause. Patients often require hospitalization in an ICU with general anesthesia and intubation. Mortality in NOSRSE patients is as high as 27%. Current treatments include steroids, plasma exchange, and IVIG. There are studies investigating the role of a ketogenic diet in patients with NOSRSE, founded on its successful use in refractory status epilepticus in children and febrile infection-related epilepsy syndrome (FIRES).  While the mechanism for ketogenic diets in NOSRSE is incompletely understood, current theories focus on the shift in substrate for neuronal metabolism from glucose to ketone bodies, alteration of neurotransmitter concentrations such as GABA, modification of gut microbiota, reduction of proinflammatory cytokines, and epigenetic modifications that suppress oxidative stress.

This patient presented with prodromal flu-like symptoms and subsequently developed new-onset super-refractory status epilepticus requiring transfer to the neurological critical care unit and intubation with general anesthesia. She was started on a 4:1 ketogenic diet on day 19 of her hospitalization and achieved ketosis three days later per urine beta-hydroxybutyrate. The patient remained in ketoacidosis or mild ketosis until she was successfully extubated on day 30, after which serial beta-hydroxybutyrate measurements were discontinued. Following a lengthy recovery period, she was discharged to an acute rehabilitation facility on hospital day 70.

We report a case of seronegative NOSRSE in a previously healthy twenty-three-year-old female who was successfully treated with a ketogenic diet and standard immunotherapy. This case supports an emerging role for the use of ketogenic diet in patients with this rare clinical presentation.