Developmental Medicine & Child Neurology | 2019
Intravenous ketogenic diet: guidelines for ketogenic parenteral therapy
Abstract
In the past two decades, there has been a resurgence of interest in the ketogenic diet for the treatment of refractory pediatric epilepsy. Two of the fastest growing new indications are the use of the ketogenic diet in infancy and as a treatment for super-refractory status epilepticus. The rationale behind the latter concept stems from recognition that the ketogenic diet works very quickly, has no obvious drug interactions, and can be provided relatively easily in intensive care settings via nasogastric tubes. Trials are underway to further evaluate the ketogenic diet for refractory status epilepticus using ketogenic diet formulas. A major limitation to using the ketogenic diet in this manner occurs when the child is unable to tolerate enteral feedings. For many years, the idea of intravenous ketogenic therapy was not considered feasible. In 1990, the first ever case report described the successful use of parenteral ketogenic nutrition for a 5-year-old female with Lennox–Gastaut syndrome. This child initially received 1 week of solely intravenous medium-chain triglyceride emulsion (to replace her oral ketogenic diet in the setting of a diarrheal illness), followed by 5 months of combination parenteral and enteral nutrition. Although, sadly, she died of cardiac arrest, she was able to maintain ketosis over this extended period. From 2011 to 2017, the literature expanded with 34 additional cases from eight publications. The new clinical practice guidelines developed by van der Louw et al. will help child neurologists understand the growing evidence for intravenous ketogenic therapy and how best to administer it safely and effectively. There are several very important key messages from these consensus guidelines. First, the use of ketogenic parenteral nutrition, either when used to replace an oral ketogenic diet or for a child in intensive care to disrupt status epilepticus, is generally meant to be temporary. No upper time limit is specified, but the authors are clear that when an enteral ketogenic diet is possible, a transition from intravenous to enteral feeds ‘should be used immediately’. Second, although a high ketogenic ratio (e.g. 4:1 of grams of fat to protein and carbohydrate) may be ideal for seizure control, in many of these difficult cases, a lower ratio (e.g. 1:1) is the only possible option, yet often equally effective. Protein should be prioritized over carbohydrates, fluid and calories maximized, and a fat intake goal of 3 to 4g/kg/day targeted. Lastly, all children receiving parenteral ketogenic nutrition should be in intensive care units with an experienced ketogenic diet team (including a pharmacist) monitoring for complications. The 14 members of this ketogenic diet expert group surveyed other ketogenic centers to ascertain a broader, international opinion. Yet it is by no means definitive, and more patients as well as prospective trials are required in order to guide this unique method of providing ketogenic therapy.