Efficacy of low-protein diet in children with secondary hyperammonemia of different etiologies

Objective. To evaluate the efficacy of a low-protein diet (LPD) in patients with secondary hyperammonemia (HA) during the period of clinical manifestation depending on its etiology and the level of ammonia, and to substantiate management tactics. Patients and methods. This study included 29 patients with secondary HA. Patients were divided into two age groups depending on the onset of HA: the neonatal group (group 1; n = 15) and the infant and toddler group (group 2; n = 14). Depending on the causes of HA, two subgroups were identified: patients with HA associated with inherited metabolic diseases (IMD) and patients with HA not associated with IMD. Results. In group 1, 5 patients with mild transient HA (THA) (116.4 [106.9–136.9] μmol/L) did not receive LPD, and HA resolved within a week. Of the remaining 10 patients, five had a positive response to LPD (patients with IMD and THA). HA was severe (1588.5 [1315.0–1862.0] μmol/L), and the normalization of parameters was noted by day 14 [9–19]. Another 5 patients had a wave-like character of HA against the background of LPD (p = 0.350). In group 2, 10 patients with mild HA (87.45 [75.25–107.6] μmol/L) were not treated with LPD, all of them belonged to subgroup 2, and the normalization of parameters was observed on day 4. Another 4 patients with moderate HA (219.15 [188.85–245.6] μmol/L) received LPD, HA had a wave-like character (patients with IMD and HA not associated with IMD). Conclusion. The study showed that the course of HA against the background of LPD varies depending on patient age, disease severity and etiology. Key words: hyperammonemia, newborns, metabolic crisis, inherited metabolic diseases, low-protein diet, valproic acid