Hypoalimentation is an important cause of hypernatremic dehydration in neonates; however, extreme values of plasma sodium make it necessary to investigate the differential diagnosis. We report the case of a 20-day-old newborn who was admitted with severe hypernatremic dehydration, with plasma sodium of 213 mEq/L and oliguric acute renal failure. The patient was treated with intravenous fluids for correction of dehydration and peritoneal dialysis for adequate sodium correction. During the etiological study, a 10-fold increase in the concentration of sodium in breast milk was detected. Peritoneal dialysis was an effective therapy in the management of the extreme hypernatremia with sodium correction within the recommended rate. At the 1-year follow-up appointment, the child had normal renal function, normal for age psychomotor development, and neurological physical was unremarkable. In conclusion, we report a case of an unusual extreme hypernatremia with discussion of the underlying pathophysiology and, more importantly, the effective treatment with a mixed approach with intravenous fluids and peritoneal dialysis.

Negative pressure pulmonary edema (NPPE) is a rare entity that can become life threatening. Its development in neonates is very rare, and its presentation as alveolar hemorrhage is uncommon. We report a case of a newborn 23 days old, previously healthy, who presented an episode of choking during breastfeeding. This progressed to acute respiratory failure due to diffuse alveolar hemorrhage. A few hours after admission, the newborn developed refractory hypoxemia, requiring high-frequency oscillatory ventilation and nitric oxide therapy for 24 hours. NPPE was postulated as a diagnosis of exclusion. The newborn recovered completely. NPPE should always be considered in a case with recent obstruction of the upper airway, even in unusual age groups. Sometimes it can manifest as alveolar hemorrhage.