Severe hypernatremic dehydration and metabolic acidosis due to neonatal intestinal microvillus inclusion disease

Neonatal microvillus inclusion disease (MID) is a congenital secretory diarrhea diagnosed by morphological enterocyte abnormalities on histology. The secretory diarrhea associated with MID occurs within the first few hours of birth and is exacerbated by enteral feeding. Affected newborns will die of dehydration and acid-base disturbances if MID is not rapidly recognized and treated with massive intravenous fluid replacement and gut rest. We report a case of a 4-day-old neonate presenting with 18% weight loss, hypernatremic dehydration and metabolic acidosis. Despite aggressive fluid resuscitation (206 ml/kg for the first 24 h), the dehydration and metabolic acidosis were only minimally improved. The diapers were found soaked with clear, non-odorous fluid on repeated examinations. Persistent secretory diarrhea was suspected. Stool electrolytes analyses showed a high NaCl content typical of secretory diarrhea and intestinal biopsy with electron microscopy was diagnostic of MID.