Diarrhea 3, secretory sodium, congenital, with or without other congenital anomalies (DIAR3) is a rare autosomal disorder, characterized by severe watery diarrhea containing high concentrations of sodium, hyponatremia and metabolic acidosis. It is caused by a functional defect in one of the sodium/proton exchangers localized to the apical membrane of small intestinal epithelial cells. Diagnosis of DIAR3 is based on the findings of a life-threatening secretory diarrhea, severe metabolic acidosis, and hyponatremia secondary to extraordinarily high fecal losses of sodium, with low or normal excretion of urinary sodium. So far, less than 15 patients have been described worldwide.
Al Makadma et al. (2004) described a pre-term baby boy, who had severe watery diarrhea with severe oliguria and acute renal failure. He was born to non-consanguineous parents with weight birth of 1.4 kg. On the first day of life, he had abdominal distention and did not pass any meconium, and had small bowel obstruction. Few weeks later, he developed hyponatremia, normal anion gap metabolic acidosis, and developed signs of dehydration; he had severe hypotension with weight loss from 1.33 to 1.05 kg. He also had acute tubular necrosis. The newborn was put on fluid therapy with sodium and bicarbonate, along with dopamine to improve renal perfusion. At the age of five months, he was doing well with a weight of 4 kg.