Neonatal congenital microvillus atrophy

Unusual feature of neonatal hypernatremic dehydration due to microvillus inclusion disease: a case report

All over the causes of intractable diarrhea of infancy, microvillous inclusion disease is a rare congenital defect of intestinal brush border of unknown aetiology. An autosomal recessive inheritance is suggested by cases occurring in siblings and high incidence of consanguinity. The prognosis of the disease is extremely poor, as life can be sustained only by total parenteral nutrition. The authors report a preterm male newborn of 35 weeks gestation presenting severe hypernatremic dehydration on day 4 after birth caused by a secretory profuse diarrhea and discuss the tools allowing the light microscopic and genetic diagnosis. The final diagnosis of microvillus intestinal disease (MVID) was made on the third month after extensive investigations using electron microscopic examination of intestinal biopsy and genetic confirmation, finding a mutation at the homozygous status of MYO5B gene. The infant died on the fourth month in spite of optimal electrolytic support and parenteral prolonged nutrition. Although MVID is extremely rare, it remains a possible cause of intractable secretory diarrhea leading to severe hypernatremic dehydration and metabolic acidosis in neonates.

Congenital diarrheal disorders: an updated diagnostic approach

Congenital diarrheal disorders (CDDs) are a group of inherited enteropathies with a typical onset early in the life. Infants with these disorders have frequently chronic diarrhea of sufficient severity to require parenteral nutrition. For most CDDs the disease-gene is known and molecular analysis may contribute to an unequivocal diagnosis. We review CDDs on the basis of the genetic defect, focusing on the significant contribution of molecular analysis in the complex, multistep diagnostic work-up.

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.

Use of an omega-3 fatty acid-based emulsion in the treatment of parenteral nutrition-induced cholestasis in patients with microvillous inclusion disease

Microvillous inclusion disease is a congenital intestinal epithelial cell disorder leading to lifelong intestinal failure. In this report, we discuss the use of a fish oil-based lipid emulsion in the treatment of 3 patients with microvillous inclusion disease who developed parenteral nutrition-associated liver disease.

Lactobacillus bulgaricus prevents intestinal epithelial cell injury caused by Enterobacter sakazakii-induced nitric oxide both in vitro and in the newborn rat model of necrotizing enterocolitis

Enterobacter sakazakii is an emerging pathogen that has been associated with outbreaks of necrotizing enterocolitis (NEC) as well as infant sepsis and meningitis. Our previous studies demonstrated that E. sakazakii induces NEC in a newborn rat model by inducing enterocyte apoptosis. However, the mechanisms responsible for enterocyte apoptosis are not known. Here we demonstrate that E. sakazakii induces significant production of nitric oxide (NO) in rat intestinal epithelial cells (IEC-6) upon infection. The elevated production of NO, which is due to increased expression of inducible NO synthase, is responsible for apoptosis of IEC-6 cells. Notably, pretreatment of IEC-6 cells with Lactobacillus bulgaricus (ATCC 12278) attenuated the upregulation of NO production and thereby protected the cells from E. sakazakii-induced apoptosis. Furthermore, pretreatment with L. bulgaricus promoted the integrity of enterocytes both in vitro and in the infant rat model of NEC, even after challenge with E. sakazakii. Infection of IEC-6 cells with E. sakazakii upregulated several genes related to apoptosis, cytokine production, and various signaling pathways, as demonstrated by rat gene array analysis, and this upregulation was subdued by pretreatment with L. bulgaricus. In agreement with these data, L. bulgaricus pretreatment protected newborn rats infected with E. sakazakii from developing NEC, resulting in improved survival.

Microvillous inclusion disease: ultrastructural variability

Microvillous inclusion disease (MVID) is a congenital, usually neonatal, autosomal recessive condition manifested by severe, prolonged secretory diarrhea. Intestinal biopsies reveal extensive microvilli abnormalities, typical inclusions and vesicles mainly of the apical-luminal enterocytes and colonocytes. Although diagnosis can be suspected by special stains of the mucosa (PAS, CD10), the definitive diagnosis, recommended in view of potential intestinal transplantation, requires electron microscopy. In view of the marked variability of ultrastructural changes, extensive illustration is considered valuable for diagnosis. While the pathogenesis is still unknown, a number of images illustrate the suspected "arrested-trafficking" hypothesis of microvillous abnormalities. Others micrographs support the "engulfing" mechanism of inclusion formation. The electron micrographs should help ultrastructural diagnosis in this heterogeneous disease and can confirm diagnosis even in the absence of the typical inclusions.