Congenital chloride diarrhoea.

Congenital chloride diarrhoea is an autosomal recessive disease characterized by life-long watery diarrhoea of prenatal onset with high faecal Cl- concentration. Seventy-nine patients have so far been reported. The basic defect involves the active Cl-/HCO3- exchange mechanism of the distal ileum and colon. The defect causes impaired absorption of Cl-, acidity of intestinal contents because of impaired excretion of HCO3-, and, secondarily, impaired Na+ absorption. Intra-uterine diarrhoea leads to hydramnios and often to premature birth. Unless adequately treated, most patients will die of hypo-electrolytaemic dehydration within the 1st few months of life. Some infants will survive in such a state, with severe alkalosis, hypochloraemia, hypokalaemia, and retarded growth and development. Their plasma renin and aldosterone concentrations will become grossly elevated, and pathological changes will develop in the kidneys. The diagnosis is established when faecal Cl- concentration exceeds 90 mmol/l after water and electrolyte deficits have been corrected. Congenital chloride diarrhoea should be treated with full oral replacement of the faecal losses of Cl-, Na+, K+, and water. This therapy will abolish all the secondary disorders, provide for normal growth and development, and prevent renal disease. Though this therapy does not abolish the diarrhoea, most children will become toilet trained at a normal age, their social adjustment will be unimpaired, and they will live a perfectly normal life.