[Severe hyponatremia as diagnostic symptom of cystic fibrosis].

Report on two babies, 5 and 6 months old with severe salt depletion were admitted to our hospital with fever and gastro-enteritis. One of them failed to thrive despite normal nutrition, the other one had a protracted gastro-enteritis. Both of them had a great loss of weight, a strong dehydration and were in reduced general condition but without any signs of coma or cerebral seizures. In the differential diagnosis cystic fibrosis with chronic loss of salt exacerbated during an infection, described as "Pseudo Bartter-Syndrome" was suspected. Both babies showed increased salt concentration in the sweat and decreased chymotrypsin in the stool.