Cystic fibrosis is a monogenic condition defined by polymorph clinical manifestations such as: chronic obstructive pneumonia, chronic diarrhea with steatorrhea, malnutrition and failure to thrive. In literature atypical phenotypes have been presented, one of them with heat shock determined by severe hypotonic dehydration.
Objectives To show the importance of quick detection of severe hyponatremia as a modality of cystic fibrosis onset.
Methods We present the case of a 2 month old female infant who presented with seizures and acute depleting syndrome caused by dehydration through insufficient supply.
Results Blood tests revealed severe hyponatremia (110 mmol/l), in this context seizures were labeled as metabolic. Sweat test: positive, values between 83 and 112 mmol/l. The diagnosis was established to be cystic fibrosis after differential diagnosis with other causes of hyponatremia and false positive sweat tests, such as hypothyroidism (although patient comes from an endemic area), adrenal cortical insufficiency through absence of hyperkalemia and hypoglycemia. There were many episodes of hypotonic dehydration (heat shock), while respiratory and digestive symptoms were rarely revealed. Later, a genetic test was performed, which revealed Delta F 508 mutation and certified the diagnosis.
Conclusion In cystic fibrosis precocious management is very important, even in cases with the poorest classical symptoms.