Cystic fibrosis in adults [letter].

An adult male was recently discovered to have cystic fibrosis after a 
unique clinical presentation not mentioned in the review article. This patient 
with recurrent episodes of heat exhaustion and hyponatremia had no extraordinary 
source of Na+ loss other than his sweat. This case represents 
an important new presentation of cystic fibrosis. Most internists view this 
disease as one seen only in chronically ill children. 