Edema as the Presenting Symptom of Cystic Fibrosis: Difficulties in Diagnosis

Edema, hypoproteinemia, and anemia may be the presenting symptoms in young infants with cystic fibrosis (CF) of the pancreas. These symptoms are believed to be due to defective protein digestion and malabsorption secondary to trypsin and chymotrypsin deficiency, and are seen most frequently in infants fed either a soy bean formula¹ that contains a trypsin inhibitor,² or human milk that has a lower protein content than most commercial formulas.³ Other causes of this symptom complex include inadequate intake of protein, decreased protein synthesis in severe liver disease, increased protein degradation in transient dysproteinemia, pseudohypoproteinemia in states of plasma volume expansion such as congestive heart failure, or when there is protein loss in the urine as in the nephrotic syndrome or into the gut in exudative enteropathy. The finding of an elevated chloride concentration in the sweat is the cornerstone of the diagnosis of CF. There have been