This is the commonest cause of pancreatic disease in childhood. It is inherited as an autosomal recessive condition and a specific gene deletion has been identified in 70% of cases. It has been suggested that the resultant protein defect produces an abnormality in the regulation of a J3-adrenergic-gated chloride channel in the cell membrane. This cystic fibrosis gene product has been named cystic fibrosis transmembrane conductance regulator (CFTR). This basic defect in all exocrine glands produces thick viscoid secretions causing cystic dilatation of the ducts. Increased numbers of patients are now surviving into adult life because of improved therapy.
SWEAT TESTING of symptomatic people and siblings of patients with cystic fibrosis identifies 77% by 2 years of age and 95% by the age of 12 years. IN INFANTS, immunoreactive trypsin assay in dried
PANCREATIC FUNCTION TESTS
Treatment is required for pancreatic insufficiency and respiratory problems. Steatorrhoea is treated with pancreatic supplements. High-dose pancreatin-containing trypsin and lipase can be given in microspherecontaining capsules which deliver high doses of enzyme to the duodenum for fat digestion. Recently, colonic strictures have been reported in a few patients and patients should be carefully monitored. H2 antagonists are not usually required with these new preparations and the fat content of the diet can be kept normal. Optimal nutrition has been recognized as improving prognosis and a high calorie intake (150% of recommended daily allowance) with vitamin supplements should be given.