Bowel Obstruction in Cystic Fibrosis

Pathophysiology of Cystic Fibrosis

Cystic fibrosis is an autosomal recessive genetic disorder caused by mutations in the CFTR gene, which encodes for the cystic fibrosis transmembrane conductance regulator protein, according to the Centers for Disease Control and Prevention 1, 2.
The CFTR protein functions as a chloride channel in epithelial cells, regulating ion and water transport across cell membranes, as reported by the European Respiratory Society 2.
Mutations in the CFTR gene lead to absent or dysfunctional CFTR protein, resulting in abnormal chloride transport and dehydration of secretions in multiple organ systems, as stated by the Centers for Disease Control and Prevention 1, 2.
There are five classes of CFTR mutations with varying degrees of protein dysfunction, with classes I, II, and III being more severe and associated with complete loss of chloride channel function, according to the Centers for Disease Control and Prevention 1.
The common ΔF508 mutation is a class II mutation associated with severe manifestations including pancreatic insufficiency, as reported by the Centers for Disease Control and Prevention 1.

Gastrointestinal complications are common in CF due to thick, viscid secretions and pancreatic insufficiency, affecting over 80% of CF patients at diagnosis, as stated by the Centers for Disease Control and Prevention 1, 3.
Pancreatic insufficiency occurs in over 90% of CF patients with age and leads to fat and protein malabsorption, resulting in steatorrhea, abdominal pain, and nutritional deficiencies, according to the Clinical Nutrition Society 1, 3.
The first manifestation of CF in 15-20% of affected children is meconium ileus, an intestinal obstruction present at birth that typically requires surgical intervention, as reported by the Centers for Disease Control and Prevention 1.

Chronic constipation related to intestinal dysmotility can progress to obstruction, as stated by the American Academy of Pediatrics 4, 3.
Fibrosing colonopathy, a rare complication associated with high-dose pancreatic enzyme supplements, can cause colonic strictures and obstruction, according to the Clinical Nutrition Society 3.