The primary pathophysiology of meconium ileus is pancreatic insufficiency.

• A. Intestinal atresia
• B. Pancreatic insufficiency
• C. Meconium plug obstruction due to prematurity
• D. Vascular accident

Answer: (B)

Meconium ileus happens when thick, sticky meconium blocks the ileum soon after birth. In cystic fibrosis, the CFTR gene is defective, which disrupts chloride transport and reduces water content in intestinal secretions. The result is inspissated, or very thick, meconium that cannot flow through the distal intestine, leading to obstruction.

Pancreatic insufficiency is a common finding in CF because the exocrine pancreas is affected by the same CFTR-related mucus abnormalities. It contributes to fat malabsorption and steatorrhea, but it is not the initial cause of the ileal obstruction itself. The other listed causes describe different neonatal bowel problems (developmental atresia, prematurity-related meconium plug, vascular events) and do not explain CF-associated meconium ileus.

So, the obstruction results from thick, inspissated meconium due to CFTR dysfunction, with pancreatic insufficiency representing a associated CF manifestation rather than the primary mechanism of the ileal obstruction.