A physician suspects cystic fibrosis in a child with foul-smelling stools. Which deficiency is likely due to malabsorption?

Cystic fibrosis is a genetic disorder that affects the lungs, digestive system, and other organs, primarily due to defective chloride channels leading to thick mucous production. In children with cystic fibrosis, pancreatic insufficiency frequently occurs because thick secretions obstruct pancreatic ducts, impairing the release of digestive enzymes. This can result in significant malabsorption of nutrients, particularly fat.

Due to this malabsorption, there is a specific concern for the absorption of fat-soluble vitamins, which include vitamins A, D, E, and K. These vitamins rely on fat for absorption, so when fat is poorly absorbed due to the lack of proper pancreatic enzyme function, the absorption of these vitamins is compromised. Children with cystic fibrosis often present with symptoms related to fat malabsorption, which can manifest as foul-smelling, greasy stools, a condition known as steatorrhea.

While deficiencies in calcium, iron, and folic acid can occur in various conditions, they are not specifically linked to the malabsorption phenomena seen in cystic fibrosis as directly as the fat-soluble vitamins are. In cystic fibrosis, the primary malabsorption issue is of fat and, by extension, the fat-soluble vitamins, making it the most likely deficiency