A 5-year-old boy presents to the clinic with his mother, who is concerned about his lack of energy and stunted growth. She reports that he often tires easily and has trouble keeping up with children his age. His diet consists mainly of corn, beans, and rice, with little meat or dairy. His physical examination reveals a distended abdomen, dermatitis, and bilateral edema of the lower extremities.
Which of the following enzymes is most likely deficient in this patient?
The patient's symptoms of distended abdomen, dermatitis, bilateral edema, fatigue, and stunted growth are consistent with kwashiorkor, a form of severe protein malnutrition. This typically occurs in children who consume a diet high in carbohydrates but deficient in protein, such as the corn, beans, and rice described. Trypsin is a crucial enzyme in protein digestion. It is produced in the pancreas as the inactive proenzyme trypsinogen and is activated in the small intestine. If trypsin is deficient, the body cannot adequately break down dietary proteins into their constituent amino acids, leading to protein malnutrition even when adequate protein is consumed. This leads to the symptoms seen in this patient. The other enzymes listed (pepsin, bromelain, amylase, and lipase) are involved in the digestion of other types of nutrients (proteins, fruits, carbohydrates, and fats, respectively), not specifically protein.