A child with phenylketonuria should avoid which type of dietary substance to prevent neurological damage?

NCL (Northern Coalfields Limited)-NO

Child Health Nursing (Pediatrics)

Easy

Appeared in: NCL (Northern Coalfields Limited)-NO

Explanation

Phenylketonuria (PKU) is a genetic disorder characterized by the deficiency of the enzyme phenylalanine hydroxylase (PAH).
This enzyme is necessary to metabolize phenylalanine, an amino acid found in protein-rich foods.
Without this enzyme, phenylalanine accumulates in the blood and body tissues, becoming toxic to the central nervous system.
This toxicity leads to severe neurological damage, including intellectual disability, seizures, and behavioral problems.
Therefore, the primary treatment is a strict, lifelong diet low in phenylalanine, which means restricting high-protein foods.

Option A: High-fiber foods are not restricted in PKU. Fiber is a type of carbohydrate that is important for digestive health and does not contain phenylalanine.
Option B: High-fat foods are not the primary restriction in PKU. In fact, fats and oils are an important source of calories in a protein-restricted diet to ensure adequate energy intake and growth.
Option D: Foods rich in calcium are not restricted in PKU. Calcium is a mineral essential for bone health. While many high-calcium foods like milk and cheese are also high in protein and must be avoided, the restriction is due to the protein content, not the calcium itself. Calcium is often supplemented in the PKU diet.

Visual 1: Infographic: A visual guide showing two columns: 'Foods to Avoid' (with pictures of meat, milk, eggs, nuts) and 'Allowed Foods' (with pictures of fruits, vegetables, special low-protein bread) for a child with PKU.
Visual 2: Diagram: A simple flowchart illustrating the metabolic pathway in a healthy person (Phenylalanine -> Tyrosine) versus a person with PKU (Phenylalanine -> Buildup -> Brain Damage).

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Dietary management of Phenylketonuria (PKU) as background academic context rather than a clinical decision trigger.
Early diagnosis through newborn screening is critical to prevent irreversible neurological damage. All states in the US mandate newborn screening for PKU.
Nurses play a vital role in educating families about the strict dietary requirements, including how to read food labels, use special phenylalanine-free formulas, and monitor blood phenylalanine levels regularly.
Lifelong adherence to the diet is challenging but essential. Discontinuing the diet, even in adulthood, can lead to a decline in cognitive function, concentration problems, and mood disorders.

How to Approach the Question

First, identify the key term in the question: 'phenylketonuria' (PKU).
Recall the basic pathophysiology of PKU. It's an 'inborn error of metabolism' related to an amino acid.
Remember that the specific amino acid is phenylalanine, and the body's inability to break it down causes it to become toxic, especially to the brain.
Connect the amino acid (phenylalanine) to its dietary source. Amino acids are the building blocks of protein.
Therefore, to avoid phenylalanine, the child must avoid its source: high-protein foods.
Evaluate the options and select the one that reflects this understanding.

Concept Tested & Keywords

Concept Tested: Dietary management of Phenylketonuria (PKU).
Stem keywords: phenylketonuria, child, avoid, dietary substance, neurological damage
Lead-in keywords: which type
Clinical cues: Age/sex group narrows the expected diagnosis, intervention, or normal reference range.

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