What is the most common cause of bronchiolitis in children younger than 2 years old?

Identifying ventricular septal defects (VSD) requires knowledge of cardiac hemodynamics and auscultation. The nurse must understand how high-pressure left-to-right shunting through a structural opening in the septum creates specific acoustic turbulence during the systolic phase of the cardiac cycle.

Choice A rationale

Cyanosis is not typically a primary sign of an isolated VSD because the shunt is left-to-right, meaning oxygenated blood enters the lungs. Cyanosis only occurs if pulmonary hypertension develops, eventually causing a reversal of the blood flow.

Choice B rationale

A wide pulse pressure is a classic clinical finding associated with patent ductus arteriosus (PDA) due to diastolic runoff into the pulmonary circulation. It is not a characteristic finding for a ventricular septal defect in a newborn.

Choice C rationale

The high-pressure gradient between the left and right ventricles forces blood through the defect, creating a holosystolic murmur. This loud, harsh sound is best heard at the lower left sternal border where the turbulent flow occurs.

Choice D rationale

Clubbing of the fingernails is a sign of chronic, long-term hypoxia and is seen in cyanotic heart defects or long-standing uncorrected shunts. It would not be present in a newborn with a recently diagnosed ventricular septal defect.

This question assesses knowledge of pediatric growth and development milestones for a toddler transitioning into the preschool stage. Application of physical, cognitive, and language development standards for a thirty-six-month-old child is required to distinguish normal findings from abnormal neurological or developmental delays.

Choice A rationale

The Babinski reflex, where the big toe dorsiflexes, should disappear by twenty-four months of age as the corticospinal tract matures. Its presence at age three is abnormal and suggests a central nervous system lesion or delayed neurological development.

Choice B rationale

Hopping on one foot is a gross motor skill usually mastered at age four. While some three-year-olds may attempt it, it is not the standard developmental expectation for this age group, who are more adept at riding tricycles.

Choice C rationale

By age three, children typically have a vocabulary of about nine hundred words and use three-word to four-word sentences. This linguistic milestone reflects normal cognitive and social development, allowing the child to communicate basic needs and observations effectively.

Choice D rationale

The absence of stranger anxiety is not a standard physical or developmental finding at this age. While it peaks earlier, children at age three still demonstrate clear preferences for primary caregivers and may show wariness toward unfamiliar individuals.