Pediatric Nurse Exam

On the PNCB CPN exam, the Health Promotion domain makes up about a quarter of the scored items, and growth and development content also drives many Assessment items (is this milestone normal for this age?) and Planning and Management items (which teaching is the priority for this family?). Expect short cases with an age and a finding, followed by a question such as "Which finding should the nurse report?" or "Which statement by the parent indicates a need for further teaching?" Knowing what is normal at each age is the foundation for spotting what is not.

This chapter covers expected patterns of weight, length and head growth, accurate measurement technique, growth charts and percentiles, body mass index, and the growth findings that should prompt the nurse to report or refer.

Growth is fastest in the first year and during the adolescent growth spurt. A single measurement tells little; the trend across several visits tells the story.

Expected Growth Milestones in Infancy

After infancy, growth slows. Toddlers gain about 2-3 kg per year; preschool and school-age children gain about 2-3 kg and about 5-7 cm per year. Adolescent growth spurts start earlier in girls (often around 10-12 years, peaking before menarche) than in boys (often around 12-14 years). Toddlers develop a "pot belly" and lordosis that disappear as abdominal muscles strengthen; physiologic anorexia (decreased appetite) in toddlers is normal because growth has slowed.

Clinical Pearl: Newborn weight loss greater than about 10% of birth weight, or failure to regain birth weight by 2 weeks, is a feeding red flag. The nurse assesses feeding frequency, latch, wet diapers and stools, and jaundice, and reports to the provider.

To calculate percent weight loss: subtract current weight from birth weight, divide by birth weight, and multiply by 100. An infant born at 3,500 g who now weighs 3,150 g has lost 350 g, which is 10% of birth weight.

Accurate technique matters, because a measurement error can look like a growth problem.

Chest circumference is measured at the nipple line when needed but is not a routine screen after infancy.

Use the WHO growth charts from birth to 2 years and the CDC growth charts from 2 to 20 years. Children with some genetic conditions, such as Down syndrome, have condition-specific charts that are used alongside the standard ones.

A child who follows a steady percentile curve is usually growing well, even if the percentile is low. Concern arises when a child crosses two or more major percentile lines (for example, from the 50th to below the 10th), when weight-for-length is below the 5th percentile, or when length or height growth stalls.

BMI-for-Age Categories (Ages 2-20)

BMI is calculated as weight in kilograms divided by height in meters squared, then plotted on a sex-specific BMI-for-age chart, because healthy body fat changes with age and sex. Adult BMI cutoffs are never applied to children.

Exam Tip: When a question shows a child at a low but stable percentile, the best answer is usually reassurance and continued monitoring. When the child has crossed percentile lines downward, the best answer is further assessment (feeding history, 24-hour diet recall, observation of a feeding) and reporting to the provider.

Faltering growth (failure to thrive): inadequate weight gain for age, sometimes with later slowing of length and head growth. Causes include inadequate intake (feeding technique, formula mixing errors, food insecurity), inadequate absorption (celiac disease, cystic fibrosis) or increased needs (heart disease). The nurse observes a feeding, checks how formula is mixed, documents intake and daily weights, and screens for psychosocial stressors.

Case Snapshot: A nurse in a clinic weighs a 4-month-old whose weight has fallen from the 50th to the 10th percentile since the 2-month visit. The parent says the baby "takes about 2 ounces every 4 hours" and that they add an extra ounce of water to each bottle "to make the can last." The nurse's priority is to explain safe formula preparation, report the weight loss and feeding history to the provider, and connect the family with WIC and social services. The growth problem has a correctable cause rooted in a social need, and diluted formula also carries a risk of hyponatremia.

Feeding is part of every growth assessment and every well visit.

Breast milk or iron-fortified formula is the main food for the first 12 months. Breastfed infants need vitamin D 400 IU daily.

Solid foods start around 6 months, when the infant has good head control and can sit with support. Introduce iron-rich foods early. Introduce common allergenic foods (including peanut in an age-appropriate form) early per current guidance; infants with severe eczema or egg allergy may need evaluation first.

No honey before 12 months (infant botulism). No cow's milk as a main drink before 12 months.

Whole cow's milk from 12 to 24 months, limited to about 16-24 ounces a day; excess milk displaces iron-rich foods and causes iron deficiency anemia.

Avoid juice before 12 months and limit it afterward; offer water.

Choking hazards under age 4: whole grapes, hot dogs, nuts, popcorn, hard candy, raw carrots, chunks of meat or cheese. Cut grapes and hot dogs lengthwise and into small pieces.

Obesity prevention message for families: 5-2-1-0 (5 or more fruits and vegetables, 2 hours or less of recreational screen time, 1 hour or more of physical activity, 0 sugar-sweetened drinks each day).

Oral Health

Clean gums before teeth erupt; the first tooth usually appears around 6 months.

Brush twice daily with fluoride toothpaste: a smear the size of a grain of rice under age 3, a pea-sized amount from 3 to 6 years.

First dental visit by the first tooth or age 12 months; fluoride varnish is applied in primary care or dental settings.

Infants regain birth weight by about 10-14 days, double it by about 4-6 months and triple it by 12 months.

Measure recumbent length until age 2, and plot on WHO charts to age 2 and CDC charts from 2 to 20 years.

Crossing two major percentile lines matters more than a low but stable percentile.

BMI-for-age 85th to below 95th percentile is overweight; 95th or higher is obesity.