Growth And Development

Question 1

A young child understands at least 50 words and follows simple commands. He often points at and identifies an object (e.g., “tree”), is able to name several body parts, and has just started to use several 2-word sentences. When he is with other children, he parallel plays.

Based on his level of development, how old is this child?

Answer 1

24 months of age
Explanation
Most 18-month-old children understand 50–100 words and follow simple commands. Pointing with words is very common (e.g., pointing and saying “house,” pointing at and identifying body parts). Around 18 months of age, many children begin to use simple 2-word sentences, though most achieve this milestone by 2 years of age. Absence of any words by 18 months of age requires evaluation for language delay. Parallel play, rather than cooperative play, is expected at this age.

Question 2

Name 3 primitive reflexes present at birth that typically disappear at 3–4 months of age.

Answer 2

Rooting, stepping, and sucking
Explanation
Other primitive reflexes include the crossed adductor (disappears by 7 months of age), toe grasp (disappears at 9–12 months), Moro (disappears at 3–6 months), palmar hand grasp (3–6 months), and Babinski (disappears at 9–12 months). The abnormal persistence of primitive reflexes in developmentally delayed children reflects central nervous system dysfunction. It interferes with the development of voluntary motor movements, causing changes in muscle tone and limb position.

Perform a full history and physical examination in any child with developmental delay, including a complete review of systems, prenatal and perinatal history, family history, and psychosocial/behavioral assessment. Laboratory tests are based on history/physical findings; always obtain results of state-mandated newborn screens in infants and younger children.

Question 3

A young child uses a cup well, has scribbled for several months, and can build a tower of 4 cubes. He began to walk well 2–3 months ago but has just started to run.

Based on his level of development, how old is this child?

Answer 3

18 months of age
Explanation
At 18 months of age, most children can build a tower of 4 cubes and walk well but are not yet able to run or go up stairs with 2 feet on each step. Most use a cup very well, but are not yet able to use a spoon. Most begin to scribble by 15–18 months of age.

Question 4

How much does birth length increase by 1 year of age?

Answer 4

Answer
50%
Explanation
The average birth length is 20 inches. Average height at 1 year of age is 30 inches, an increase of 50%.

Question 5

How soon does an infant regain birth weight?

Answer 5

10–14 days of life
Explanation
Birth weight is regained by 10–14 days of life. Infants gain 30 grams/day in the first 3 months of life, 20 grams/day in months 3-6, and 10 grams/day for the remainder of the first year.

Question 6

A female infant is able to lift her head to 45° and can lift her head, but not her chest, off a table when lying down. Head lag is present when she is pulled to sitting. She has a social smile and “coos” but does not smile at a mirror. The palmar grasp reflex and Moro reflex are both present.

Based on her level of development, how old is this infant?

Answer 6

Answer
2 months of age
Explanation
A developmentally normal 2-month-old should be able to lift her head to 45° and lift her head (but not chest) off a table when lying down. Head lag persists until 4 months of age when pulled to sitting. Absence of a social smile in a 2-month-old is abnormal; many, but not all, 2-month-old infants also “coo” (“cooing” can occur anywhere from 2 to 4 months of age). Smiling at a mirror typically begins at 4 months of age. The palmar grasp reflex persists until 3–6 months of age, and the Moro reflex persists until 3–6 months of age.

Question 7

A young child, for the past 2–3 months, cries whenever he is left with an unfamiliar person. He has just started to say “Mama” and “Dada” nonspecifically and has started to use polysyllabic babbling. He pulls to stand.

Based on his level of development, how old is this child?

Answer 7

Answer
9 months of age
Explanation
Stranger anxiety typically begins around 6 months of age. Polysyllabic babbling begins at 9 months of age; most 9-month-old children say “Mama” and “Dada” nonspecifically. Specific use of “Mama” and “Dada” usually begins at 9–12 months of age. Most 9-month-old children are able to pull to stand but are not yet able to walk while holding onto furniture

Question 8

An 18-month-old can:

Squeal and babble
Say “Mama”
Point at a bottle or chair
The child cannot:

Say more words than “Mama”
Identify body parts
Does this child have delayed development?

Answer 8

Answer
Yes
Explanation
This child has an expressive language delay. By 18 months of age, the child should be able to say 10–25 words, identify 2 body parts, and follow simple instructions. Conduct a hearing screen whenever a language delay is suspected.

Question 9

After 9 months of dietary changes and daily exercise, a 17-year-old boy with obesity, hypertension, and poorly controlled Type 2 diabetes fails to lose any weight.

At what BMI should bariatric surgery be considered an appropriate treatment option for this patient?

Answer 9

Answer
BMI ≥ 120% of the 95th percentile for age
Explanation
Bariatric surgery should be considered only in a mature adolescent dedicated to losing weight and able to give informed consent. The family must be equally committed to and supportive of the surgery. Additional criteria include:
Failure to lose weight after ≥ 6 months of organized attempts at weight loss
Physiologic maturity (i.e., late SMR 4, SMR 5)
BMI ≥ 120% of the 95th percentile for age with a severe comorbidity (e.g., poorly controlled Type 2 diabetes, hypertension, obstructive sleep apnea, hypoventilation syndrome)
BMI ≥ 140% of the 95th percentile for age with less severe comorbidities

Question 10

A female infant is able to lift her head only momentarily when lying down; head lag is present when pulled to sitting. She recently developed a social smile but does not yet “coo.” She still has a palmar grasp reflex.

Based on her level of development, how old is this infant?

Answer 10

1 month of age
Explanation
A developmentally normal 1-month-old is able to lift her head when lying down only momentarily; by 2 months of age, most infants lift their head to 45°. Head lag when pulled to sitting persists for the first 4 months of life. A social smile is present by 1–2 months of age; an infant’s first “coo” is present at 2–4 months of age. The palmar grasp reflex disappears by 3–6 months of age.

Question 11

At what age do most children first develop the ability to follow rules while playing a game and begin to demonstrate operational thinking?

Answer 11

6 years of age
Explanation
By 6 years of age, memory and imagination are well ingrained. Children begin to develop operational thinking, becoming less egocentric and more aware of external events and feelings other than their own. They can follow rules while playing a simple game, skip, and tie their shoes.

Question 12

If an infant presents with abnormally slow head growth or absolute microcephaly, what is the best diagnostic test to order to evaluate for structural abnormalities?

Answer 12

MRI of the head
Explanation
Microcephaly may be primary (e.g., due to a genetic disorder) or secondary (e.g., due to infection). Structural abnormalities are often associated with microcephaly and are best evaluated by MRI, while cerebral calcifications (e.g., due to congenital CMV, toxoplasmosis) are best evaluated by CT scan.

Question 13

A child was born with a “large head” (but within normal range). Now, at 3 months of age, they present with a head circumference that exceeds the 98th percentile. Radiologic study confirms isolated enlargement of the subarachnoid space.

What is the recommended treatment?

Answer 13

Reassurance
Explanation
Isolated enlargement of the subarachnoid space is a common cause of benign macrocephaly. The head is large, but within normal limits at birth, and subsequently parallels or exceeds the 98th percentile. In addition to an enlarged subarachnoid space, minimally increased ventricular size and widening of the sulci and sylvian fissure are often noted on CT. About 2/3 of affected infants are boys. No intervention is necessary.

Question 14

At what ages can a child copy a circle? A cross? A square? A triangle?

Answer 14

Answer
3 years of age; between 3 and 4 years of age; 4 years of age; 5 years of age
Explanation
A child should be able to copy a circle at 3 years of age, copy a cross between 3 and 4 years of age, copy a square at 4 years of age, and copy a triangle at 5 years of age. These are some of the major developmental milestones that should be memorized.

Question 15

If you suspect a language disorder, what is the first test to order?

Answer 15

Hearing screen
Explanation
Know this! A hearing screen is the most important thing to do when evaluating a language problem (receptive or expressive) in a child. Common causes of language disorders include hearing deficits, intellectual disability, genetics, structural anomalies (i.e., lip/palate/oropharynx), and child abuse.

Question 16

How is body mass index (BMI) calculated?

Answer 16

Answer
BMI = (weight in kilograms) / (height in meters)2
Explanation
BMI is calculated using a ratio of a person’s weight and height. The percentiles are age and sex based for children and fixed values for adults

Question 17

At what age does the AAP recommend initial autism screening?

Answer 17

Answer
18 months
Explanation
The AAP recommends universal screening for autism with an autism-specific tool (e.g., M-CHAT-R/F) at both the 18- and 24-month visits or whenever parental concerns are raised. In addition, perform developmental surveillance at every preventive visit.

Question 18

A premature neonate presents with possible macrocephaly.

What is the diagnostic test of choice?

Answer 18

Answer
Ultrasound of the head
Explanation
A premature neonate is at risk for hydrocephalus, often the result of an intraventricular hemorrhage. Therefore, an ultrasound of the head is indicated in all premature neonates with enlarged head circumferences. An ultrasound is the imaging study of choice while the fontanelles remain open; a CT or MRI is preferable once the sutures have fused.

Question 19

When does a full-term infant’s birth weight double? Triple? Quadruple?

Answer 19

Answer
4 months of age; 12 months of age; 24 months of age
Explanation
Full-term infants double their birth weight by 4 months of age, triple their birth weight by 12 months of age, and quadruple their birth weight around 24 months of age. Average weight gain is about 5 pounds per year.

Question 20

At what age can most children hop on 1 foot?

Answer 20

Answer
4 years of age
Explanation
4-year-old children can hop on 1 foot, balance on 1 foot for 6–10 seconds, and use a fork without difficulty.

Question 21

A young child has a vocabulary of 50–100 words, uses 2-word sentences, and is able to identify 6 body parts. He has just started to use personal pronouns but does not yet use prepositions. When he is with other children, he parallel plays. He is not able to button large buttons.

Based on his level of development, how old is this child?

Answer 21

Answer
24 months of age
Explanation
At 24 months of age, most children have a vocabulary of 50–100 words, can identify at least 6 body parts, and use 2-word sentences. Personal pronouns are first used around 24 months of age. Use of prepositions or articles begins around 30 months of age. Absence of meaningful phrases by 24 months of age requires evaluation. Parallel play, rather than cooperative play, is to be expected. Most children cannot dress themselves completely, including large buttons, until 3 years of age.

Question 22

A 6-month-old boy plots below the 3rd percentile for weight. Height and head circumference plot at the 10th and 12th percentiles, respectively.

Birth history is unremarkable.
Newborn metabolic screen is normal.
Physical examination demonstrates an apathetic child with wasting of subcutaneous tissue in the lateral buttocks and thighs.
What is the most likely cause of failure to thrive (FTT) in this infant?

Answer 22

Inadequate consumption of appropriate amounts and/or kinds of food.
Explanation
The majority of FTT cases are the result of inadequate consumption of appropriate amounts and/or kinds of food, and can be managed on an outpatient basis. Psychosocial and behavioral feeding problems are common, while organic causes are rare (and typically associated with specific signs and symptoms of underlying disease). Perform step-wise laboratory evaluation only if caloric intake is proven to be adequate.

Question 23

What is the most common type of craniosynostosis?

Answer 23

Scaphocephaly
Explanation
Scaphocephaly (a.k.a. dolichocephaly) is the premature closure of the midline sagittal suture and is characterized by a long, narrow skull. It has a 4:1 male predominance and is typically sporadic in occurrence.

Question 24

A young girl can run well and go up and down stairs using 2 feet on each step. She will sometimes jump off the ground with 2 feet up. She has used a cup and spoon well for several months. She can stack up to 6 blocks.

Based on her level of development, how old is this child?

Answer 24

24 months of age
Explanation
Most 2-year-old children run well and are able to independently walk up and down stairs using both feet on each step. They often are just beginning to master jumping off the ground with 2 feet up. By 18 months of age, most children can use a spoon well and have been using a cup well for a few months (usually starting between 15 and 18 months of age). Most 2-year-olds can stack up to 6 blocks.

Question 25

A 12-year-old boy is noted to have:

A BMI at the 98th percentile
A waist circumference at the 95th percentile
Systolic and diastolic blood pressure at the 95th percentile
List the indices for serum HDL cholesterol, triglycerides, and fasting glucose that would support the diagnosis of metabolic syndrome in this patient.

Answer 25

Answer
HDL cholesterol < 40 mg/dL; triglycerides > 110 mg/dL; fasting glucose > 110 mg/dL
Explanation
Obesity can cause insulin resistance, which leads to hyperinsulinemia, hyperglycemia, and dyslipidemia associated with hypertension and vascular inflammation. The co-occurrence of metabolic risk factors for both Type 2 diabetes and atherosclerotic cardiovascular disease is referred to as “metabolic syndrome.” The presence of ≥ 3 of the following measures fulfills the suggested criteria for the diagnosis of metabolic syndrome:
BMI > 97th percentile
Systolic/diastolic BP > 90th percentile
Waist circumference > 90th percentile
Triglycerides > 110 mg/dL
HDL cholesterol < 40 mg/dL, and/or
Fasting glucose > 110 mg/dL or oral glucose tolerance test > 140 mg/dL

Question 26

When is the fastest rate of head growth?

Answer 26

Answer
Between 0 and 2 months of age
Explanation
The fastest rate of head growth is between 0 and 2 months of age, when the child’s head grows at 0.5 cm/week (2 cm/month). The average head circumference at full term is 35 cm (with a range of 33–37 cm). By 12 months of age, the brain has completed half its postnatal growth and is 75% of adult size.

Question 27

After using polysyllabic babbling for the last 2–3 months, a child now says both “Mama” and “Dada” specifically. He is wary of strangers and has been for the last several months. He first waved “bye-bye” 2 months ago and enjoys showing a toy to an adult. He does not yet understand a 1-step command.

Based on his level of development, how old is this child?

Answer 27

Answer
12 months of age
Explanation
Polysyllabic babbling and the nonspecific use of “Mama” and “Dada” develop at 9 months of age. By 12 months of age the majority of children use “Mama” and “Dada” specifically. Stranger anxiety, which begins around 6 months of age, is often still present at 12 months of age. Children first learn to wave “bye-bye” around 10 months of age and enjoy showing toys to others by 11 months of age. The ability to understand a 1-step command is usually not present prior to 15 months of age.

Question 28

After 2 years of age, what is the normal weight gain per year until adolescence?

Answer 28

Answer
5 lbs/year
Explanation
After 2 years of age, normal weight gain is about 5 lbs/year until adolescence. Calculate average weights for different ages as follows:
1–6 years: weight in pounds = (age × 5) + 17
7–12 years: weight in pounds = (age × 7) + 5

Question 29

A child enjoys playing “pat-a-cake” and uses her thumb to grasp a cube. She pulls to stand and stands momentarily; however, she has yet to take a step. She recently developed a parachute reflex.

Based on her level of development, how old is this child?

Answer 29

9 months of age
Explanation
Children are likely to understand and enjoy playing “pat-a-cake” or similar games at 9 months of age. Infants 6–8 months of age typically use the thumb to grasp a cube; a pincer grasp (fingertip and distal thumb) develops at 9–12 months of age. The parachute reflex is first noted at 8–9 months of age. Most 9-month-old children easily pull to a stand and are able to stand momentarily before falling.

Question 30

A 10-year-old presents with the following:

BMI ≥ 97th percentile
Triglycerides 160 mg/dL
HDL cholesterol 20 mg/dL
Systolic BP > 90th percentile
Fasting glucose 100 mg/dL
Waist circumference > 90th percentile
What is the most likely diagnosis?

Answer 30

Metabolic syndrome
Explanation
Metabolic syndrome is not a disease but rather a cluster of related diseases that are well described in adults but not in children. Even though there is no clear definition for children, if a child has ≥ 3 of the 6 suggested metabolic syndrome indices, a diagnosis of metabolic syndrome can be made:
BMI ≥ 97th percentile
Triglycerides > 110 mg/dL
HDL cholesterol < 40 mg/dL
Systolic/diastolic BP > 90th percentile
Fasting glucose > 110 mg/dL or oral glucose tolerance test > 140 mg/dL
Waist circumference > 90th percentile

Question 31

A young girl can:

Run well and climb up and down stairs, 2 feet each step
Balance on 1 foot for 2–3 seconds
Dress herself (except buttons in the back)
Use 3-word sentences
But she cannot:

Hop on 1 foot
Use 4-word sentences
Skip
Based on this level of development, what is the likely age of this girl?

Answer 31

3 years of age
Explanation
A 3-year-old child should be able to balance on 1 foot for 2–3 seconds, dress herself, and use 3-word sentences. A 2-year-old can run well and climb up and down stairs, 2 feet each step. A 4-year-old should be able to hop on 1 foot and use 4-word sentences. A 5-year-old should be able to skip. She meets the milestones of a 2-year-old and a 3-year-old but is not able to do what a 4-year-old or 5-year-old should. Therefore, she is likely 3 years of age.

Question 32

At what age can most children walk well, build a tower of 2 cubes, and start to scribble?

Answer 32

15 months of age
Explanation
Most children are able to walk holding onto furniture at 11 months of age, walk without assistance at 13 months of age, and walk well at 15 months of age. At 13–15 months of age, most children can also build a tower of 2 cubes. Scribbling occurs from 15 to 18 months of age.

Question 33

At what age can most children follow a 1-step command and use at least several words other than “Mama” and “Dada”?

Answer 33

15 months of age
Explanation
Most children are able to follow a 1-step command by 15 months of age. The number of vocabulary words may vary greatly at this age, but the majority of 15-month-old children have 3–6 words in their vocabulary in addition to “Mama” and “Dada.”

Question 34

An infant has recently started to cry whenever his mother leaves him with an unfamiliar person. He smiles when he looks in a mirror and often babbles but with no discernible words. He can track an object to 180°. He visually tracks an object through a fall and searches for a partially hidden toy.

Based on his level of development, how old is this infant?

Answer 34

Answer
6 months of age
Explanation
Stranger anxiety begins around 6 months of age and can persist until 1 year of age (as opposed to separation anxiety, which occurs anywhere from 8 months to 2 years of age). Infants begin to smile at a mirror at 4 months of age. “Cooing” begins at 2–4 months of age; most 4-month-old infants squeal. Babbling begins at 6 months of age; polysyllabic babbling does not begin until 9 months of age. Object tracking to 180° should be present at 2 months of age. At 6 months of age, most infants are able to track an object visually through a fall and search for a partially hidden toy.

Question 35

At what age range are the majority of children able to walk without help and grasp a cube with the fingertip and distal thumb?

Answer 35

11–13 months of age
Explanation
Wide ranges in the attainment of early gross motor milestones in healthy children are the rule rather than the exception. On average, children pull to stand at 9 months of age, walk holding onto furniture at 11 months of age, and walk without help by 13 months of age. Almost all children have developed a “mature” cube grasp (fingertip and distal thumb) by 12 months of age.

Question 36

At what age should a child be able to sit with support? With no support?

Answer 36

Answer
6 months of age; 7 months of age
Explanation
A child should be able to sit with support by 6 months of age and with no support by 7 months of age.

Question 37

At what age should children be able to hold their heads up to 90° and lift their chests?

Answer 37

4 months of age
Explanation
Most infants can lift their heads to 90° and lift their chests by 4 months of age. Head lag when pulled to sitting at this age is a red flag for referral.

Question 38

What is the most common reason for failure to thrive (FTT)?

Answer 38

Inadequate consumption of appropriate amounts and/or kinds of food
Explanation
FTT is the result of insufficient nutrition to maintain appropriate growth. Most cases can be managed on an outpatient basis. Definitions for FTT include:
cessation of weight gain after a period of stable growth that manifests as weight < the 3rd percentile for age,
weight for height < the 5th percentile, or
growth that has fallen, crossing 2 percentile curves in a short time.

Question 39

At what age does a child roll from front to back? Back to front?

Answer 39

4–5 months of age; 5–6 months of age
Explanation
A child should be able to roll from front to back by 4–5 months of age and from back to front by 5–6 months of age.

Question 40

When does birth length double? Triple?

Answer 40

4 years of age; 13 years of age
Explanation
Birth length doubles by 4 years of age, triples by 13 years of age, and increases an average of 2 inches/year from 4 years of age until adolescence.

Question 41

A male infant has a social smile and has just started to “coo.” He does not smile at a mirror.

Based on his level of development, how old is this infant?

Answer 41

2 months of age
Explanation
Developmentally normal infants at 2 months of age will have a social smile; absence of this would be abnormal. Many (but not all) 2-month-old infants “coo,” a milestone that occurs from 2 to 4 months of age. Smiling at a mirror typically does not occur until 4 months of age.

Question 42

At what age do most children lose their Moro reflex?

Answer 42

3–6 months of age
Explanation
The Moro reflex is absent in most children by 3–6 months of age. The abnormal persistence of primitive reflexes like the Moro indicates central nervous system dysfunction. This can interfere with the development of voluntary motor movements, causing changes in muscle tone and limb position.