Growth And Development

Question 1

After 9 months of dietary changes and daily exercise, a 17-year-old male with 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 1

BMI > 40

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 > 40 with a serious obesity-related morbidity (e.g., poorly controlled Type 2 diabetes, hypertension, obstructive sleep apnea, hypoventilation syndrome)
• BMI > 50 with less severe comorbidities

Question 2

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

Answer 2

Inadequate Consumption of Appropriate Amounts

and/or Kinds of Food

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 3^rd percentile for age,
• weight for height < the 5^th percentile, or
• growth that has fallen, crossing 2 percentile curves in a short time.

Question 3

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

Answer 3

6 Years of Age

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. In language development, most 6-year-olds have mastered consonant blends (e.g., sh, zh).

Question 4

An infant female 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 is absent; the Moro reflex is present.

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

Answer 4

2 Months of Age

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.” Smiling at a mirror typically begins at 4 months of age. The palmar grasp is normally absent by 2–3 months of age; the Moro reflex persists until 3–4 months of age.

Question 5

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

Answer 5

15 Months of Age

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 at least several words in their vocabulary in addition to “mama” and “dada.”

Question 6

A premature neonate presents with possible macrocephaly.

What is the diagnostic test of choice?

Answer 6

Ultrasound of the Head

A premature neonate is at risk for hydrocephalus, often the result of an intraventricular hemorrhage; hence, in all premature neonates with enlarged head circumferences, ultrasound of the head is indicated. A CT or MRI is not needed for the diagnosis.

Question 7

How soon does an infant regain birth weight?

Answer 7

10-14 Days of Life

Birth weight is regained by 10–14 days of life. Infants gain 20–30 g/day for the first 3–4 months, then gain 15–20 g/day for the rest of the year.

Question 8

At what age can most children hop on one foot?

Answer 8

4 Years of Age

4-year-old children can hop on one foot, balance on one foot for up to 10 seconds, and use a fork without difficulty.

Question 9

What p-value is considered statistically significant?

Answer 9

p < 0.05

In other words, there is only a 5% chance that the result we got showing an effect was a random chance effect.

Question 10

A young child has, for the last 2–3 months, cried whenever one or both of his parents leave his sight. He has just started to say “mama” and “dada” nonspecifically and to use polysyllabic babbling. He pulls to stand.

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

Answer 10

9 Months of Age

Separation 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 11

What supplements should be given to exclusively breastfed babies?

Answer 11

Vitamin D and Iron

Vitamin D (400 IU/day) should begin in all exclusively breastfed infants in the first few days of life and continued until the infant is weaned to at least 1 quart a day of vitamin D-fortified formula or milk (which milk should not be started until after 12 months of age). Full-term healthy breastfed babies should begin on daily supplementation of iron with 1 mg/kg at 4 months of age.

Question 12

An infant female 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 12

1 Month of Age

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; infants first “coo” at 2–3 months of age. The palmar grasp reflex disappears by 2–3 months of age.

Question 13

At what age do most children lose their Moro reflex?

Answer 13

3-4 Months of Age

The abnormal persistence of primitive reflexes like the Moro indicates central nervous system dysfunction. This interferes with the development of voluntary motor movements, causing changes in muscle tone and limb position. This is one of the major developmental milestones you should commit to memory.

Question 14

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

Answer 14

6 Months of Age; 7 Months of Age

A child should be able to sit with support at 6 months of age and with no support by 7 months of age. These are 2 major developmental milestones you need to memorize.

Question 15

At what age can a child use a cup well?

Answer 15

15-18 Months

Question 16

Which statistical tests are influenced by the prevalence of the disease?

Answer 16

Positive and Negative Predictive Values

If a disease is very prevalent, the a positive test is likely to be true positive. If a disease is very rare, a positive test is likely to be a false positive. Sensitivity and specificity are not influenced but the prevalence of the disease/condition.

Question 17

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 17

18 Months of Age

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” or pointing at and identifying body parts). Around 18 months of age, many children begin to use simple 2-word sentences. Absence of any words by 18 months of age requires evaluation for language delay. Parallel, rather than cooperative play is expected at this age.

Question 18

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 18

11–13 Months of Age

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, walk holding onto furniture at 11 months, and walk without help by 13 months. Almost all children have developed a “mature” cube grasp (fingertip and distal thumb) by 12 months of age.

Question 19

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 is not yet able to run well.

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

Answer 19

18 Months of Age

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. 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 20

Name 5 primitive reflexes present at birth that typically disappear at 3–4 months of age.

Answer 20

Rooting, Stepping, Sucking, Hand Grasp, and Moro Reflexes

Other primitive reflexes include the crossed adductor (disappears by 7 months), toe grasp (disappears at 8–15 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 21

How is body mass index (BMI) calculated?

Answer 21

(Weight in kg) / (Height in Meters)²

Calculate BMI using a ratio of a person’s weight and height. The percentiles are age and gender based.

Question 22

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

• A BMI at the 98^th percentile
• A waist circumference at the 95^th percentile
• Systolic and diastolic blood pressure at the 95^th percentile

List the indices for serum HDL cholesterol, triglycerides, and fasting glucose levels that would support the diagnosis of metabolic syndrome in this patient.

Answer 22

HDL Cholesterol < 40 mg/dL; Triglycerides > 110 mg/dL;

Fasting Glucose > 110 mg/dL

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 criteria for the diagnosis of metabolic syndrome:

1. BMI > 97^th percentile,
2. systolic/diastolic BP > 90^th percentile,
3. waist circumference > 90^th percentile,
4. triglycerides > 110 mg/dL,
5. HDL cholesterol < 40 mg/dL, and/or
6. fasting glucose > 110 mg/dL or oral glucose tolerance test > 140 mg/dL.

Question 23

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

Answer 23

CT or MRI of the Head

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. (If MRI is not listed as an option, choose CT.) An ultrasound (the correct choice for infants with macrocephaly to evaluate for hydrocephalus) is not indicated in the evaluation of microcephaly.

Question 24

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

Do you think this child has expressive language delay?

Answer 24

Yes

By 18 months of age, the child should be able to use > 10–50 words, identify 4 body parts, and follow simple instructions. The ability to speak in 2-word sentences should be present between 18 and 24 months of age. Conduct a hearing screen as the first test when you suspect a language delay.

Question 25

What is the most common type of craniosynostosis?

Answer 25

Scaphocephaly

Scaphocephaly (a.k.a. dolichocephaly) is 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 26

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

Answer 26

4–5 Months of Age; 5–6 Months of Age

A child should be able to roll from front to back by 4–5 months of age and back to front by 5–6 months of age. These are 2 of the major developmental milestones you should memorize.

Question 27

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 27

2 Years of Age

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 15–18 months of age). Most 2-year-olds can stack up to 6 blocks.

Question 28

A young girl can:

• Run well; and climb up and down stairs, 2 feet each step
• Balance on one foot for 2–3 seconds
• Dress herself (except buttons in the back)
• Use 3-word sentences

But she cannot:

• Hop on one foot
• Use 4-word sentences
• Skip

Based on this level of development, what is the likely age of this girl?

Answer 28

3 Years of Age

A 3-year-old child should be able to balance on one 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 one 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. These are some of the major developmental milestones you should memorize.

Question 29

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

Answer 29

Hearing Screen

Know this! A hearing screen is the most important thing to do when evaluating a language problem (receptive or expressive) in a child.

Question 30

When does birth length double by? Triple by?

Answer 30

4 years; 13 years

After 2 years of age, average height increase is 2 inches per year until adolescence.

Question 31

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

Answer 31

5 lbs/year

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 32

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

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

Answer 32

9 Months of Age

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 mature (fingertip and distal thumb) cube grasp develops at 9–12 months. The parachute reflex is first noted at 6–9 months. Most 9-month-old children easily pull to a stand and are able to stand momentarily before falling.

Question 33

How rapidly does the head grow in the first year of life?

Answer 33

1 cm/month

Normally the head grows 1 cm per month for the 1st year of life, with the most rapid growth occurring in the first 6 months. The head stops growing at 4 years of age.

Question 34

A 6-month-old boy plots below the 3rd percentile for weight. Height and head circumference plot at the 10thand 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 FTT in this infant?

Answer 34

Inadequate Consumption of Appropriate Amounts

and/or Kinds of Food

The majority of cases of FTT 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 35

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

Answer 35

50%

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

Question 36

At what age can infants be transitioned to cow’s milk?

Answer 36

12 Months

Before 12 months of age, infants should only receive their milk product as breast milk (preferred) or iron-fortified formula. At 12 months of age, you can switch to whole cow’s milk or 2% milk if the infant is at risk of being overweight or has family history of high cholesterol, obesity, or heart disease.

Question 37

An infant has recently started to cry whenever his mother leaves the room. 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 37

6 Months of Age

Separation anxiety begins around 6 months 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 38

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 38

12 Months of Age

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. Separation (stranger) anxiety, which begins at 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 39

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

Answer 39

15 Months of Age

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 and scribble.

Question 40

A 10-year-old presents with the following:

• BMI ≥ 97^th percentile
• Triglycerides 160 mg/dL
• HDL cholesterol 20 mg/dL
• Systolic BP > 90^th percentile
• Fasting glucose 100 mg/dL
• Waist circumference > 90^th percentile

What is the most likely diagnosis?

Answer 40

Metabolic Syndrome

Metabolic syndrome is not a disease but a cluster of related diseases that are well described in adults but not in children. Even though there is no definite definition for children, if a child has ≥ 3 of the 6 suggested metabolic syndrome indeces, a diagnosis of metabolic syndrome can be made:

1. BMI ≥ 97^th percentile
2. Triglycerides > 110 mg/dL
3. HDL cholesterol < 40 mg/dL
4. Systolic/diastolic BP > 90^th percentile
5. Fasting glucose > 110 mg/dL or oral glucose tolerance test > 140 mg/dL
6. Waist circumference > 90^th percentile

Question 41

At what age does the AAP recommend initial autism screening?

Answer 41

18 Months

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

Question 42

When is the fastest rate of head growth?

Answer 42

Between 0 and 2 months of age

The fastest rate of 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 33–37 cm. By 12 months, the brain has completed half its postnatal growth and is 75% of adult size.

Question 43

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

Answer 43

4 Months of Age

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. This is one of the major developmental milestones you should commit to memory.

Question 44

A young child has a vocabulary of 100–200 words, uses many 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 dress himself.

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

Answer 44

24 Months of Age

At 24 months of age most children have a vocabulary of 100–200 words, can identify at least 6 body parts, and use many 2-word sentences; longer sentences are simple constructions. 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, rather than cooperative play is to be expected. Most children cannot dress themselves until 3 years of age.

Question 45

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

Answer 45

3 Years of Age; Between 3 and 4 Years of Age;

4 Years of Age; 5 Years of Age

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 you must memorize.

Question 46

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

What is the recommended treatment?

Answer 46

Reassurance

Enlargement of the subarachnoid space is a benign condition that requires no intervention. About 2/3 of affected infants are boys.

Question 47

When does birth weight double? Triple? Quadruple?

Answer 47

4 Months of Age; 12 Months of Age; 24 Months of Age

Full-term infants double their birth weight by 4 months, triple their birth weight by 12 months, and quadruple their birth weight around 2 years. Average weight gain is then about 5 pounds per year.

Question 48

An infant male 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 48

2 Months of Age

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 also “coo.” Smiling at a mirror typically does not occur until 4 months of age.