Growth, Development and Behavioral Pediatrics
What to master
You must know normal growth trajectories (weight, length/height, head circumference) and the milestone windows for gross motor, fine motor, language, and social development. Understand growth chart interpretation: crossing centiles, mid-parental height, and the difference between constitutional delay and pathologic failure to thrive. Know the red flags of developmental delay: loss of milestones, asymmetry, persistent primitive reflexes, and absent social smile by 2 months.
Concepts that recur
Head circumference tracks brain growth and should be interpreted with weight and length-macrocephaly with normal growth differs from hydrocephalus with a crossing centile. Language delay is the most common isolated delay; hearing must be excluded first. Know the difference between global delay (two or more domains) and specific delay. Understand temperament, attachment, and the distinction between regression (pathologic) and transient plateau (often normal). Autism spectrum warning signs include no pointing by 12–14 months, no words by 16 months, and no two-word phrases by 24 months. ADHD is a diagnosis of pervasive, impairing inattention/hyperactivity across settings, not a single-context behavior.
Traps
Examiners exploit corrected age in preterm infants-milestones should be adjusted until about 2 years. Another trap is attributing short stature to familial causes when bone age is markedly delayed or growth velocity is falling. Beware questions that offer a normal variant (e.g., benign macrocephaly) alongside a serious cause; the stem usually gives a clue such as normal development and family history.
Worked rule
For a child with short stature: plot height, calculate height velocity, compare with mid-parental height, and obtain bone age. If bone age is delayed and velocity is normal, constitutional delay is likely; if velocity is low, investigate systemic or endocrine disease.