Pediatric conditions encompass the health of children from birth through adolescence. Children are not simply small adults — they have unique physiology, developmental stages, disease patterns, and pharmacokinetics. Pediatric care emphasizes prevention through immunization and well-child visits, early detection of developmental delays, and family-centered care.
Growth and Development
Growth Assessment
Growth is a fundamental indicator of child health. Serial measurements of weight, length/height, and head circumference are plotted on WHO (0–2 years) or CDC (2–20 years) growth charts. Key concepts: growth velocity (abnormal slowing may indicate disease), body mass index (BMI) percentile for obesity screening, and tracking (maintaining a consistent percentile over time).
Failure to thrive (FTT). Inadequate weight gain or weight loss across percentile lines. Organic causes: feeding difficulties, malabsorption (celiac disease, cystic fibrosis), congenital heart disease, infectious diseases, endocrine (hypothyroidism, GH deficiency), and genetic disorders. Inorganic (psychosocial) causes: neglect, food insecurity, dysfunctional feeding interactions. Management requires addressing the underlying cause, nutritional intervention, and multidisciplinary support.
Short stature. Height below the 3rd percentile. Normal variants: familial short stature and constitutional delay of growth and puberty. Pathologic causes: growth hormone deficiency, hypothyroidism, Turner syndrome, chronic disease (IBD, celiac, renal disease), skeletal dysplasias, and psychosocial dwarfism. Growth hormone therapy is indicated for GH deficiency, Turner syndrome, Prader-Willi syndrome, and chronic renal insufficiency.
Developmental Milestones
Development follows predictable sequences in four domains: gross motor, fine motor/vision, language/hearing, and social/emotional. The CDC’s Learn the Signs. Act Early. program provides milestone checklists at each well-child visit.
Key milestones. 2 months: social smile, tracks objects. 4 months: rolls, reaches for objects. 6 months: sits with support, babbles. 9 months: crawls, pulls to stand. 12 months: walks with support, says 1–2 words. 18 months: walks independently, says 10+ words. 24 months: runs, two-word phrases. 36 months: speaks in sentences, rides tricycle.
Red flags (prompt referral). No social smile by 3 months, no babbling by 9 months, no single words by 15 months, loss of previously acquired skills (suggests regressive disorder), and asymmetric motor development.
Neonatal Disorders
Preterm Birth
Birth before 37 weeks gestation, affecting 10% of pregnancies worldwide. Extremely preterm (<28 weeks), very preterm (28–32 weeks), moderate to late preterm (32–37 weeks). Complications: respiratory distress syndrome (surfactant deficiency), intraventricular hemorrhage, necrotizing enterocolitis, patent ductus arteriosus, retinopathy of prematurity, and neurodevelopmental impairment. Prenatal corticosteroids, surfactant therapy, and developmental care improve outcomes.
Jaundice
Neonatal hyperbilirubinemia is common (60% of term newborns). Physiologic jaundice: unconjugated, appears after 24 hours, resolves by week 2. Pathologic jaundice: appears within 24 hours, rapidly rising levels, or conjugated hyperbilirubinemia. Severe unconjugated hyperbilirubinemia risks kernicterus (bilirubin-induced neurological dysfunction). Phototherapy is the mainstay of treatment; exchange transfusion for extreme levels.
Birth Injuries
Brachial plexus injury (Erb-Duchenne palsy — C5–C7, waiter’s tip posture). Clavicular fracture (most common obstetric fracture). Cephalohematoma (subperiosteal hemorrhage, does not cross suture lines). Caput succedaneum (subcutaneous edema, crosses suture lines, resolves in days).
Childhood Infections
Vaccine-Preventable Diseases
Routine childhood immunization targets 14 diseases: hepatitis B, rotavirus, diphtheria, tetanus, acellular pertussis (DTaP), Haemophilus influenzae type b (Hib), pneumococcal (PCV13), polio (IPV), influenza, measles, mumps, rubella (MMR), varicella, and hepatitis A. The COVID-19 vaccine and HPV vaccine (starting at age 11–12) are also recommended. Herd immunity protects vulnerable populations who cannot be vaccinated.
Measles. Highly contagious (R₀ = 12–18). Prodrome: fever, cough, coryza, conjunctivitis, Koplik spots (buccal mucosa). Maculopapular rash starts on the face and spreads downward. Complications: pneumonia, encephalitis, and death. No specific antiviral; treatment is supportive. Measles resurgence has occurred due to vaccine hesitancy.
Pertussis (whooping cough). Paroxysmal cough with inspiratory whoop and post-tussive emesis. Infants are at highest risk of apnea, hypoxia, and death. Prevention by DTaP (children) and Tdap (adolescents, adults, pregnant women — cocooning strategy). Treatment: azithromycin reduces transmission but does not alter cough course.
Common Childhood Infections
Otitis media. Acute otitis media presents with ear pain, fever, and bulging tympanic membrane. Most cases are viral; antibiotics (amoxicillin) are reserved for moderate to severe or persistent symptoms. Recurrent otitis media may require tympanostomy tubes.
Bronchiolitis. The leading cause of hospitalization in infants <1 year. Caused by respiratory syncytial virus (RSV). Presents with rhinorrhea, cough, tachypnea, wheeze, and hypoxemia. Treatment is supportive (oxygen, hydration). Palivizumab prophylaxis is indicated for high-risk infants.
Gastroenteritis. Rotavirus (severe, watery diarrhea, vomiting) is now less common due to vaccination. Norovirus causes outbreaks in congregate settings. Management focuses on rehydration (oral rehydration solution or IV fluids). Zinc supplementation reduces severity and duration.
Genetic and Metabolic Disorders
Down syndrome (trisomy 21). The most common chromosomal abnormality (1 in 700 live births). Features: hypotonia, flat facial profile, upslanting palpebral fissures, single palmar crease, intellectual disability, and congenital heart disease (AV canal defect, VSD, ASD). Comorbidities: hearing loss, vision problems, thyroid disease, celiac disease, atlantoaxial instability, and increased risk of leukemia and Alzheimer disease. Lifelong surveillance and early intervention optimize outcomes.
Cystic fibrosis. Autosomal recessive disorder of CFTR, a chloride channel. Thick secretions in the lungs (chronic infection, bronchiectasis), pancreas (exocrine insufficiency, CFRD), liver (cirrhosis), and reproductive tract (obstructive azoospermia). Diagnosis by newborn screening (immunoreactive trypsinogen) confirmed by sweat chloride test. CFTR modulators (ivacaftor, lumacaftor, tezacaftor, elexacaftor) have transformed outcomes for eligible genotypes.
Inborn errors of metabolism. Individually rare but collectively significant. Phenylketonuria, maple syrup urine disease, medium-chain acyl-CoA dehydrogenase (MCADD) deficiency, and galactosemia are detected by newborn screening. Presents with encephalopathy, hypoglycemia, metabolic acidosis, hyperammonemia, or acute illness triggered by catabolic stress. Management: dietary restriction (PKU, MSUD), avoidance of fasting (MCADD), and cofactor supplementation.
Developmental Disabilities
Autism spectrum disorder (ASD). A neurodevelopmental disorder characterized by persistent deficits in social communication and interaction, restricted interests, and repetitive behaviors. Prevalence: 1 in 36 children. Etiology: strong genetic component with environmental modifiers. Early diagnosis by 18–24 months through surveillance (M-CHAT) and diagnostic evaluation. Early intensive behavioral intervention (EIBI, ABA therapy) improves cognitive and adaptive outcomes.
Attention-deficit/hyperactivity disorder (ADHD). Persistent pattern of inattention, hyperactivity, and impulsivity interfering with functioning. Diagnosis after age 6 requires symptoms in multiple settings. Treatment: behavioral therapy (first-line for preschool), stimulant medications (methylphenidate, amphetamine derivatives), non-stimulants (atomoxetine, guanfacine). Behavioral interventions and academic accommodations are essential.
Cerebral palsy. A group of permanent movement disorders caused by non-progressive brain injury in the developing fetal or infant brain. Spastic types (hemiplegic, diplegic, quadriplegic) are most common. Comorbidities: intellectual disability, epilepsy, vision and hearing impairment. Management: physical and occupational therapy, botulinum toxin for spasticity, baclofen, selective dorsal rhizotomy, and orthopedic surgery for contractures.
Childhood Cancer
Cancer is the second leading cause of death in children (after accidents). The most common childhood cancers: leukemia (ALL), brain tumors (medulloblastoma, pilocytic astrocytoma, ependymoma), lymphoma, neuroblastoma, Wilms tumor (nephroblastoma), rhabdomyosarcoma, retinoblastoma, and bone tumors (osteosarcoma, Ewing sarcoma).
Compared to adult cancers, childhood cancers are more responsive to chemotherapy and have higher cure rates (overall 85% 5-year survival). However, survivors face significant late effects: cardiotoxicity (anthracyclines), cognitive impairment (cranial radiation), secondary malignancies, infertility, and endocrine deficiencies. Life-long survivorship follow-up is essential.
Summary
Pediatric conditions span a unique spectrum from neonatal disorders to childhood infections, genetic conditions, developmental disabilities, and childhood cancer. Prevention through vaccination, newborn screening, and well-child surveillance is the cornerstone of pediatric care. Growth and developmental monitoring identify problems early, when intervention is most effective. Congenital heart disease and genetic syndromes require multidisciplinary specialty care. Childhood cancers, though devastating, are increasingly curable. The transition from pediatric to adult care for children with chronic conditions requires careful planning. The health of children and adolescents lays the foundation for lifelong well-being.