Pediatrics
Childhood Obesity
Childhood obesity for MBBS: constitutional versus secondary obesity, BMI cut-offs on IAP charts, acanthosis nigricans and referral criteria, mapped to NMC codes PE11.1 to PE11.6.
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Childhood Obesity
Childhood obesity for MBBS: constitutional versus secondary obesity, BMI cut-offs on IAP charts, acanthosis nigricans and referral criteria, mapped to NMC codes PE11.1 to PE11.6.
This chapter covers the etiology, assessment and management of childhood obesity, including the distinction between constitutional and secondary obesity, BMI interpretation using IAP charts, examination signs and referral criteria. It stresses family-centred prevention.
High-yield: Childhood Obesity
- Most childhood obesity is constitutional (about 95 percent), showing tall stature, generalised fat, normal development and no dysmorphism.
- Pathological or secondary obesity (fewer than 5 percent) is suggested by short stature, abnormal development or dysmorphic features.
- The distinction between a tall well-developed child and a short dysmorphic child drives the entire obesity workup decision.
- Body mass index (BMI) is weight in kilograms divided by height in metres squared, and it is used with age- and sex-specific charts in children.
- Overweight is a BMI at the 85th to 94th centile, obese is at or above the 95th centile, and severe obesity is at or above the 99th centile.
- IAP 2015 charts should be used for Indian children rather than CDC charts to avoid underestimating obesity.
- Acanthosis nigricans is a marker of insulin resistance and prompts screening with fasting glucose and an oral glucose tolerance test.
- Purple striae with a moon face and growth failure suggest Cushing syndrome, whereas white striae occur in simple constitutional obesity.
- Rapid-onset obesity after a neurological illness suggests hypothalamic obesity.
- Infantile hypotonia followed by hyperphagia from around 2 years suggests Prader-Willi syndrome.
- Early adiposity rebound before age 5, both parents being obese, and formula feeding are the three highest-risk scenarios for childhood obesity.
- Assessment includes BMI calculation and interpretation, waist-hip ratio, and examination for acanthosis, striae and pseudogynaecomastia.
- Referral is needed for secondary-cause features, metabolic complications such as type 2 diabetes or fatty liver, severe comorbidities like slipped capital femoral epiphysis, or failure of 3 to 6 months of lifestyle change.
- Prevention of childhood obesity requires family-centred, multi-level lifestyle intervention rather than counselling the child alone.
BMI-based obesity classification
- **Overweight:** BMI at the 85th to 94th centile for age and sex.
- **Obese:** BMI at or above the 95th centile.
- **Severe obesity:** BMI at or above the 99th centile or above 120% of the 95th centile.
- **Charts to use:** IAP 2015 charts for Indian children, not CDC charts.
NMC competencies in this chapter
- **PE11.1:** Common etiology, clinical features and management of obesity in children
- **PE11.2:** Risk approach for obesity and prevention strategies
- **PE11.3:** Assessment of a child with obesity: history, physical activity, charting and dietary recall
- **PE11.4:** Examination including BMI, waist-hip ratio, acanthosis, striae and pseudogynaecomastia
- **PE11.5:** Calculate BMI, document in a BMI chart and interpret
- **PE11.6:** Criteria for referral of obese children
Frequently Asked Questions
How do you distinguish constitutional from pathological obesity?
Constitutional obesity, about 95 percent of cases, shows tall stature, generalised fat, normal development and no dysmorphism, while pathological or secondary obesity is suggested by short stature, abnormal development or dysmorphic features and needs targeted investigation.
What are the BMI cut-offs for overweight and obese children?
Overweight is a BMI at the 85th to 94th centile, obese is at or above the 95th centile, and severe obesity is at or above the 99th centile, using IAP 2015 charts for Indian children.
What does acanthosis nigricans indicate?
Acanthosis nigricans, a velvety dark thickening usually at the neck and axillae, is a marker of insulin resistance and should prompt screening with fasting glucose and an oral glucose tolerance test.
When should an obese child be referred?
Referral is warranted for features of a secondary cause, metabolic complications such as type 2 diabetes, impaired glucose tolerance, fatty liver or dyslipidaemia, severe comorbidities, severe obesity, or failure of 3 to 6 months of lifestyle modification.
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