Principles and pitfalls in the differential diagnosis and management of childhood obesities.

Obesity is currently the most prevalent chronic childhood disease in Western countries. It is one of the most frequent consultations in general pediatrics and is even more common in pediatric endocrinology. As might be predicted, the prevalence of obesity-associated comorbidities is also increasing in children and adolescents. It is widely accepted that this increase in obesity results from an imbalance between energy intake and expenditure, with an increase in positive energy balance being closely associated with the current lifestyle in Western countries. However, there is increasing evidence indicating that an individual's genetic background is important in determining obesity risk. The physiologic mechanisms controlling appetite and energy expenditure are being revealed in part because of the identification of new causes of human monogenic, syndromic, and endocrine-related obesity. Thus, it is no longer appropriate to talk about obesity, but rather about "obesities" or "different diseases causing obesity," because their pathophysiologic bases differ. Moreover, these obesities require different diagnostic and management approaches. The pediatrician must be aware of this issue and focus the clinical history and physical examination toward specific clinical signs and symptoms to better exploit the available diagnostic and therapeutic resources when facing a child with obesity. Genetic, genomic, and metabolomic studies are often necessary to obtain a more appropriate diagnosis. Cognitive behavioral therapy is fundamental in obese children. The identification of potential targets will hopefully result in new pharmacologic approaches for translational and personalized medicine for obesity in the near future.