Underweight  >2 years old

• Poverty and/or food insecurity
• Dysphagia/ Odynophagia (e.g. GERD, esophagitis, dental caries, chronic constipation)
• Oromotor dysfunction – Problems with chewing and swallowing can be common in children with CNS or neuromuscular disorders (may not present until child is older)
• Behavioral issues.
• Feeding aversion in toddlers secondary to poor caregiver-child interactions where issues of control dominate; these dietary control issues are a frequent component of poor weight gain. Food aversion also can be a learned behavior related to sensations associated with food textures, consistencies, temperatures, or smells
• "Picky" or "selective" eaters (ages 2-5) At this age, increased exploratory activities may limit the time a child focuses on eating. Strange eating habits or limited intakes of a variety of foods and beverages generally are a temporary developmental phase and may be causally related to the normal pattern of slower growth at this age.
• However, if other causes of picky eating (eg, gastroesophageal reflux, constipation, etc) have been excluded, selective eating in the context of poor weight gain may be a marker for psychosocial problems, including poor caregiver-child interactions, or may indicate an eating disorder: avoidant/restrictive food intake disorder
• Other behavioral issues that can affect dietary intake include hyperactivity and attention problems (which may decrease time spent eating), as well as anorexia nervosa and bulimia nervosa
  
• Decreased appetite – Decreased appetite can occur for a variety of reasons:
  
• 1. too much juice or other nonnutritious liquid, resulting in satiation and decreased appetite for higher caloric density or more nutritious solid foods
  
• 2. Children with any chronic disease, including gastrointestinal (eg, celiac disease, lactose intolerance, IBD), renal, cardiac, or pulmonary conditions, may have anorexia, vomiting, early satiety, abdominal pain, constipation, or diarrhea.
  
• 3. Medications (eg, for seizures or attention deficit disorder)
• 4. Stressful psychosocial conditions.
• Dietary restriction – Older children and adolescents may impose limits on their dietary intake in an effort to lose weight or be healthy. Eating disorders may develop.
•  Dietary restriction also may be related to actual or perceived food intolerance or allergy and cultural or personal beliefs.
• Restrictive diets (eg, dairy-free, vegetarian, low-fat, low-carbohydrate) may not supply all the energy and nutrient needs for a growing child or adolescent
• Child abuse / Neglect

•     Congenital heart disease - possibly secondary to hypoxia, poor weight gain, vomiting, alterations in carbohydrate and fat metabolism, and the energy cost of physical activity
•     Chronic lung disease - increased energy expenditure due to increased work of breathing and recurrent respiratory illnesses.
•     Hyperthyroidism - increased heart rate and blood pressure, but unclear
•     Obstructive sleep apnea - ? increased work of breathing during sleep
•     Diencephalic syndrome, (disorder associated with central nervous system tumors), is a rare cause of profound weight loss related to increased energy expenditure
•     Inflammation – Diseases that have an inflammatory or catabolic component, such as cystic fibrosis, IBD, or malignancy, may be associated with weight loss and subsequently poor weight gain. Increased inflammatory cytokines may stimulate the release of leptin, a satiety factor that leads to poor weight gain in some of these disorders
•     Increased activity – The fidgety, hyperactive, or "busy" child may expend more energy. However, this increase in physical activity is a debatable cause of poor weight gain

•     Celiac disease
•     IBD       
•     Cystic fibrosis
•     Bulimia nervosa
•     Short bowel syndrome
•     Eosinophilic gastrointestinal disorders
•     Pancreatitis
•     Chronic liver disease
•     Diabetes mellitus
•     Chronic renal disease
•     Inborn errors of metabolism
•     Renal tubular acidosis
•     Carbohydrate intolerance

Evaluation

Indications for Hospitalization

•     Moderately to Severely malnourished (eg, weight-for-age z-score <-2 [approximately 2nd percentile], weight-for-height <80 percent of the median, or body mass index (BMI) <12 kg/m2)
•     Serious organic cause is suspected (eg, malignancy)
•     Suspicion for neglect or abuse
•     Need for observation of Eating patterns