What is the appropriate work‑up for a 9‑year‑old child presenting to primary care with a new or persistent decrease in appetite?

Work-Up for a 9-Year-Old with Decreased Appetite in Primary Care

The first and most critical step is to immediately plot the child's weight and height on CDC growth charts and compare against all prior data points to determine if appetite concerns are translating into actual growth deviation—this objective measure determines whether you are dealing with a benign behavioral issue or a clinically significant problem requiring intervention. 1

Immediate Objective Assessment

• Plot current weight, height, and BMI percentile on CDC 2000 growth charts and compare with the child's established growth trajectory from previous visits 1, 2
• Calculate BMI percentile (for children ≥2 years) to determine if growth is maintained despite parental concerns 1
• Look specifically for downward crossing of two major percentile lines, which signals need for specialist referral 1
• Document total weight loss if present and calculate percentage below ideal body weight 2

Normal growth despite decreased appetite often indicates age-appropriate eating patterns rather than pathology and requires only reassurance and behavioral guidance 1. However, any deviation from established growth trajectory mandates further evaluation.

Red Flag Screening (Critical in This Age Group)

Screen for Eating Disorders

Even at age 9, eating disorders must be considered, particularly in girls. Ask directly about:

• Weight control behaviors and body image concerns 2
• Fear of gaining weight or becoming fat 2
• Purging methods including self-induced vomiting, laxative/diuretic misuse, or excessive exercise 2, 3
• Restrictive eating patterns (eating <500 kcal/day, prolonged fasting, diet pill use) 2

Adolescent girls who diet are 18 times more likely to develop an eating disorder than non-dieters, and moderate dieters have a fivefold increased risk 4. While this child is pre-adolescent, early identification is critical as subclinical presentations carry the same morbidity and mortality risk as full-syndrome eating disorders 2.

Screen for Depression

• Assess for depressed or irritable mood, loss of interest in previously enjoyed activities, social withdrawal, and sleep changes 4
• Ask directly: "Have you ever thought about killing yourself or wished you were dead?" 4
• Depression commonly presents with decreased appetite in children and should never be dismissed 4

Obtain Targeted History

• Dietary intake: Document a detailed 24-hour recall and typical eating patterns, not just "decreased appetite" 1, 5
• Activity level and screen time: Specifically ask about television viewing hours and physical activity 1, 5
• Associated symptoms: Nausea, vomiting, diarrhea, abdominal pain, or other GI symptoms lasting >2 weeks 4
• Unintentional weight loss: Quantify amount and timeframe (>3 kg in last month or >6 kg in last 6 months is significant) 4
• Psychosocial stressors: School performance, peer relationships, family conflict, bullying, or recent life changes 4, 2

Physical Examination Priorities

• Vital signs with orthostatic measurements: Heart rate <50 bpm, blood pressure <90/45 mmHg, temperature <96°F (35.6°C), or orthostatic pulse increase >20 bpm are hospitalization criteria 2, 3
• Signs of malnutrition: Muscle wasting, lanugo hair, dry skin, brittle nails, cold extremities 2
• Acanthosis nigricans: May indicate insulin resistance or metabolic syndrome 4
• Abdominal examination: Organomegaly, masses, or tenderness 6

Laboratory Evaluation (When Indicated)

Do NOT order labs reflexively—they are indicated only when growth deviation is documented or red flags are present. When ordered:

• Comprehensive metabolic panel: To detect electrolyte abnormalities (hypokalemia, hyponatremia, hypochloremic alkalosis from purging) 2, 3
• Complete blood count: Anemia, leukopenia, thrombocytopenia may indicate malnutrition 2, 3
• Thyroid function: Only if clinical signs of thyroid disease are present—hypothyroidism is a very rare cause of decreased appetite and obesity, and routine screening is not recommended 5
• Fasting glucose or HbA1c: Only if family history of type 2 diabetes or signs of insulin resistance 4
• ECG: If eating disorder suspected or vital sign abnormalities present, to assess QTc prolongation 2, 3

Critical caveat: More than half of medically unstable youth with eating disorders have completely normal laboratory results—never use normal labs to provide false reassurance 2.

First-Line Management for Benign Decreased Appetite

If growth is normal and red flags are absent, implement behavioral interventions:

• Establish 4-6 small, scheduled meals daily rather than grazing or irregular patterns 1
• Create distraction-free eating environment: Remove television, tablets, phones, and other electronics during meals 1
• Prioritize nutrient-dense foods when appetite is limited—focus on calories per bite rather than volume 1
• Offer variety using MyPlate method: Fruits, vegetables, proteins, whole grains 1
• Avoid weight-focused comments: Parental comments about weight are linked to higher rates of eating disorders five years later 2

Follow-Up Protocol

• Reassess weight and growth every 2-4 weeks initially when implementing behavioral interventions 1
• If no improvement after 4-6 weeks of consistent behavioral strategies, escalate to specialist consultation 1
• Immediate specialist referral if weight loss or failure to gain weight occurs despite interventions 1

Immediate Hospitalization Criteria

If any of the following are present, hospitalize immediately before attempting outpatient management:

• Heart rate <50 bpm (daytime) 2, 3
• Blood pressure <90/45 mmHg 2, 3
• Core temperature <96°F (35.6°C) 2, 3
• Orthostatic pulse increase >20 bpm 2, 3
• Rapid or severe weight loss 2, 3
• Severe electrolyte abnormalities 3
• Inability to control purging behaviors 3
• Suicidal ideation 3

Common Pitfalls to Avoid

• Delaying evaluation while "watching and waiting": Growth deviation requires prompt action, not prolonged observation 1, 2
• Ordering thyroid function tests reflexively: This is rarely helpful and diverts attention from behavioral and psychiatric causes 5
• Dismissing parental concerns without objective growth assessment: Always plot growth charts even when you suspect the concern is unfounded 1
• Missing eating disorders in younger children: While more common in adolescents, eating disorders can present in pre-pubertal children and carry identical mortality risk 2
• Focusing exclusively on diet while ignoring activity: Decreased appetite is multifactorial and requires assessment of both nutritional intake and physical activity patterns 1, 5