Runting (Failure to Thrive)

What is Runting (failure to thrive)?

Runting, clinically known as failure to thrive (FTT), describes a pattern of inadequate growth in infants or young children. It is not a disease itself but a sign that the child’s weight, length/height, or head circumference is falling below expected growth curves for age and sex. In most contexts FTT is used for children younger than 5 years, because growth monitoring is most reliable during this period.

In practice, health professionals define FTT in three ways:

• Weight‑for‑age < 5th percentile on standardized growth charts (CDC or WHO).
• Weight‑for‑length/height < 3rd–5th percentile or a drop of two major percentile lines on two consecutive measurements.
• Consistently poor weight gain – e.g., less than 2 kg (4.4 lb) weight gain over the first six months of life or failure to gain at least 150 g (5 oz) per week after the first month.

Runting can result from a wide range of medical, social, and environmental factors. Early identification is crucial because prolonged under‑nutrition can affect brain development, immunity, and long‑term health.

Common Causes

FTT is a multifactorial problem. Below are the most frequently encountered etiologies, grouped by category.

• Inadequate caloric intake – poor feeding technique, low‑calorie diet, or early cessation of breastfeeding.
• Malabsorption syndromes – cystic fibrosis, celiac disease, chronic diarrhoea, pancreatic insufficiency.
• Congenital metabolic disorders – phenylketonuria (PKU), maple‑syrup urine disease, galactosemia.
• Cardiac disease – congenital heart defects (e.g., ventricular septal defect, patent ductus arteriosus) that increase metabolic demands.
• Chronic respiratory disease – cystic fibrosis, severe asthma, bronchopulmonary dysplasia.
• Endocrine disorders – hypothyroidism, growth hormone deficiency, adrenal insufficiency.
• Neurologic or developmental conditions – cerebral palsy, Down syndrome, autistic spectrum disorder affecting feeding.
• Gastro‑esophageal reflux disease (GERD) or esophageal motility disorders – cause pain‑related feeding aversion.
• Infections – chronic viral (e.g., HIV), parasitic, or bacterial infections that increase metabolic needs.
• Psychosocial factors – neglect, poverty, parental mental health issues, or feeding practices that limit nutrient intake.

Associated Symptoms

Children with runting often present with a constellation of other signs that help clinicians narrow the cause.

• Failure to gain weight despite adequate milk or formula intake.
• Frequent vomiting, especially after feeds.
• Chronic diarrhoea or oily, foul‑smelling stools.
• Excessive fatigue, poor activity tolerance.
• Dry skin, hair loss, or brittle nails (nutritional deficiency).
• Developmental delays – both motor and cognitive.
• Recurrent respiratory infections or wheezing.
• Palpable abdominal masses (e.g., hepatomegaly in metabolic disease).
• Heart murmur or signs of congestive failure (tachypnoea, poor peripheral pulses).

When to See a Doctor

Parents and caregivers should act promptly if any of the following occur:

• Weight falls below the 5th percentile or drops two major percentile lines on the growth chart.
• Child consistently refuses to eat or eats significantly less than age‑appropriate portions.
• Persistent vomiting, diarrhoea, or constipation lasting more than 2 weeks.
• Visible signs of dehydration – dry mouth, sunken fontanelle, reduced urine output.
• Developmental milestones are not being met (rolling, sitting, speaking).
• Frequent infections or prolonged fevers.
• Any concern about neglect, abuse, or an unstable home environment.

Early pediatric evaluation can prevent long‑term consequences and often uncovers a treatable underlying condition.

Diagnosis

Diagnosing FTT involves a systematic approach that combines growth data, medical history, physical examination, and targeted investigations.

1. Growth assessment

• Plot weight, length/height, and head circumference on WHO (0–2 years) or CDC (2–20 years) growth charts.
• Calculate weight‑for‑age, weight‑for‑length/height, and BMI percentiles.

2. Detailed history

• Prenatal and perinatal events (prematurity, birth weight, complications).
• Feeding practices – breast‑ vs. bottle‑feeding, formula type, introduction of solids.
• Frequency and character of stools, presence of vomiting, reflux, or choking.
• Family medical history (e.g., cystic fibrosis, metabolic diseases).
• Social factors – income, parental education, caregiving stability.

3. Physical examination

• Assess for dysmorphic features, organomegaly, heart murmurs, skin changes.
• Examine oral cavity for clefts, thrush, or dental problems.
• Check for signs of anemia (pallor) or micronutrient deficiencies.

4. Laboratory and imaging studies

• Basic labs: CBC, electrolytes, blood glucose, serum albumin, liver function tests.
• Screen for thyroid function (TSH, free T4), celiac disease (tTG‑IgA), and cystic fibrosis (sweat chloride).
• Metabolic panel: plasma amino acids, urine organic acids, lactate, ammonia.
• Stool studies if diarrhoea persists – ova & parasites, fat content.
• Chest X‑ray or echocardiogram if cardiac disease is suspected.
• Bone age (hand‑wrist X‑ray) in older children to assess growth potential.

5. Multidisciplinary evaluation

When psychosocial factors dominate, a social worker, nutritionist, and sometimes a psychologist are added to the team.

Treatment Options

Therapy is individualized. The overarching goals are to restore appropriate weight gain, address the underlying cause, and support normal development.

Medical Interventions

• Nutritional supplementation – high‑calorie formulas (e.g., Nutriben™, Enfamil Enfagrow) or specialized formulas for malabsorption.
• Medication – proton‑pump inhibitors for reflux, pancreatic enzymes for cystic fibrosis, levothyroxine for hypothyroidism, antibiotics for chronic infections.
• Management of chronic disease – cardiac surgery for severe congenital heart defects, enzyme replacement for certain metabolic disorders.
• Enteral feeding – nasogastric tube or gastrostomy (G‑tube) when oral intake is insufficient.

Home & Lifestyle Measures

• Increase feeding frequency – offer 6–8 small meals/snacks per day.
• Use calorie‑dense foods (e.g., avocado, full‑fat yogurt, nut butters) if tolerated.
• Provide a calm feeding environment; limit distractions.
• Position infant upright after feeds to reduce reflux.
• Monitor weight at home weekly using a calibrated scale.
• Ensure adequate fluid intake; consider oral rehydration solutions if diarrhoea persists.
• Engage a registered dietitian experienced in pediatric nutrition.

Psychosocial Support

• Connect families with community resources (WIC, SNAP, local food banks).
• Offer parental education on responsive feeding cues.
• Provide mental‑health counseling when parental depression, anxiety, or substance abuse is present.

Prevention Tips

While some causes (e.g., genetic disorders) cannot be prevented, many contributors to runting are modifiable.

• Breast‑feed exclusively for the first 6 months when possible; it provides optimal calories and immune protection.¹
• Introduce complementary foods at about 6 months, focusing on nutrient‑dense options.
• Ensure regular well‑child visits for growth monitoring.
• Promptly treat and follow up on any episode of prolonged vomiting, diarrhoea, or fever.
• Maintain up‑to‑date immunizations to reduce infection‑related catabolism.
• Screen newborns for cystic fibrosis, sickle cell disease, and metabolic disorders per national guidelines.
• Address socioeconomic barriers early – referral to social services, nutrition assistance, and parental support groups.
• Educate caregivers on safe sleep and positioning to reduce reflux‑related feeding difficulties.

Emergency Warning Signs

Key Take‑aways

• Runting (failure to thrive) signals inadequate growth and warrants prompt evaluation.
• Causes range from simple caloric insufficiency to complex organ disease; a thorough work‑up is essential.
• Early identification, multidisciplinary treatment, and ongoing monitoring can reverse growth faltering and protect neurodevelopment.
• Families benefit from nutritional guidance, social support, and education about safe feeding practices.

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References:
1. American Academy of Pediatrics. “Breastfeeding and the Use of Human Milk.” Pediatrics. 2012;130(3):e827‑e841.
2. Mayo Clinic. “Failure to thrive in children.” Accessed May 2026.
3. National Institute of Diabetes and Digestive and Kidney Diseases. “Celiac Disease.” Updated 2024.
4. CDC. “Growth Charts – United States.” 2023.
5. Cleveland Clinic. “Congenital heart defects in infants.” 2024.
6. WHO. “Infant and Young Child Feeding: Guideline.” 2022.