Acute primary malnutrition in children

Acute malnutrition in children manifests as childhood wasting and/or nutritional edema. It most commonly affects children ≤ 5 years of age and is caused by a combination of biological, sociopolitical, and environmental factors. Primary malnutrition is inadequate intake of the nutrients needed for normal growth and development. Secondary malnutrition is caused by systemic disease. Acute malnutrition is a clinical diagnosis, and severity is determined by anthropometric diagnostic criteria. Diagnostic studies can assess for complications and exclude causes of secondary malnutrition. Management is primarily focused on nutritional rehabilitation and addressing modifiable risk factors and complications. Prevention requires comprehensive interventions, such as caregiver education and ensuring the availability of food and health care services.

Secondary malnutrition is covered in a separate article. See "Growth faltering" and "Overweight and obesity in children" for details on other types of malnutrition in children.

• Acute malnutrition in children: malnutrition in a child < 5 years of age leading to either childhood wasting or nutritional edema ^[1][2]
  • Childhood wasting: a low weight-for-height or weight-for-length score or low mid-upper arm circumference (MUAC)
  • Nutritional edema: bilateral pitting swelling caused by severe malnutrition; low protein intake and metabolic derangements lead to fluid accumulation in tissues, starting at the feet and moving up the legs and body ^[1]
• Severe acute malnutrition: malnutrition with any of the following criteria ^[1]
  • Z-score below 3 standard deviations on WHO weight-for-height or weight-for-length growth charts
  • MUAC < 115 mm
  • Nutritional edema
• Moderate acute malnutrition: malnutrition with either of the following characteristics (nutritional edema must be absent) ^[1]
  • A z-score between -2 and -3 standard deviations on WHO weight-for-height or weight-for-length growth charts
  • MUAC between 115 and 125 mm
• Primary malnutrition: inadequate intake of the nutrients needed for normal growth and development ^[1][2]
• Secondary malnutrition (disease-associated malnutrition): undernutrition caused by an underlying medical condition that impairs nutrient intake, absorption, or use or increases metabolic demands, not by a lack of food ^[3]

Mild acute malnutrition is not defined in the latest WHO diagnostic criteria. However, children with a z-score between -1 and -1.9 standard deviations below the median for weight-for-height or MUAC may be categorized as having mild acute malnutrition according to older definitions. ^[2]

Phenotypes of severe primary malnutrition

The following definitions describe classic phenotypes of severe malnutrition; however, current guidelines primarily classify malnutrition by severity rather than appearance. ^[1]

• Marasmus: manifests as a profound wasting of the muscles and subcutaneous fat without edema; caused by a severe deficiency in all major nutrients due to starvation ^[3][4]
• Kwashiorkor: manifests as depigmentation of hair and skin, muscle atrophy, bilateral pitting edema, and a distended abdomen due to ascites and hepatomegaly; caused by severe protein deficiency^[4]
• Marasmic kwashiorkor: severe undernutrition with features of both marasmus and kwashiorkor ^[3]

Overview of severe malnutrition phenotypes
	Marasmus	Kwashiorkor
Deficiency	All major nutrients	Protein
Calorie intake	Deficient	Variable (can be normal or even high)
Pathophysiology	Severe energy deficiency leads to a catabolic state → breakdown of adipose tissue, muscle, and, ultimately, organ tissue for energy	The lack of protein leads to: Muscle atrophy ↓ Plasma protein (especially albumin) → ↓ plasma oncotic pressure → edema ↓ Apolipoprotein synthesis → ↓ secretion of hepatic triglycerides → enlarged fatty liver Increased oxidative damage to cellular protein synthesis [5]
Distinguishing features [4]	No edema Profound muscle wasting Loss of subcutaneous fat Thin, dry skin with few hairs [3][4]	Nutritional edema [1] Distended abdomen (due to hepatomegaly , intestinal distention, and weakened abdominal muscles) [3] Thin, dry, peeling skin with areas of hyperpigmentation, hyperkeratosis, hypopigmentation, and erythema [3]

Protein-deficient KWick MEALS lead to Kwashiorkor: Malnutrition, Edema, Anemia, fatty Liver, Skin lesions.

Marasmus causes Muscle wasting but no edema.

• In children < 5 years of age, worldwide: ^[2]
  • ∼ 45 million experience childhood wasting every year ^[1]
  • ∼ 20 million have severe acute malnutrition
  • ∼ 45% of deaths are associated with undernutrition. ^[6]
• Prevalence of childhood wasting is highest in children < 5 years of age in resource-limited regions, e.g.: ^[7]
  • Southern Asia: 13.6%
  • Southeast Asia: 7%
  • Western Africa: 6.5%
  • Middle Africa: 5.5%
  • Northern Africa: 5.2%

Childhood wasting is rare in the US and Canada (affecting 0.2% of children < 5 years of age); excessive energy intake is the most common form of malnutrition in this region. ^[7]

Epidemiological data refers to the US, unless otherwise specified.

Acute malnutrition is caused by a combination of biological, sociopolitical, and environmental factors. ^[4]

Risk factors for acute malnutrition in children

• Environmental ^[1][2][8]
  • Food insecurity or famine
  • Displacement (e.g., due to a natural disaster, geopolitical tension)
  • Limited access to health care and clean water ^[4][8]
• Biological ^[1][4]
  • Inadequate nutrition and weight gain during pregnancy
  • Birth factors: preterm birth, low birth weight, fetal growth restriction ^[3]
  • Chronic conditions (e.g., congenital heart disease) and/or infections (e.g., HIV)
  • Inadequate infant nutrition and breastfeeding ^[8]
• Social
  • Child maltreatment ^[2][8]
  • Social determinants of health
  • Caregivers with physical or mental health conditions ^[1]

• Irritability and weakness ^[4]
• Slowed movement and impaired speech ^[4]
• Clinical features of growth faltering, e.g.: ^[1]
  • Childhood wasting
  • Growth stunting ^[2][4]
  • Recurrent infections ^[4]
• In severe acute malnutrition; bradycardia, hypotension, and hypothermia may be present.
• For distinguishing features of marasmus and kwashiorkor, see "Overview of severe malnutrition phenotypes."

All children should undergo a comprehensive clinical evaluation and anthropometric assessment to determine the severity of acute malnutrition in children. Consider diagnostic studies to assess for complications. ^[1]

Clinical evaluation ^[1]

• Comprehensive pediatric history and physical examination, including:
  • Evaluation for weight loss using weight checks on two separate occasions or a caregiver's report
  • Examination for pitting edema
  • Evaluation for causes of secondary malnutrition
• Feeding and nutrition assessment
  • Number and frequency of feeds
  • Types of food consumed
  • Use of nutrition supplements
  • Food refusal
  • Assessment of breastfeeding if the child is breastfed
• Social history: Assess for risk factors such as food insecurity and caregiver wellbeing.

Diagnostic studies

There are no standard diagnostics; selection should be guided by clinical suspicion.

• CBC with differential for: ^[4][9]
  • Anemia; if present, obtain iron studies, B12, and folate levels
  • Signs of infection
• CMP to assess for: ^[4][9]
  • Hypoglycemia
  • Electrolyte disturbances (e.g., hypokalemia, hypomagnesemia, hypophosphatemia)
  • Impaired renal function
• Liver chemistries to assess albumin (decreased when nutritional edema is present) ^[4]

Electrolyte disturbances may suggest refeeding syndrome in patients receiving nutritional rehabilitation. ^[10]

Exclusion of causes of secondary malnutrition

• Assessment for clinical features, e.g.:
  • Symptoms of exocrine pancreatic insufficiency ^[4]
  • Symptoms of tuberculosis
  • Symptoms of celiac disease
• Testing for common underlying infections, depending on prevalence, e.g.:
  • HIV screening ^[1][10]
  • Tuberculosis screening ^[1]
  • Stool microscopy and culture ^[10]
• See also "Diagnostics for growth faltering."

The following information is based on guidance for children < 5 years of age. There is a paucity of guidance for older children. ^[1]

Approach ^[1]

• Determine the severity of malnutrition and assess for admission criteria.
• Coordinate care with a multidisciplinary team.
• Address modifiable risk factors, underlying chronic diseases, and complications.
• Start nutritional rehabilitation.
• Provide caregivers with community resources.

Admission criteria ^[1]

• Red flags in acute malnutrition in children
  • Poor appetite, food refusal, and/or inability to tolerate oral intake (e.g., unremitting vomiting)
  • Altered mental status
  • Seizures
  • Signs of hemodynamic instability (e.g., bradycardia, hypothermia) ^[4]
  • Clinical signs of significant dehydration (e.g., hypotension)
  • Nutritional edema
• Serious underlying conditions, e.g.:
  • Red flags for pediatric fever
  • Pediatric pneumonia
  • Severe persistent diarrhea
  • Skin and soft tissue infections associated with nutritional edema
  • Severe iron deficiency anemia in children
  • HIV
• Psychosocial factors that could hinder successful outpatient management.
• Unsuccessful outpatient management

Initial management

Inpatient management for acute pediatric malnutrition ^[1][11]

• Treat hypoglycemia and manage hypothermia (< 35.0°C axillary or < 35.5°C rectal).
• Start fluid resuscitation. ^[1]
  • Children with shock: IV fluids
  • Children without shock: oral rehydration solution for malnourished children (preferred) or hypotonic oral rehydration solution ^[1]
• Replete electrolytes.
• Transfuse packed red blood cells within 24 hours if hemoglobin is either: ^[12]
  • < 4 g/dL
  • < 6 g/dL and there are signs of respiratory distress or hemodynamic compromise
• Additional management for children with severe acute malnutrition
  • Start empiric antibiotics for sepsis in children (e.g., ampicillin and gentamicin). ^[1][11]
  • Ensure the child receives 5000 IU of oral vitamin A, either in fortified food or supplements. ^[1]
• Give frequent, small oral feeds (e.g., every 2–4 hours) and adjust as tolerated. ^[1][11]
  • Infants
    • Breastfed: Continue breastfeeding and give supplementary feeds of infant formula or fortified milk (e.g., F-75), ideally via supplementary suckling. ^[1]
    • Not breastfed: Give commercial formula or F-75.
  • Children: Give fortified milk (usually F-75). ^[1]
• Monitor closely for refeeding syndrome.
• Once appetite improves and edema starts to resolve, gradually transition to F-100 or ready-to-use therapeutic foods (e.g., over 2–3 days). ^[1][11]
  • Ensure a calorie density of 150–185 kcal/kg/day with a target weight gain of 5–10 g/kg/day.
  • Consider a lower calorie density of 100–139 kcal/kg/day once severe acute malnutrition resolves.
  • There is no established method for transitioning patients to a regular diet. ^[1]

Nutritional repletion must be slow to prevent refeeding syndrome. ^[1]

Do not use diuretics to treat nutritional edema, as this can worsen electrolyte imbalances. ^[10]

Outpatient management ^[1]

Most children with a good appetite and no admission criteria can be managed as outpatients.

• Treat dehydration with low-osmolarity oral rehydration solution.
• Prescribe antibiotics when infection is suspected or prophylactically for children with uncomplicated severe acute malnutrition. ^[1]
• Encourage continued breastfeeding; additional food may be given via supplementary suckling. ^[1]
• Provide ready-to-use therapeutic food to:
  • All children with severe acute malnutrition
  • Children with moderate malnutrition and any of the following:
    • Age < 24 months
    • Recurring acute malnutrition
    • Chronic underlying disease, such as tuberculosis or a disability
    • Extreme psychosocial factors, such as the death or poor health of a caregiver
    • Failure to improve on standard treatment
• All other children: Encourage a nutrient-dense diet.

Prophylactic oral antibiotics (e.g., amoxicillin) are recommended for children with uncomplicated severe acute malnutrition because of the increased risk of infection. ^[1][12]

Ongoing management

• Reduce the risk of infections through:
  • Hand hygiene and respiratory hygiene
  • Age-appropriate immunizations
• Check weight regularly and adjust frequency as appropriate (e.g., initially every 2 days, then weekly). ^[1]
• Assess for signs of nutritional recovery, e.g.: ^[1]
  • No red flags in acute malnutrition in children
  • No longer meets diagnostic criteria for acute malnutrition on ≥ 2 consecutive measurements
  • No nutritional edema on ≥ 2 consecutive measurements
• Provide caregiver education on the prevention of acute malnutrition in children and refer to nutrition support programs if available.

Percentage weight gain and absolute weight gain are not recommended as measures of nutritional recovery in children with acute malnutrition, as these children have a very low starting weight. ^[1]

• Infections (e.g., pneumonia, gastroenteritis, urinary tract infection, sepsis)
• Delayed wound healing
• Growth stunting: typically occurs in chronic malnutrition (in acute protein-energy malnutrition, linear growth is usually not affected)
• Micronutrient deficiencies (e.g., vitamin deficiencies, iron deficiency, zinc deficiency)
• Dehydration
• Developmental delay ^[13]
• Multiorgan failure and death if left untreated

We list the most important complications. The selection is not exhaustive.

Prevention of acute malnutrition in children requires comprehensive intervention. ^[1]

• Counseling on nutrition ^[1]
  • Nutrition and weight gain during pregnancy
  • Breastfeeding, infant nutrition, and weaning
  • Pediatric nutrition
• Regular monitoring of children and caregivers ^[1]
  • Assess for risk factors for acute malnutrition in children and address accordingly.
  • Monitor for clinical features of acute malnutrition in children. ^[1]
• Addressing food insecurity ^[1]
  • Provide food aid to the whole family.
  • If nutritious foods are unavailable, consider temporary nutritional support for children 6–23 months of age.
    • Areas with severe food insecurity: lipid-based nutrient supplements
    • Areas with iron deficiency: micronutrient powders