The World Health Organization (WHO) provides the globally accepted criteria for diagnosing severe acute malnutrition (SAM), a critical public health issue most prevalent among children under five. SAM is a medical emergency that results from a severely inadequate intake of energy, protein, and other nutrients, often combined with repeated infections. The WHO's definition and management protocols have evolved to improve diagnosis and provide effective, life-saving treatment in both hospital and community settings.
WHO Diagnostic Criteria for Severe Acute Malnutrition
To standardize diagnosis and treatment globally, the WHO established three independent criteria for identifying SAM in children aged 6 to 59 months. A child with any one of these signs is considered severely malnourished and requires immediate nutritional support.
- Weight-for-Height/Length below -3 Z-scores: This measurement compares a child's weight to the WHO child growth standards for their specific height or length. A z-score of less than -3 indicates severe wasting, where the child is dangerously thin for their height.
- Mid-Upper Arm Circumference (MUAC) less than 115 mm: The MUAC measurement is a simple, effective tool used to screen for SAM, particularly in community settings. A tape is used to measure the circumference of the child's upper arm, and a reading below 115 mm is a key indicator of severe malnutrition.
- Bilateral Pitting Oedema: This refers to the presence of swelling, typically in both feet, caused by fluid retention in the tissues. To check for it, pressure is applied to the child's feet for a few seconds; if a pit remains after the finger is removed, the child has pitting oedema.
Types of Severe Acute Malnutrition
Historically, SAM was categorized into different clinical conditions, namely Marasmus and Kwashiorkor, and Marasmic Kwashiorkor. While these terms are less focused on for treatment purposes under the latest WHO guidelines, which emphasize treating the specific clinical signs, they are important for understanding the different manifestations of the condition.
| Characteristic | Marasmus | Kwashiorkor |
|---|---|---|
| Primary Feature | Severe wasting with extreme thinness | Bilateral pitting oedema (swelling) |
| Appearance | Skin and bone appearance due to severe loss of muscle and subcutaneous fat | Puffy or swollen appearance, which can mask the underlying wasting |
| Weight | Very low weight-for-height (-3 z-scores) | May have a deceptively normal weight-for-height due to fluid retention |
| Hair/Skin | Often dry skin and brittle hair | Skin lesions, rashes, and hair colour changes are common |
| Mental State | Alert but often irritable and anxious | Lethargic, apathetic, and withdrawn |
Causes and Risk Factors of SAM
The causes of SAM are often complex and interconnected, ranging from household factors to broader environmental and economic issues. Understanding these factors is crucial for both prevention and effective treatment.
Child-Level Factors
- Inadequate Breastfeeding: Suboptimal or non-exclusive breastfeeding in the first six months significantly increases vulnerability.
- Poor Complementary Feeding: From six months onwards, a lack of appropriate, nutrient-dense complementary foods can lead to SAM.
- Frequent Infections: Children with SAM have compromised immunity, making them highly susceptible to repeated infections like diarrhea, pneumonia, and malaria, which further deplete their nutritional reserves.
Household and Environmental Factors
- Poverty and Food Insecurity: Limited access to nutritious food is a primary driver, with poorer households disproportionately affected.
- Illiteracy and Lack of Education: Parental education, particularly maternal, is a significant determinant of child nutritional status.
- Inadequate Sanitation: Poor hygiene practices and unsanitary living conditions increase the risk of infections that exacerbate malnutrition.
WHO Treatment Protocols
The WHO developed a systematic, phased approach to manage SAM, moving from inpatient stabilization to community-based rehabilitation where appropriate.
Phase 1: Stabilization (Inpatient Care)
This phase focuses on treating life-threatening complications and lasts for approximately 1–7 days.
- Treat or Prevent Hypoglycaemia: Restore blood glucose levels immediately with feeds or glucose solution.
- Treat or Prevent Hypothermia: Re-warm the child to prevent fatal drops in body temperature.
- Manage Severe Dehydration: Use a specific oral rehydration solution (ReSoMal) cautiously.
- Correct Electrolyte Imbalance: Address potassium and magnesium deficiencies without using diuretics.
- Treat Infection: Administer broad-spectrum antibiotics, as infections are often present without obvious signs.
- Correct Micronutrient Deficiencies: Provide essential vitamins and minerals, withholding iron initially due to its potential to worsen infection.
- Initiate Cautious Feeding: Start small, frequent feeds with low-osmolarity, low-lactose therapeutic milk (F-75).
Phase 2: Rehabilitation (Outpatient or Inpatient Care)
Once a child is stabilized, treatment shifts towards weight gain and recovery, which can often be managed in the community.
- Provide Catch-Up Feeding: Introduce energy-dense Ready-to-Use Therapeutic Foods (RUTF) to support rapid weight gain.
- Provide Sensory Stimulation and Emotional Support: Engage the child to encourage emotional and developmental recovery.
- Prepare for Follow-Up and Discharge: Plan for sustained support to prevent relapse.
Conclusion
The WHO's clear and evidence-based definition of severe acute malnutrition has been instrumental in standardizing the response to this devastating condition globally. By focusing on specific anthropometric measurements and clinical signs, health workers can accurately identify affected children and implement the appropriate two-phase treatment protocols. The development of community-based treatment using RUTF has significantly improved recovery rates and coverage, demonstrating that with timely detection and proper care, it is possible to dramatically reduce the mortality associated with severe acute malnutrition. Continuous investment in community health and preventative measures remains vital to combat the root causes of SAM. For more information on WHO guidelines, refer to resources like the NCBI Pocket Book of Hospital Care for Children.
