Understanding Moderate Acute Malnutrition (MAM)
Moderate Acute Malnutrition (MAM) is a significant public health issue, primarily affecting children in low- and middle-income countries. It is a form of wasting, characterized by a rapid reduction in food intake or quality, often in combination with illness. Unlike severe acute malnutrition (SAM), which poses an immediate and life-threatening risk, MAM presents a lower, but still significant, risk of morbidity and mortality. A precise diagnosis is the first step toward effective intervention, which typically involves supplemental feeding programs to prevent deterioration into a more severe state. The diagnostic criteria are primarily based on anthropometric measurements, as defined by the World Health Organization (WHO) Child Growth Standards.
Core Anthropometric Indicators for Diagnosis
For children aged 6 to 59 months, the diagnostic criteria for moderate acute malnutrition rely on two primary anthropometric indicators: the Weight-for-Height Z-score (WHZ) and the Mid-Upper Arm Circumference (MUAC). Crucially, the absence of bilateral pitting edema is also a requirement, as its presence automatically classifies a child as severely malnourished. A combination of these measurements is used to identify children who require targeted nutritional support.
Weight-for-Height Z-score (WHZ)
The Weight-for-Height Z-score (WHZ) compares a child's weight relative to their height against a standardized reference population of well-nourished children of the same age and gender. A child is diagnosed with MAM if their WHZ falls within the range of ≥ -3 and < -2 standard deviations (SD) from the median of the WHO Child Growth Standards. A WHZ below -3 SD is indicative of severe acute malnutrition (SAM).
Mid-Upper Arm Circumference (MUAC)
Mid-Upper Arm Circumference (MUAC) is a simple screening tool. For children aged 6 to 59 months, a MUAC measurement is considered indicative of MAM if it is ≥ 115 mm and < 125 mm.
Absence of Bilateral Pitting Edema
Bilateral pitting edema is a clinical sign of nutritional edema. Its presence is a defining criterion for severe acute malnutrition. Therefore, a diagnosis of MAM requires the absence of this sign. A healthcare worker checks for pitting edema by applying thumb pressure to both feet.
A Comparison of Diagnostic Criteria: MAM vs. SAM
{Link: NCBI Books https://www.ncbi.nlm.nih.gov/books/NBK361900/} provides a table summarizing the key distinctions in the diagnostic criteria for moderate and severe acute malnutrition for children 6-59 months, based on WHO guidelines.
The Role of Screening and Assessment in Practice
The diagnostic process for acute malnutrition involves both screening and comprehensive assessment. Screening often uses MUAC to quickly identify children needing further evaluation. Children identified through screening are typically referred to a health facility for full assessment.
Lists of Diagnostic Markers
Clinicians may also look for other signs and symptoms to support the diagnosis and guide management.
Phenotypic Criteria (Observable Signs)
- Low Body Weight: Unplanned weight loss.
- Faltering Growth: Slowdown or cessation of growth in children.
- Weakness and Fatigue: General lethargy.
- Loss of Subcutaneous Fat and Muscle Mass: Visible wasting.
Etiologic Criteria (Underlying Causes)
- Insufficient Energy Intake: Inadequate dietary consumption.
- Chronic Diarrhea or Infection: Persistent illness.
Conclusion
Accurate diagnosis of moderate acute malnutrition in children aged 6-59 months relies on the World Health Organization's criteria, primarily using specific ranges for Mid-Upper Arm Circumference and Weight-for-Height Z-scores, and the absence of bilateral pitting edema. Applying these anthropometric measurements helps health workers identify children with MAM, enabling timely supplemental feeding and follow-up. Continuous community screening and comprehensive facility assessment are crucial strategies. For further information on global nutrition strategies, see the World Health Organization's website.
