Understanding the Basics of Wasting
Wasting, also known as acute malnutrition, is a form of undernutrition that results from a recent and severe lack of food or an infectious disease that causes rapid, significant weight loss. It is distinct from stunting, which is the result of chronic or recurrent undernutrition leading to a low height-for-age. Wasting can have devastating consequences, especially in children, where it is a medical emergency with a high risk of mortality. Early detection through established criteria is vital for effective treatment and improved health outcomes.
Criteria for Wasting in Children (6–59 months)
The World Health Organization (WHO) has established clear criteria for identifying wasting in children under five. These criteria rely on a combination of anthropometric measurements and a key clinical sign. The three main indicators are independent and can be used to diagnose wasting, although they often identify different children.
Anthropometric Measurements
- Weight-for-Height Z-score (WHZ): This measure compares a child's weight to their height, relative to a standardized reference population. A z-score is a statistical measure of deviation from the median. Low WHZ indicates insufficient weight relative to a child's height, a hallmark of wasting.
- Mid-Upper Arm Circumference (MUAC): A simple, effective tool for screening wasting in communities, MUAC uses a color-coded band to measure the circumference of a child's upper arm. It is particularly effective at identifying children at the highest risk of mortality.
Clinical Sign
- Bilateral Pitting Oedema: This is swelling caused by fluid accumulation, which begins in the feet and can progress to the legs and face. It is a clinical sign of severe acute malnutrition and is assessed by pressing a thumb on both feet for a few seconds. If an indentation remains, oedema is present.
Severity Classification in Children
Wasting is further categorized into moderate and severe based on the specific cut-offs for these indicators:
- Moderate Acute Malnutrition (MAM):
- WHZ between -3 and -2 standard deviations below the median of the WHO growth standards.
- MUAC between 115 mm and <125 mm.
- Severe Acute Malnutrition (SAM):
- WHZ less than -3 standard deviations below the median.
- MUAC less than 115 mm.
- Presence of bilateral pitting oedema.
Criteria for Wasting in Adults
In adults, severe weight loss resulting from disease is often termed cachexia or wasting syndrome. It is defined by unintentional weight loss of more than 10% of body weight, which can include both muscle mass and fat. This loss is typically accompanied by other symptoms over a prolonged period.
Key criteria for adult wasting syndrome include:
- Unintentional Weight Loss: Loss of more than 10% of baseline body weight, or more than 5% over 3 months.
- Associated Symptoms: The weight loss is accompanied by symptoms such as:
- Chronic weakness
- Fever lasting at least 30 days
- Chronic diarrhea
- Underlying Disease: Wasting syndrome is commonly associated with advanced chronic diseases, such as advanced cancer, AIDS, or other serious systemic illnesses.
Comparison of Wasting Criteria: Children vs. Adults
The criteria for wasting differ significantly between children and adults, primarily reflecting the physiological differences and underlying causes of the condition.
| Feature | Children (6-59 months) | Adults (Wasting Syndrome) |
|---|---|---|
| Primary Indicators | Weight-for-Height Z-score, Mid-Upper Arm Circumference (MUAC), Bilateral Pitting Oedema | Unintentional weight loss >10%, clinical symptoms (fever, weakness, diarrhea) associated with chronic disease |
| Diagnosis Method | Anthropometric measurements and clinical examination (e.g., thumb pressure for oedema) | Monitoring weight changes, clinical evaluation for underlying disease and associated symptoms |
| Severity Classification | Standardized tiers (Moderate vs. Severe) based on z-scores and MUAC cut-offs | Often related to the severity of the underlying chronic disease |
| Causes | Often linked to acute periods of inadequate food intake, infectious diseases like diarrhea, and poor WASH conditions | Primarily associated with advanced chronic diseases (e.g., AIDS, cancer) and their effects on metabolism and appetite |
The Causes and Consequences of Wasting
Wasting is the result of a complex interplay of immediate, underlying, and systemic factors. The immediate causes are inadequate dietary intake and illness, which create a vicious cycle. Illnesses like persistent diarrhea, respiratory infections, or malaria can lead to poor appetite and malabsorption, worsening nutritional status. Underlying factors include poverty, lack of food security, poor sanitation and hygiene (WASH), insufficient maternal and child care, and limited access to healthcare. These factors are, in turn, influenced by broader socioeconomic and political conditions.
The consequences of wasting, particularly severe wasting, are profound:
- Increased Mortality: Wasted children, especially those who are severely wasted, have a significantly elevated risk of death.
- Weakened Immune System: Malnutrition suppresses the immune system, making children more susceptible to infections.
- Impaired Development: Recovering children may still experience long-term cognitive and physical developmental impairments.
- Increased Health Costs: Wasting places a significant burden on health systems due to the need for intensive care.
Preventing and Treating Wasting
Effective strategies for addressing wasting involve both prevention and comprehensive treatment.
- Prevention: The focus is on strengthening multisectoral systems that influence child health and nutrition. Key preventive measures include:
- Ensuring access to healthy, diverse, and safe diets for mothers and children.
- Promoting optimal infant and young child feeding practices, including exclusive breastfeeding for the first six months and appropriate complementary feeding.
- Improving water, sanitation, and hygiene (WASH) infrastructure.
- Implementing targeted interventions, such as lipid-based nutrient supplements (LNS) in high-risk areas during periods of food insecurity.
- Treatment: The standard of care for moderate and severe wasting includes:
- Nutritional Therapy: Using specially formulated foods, such as Ready-to-Use Therapeutic Foods (RUTFs) for SAM and supplementary foods for MAM.
- Medical Management: Treating and managing infections and other complications, which is particularly critical in cases of severe wasting.
- Psychosocial Support: Providing counseling and support to caregivers and psychosocial stimulation for children.
Conclusion
Wasting is a critical form of malnutrition, and recognizing its specific criteria is the first step toward effective management and prevention. The criteria for children, involving anthropometric measures like weight-for-height and MUAC, alongside the presence of bilateral pitting oedema, are clear diagnostic tools. In adults, wasting syndrome is identified by significant unintentional weight loss in the context of chronic disease. Addressing this serious public health issue requires a holistic and multisectoral approach, focusing on improving nutritional intake, preventing illness, and strengthening health systems. Early and accurate diagnosis based on these criteria can save lives and improve the long-term health and developmental prospects of affected individuals. For more information, the World Health Organization provides comprehensive guidelines on the prevention and management of wasting and nutritional oedema.
