What Is Severe Acute Malnutrition (SAM)?
Severe acute malnutrition is the most lethal form of malnutrition and is a major killer of children under five. It is a state of severe undernutrition resulting from insufficient intake of energy, fat, protein, and other nutrients. SAM is characterized by either severe wasting (very low weight-for-height) or nutritional edema (kwashiorkor). The condition weakens the body's immune system, making children highly susceptible to infections and other medical complications. Understanding the core indicators for diagnosis is crucial for identifying and treating affected children effectively.
The Three Core Diagnostic Criteria
Diagnosis of SAM is typically based on three main criteria, as defined by the World Health Organization (WHO), used for children aged 6 to 59 months. A child with any one of these three signs should be referred for full assessment and management.
- Low Weight-for-Height/Length (Z-score < -3 SD): This is the most common indicator of severe wasting. The weight-for-height Z-score compares a child's weight to the weight of a healthy child of the same height, and a score below -3 standard deviations (SD) indicates severe wasting.
- Mid-Upper Arm Circumference (MUAC < 115 mm): This is a simple, quick, and low-cost field measurement used for screening and diagnosis in community settings. The MUAC measurement is taken using a colored plastic tape and a reading below 115 mm is indicative of SAM. MUAC is particularly useful for identifying children at high risk of mortality.
- Bilateral Pitting Edema: Edema is a clinical sign of kwashiorkor, a form of SAM. It is identified by the presence of swelling on both feet that leaves a visible indentation, or “pitting,” when pressure is applied. Edema automatically classifies a child as having SAM, regardless of other anthropometric measurements.
Comprehensive Clinical Assessment
Beyond the three core criteria, a comprehensive clinical assessment is essential to determine the severity and type of SAM, identify complications, and guide management.
- Medical History: Inquire about the child's diet, feeding practices (especially breastfeeding), duration and frequency of diarrhea and vomiting, and recent history of illness like measles. A family's socio-economic circumstances and history of tuberculosis (TB) or HIV exposure are also important contextual factors.
- Physical Examination: Look for specific signs, including:
- Marasmus: The child appears emaciated with severe muscle wasting and loss of subcutaneous fat, giving an "old man" or "skin and bones" appearance.
- Kwashiorkor: In addition to bilateral pitting edema, look for skin changes (hypo- or hyper-pigmentation, desquamation, ulceration), brittle hair, and a characteristic bloated abdomen.
- Associated Conditions: Check for lethargy, poor appetite, eye signs of vitamin A deficiency (Bitot spots, corneal ulceration), severe anemia, and localizing signs of infection like pneumonia or ear infections.
Comparison of Screening and Diagnostic Methods
| Feature | MUAC Screening | Weight-for-Height Z-score (WHZ) | Bilateral Pitting Edema |
|---|---|---|---|
| Application | Community-level screening, identifying high-risk children. | Facility-based diagnosis and monitoring. | Immediate diagnosis at community or facility level. |
| Ease of Use | Very simple and quick; uses a colored tape. | Requires accurate height measurement, which can be difficult in young infants. | A visual and manual assessment that is simple to perform. |
| Cost | Low cost, making it ideal for resource-poor settings. | Higher cost due to specialized equipment (scales, stadiometers). | No additional cost, as it relies on visual and manual checks. |
| Predictive Value | Strong predictor of mortality. | Also a strong predictor of mortality, often used to assess recovery progress. | High predictive value for mortality. |
| Limitations | Does not identify all wasted children. | Prone to measurement errors, especially in infants. | Edema can mask severe wasting and requires careful monitoring. |
Appetite Test
An appetite test is a crucial step in assessing the management plan for a child with SAM. It helps determine if the child has a good appetite and can be treated at home (uncomplicated SAM) or requires inpatient care for complications. During the test, a child is offered a portion of Ready-to-Use Therapeutic Food (RUTF). If they can eat at least a certain amount and are otherwise well, they can be treated as an outpatient.
Conclusion
Diagnosing SAM correctly relies on a systematic approach using a combination of anthropometric measures and clinical signs, following internationally recognized guidelines from the WHO. Early identification, often via simple community-based tools like MUAC, is crucial for timely intervention and improving outcomes. A thorough clinical assessment is then necessary to identify any medical complications, allowing healthcare providers to tailor appropriate inpatient or outpatient treatment strategies. The combination of these methods is vital for effectively managing this critical public health issue and reducing child mortality. The community-based approach, involving community health workers for early detection and home-based treatment for uncomplicated cases, has proven to be highly effective in expanding coverage and impact. For more detailed guidelines on management, refer to the WHO's pocket book on hospital care for children.
