The Importance of Nutritional Screening and Assessment
Nutritional status has a significant impact on health outcomes, with malnutrition increasing the risk of infections, prolonging hospital stays, and increasing mortality. A systematic approach to nutritional care begins with screening to identify individuals at risk, followed by a more detailed assessment for those identified as high-risk.
Step 1: Initial Nutritional Screening
Initial screening is a quick, simple process to identify individuals who are malnourished or at risk. Several validated tools are available, designed for different settings. If a patient screens positive, a more comprehensive assessment is necessary.
Commonly Used Screening Tools:
- Malnutrition Universal Screening Tool (MUST): A widely used, five-step tool that considers BMI, unintentional weight loss, and the acute disease effect. It classifies adults into low, medium, or high-risk categories for malnutrition.
- Mini Nutritional Assessment-Short Form (MNA-SF): Specifically designed and validated for geriatric patients aged 65 and over. It includes questions on food intake, weight loss, mobility, and psychological stress.
- Nutritional Risk Screening 2002 (NRS-2002): Recommended by the European Society for Clinical Nutrition and Metabolism (ESPEN) for the hospital setting. It incorporates pre-screening questions followed by a more detailed assessment of BMI, weight loss, disease severity, and age.
Step 2: Comprehensive Nutritional Assessment
For those identified as at risk during screening, a thorough assessment is conducted by a nutrition specialist, such as a registered dietitian, often guided by criteria from the Global Leadership Initiative on Malnutrition (GLIM). The GLIM framework is based on a dual-criterion system, requiring at least one etiologic (causative) and one phenotypic (observable) criterion for diagnosis.
Etiologic Criteria:
- Reduced food intake or assimilation (e.g., due to poor appetite, swallowing issues, or malabsorption).
- Inflammation from acute disease/injury or chronic conditions.
Phenotypic Criteria:
- Unintentional weight loss.
- Low Body Mass Index (BMI).
- Reduced muscle mass.
Step 3: Performing a Physical Examination
A nutrition-focused physical examination (NFPE) is a key component of the assessment, identifying specific signs of nutritional deficiencies.
- Muscle Wasting: Look for loss of muscle mass around the temples, collarbone, shoulders, and calf muscles. Handgrip strength can also be used to assess functional status and muscle strength.
- Subcutaneous Fat Loss: Check for reduced fat stores under the skin in areas like the orbital region (around the eyes), triceps, and ribs.
- Fluid Accumulation: Assess for edema (swelling) in the ankles or sacral area, and for ascites (fluid in the abdomen). This can mask weight loss and is a sign of protein deficiency.
- Oral Health: Examine the mouth and lips for signs like cheilosis (cracking at the corners), glossitis (inflamed tongue), and bleeding gums, which can indicate vitamin deficiencies.
- Skin and Hair: Look for dry, inelastic skin, rashes, brittle hair, or hair loss.
Step 4: Anthropometric Measurements
Anthropometric measures provide objective data on body size and composition. When standard measurements are not possible, alternative methods can be used.
- Height and Weight: To calculate BMI and monitor weight changes over time. If height cannot be measured directly, techniques like demi-span or knee height can be used.
- Body Mass Index (BMI): A simple calculation of weight divided by height squared ($$kg/m^2$$). BMI cutoffs for undernutrition vary slightly by age, with a higher threshold for older adults.
- Circumference Measurements: Mid-upper arm circumference (MUAC) and calf circumference (CC) are simple, effective indicators of protein and energy reserves, particularly useful when BMI is difficult to obtain.
- Body Composition Analysis: Advanced techniques like Bioelectrical Impedance Analysis (BIA) or Dual-energy X-ray Absorptiometry (DXA) can provide detailed information on fat-free mass and muscle mass.
Step 5: Laboratory and Functional Assessments
While no single lab test can diagnose malnutrition, they provide crucial supportive information and help identify micronutrient deficiencies.
- Biochemical Markers: Includes a full blood count, electrolytes, and liver function tests. Low levels of serum albumin or prealbumin, while not definitive for malnutrition due to inflammation, can indicate poor protein status. Elevated C-reactive protein (CRP) levels can signal inflammation, an etiologic factor in malnutrition.
- Micronutrient Levels: Specific vitamin and mineral levels can be tested if deficiencies are suspected based on clinical signs.
- Functional Assessment: Measures of functional status, such as handgrip strength using a dynamometer, correlate with nutritional status and can predict outcomes.
Comparison of Malnutrition Screening Tools
| Feature | Malnutrition Universal Screening Tool (MUST) | Mini Nutritional Assessment (MNA) | Nutritional Risk Screening (NRS-2002) |
|---|---|---|---|
| Target Population | All adults in any care setting. | Adults aged 65 and over. | Hospitalized adult patients. |
| Key Components | BMI, unintentional weight loss, acute disease effect. | Food intake decline, weight loss, mobility, psychological stress, neuropsychological problems, BMI/calf circumference. | Pre-screening questions, BMI, weight loss, severity of disease, age. |
| Output | Categorizes risk as low, medium, or high. | Determines normal nutritional status, at risk, or malnourished. | Identifies patients at nutritional risk. |
| Ease of Use | Simple and quick, requiring basic measurements. | Also has a rapid short form (MNA-SF). | Designed for easy hospital implementation. |
Conclusion
Assessing malnutrition in adults requires a systematic, multi-step approach that moves from initial screening to comprehensive assessment. The combination of validated screening tools like MUST or MNA-SF with a detailed clinical history, targeted physical examination, anthropometric measurements, and supportive lab work provides a robust framework for identifying and diagnosing malnutrition. By following consensus criteria like those from GLIM, healthcare professionals can ensure consistent and accurate diagnosis, leading to timely and effective nutritional interventions that improve patient outcomes. For further guidance and resources on clinical nutrition, organizations like the European Society for Clinical Nutrition and Metabolism (ESPEN) offer valuable materials.
Potential Complications of Undiagnosed Malnutrition
Ignoring or failing to accurately assess malnutrition can lead to a cascade of negative health consequences, including a weakened immune system, delayed wound healing, and decreased overall strength and functional ability. This can result in a longer recovery period from illness or surgery, increased risk of falls, and a higher probability of hospital readmission. The vicious cycle of illness-induced malnutrition and malnutrition-aggravated illness must be broken through early detection and intervention.
Tailoring the Assessment to the Individual
It is important to remember that the assessment process should be tailored to the individual's specific context. Factors such as age, underlying chronic diseases, medication use, socioeconomic conditions, and mental health all influence a person's nutritional status. For instance, an elderly person with dementia may face different challenges than a younger patient with a chronic inflammatory condition, and the assessment must account for these differences. Collaboration among interprofessional teams—including nurses, physicians, dietitians, and social workers—is often necessary to gather a complete picture of the patient's nutritional health.
