Malnutrition among pediatric patients is an ongoing problem that is often underdiagnosed. A new report examines alternate methods for recognizing malnutrition beyond anthropometric percentiles.
Malnutrition is an ongoing problem among hospitalized pediatric patients with chronic illnesses, but perhaps the bigger problem is identifying standardized methods for identifying the condition.
Pediatricians who suspect malnutrition have a number of assessments that can be performed, but some disease processes-particularly among inpatient children with chronic illness-present unique challenges. The American Academy of Pediatrics offers guidelines for assessing malnutrition, but those guidelines rely heavily on anthropometric data.
Despite having a worldwide prevalence of 24% to 50%, only about 4% of pediatric patients with chronic illness are diagnosed with malnutrition in the United States. In an effort to more accurately identify and treat cases involving malnutrition, the Academy of Nutrition and Dietetics and American Society for Parenteral and Enteral Nutrition have clarified and redefined assessments.
Pediatricians have typically relied on anthropometrics to define pediatric malnourishment, but the new report notes that assessments should be much more complex and involve 5 criteria: anthropometrics, growth, chronicity, etiology, and impact on functional status.
Anthropometrics can pose difficulty in determining nutritional status due to the broad range in international cutoff points, according to the report. The consensus has been to use “z” scores. Z scores are useful in charting serial measurements by utilizing deviations from a given measurement from the size or age-specific population, according to the National Institutes of Health.
In children aged younger than 2 years, weight, length obtained using a length board, and head circumference should be recorded at each encounter and plotted on a World Health Organization (WHO) growth chart that indicates nutrition risk. For children aged older than 2 years, weight and height measurements should be taken at each encounter and plotted on a Centers for Disease Control and Prevention growth chart.
Height/length is the best predictor of chronic malnutrition, which can be defined as a -2 z score in height/length for age. For populations where an accurate height/length cannot be obtained, such as in children with cerebral palsy, proxy measurements including knee height or tibia length may be substituted.
Mid-upper-arm circumference (MUAC) is also a highly useful method in malnutrition assessment, according to the report, and can be used in a wide variety of patient populations, including those with fluid overload or wasting related to underlying disease processes.
“Given that current recommendations call for a shift from the use of percentiles to z scores, it is important to have an accurate and dependable system to calculate these values,” the report authors note. “Many electronic medical records have been able to build this into their anthropometrics flowsheets and/or growth charts. In circumstances when this is not available, peditools.org is a readily available resource that accurately calculates z scores.”
Z scores may also be useful in identifying malnutrition when risks first appear rather than when malnutrition and its sequelae fully manifest.
In terms of growth as a marker for malnutrition, although it may be the “gold standard” for assessing nutrition in general pediatrics, they are not precise in assessments related to stagnant growth or weight loss, according to the report. Growth velocity must also be considered, and is a component of malnutrition criteria when paired with weight loss. The report notes that a 5% weight loss in 1 month is a critical threshold for an adverse clinical outcome, and a 2% weight loss over 1 week has been identified with malnutrition. However, The authors note that similar thresholds have not been established for growth changes and should be studied further.
“The clinical practice guidelines currently address weight velocity in less than 2 years and weight loss for greater than 2 years. It may be more clinically feasible if the guidelines were similar across all age groups and to consider the use of change in weight velocity after the age of 2 years given growth potential throughout childhood,” the study authors note.
Malnutrition can also be assessed based on its stage-acute or chronic. Chronic cases have been deemed to last 3 months or longer, compared to acute cases, which last less than 3 months, according to the report.
The cause of the malnutrition is another complicated aspect of assessment, however. “The etiology of malnutrition is often more than a simple lack of food,” the authors state. “Many other factors are contributory. Most malnutrition in developed countries is due to secondary factors. Decreased nutrition intake, increased resting energy expenditure, increased losses, malabsorption, infection, inflammation, and deterioration in chronic disease increase the risk of malnutrition in children. Malnutrition occurs when there is imbalance between nutrients required for normal growth and development, as well as nutrient intake.”
Nutrition imbalance can result from a number of factors. In cases of decreased intake in chronically ill children, it is important to note that careful assessment of energy and protein needs and important in ensuring adequate nutrition.
“Providing adequate nutrition is shown to improve overall outcomes in critically ill ventilated children,” the authors state, noting research that found that increasing energy intake from 33% to 66% significantly decreased mortality risks, as well as infection rates, length of hospital stays, and more.
Excessive losses through vomiting and diarrhea stemming from chronic illness may also contribute to malnutrition etiology, and the incidence of these symptoms are higher in malnourished patients. The report notes that WHO figures estimate that diarrhea kills 10% of children aged younger than 5 years globally, and is a leading cause of childhood malnutrition. Additionally, vomiting occurs in about 26% of malnourished patients compared to 14% of well-nourished patients, according to the report, and diarrhea occurred in 22% of malnourished compared to 12% of well-nourished children. The symptoms also lasted for a longer duration in malnourished children.
Sodium wasting disorders related to chronic renal and intestinal problems, increased nutritional requirements due to hypermetabolism, malabsorption, metabolic acidosis, and inflammation are all additional chronic and acute issues that may contribute to malnutrition.
Functional status-including changes in muscle strength, developmental delays, cognitive impairment, immune dysfunction, and more-can also accompany malnutrition and requires a variety of assessments.
It is also important to consider that not all growth failure ay be related to malnutrition. In some cases, another chronic illness map be to blame-such as corticosteroid exposure, radiation, and chronic kidney disease.
The study authors note that while the use of z scores rather than percentiles from anthropometric measurements may provide more useful assessment of pediatric malnutrition, it is a challenge to establish guidelines that can be used in clinical practice. Additional research is needed in the use of MUAC in larger patient populations and special needs groups, growth velocity across all age groups, appropriate dietary intake, and how to interpret fat and muscle stores across the delayed/advanced Tanner stage.