Failure to Thrive

Excerpt

Failure to thrive (FTT) is a common term to describe a lack of adequate weight gain in pediatric-aged patients. Despite its common use as a descriptive diagnosis, the exact definition of the condition remains debated. Therefore, measuring patient outcomes and complications specifically associated with the finding of FTT can be challenging. Various anthropometric criteria for the diagnosis have been proposed. Current consensus defines FTT as a weight for age less than the fifth percentile on standardized age-based growth charts, a decrease in weight percentile of more than 2 major percentile lines on the growth chart, or less than the 80th percent of median weight for height/length ratio. Growth percentiles should be adjusted for infants born prematurely to reflect corrected gestational age through the first 2 years of life. In general, a decline in weight percentile is more concerning than a patient who has always trended in a lower percentile range and may be meeting their expected growth potential. As the unifying concern relates to inadequate nutrient intake to meet the body's demands resulting in poor weight gain over time, the renaming of the condition as "weight faltering" has been proposed. Weight faltering offers a clearer description of the objective criteria utilized by clinicians to make the diagnosis and removes the term "failure," which has been interpreted by many patient families as overly critical.

The diagnosis of FTT/weight faltering hinges on routine weight and length/height measurements trended over time by the astute clinician for pediatric patients of all ages. In addition to the accepted percentile-based definitions, z-score is a helpful additional assessment of how far a child's weight for length/height deviates from the expected mean. Expressed in standard deviation (SD), a z-score of -1 represents a weight for length/height 1 SD below the mean. Utilizing z-scores rather than absolute percentiles can paint a more accurate picture of the patient's growth status relative to expected norms. This calculation also offers a more precise way to trend weights over time, especially for those children whose anthropometric percentiles fall well below the established curve.

FTT/weight faltering is a significant risk factor for malnutrition. Furthermore, the lower the z-score (suggesting a larger negative deviation from the mean), the higher the risk for severe malnutrition. Therefore, recognizing and evaluating the findings of FTT by optimizing nutrition and treating any underlying medical etiologies are essential. Left untreated, FTT can lead to stunted growth and has been associated with developmental delays and other significant long-term effects in the developing child. Increasingly, it has been recognized that not all calories are created equal. The true goal is ensuring that the developing pediatric patient consumes needed macronutrients, vitamins, and minerals to support healthy brain development in addition to baseline weight gain. Multiple studies have demonstrated that the effects of poor nutrition on cognitive development are more profound in younger patients, especially those younger than the age of 2 years and those with more prolonged malnutrition. In these studies, FTT was associated with decreased IQ, increased neurocognitive or behavioral challenges such as Attention-Deficit Hyperactivity Disorder (ADHD), learning disabilities, and impaired communication skills.