Rudolph's Pediatrics, 22nd Ed.

CHAPTER 30. Poor Weight Gain

Karen A. Francolla and Praveen S. Goday

Failure to thrive describes the condition of infants and toddlers under age 3 years who have an abnormally low weight for their age and sex. With prolonged and/or severe malnutrition, stature and head circumference can be secondarily affected. The prevalence of failure to thrive is reported to be 10% to 20% of all children treated in ambulatory care centers and up to 5% of all referrals to pediatric hospitals.¹Regardless of specific etiology, failure to thrive may have profound effects on the growing child, including persistent short stature, decreased resistance to infection, and possible developmental impairment and/or disabilities.^2,3

DEFINITION

Failure to thrive is characterized by insufficient growth recognized by the observation of growth over time using standard growth curves. This entity is also called failure to gain weight, growth failure, and growth faltering. There is a lack of consensus regarding the specific anthropometric criteria required to classify a child as failure to thrive. Thus, many “definitions” for failure to thrive are commonly used. These include: weight less than 3rd percentile, weight-for-height less than 5th percentile, or downward crossing of 2 or more major percentiles on the growth chart.

PATHOGENESIS

Three basic mechanisms underlie failure to thrive: (1) inadequate caloric intake, (2) insufficient utilization or absorption of consumed calories, and (3) increased metabolic requirements. There are numerous specific etiologies for failure to thrive (see Table 30.1). However, most commonly, failure to thrive results from insufficient caloric intake due to either lack of food or feeding and/or behavioral problems that limit a child’s intake. In many cases, a specific organic etiology for a child’s failure to thrive is never identified, and when one is, it rarely presents with growth failure in isolation. Behavioral and psychosocial feeding problems are common and should not be thought of as diagnoses of exclusion.

Table 30-1. Major Etiologies of Failure to Thrive

CONTRIBUTORY FACTORS

Prematurity and low birth weight likely are risk factors for the development of feeding problems.⁴ Other known risk factors for this type of failure to thrive can be thought of as infant-, maternal-, or family-related and include chronic diseases, malabsorption, lack of maternal support and/or education, and lower income and access to food (see Table 30.2). Poverty is the single largest risk factor for failure to thrive.

Difficulty in establishing breast-feeding or bottle-feeding in infancy can be due to underlying medical problems that impact upon feeding, and this can lead to dysfunctional maternal-child bonding. Resultant disruption of the mutually rewarding parent-child relationship then may negatively affect the child’s mealtime behavior and consequently the child’s food intake. Weaning is a prime time for the emergence of problems with failure to thrive.⁵ It is at this time that a child’s oral motor skills have developed to allow the consumption of more solid textures. For some children, food refusal for new textures and/or solids leads to inadequate calorie consumption. The reasons for this failure to feed are myriad and are further discussed in Chapter 31.

Psychological factors should be screened for since these can contribute to a child’s failure to thrive. These include poor parenting, lack of child-parent attachment, low socioeconomic standing, and neglect and/or abuse. These problems may arise in the presence of poor social supports and mental illness.⁶ Younger maternal age is also a risk factor for failure to thrive. Suspicion of neglect and/or abuse should be promptly reported to local child protective services.

EVALUATION

A thorough patient history, physical examination, and review of past and present growth data are the first steps in the evaluation of failure to thrive (see Table 30.3). Often, the history will yield clues that may either direct further testing or eliminate the need for extensive testing. The physician’s role is to determine whether the child’s failure to thrive is primarily due to insufficient caloric intake, energy wasting, an increased caloric requirement, or altered growth potential. Dietary assessment should include a 24-hour dietary recall and/or completion of a 3-day food diary and observation of feeding when possible. Global assessment of parent-child interactions should also be undertaken. Clinical signs of protein-energy malnutrition may be present: loss of skin turgor, little subcutaneous fat, lack of activity (apathy), emaciation, sparse or lusterless hair, and poor nail growth. Additionally, there may be skin hypopigmentation or hyperpigmentation, rash, and edema. When needed, investigations should be selected on the basis of patient history and physical examination rather than ordered as a matter of routine. Laboratory tests not suggested by the patient history and physical examination are rarely helpful. A complete blood count, serum electrolytes, blood urea nitrogen, creatinine, albumin, calcium, phosphorus, alkaline phosphatase, urinalysis, and urine culture may assist in excluding systemic disease. Other more specific tests sometimes employed in the evaluation are shown in Table 30.4, and an algorithm is provided in Figure 30-1.

Table 30-2. Risk Factors for Failure to Thrive

MANAGEMENT

The role of the physician in the management of failure to thrive is multifaceted: He or she must be an astute diagnostician, clinician, and advocate for the patient. Frequent follow-up visits with growth monitoring are essential. Hospitalization may be necessary to verify reported feeding patterns when the history seems discordant with growth values or when the physical well-being of the child is at risk because of serious illness or abuse. Assisting parents in the care of their child with failure to thrive must be accomplished in a sensitive, nonjudgmental manner. Management involves the following: (1) increasing nutritional intake, (2) evoking catch-up growth, (3) resolving feeding difficulties if possible, and (4) strengthening positive feeding interactions between parent and child.⁷

Table 30-3. Factors That Aid in Diagnosing Failure to Thrive

Table 30-4. Laboratory Findings That Aid in Evaluating Failure to Thrive

Failure to thrive is largely managed by dietary intervention; the ultimate goal is to increase the caloric intake of the child to enable catch-up growth. Catch-up weight gain is a weight gain at a rate more rapid than the basal requirement for age such that the weight deficit is overcome. Caloric needs for catch-up growth can be calculated formulaically: estimated energy requirement for age (kcal/kg) multiplied by ideal weight-for-height (kg) divided by actual weight (kg), where ideal weight-for-height is the median weight for the patient’s height (as determined from the weight-for-height curves). One method for initiating catch-up growth is increasing the caloric intake by 50%. For example, the caloric intake for a 1-year-old child might increase from the basic caloric requirement of 100 kcal/kg/day to a new requirement of 150 kcal/kg/day. However, this is difficult to do in practice. In practice, one recommends a focus on intake of high-calorie foods, addition of extra calories to foods, limited consumption of low-calorie foods (especially juice), and structured mealtimes and snacks.

Incorporating high-calorie foods into a young child’s diet may be challenging because of patient and family food preferences. Strategies for adding higher calorie foods to the toddler’s diet include offering frequent child-sized meals, energy-dense foods, and the addition of extra calories via high-fat condiments such as oils, butter, and cheese. Children should be offered 3 meals and 2 to 3 snacks daily, or 5 to 6 small meals daily. Portion size should be individualized to fit the size of the child; portions that are too large are often overwhelming. Energy-dense foods include cheese, eggs, peanut butter, whole milk, meats, and nuts/seeds (which are only appropriate in children older than 3 years of age because of their choking potential in younger children). Powdered whole milk may also be added to meals and provide an extra 40 calories per tablespoon.

Mealtime behavior should be structured. Meals for the toddler should be offered in a high-chair at the table, and distractions should be minimized. The child should be allowed to experiment with the food, and forceful feeding should be avoided. The “two-spoon method” is a commonly employed strategy in which the child is allowed to play with one spoon while the parent feeds with the other. Parents should be instructed to keep relaxed and calm at mealtime and offer praise for the child when he eats well. The child should be allowed to determine when he is finished eating and should not be forced to finish portions of food. Snacking in between mealtime and drinking juice should be eliminated. Beverages should be limited before and at mealtime because drinking too much at mealtime can make a child feel full and preclude the intake of solids. The consumption of milk should be tailored to patient age but in general should be between 16 and 24 ounces daily. The use of high-calorie drinkable supplements, shakes, and puddings may be helpful.

Close follow-up of the patient recovering from malnutrition is essential. In the early refeeding phase, the child with substantial malnourishment may be at risk for refeeding syndrome (see Chapter 29). Additionally, some children with malnutrition experience nutritional recovery syndrome. This is characterized by hepatomegaly (secondary to increased glycogen deposition in the liver), sweatiness, mild irritability or hyperactivity, and widening of the cranial sutures in infants with open sutures (as brain growth is more rapid than skull growth). If weight gain has not occurred after 4 to 6 weeks of oral feeding, supplemental feeding with a nasogastric tube should be considered. In children requiring prolonged supplemental feeding (> 2–3 months), placement of a gastrostomy tube may be indicated. Feeding assessment by a speech pathologist or occupational therapist may allow for the development of strategies to improve sucking and swallowing. Finally, a multidisciplinary team approach involving a pediatric gastroenterologist, nurse, psychologist, dietitian, occupational therapist, and/or speech and language pathologist, may be helpful for improving oral intake in the child with behavioral feeding refusal (see Chapter 31).

FIGURE 30-1. Algorithm for the evaluation of failure to thrive.

OUTCOMES

Adequate nutrition is especially important in the first 3 years of a child’s life, the period when exponential development of the brain and cognitive processes takes place. Malnutrition in this period may carry the risk of a negative impact on cognitive development. The prognosis with respect to stature and weight is good for children with failure to thrive; however, up to 60% of infants with failure to thrive remain below the 20th percentile for height and weight. Approximately 50% of children with failure to thrive have below-normal cognitive function. Additionally, behavioral problems and learning difficulties are identified in a significant portion of this population. It is unclear whether these effects are secondary to malnutrition or of the lack of an intellectually stimulating environment in early childhood. Of note, cognitive recovery in children with failure to thrive appears to mirror their nutritional recovery; this emphasizes the need for quick nutritional interventions for these children.