Failure to thrive (FTT) is a medical term[1] which denotes poor weight gain and physical growth failure over an extended period of time. Common usage refers to infancy. However, the term is also applied to geriatrics. As used by pediatricians, it covers poor physical growth of any cause and does not imply abnormal intellectual, social, or emotional development. Failure to thrive is weight consistently below the 3rd to the 5th percentile for age, progressive decrease in weight to below the 3rd to the 5th percentile, or a decrease in the percentile rank of 2 major growth parameters in a short period. The cause may be an identified medical condition or related to environmental factors. Both types relate to inadequate nutrition. Treatment aims to restore proper nutrition.
Etiology and pathophysiology
The physiologic basis for failure to thrive (FTT) of any etiology is inadequate nutrition.
Organic
Growth failure is due to an acute or chronic disorder that interferes with nutrient intake, absorption, metabolism, or excretion or that increases energy requirements. Illness of any organ system can be a cause.
For example, Gastro-esophogeal reflux (GER) can interfere with necessary nutrient intake by making it difficult or impossible for the baby to continue feeding, or by causing a feeding aversion which causes the baby to avoid feeding entirely.
Nonorganic
Up to 80% of children with growth failure do not have an apparent growth-inhibiting (organic) disorder; growth failure occurs because of environmental neglect (eg. lack of food) or stimulus deprivation.
Lack of food may be due to impoverishment, poor understanding of feeding techniques, improperly prepared formula (eg. overdiluting formula to "stretch" it because of financial difficulties), or an inadequate supply of breast milk (e.g., because the mother is under extreme stress, poorly nourished, feeding too infrequently, baby has poor latch, or mother is consuming drugs that lower milk supply.).
Nonorganic FTT is often a complex of disordered interaction between a child and caregiver. In some cases, the psychologic basis of nonorganic FTT appears similar to that of "hospitalism," a syndrome observed in infants who have depression secondary to stimulus deprivation. The unstimulated child becomes depressed, apathetic, and ultimately anorexic. Stimulation may be lacking because the caregiver is depressed or apathetic, has poor parenting skills, is anxious about or unfulfilled by the caregiving role, feels hostile toward the child, or is responding to real or perceived external stresses (eg. demands of other children in large or chaotic families, marital dysfunction, a significant loss, financial difficulties).
Poor caregiving does not fully account for all cases of nonorganic FTT. The child's temperament, capacities, and responses help shape caregiver nurturance patterns. Common scenarios involve parent-child mismatches, in which the child's demands, although not pathologic, cannot be adequately met by the parents, who might, however, do well with a child who has different needs or even with the same child under different circumstances.
Mixed
In mixed FTT, organic and nonorganic causes can overlap; those with organic disorders also have disturbed environments or dysfunctional parental interactions. Likewise, those with severe undernutrition from nonorganic FTT can develop organic medical problems.
Diagnosis
Children with organic FTT may present at any age depending on the underlying disorder. Most children with nonorganic FTT manifest growth failure before age 1 yr and many by age 6 mo. Age should be plotted against weight, height, and head size. Until premature infants reach 2 yr, age should be corrected for gestation.
Weight is the most sensitive indicator of nutritional status. Reduced linear growth usually indicates more severe, prolonged malnutrition. Because the brain is preferentially spared in protein-energy malnutrition, reduced growth in head circumference occurs late and indicates very severe or long-standing malnutrition.
Usually, when growth failure is noted, a history (including diet history) is obtained, diet counseling is provided, and the child's weight is monitored frequently. A child who does not gain weight satisfactorily in spite of outpatient assessment and intervention is usually admitted to the hospital so that all necessary observations can be made and diagnostic tests performed quickly. Without historic or physical evidence of a specific underlying etiology for growth failure, no single clinical feature or test can reliably distinguish organic from nonorganic FTT. Because nonorganic FTT is not a diagnosis of exclusion, the physician should simultaneously search for an underlying physical problem and for personal, family, and child-family characteristics that support a psychosocial etiology. Optimally, evaluation is multidisciplinary, involving a physician, a nurse, a social worker, a nutritionist, an expert in child development, and often a psychiatrist or psychologist. The child's feeding behaviors with health care practitioners and with the parents must be observed, whether the setting is inpatient or outpatient.
Engaging the parents as co-investigators is essential. It helps foster their self-esteem and avoids blaming those who may already feel frustrated or guilty because of a perceived inability to nurture their child. The family should be encouraged to visit as often and as long as possible. Staff members should make them feel welcome, support their attempts to feed the child, and provide toys and ideas that promote parent-child play and other interactions. Staff members should avoid any comments implying parental inadequacy, irresponsibility, or other fault as the cause of FTT. However, parental adequacy and sense of responsibility should be evaluated. Suspected neglect or abuse must be reported to social services, but in many instances, referral for preventive services that are targeted to meet the family's needs for support and education (eg, additional food stamps, more accessible child care, parenting classes) is more appropriate.
During hospitalization, the child's interaction with people in the environment is closely observed, and evidence of self-stimulatory behaviors (eg, rocking, head banging) is noted. Some children with nonorganic FTT have been described as hypervigilant and wary of close contact with people, preferring interactions with inanimate objects if they interact at all. Although nonorganic FTT is more consistent with neglectful than abusive parenting, the child should be examined closely for evidence of abuse (see Child Maltreatment). A screening test of developmental level should be performed and, if indicated, followed with more sophisticated assessment.
Testing: Extensive laboratory tests are usually nonproductive. If a thorough history or physical examination does not indicate a particular cause, most experts recommend limiting screening tests to a CBC with differential, an ESR, BUN or serum creatinine level, urinalysis (including ability to concentrate and acidify), urine culture, and examination of the stool for pH, reducing substances, odor, color, consistency, and fat content. Consider malabsorption conditions, such as coeliac disease. Depending on prevalence of specific disorders in the community, blood lead level, HIV, or TB testing may be warranted.
Other tests that are sometimes appropriate include electrolyte concentrations if the child has a history of significant vomiting or diarrhea; a thyroxine level if growth in height is more severely affected than growth in weight; and a sweat test if the child has a history of recurrent upper or lower respiratory tract disease, a salty taste when kissed, a ravenous appetite, foul-smelling bulky stools, hepatomegaly, or a family history of cystic fibrosis. Investigation for infectious diseases should be reserved for children with evidence of infection (eg, fever, vomiting, cough, diarrhea). Radiologic investigation should be reserved for children with evidence of anatomic or functional pathology (eg, pyloric stenosis, gastroesophageal reflux).
Prognosis
Prognosis with organic FTT depends on the cause. With nonorganic FTT, 50 to 75% of children > 1 yr achieve a stable weight > 3rd percentile. Cognitive function, especially verbal skills, remains below the normal range in about 1/3; children who develop FTT before 1 yr of age are at high risk, and those diagnosed at < 6 mo of age when the rate of postnatal brain growth is maximal are at highest risk. General behavioral problems, identified by teachers or mental health professionals, occur in about 50%. Problems specifically related to eating (eg, pickiness, slowness) or elimination tend to occur in a similar proportion of children, usually those with other behavioral or personality disturbances.
Treatment
Treatment aims to provide sufficient health and environmental resources to promote satisfactory growth. A nutritious diet containing adequate calories for catch-up growth (about 150% of normal caloric requirement) and individualized medical and social supports are usually necessary. Ability to gain weight in the hospital does not always differentiate infants with nonorganic FTT from those with organic FTT; all children grow when given sufficient nutrition. However, some children with nonorganic FTT lose weight in the hospital, highlighting the complexity of this condition.
For children with organic or mixed FTT, the underlying disorder should be treated quickly. For children with apparent nonorganic FTT or mixed FTT, management includes provision of education and emotional support to correct problems interfering with the parent-child relationship. Because long-term social support or psychiatric treatment is often required, the evaluation team may be able only to define the family's needs, provide initial instruction and support, and institute appropriate referrals to community agencies. The parents should understand why the referrals are being made and, if options exist, should participate in decisions concerning which agencies will be involved. If the child is hospitalized in a tertiary care center, the referring physician should be consulted regarding local agencies and the level of expertise available in the community.
A predischarge planning conference involving hospital-based personnel, representatives from the community agencies that will provide follow-up services, and the child's primary physician is ideal. Areas of responsibility and lines of accountability must be clearly defined, preferably in writing, and distributed to everyone involved. The parents should be invited to a summary session after the conference so that they can meet the community workers, ask questions, and arrange follow-up appointments.
In some cases, the child must be placed in foster care. If the child is expected to eventually return to the biologic parents, parenting skill training and psychologic counseling must be provided for them. Their child's progress must be monitored scrupulously. Return to the biologic parents should be based on the parents' demonstrated ability to care for the child adequately, not only on the passage of time.
In adult medicine, failure to thrive is a descriptive, non-specific term that encompasses "not doing well": e.g. malaise, weight loss, poor self-care that can be seen in elderly individuals.
Recently the term 'faltering growth' has become a popular replacement for 'failure to thrive', which in the minds of some represents a more euphemistic term.
Causes
Traditionally, causes of FTT have been divided into endogenous, such as an inborn error of metabolism, and exogenous, such as having a mother with postpartum depression. To think of the terms as dichotomous can be misleading, since both endogenous and exogenous factors may co-exist. A child with a disease or disability may be more vulnerable to poor care by a mother with marginal competence or resources. These infants typically look cachectic, are prone to infections with difficulty recovering, are often developmentally delayed, have unusual postures, and look sad, withdrawn, apathetic OR hypervigilant, irritable, or angry. Underlying physical causes may not be immediately obvious such as the mother's mastitis, occult urinary tract infections (UTIs), undiagnosed Cystic Fibrosis (CF) or asthma. Initial investigation should consider physical causes, calorie intake and pyschosocial assessment.
References
Christian, CW, Blum, NJ; Nelson's Essentials of Pediatrics 5th edition, Section V, Chapter 21, Elsevier, 2005, ISBN 978-1-4160-0159-1.
