OVERVIEW: What every practitioner needs to know

Are you sure your patient has failure to thrive? What are the typical findings for this disease?

A variety of nutritional abnormalities exist affecting infants and children including undernutrition, overnutrition, and certain malnutrition states. These acquired metabolic derangements highlight the extreme importance of nutrition in the pediatric population.

Undernutrition and failure to thrive

Historically, the term “failure to thrive” was used to describe institutionalized infants suffering from a possible combination of infection, nutritional deficiency, and psychosocial neglect. Although large scale institutionalization has ceased in the more affluent nations, failure to thrive is still used to used to describe the infant or child that does not appear to be growing appropriately. Often, inadequate nutrition or undernutrition is the cause behind an infant/child that has been labeled as failure to thrive. There are many definitions for failure to thrive using a variety of growth indices, and none of them are perfect. More commonly, weight is used to define failure to thrive although length/height is also important.

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There are several commonly described symptoms of failure to thrive including a decrease in weight-for-age ≥ 2 percentiles, weight-for-age < 3rd percentile, weight-for-height < 5th percentile, or documented weight loss.

See Figure 1 for the growth chart depicting undernutrition. Note the asymmetric faltering of growth failure due to undernutrition. Weight gain decelerates first, followed by length and lastly head circumference in severe cases.

Figure 1.


When evaluating apparent growth failure, it is important to consider other factors such as whether or not the growth faltering is symmetric or asymmetric. Are weight and length/height affected to the same degree. The apparent faltering should be specified as much as possible. Is there slow but consistent growth, plateauing, or actual weight loss?

Symptoms that would explain inadequate nutrition such as vomiting/diarrhea are an important part of the evaluation as is the general appearance of the infant/child. Is the child small but “well” appearing or emaciated? Some conditions are not nutritional deficiency but still involve growth deceleration. This apparent growth faltering may be constitutional or represent a disease process, and differentiating between these conditions relies a great deal on growth chart assessment.

What other diseases/condition shares some of these symptoms?

  • Constitutional growth delay

  • Familial short stature

  • Intrauterine growth retardation

  • Endocrinopathy

  • Genetic abnormality

A careful review of serial growth measurements plotted on an age-appropriate growth chart may suggest one of the above conditions as a cause of failure to thrive (See Figure 1, Figure 2, and Figure 3).

Figure 2.

Intrauterine growth retardation

Figure 3.

Constitutional growth delay

Symmetric faltering of growth indices beginning at birth suggest an intrauterine insult or genetic abnormality (See Figure 2).

Symmetric faltering of weight and linear growth with preservation of head circumference may suggest an endocrinopathy or constitutional growth delay (See Figure 3).

In some endocrinopathies, such as hypothyroidism, linear growth is mainly affected while weight may be either preserved or obese.

What caused this disease to develop at this time?

The three basic mechanisms responsible for undernutrition include inadequate caloric intake, excessive caloric loss, and impaired metabolism. They may exist singly or in combination. For example, a child with Crohn’s Disease may have insufficient intake secondary to abdominal pain, malabsorption due to intestinal inflammation, and a persistent catabolic state due to chronic inflammation. There may be several predisposing factors including genetics, psychosocial factors, and disease states.

Because there are so many different causes of undernutrition, the history and physical exam are the most important tools in the evaluation of undernutrition. Since inadequate intake of calories is the most common cause, a complete and detailed dietary history is critical.

What laboratory studies should you request to help confirm the diagnosis? How should you interpret the results?

There are no routine laboratory studies used in the evaluation of failure to thrive. History and physical exam should guide each individual evaluation.

Would imaging studies be helpful? If so, which ones?

There are no routine imaging studies used in the evaluation of failure to thrive. History and physical exam should guide each individual evaluation.

Confirming the diagnosis

The diagnosis of failure to thrive/undernutrition is suspected and later confirmed by evaluating growth indices. These anthropometrical indices may reflect a static growth (weight-for-age) or a dynamic growth measure (decelerating growth > 2 percentiles).

A detailed history including social and diet history, physical examination findings and growth chart measurement review are required for confirming the diagnosis. All patients with suspected failure to thrive should have a calorie assessment.

If you are able to confirm that the patient has failure to thrive, what treatment should be initiated?

Calorie replacement is frequently the first step in the management of suspected undernutrition. This may be done with the involvement of a dietician who recommends a caloric intake goal based on desired catch-up growth.

If recommendations for increasing calorie intake are not working, then the patient with suspected failure to thrive is further evaluated/treated in a hospital setting. Because failure to thrive is often multifactorial, a team approach is generally considered the best approach (Table I). This team approach is often more convenient in the hospital setting. Social workers, feeding therapists, dieticians and medical staff can further evaluate and address the particular issues regarding each individual patient.

Table I.
FTT Team Member Responsibilities
Dietician Evaluates calorie intake and recommends goal calories for catch-up growth
Feeding Therapist Evaluates feeding skills and may recommend a swallow study and initiate oral/feeding therapy as indicated
Social Worker Evaluates psychosocial issues affecting the family/child and helps provide resources to address concerns
Practitioner Coordinates the team and insures that goal calories are provided and medical issues have been addressed.

There are several organic or identifiable medical diseases responsible for causing undernutrition such as heart disease or endocrine disorders. When medical disease is responsible for undernutrition, controlling that disease is a critical part of correcting the co-existent undernutrition. Specific treatment would depend on the initial cause of the undernutrition although observation of growth over time is very important regardless of the initial cause.

What are the adverse effects associated with each treatment option?

Patients with severe undernutrition who are receiving nutritional therapy should be watched closely for refeeding syndrome. Refeeding syndrome is the metabolic derangement that occurs when someone is suddenly shifted from a catobolic state to anabolism. There are several electrolyte abnormalities that can occur, and hypophosphatemia is the hallmark. Electrolyte abnormalities can be associated with significant morbidity and mortality including cardiac arrhythmias. Also, suddenly increased intravascular volume may predispose the undernourished patient to develop congestive heart failure.

Refeeding syndrome can be avoided by slowly refeeding calories beginning with as low as 10% of resting energy expenditure and increasing slowly from there. Monitoring and correction of electrolyte abnormalities is critical. Protein is not restricted during refeeding, but total calories in general and carbohydrates in particular are started low and advanced slowly.

Metabolic abnormalities seen with refeeding syndrome:






What are the possible outcomes of failure to thrive?

Increased mortality, particularly in developing countries, has been associated with undernutrition. Outcomes are dependent on the cause of the growth failure although chronic undernutrition may lead to delayed development and failure to reach full growth potential.

Cognitive, behavioral, and developmental problems have been studied in infants and children with failure to thrive with contradictory results. Whether any observed effects of failure to thrive such as behavioral problems diminish over time is unknown.

What causes this disease and how frequent is it?

Most failure to thrive is believed to be due to non-medical causes and inadequate intake of calories in particular. The literature typically refers to failure to thrive as being a common pediatric problem. The exact prevalence is unknown, and the lack of consensus regarding definition is partly the reason.

There are several definitions for failure to thrive, and the concurrence between them is poor. For example, decreasing weight across 2 centile lines may have a prevalence rate of 15-20%. Using another accepted method in the same population, the rate is closer to 1%. Thus, lack of agreement regarding the best anthropometic index makes defining and determining frequency difficult. Furthermore, epidemiological studies may represent a hospital-based population rather than a general population leading to referral or selection bias.

Potential risk factors such as poverty, neglect, birthweight, parity, maternal-child interaction, maternal age, parental education, feeding difficulty, and postnatal depression have been evaluated with conflicting or mixed results. Determination of risk is hampered by lack of consensus regarding definition as well as conflicting results using the same criteria for failure to thrive.

As most failure to thrive is due to inadequate caloric intake, genetic causes of suspected failure to thrive may not reflect an undernourished state. Likewise, parental growth parameters are an important part of the evaluation as apparent growth faltering may be more constitutional rather than nutritional. The small but well child who is growing along their own curve may not be undernourished and therefore not represent a true case of failure to thrive.

Other nutritional abnormalities

Marasmus and Kwashiorkor are much more common in impoverished countries, but they can also be seen in industrialized nations. Lack of dietary education and practitioner unfamiliarity with these conditions can result in missed diagnoses or treatment errors. These malnutrition states may exist singly or together, such as an acute episode of Kwashiorkor superimposed on a chronic state of Marasmus.

Marasmus is an adapted (normal albumin) malnutrition due to total calorie deficiency. Symptoms include wasting and growth stunting due to more chronic caloric deprivation over months or years. There is typically a higher need for catch-up growth, and body functions are depressed (hypothermia, bradycardia).

Kwashiorkor is a disadapted (low albumin and generalized edema) malnutrition due to inadequate protein intake despite sufficient calorie intake. Kwashiorkor is typically more acute than Marasmus. Symptoms include lethargy, anorexia, growth failure, desquamative rash, generalized edema, and a large protuberant abdomen. Infections are common. Zinc deficiency is often seen in patients with Kwashiorkor. The rash of zinc deficiency resembles that of Kwashiorkor except that it has a periorificial distribution (acrodermatitis enteropathica). Growth failure associated with Kwashiorkor may be missed due to the severe edema and swelling caused by hypoalbuminemia.

Treatment of Kwashiorkor should be cautious, gradual, and enteral to avoid refeeding syndrome. Intravenous therapy is generally avoided unless there is shock, dehydration, or infection. Overly aggressive early feeding or IV infusions as well as missed electrolyte/glucose disturbances and fluid overload (refeeding syndrome) can be fatal. Prognosis is good if treatment is started early. In cases of delayed treatment, the affected child may never reach potential levels of growth. Failure to treat, particularly severe cases, can be fatal.

Obesity (overnutrition) is defined as a body mass index (BMI) of 30 or greater. Obesity is described elsewhere in more detail. Obesity is one of the most serious pediatric health issues in the United States. Co-morbidity such as hypertension and glucose intolerance is associated with shortened lifespan. Medical costs associated with childhood obesity are substantial and increasing.

How can failure to thrive be prevented?

The first step is routine pediatric care and monitoring of growth parameters. If growth appears to be affected, then a thorough history including dietary history as well as physical exam are the next step in monitoring and preventing the development of significant growth failure.

Psychosocial concerns should be addressed and providing dietary education when applicable may also help prevent undernutrition.

What is the evidence?

Jolley, CD. “Failure to Thrive”. Curr Probl Pediatr Adolesc Health Care. vol. 33. 2003 Jul. pp. 183-206. (This review addresses background of this diagnosis, the varying definitions, and an overview of the team approach.)

Rabinowitz, SS, Katturpalli, M, Rogers, G. “Nutritional Considerations in Failure to Thrive”. http://emedicine.medscape.com/article/985007-overview, updated May. 2010. (This very complete review also discusses normal growth and important considerations when evaluating growth charts and dietary history.)

Olsen, EM. “Failure to Thrive: Still a Problem of Definition”. Clin Pediatr. vol. 45. 2006. pp. 1(This article describes the various definitions of failure to thrive and details the lack of consensus regarding this diagnosis.)

Spencer, NJ. “Failure to think about failure to thrive”. Arch Dis Child. vol. 92. 2007. pp. 95-6. (This perspective article summarizes important points regarding failure to thrive as well as suggestions to avoid common pitfalls.)

Krugman, SD, Dubowitz, H. “Failure to Thrive”. Am Fam Physician. vol. 68. 2003. pp. 878-84, 886. (This review includes a very complete history evaluation, and it addresses management aspects as well.)

Tierney, EP, Sage, RJ, Shwayder, T. “Kwashiorkor from a severe dietary restriction in an 8-month infant in suburban Detroit, Michigan: case report and review of the literature”. International Journal of Dermatology. vol. 49. 2010. pp. 500-6. (This case report includes a review of both kwashiorkor and marasmus.)

Fuentebella, J, Kerner, JA. “Refeeding Syndrome”. Pediatr Clin N Am. 2009. pp. 1201-10. (This very concise review is one of the most current and comprehensive reviews of refeeding syndrome.)

Ongoing controversies regarding etiology, diagnosis, treatment

Failure to thrive is a description rather than a true diagnosis. It is used to describe those infants/children that appear to suffer from growth failure. There are several definitions for that apparent growth failure, and there is no consensus regarding the best definition. Also, concurrence among definitions is often poor. Many cases of apparent growth failure may represent normal children with slow growth, endocrinopathy, or genetic causes. Most cases of growth failure are due to inadequate intake and not due to medical disease.

There are many potential risk factors that have been associated with failure to thrive. Many of these such as abuse, poverty, or psychopathology may have been overstated. Studies evaluating the long term behavioral effects of failure to thrive have shown contradictory results.