Failure to thrive (FTT): Nursing

Failure to thrive, or FTT for short, refers to inadequate growth, typically seen in infancy and childhood. This can happen because of an underlying disorder, insufficient caloric intake, or sometimes a mixture of both! Let’s start by looking at the physiology of pediatric growth. A child’s growth is monitored by several parameters, including weight, length or stature, and head circumference, based upon what is considered typical for a given age. This is done by plotting a child’s growth parameters on growth charts which show the percentile of the child on each parameter compared to a large representative population. These charts are standardized by the Centers for Disease Control and Prevention or CDC. Separate charts are available for those assigned male and female at birth. For infants between 0 and 36 months, the growth charts used are length for age and weight for age, head circumference for age, and weight for length. Finally, between 2 and 20 years of age, the standard charts include stature for age and weight for length and body mass index or BMI for age.

Now, the causes of failure to thrive can be classified into three broad categories; organic, non-organic, and mixed causes. Organic causes are those that result from an underlying disorder interfering with bodily functions necessary for growth and development such as nutrient intake, absorption, and metabolism. Such disorders include gastroesophageal reflux; celiac disease, which is when absorption in the small intestine is impaired; nephrotic syndrome, which is when the kidneys leak too many proteins in the urine; cystic fibrosis, which is a genetic condition that affects pancreatic enzyme secretion; as well as genetic syndromes like Down syndrome, or congenital malformations like hypertrophic pyloric stenosis or cleft lip and palate.

Non-organic causes result from external factors, particularly an insufficient calorie intake which initially affects weight and later on can affect stature. Some causes that directly affect nutrition intake include inappropriate feeding methods and lower socioeconomic status or parental education level. A major contributing factor is structural racism and practices like redlining that leads to inequality in income and access to healthcare. Family stress or substance use disorder, as well as domestic abuse and violence can also indirectly cause failure to thrive. And finally, mixed causes are a combination of organic, and non-organic causes.

There are four main mechanisms involved in the pathology of failure to thrive, which all converge on the lack of adequate nutrients or calories to sustain typical growth. First, an infant or child may not be eating enough nutrients or calories leading to undernutrition. Second, the body could be unable to use those nutrients because of conditions like celiac disease or nephrotic syndrome. Third, they could have an increased caloric demand that they are not meeting, such as when there is heart failure. Fourth, a metabolic disease like diabetes mellitus can interfere with the body's ability to utilize the nutrients and calories from food that was eaten. Complications of failure to thrive can arise when the underlying cause isn’t treated properly. These include recurrent infections like infectious diarrhea, sepsis, and respiratory tract infections, as well as permanent effects on growth and development. Examples of these include short stature, poor cognitive development, and poor academic performance in late childhood and adulthood.

Now, although the clinical manifestations of failure to thrive can vary based on the underlying cause, most children present with a failure to gain weight or height, compared to children of similar age. They may also experience delays in reaching developmental milestones or lose acquired milestones. Some children may also have poor muscle tone and exhibit reduced activity, while others are easily irritable, refuse food, or are uninterested in feeding. Additional signs and symptoms depend on the underlying cause. For example, with hypertrophic pyloric stenosis, there could be postprandial vomiting; while with diabetes mellitus, there could be polydipsia, polyuria and polyphagia, as well as weight loss.

The diagnosis of failure to thrive starts with the child’s birth, medical and nutritional history, and physical assessment. On the growth charts, a child can be under the 5th percentile on the weight for age, be under the 80th percentile for median weight for height ratio, weight deceleration crossing more than two major percentile lines on age and population, or have a body mass index or BMI for chronologic age less than 5th percentile. Head circumference could also be decreased. Afterward, laboratory tests can be performed based on the suspected underlying causes. Τhese tests may include a complete blood count, urinalysis, urine culture, and stool analysis.