A mother brings her 12-month-old child, a new patient for your clinic, for a well-child visit. You immediately note the child to be small for her age. Her weight is below the 5th percentile on standardized growth curves (50th percentile for an 8-month-old), her length is at the 25th percentile, and her head circumference is at the 50th percentile. Her vital signs and her examination otherwise are normal.
What is the next step in the management of this patient?
What is the most likely diagnosis?
What is the next step in the evaluation?
ANSWERS TO CASE 1: Failure to Thrive
Summary: A 12-month-old girl has poor weight gain, but no etiology is suggested on examination.
• Next step: Gather more information, including birth, past medical, family, social, and developmental histories. A dietary history is especially important.
• Most likely diagnosis: Failure to thrive (FTT), most likely “nonorganic” in etiology.
• Next step in evaluation: Limited screening laboratory testing to identify organic causes of FTT, dietary counseling, and frequent office visits to assess weight gain.
1. Know the historical clues necessary to recognize organic and nonorganic FTT.
2. Understand the appropriate use of the laboratory in an otherwise healthy child with FTT.
3. Appreciate the treatment and follow-up of a child with nonorganic FTT.
This patient’s growth pattern (inadequate weight gain, potentially modest length retardation, and head circumference sparing) suggests FTT, most likely nonorganic given that the examination is normal. A nonorganic FTT diagnosis is made after organic etiologies are excluded, and, after adequate nutrition and an adequate environment is assured, growth resumes normally after catch-up growth is demonstrated. Diagnostic and therapeutic maneuvers aimed at organic causes are appropriate when supported by the history (prematurity, maternal infection) or examination (enlarged spleen, significant developmental delay). Although organic and nonorganic FTT can occur simultaneously, attempts to differentiate the two forms are helpful because the evaluation, treatment, and follow-up may be different.
Note: Had the same practitioner followed this patient since birth or had records from the previous health-care provider, earlier detection of FTT and its potential etiology might have occurred, thus allowing more rapid intervention. For instance, patients with poor caloric intake usually fail to gain weight but maintain length and head circumference. As nutrition remains poor, length becomes affected next and then ultimately head circumference.
Failure to Thrive
FAILURE TO THRIVE (FTT): A physical sign, not a final diagnosis. It is suspected when a child’s growth is below the 3rd or 5th percentile, in a child less than 6 months old who does not gain weight for 2 to 3 months, or in a child whose growth crosses more than two major growth percentiles in a short time frame. Usually seen in children younger than 5 years whose physical growth is significantly less than that of their peers.
NONORGANIC (PSYCHOSOCIAL) FTT: Poor growth without a medical etiology. Nonorganic FTT often is related to poverty or poor caregiver–child interaction. It constitutes one-third to one-half of FTT cases identified in tertiary care settings and nearly all cases in primary care settings.
ORGANIC FTT: Poor growth caused by an underlying medical condition, such as inflammatory bowel disease, renal disease, or congenital heart conditions.
The goals of the history, physical examination, and laboratory testing are to establish whether the child’s caregiver is supplying enough calories, whether the child is consuming enough calories, and whether the child is able to use the calories for growth. Identification of which factor is the likely source of the problem helps guide management.
The history and physical examination are the most important tools in an FTT evaluation. A dietary history can offer important clues to identify an etiology. The type of milk (breast or bottle) and frequency and quality of feeding, voiding, vomiting, and stooling should be recorded. The milk used (commercial or homemade formula) and the mixing process (to ensure appropriate dilution) should be reviewed (adding too much water to powdered formula results in inadequate nutrition). The amount and type of juices and solid foods should be noted for older children. Significant food aversions might suggest gastric distress of malabsorption. A 2-week food diary (the parent notes all foods offered and taken by the child) and any associated symptoms of sweating, choking, cyanosis, difficulty sucking, and the like can be useful.
Pregnancy and early neonatal histories may reveal maternal infection, depression, drug use, intrauterine growth retardation, prematurity, or other chronic neonatal conditions. When children suspected of having FTT are seen in families whose members are genetically small or with a slow growth history (constitutional delay), affected children are usually normal and do not require an exhaustive evaluation. In contrast, a family history of inheritable disease associated with poor growth (cystic fibrosis) should be evaluated more extensively. Because nonorganic FTT is more commonly associated with poverty, a social history is often useful. The child’s living arrangements, including primary and secondary caregivers, housing type, caregiver’s financial and employment status, the family’s social supports, and unusual stresses (such as spousal abuse) should be reviewed. While gathering the history, the clinician can observe for unusual caregiver–child interactions.
All body organ systems potentially harbor a cause for organic FTT (Table 1-1). The developmental status (possibly delayed in organic and nonorganic FTT) needs evaluation. Children with nonorganic FTT may demonstrate an occipital bald spot from lying in a bed and failure to attain appropriate developmental milestones resulting from lack of parental stimulation; may be disinterested in their environment; may avoid eye contact, smiling, or vocalization; and may not respond well to maternal attempts of comforting. Children with some types of organic FTT (renal tubular acidosis) and most nonorganic FTT show “catch-up” in developmental milestones with successful therapy. During the examination (especially of younger infants) the clinician can observe a feeding, which may give clues to maternal-child interaction bonding issues or to physical problems (cerebral palsy, oral motor or swallowing difficulties, velum cleft palate).
Table 1-1 • MAJOR CAUSES OF INADEQUATE WEIGHT GAIN
The history or examination suggestive of organic FTT directs the laboratory and radiologic evaluation. In most cases, results of the newborn state screen are critical. A child with cystic fibrosis in the family requires sweat chloride or genetic testing, especially if this testing is not included on the newborn state screen. A child with a loud, harsh systolic murmur and bounding pulses deserves a chest radiograph, an electrocardiogram (ECG), and perhaps an echocardiogram and cardiology consult.
Most FTT children have few or no signs. Thus, laboratory evaluation is usually limited to a few screening tests: a complete blood count (CBC), lead level (especially for patients in lower socioeconomic classes or in cities with a high lead prevalence), thyroid and liver function tests, urinalysis and culture, and serum electrolyte levels (including calcium, blood urea nitrogen [BUN], and creatinine). A tuberculosis skin test and human immunodeficiency virus testing may also be indicated. Abnormalities in screening tests are pursued more extensively.
Treatment and Follow-up
The treatment and follow-up for organic FTT are disease specific. Patients with nonorganic FTT are managed with improved dietary intake, close follow-up, and attention to psychosocial issues.
Healthy infants in the first year of life require approximately 120 kcal/kg/d of nutrition and about 100 kcal/kg/d thereafter; FTT children require an additional 50% to 100% to ensure adequate catch-up growth. A mealtime routine is important. Families should eat together in a nondistracting environment (television off!), with meals lasting between 20 and 30 minutes. Solid foods are offered before liquids; children are not force-fed. Low-calorie drinks, juices, and water are limited; age-appropriate high-calorie foods (whole milk, cheese, dried fruits, peanut butter) are encouraged. Formulas containing more than the standard 20 cal/oz may be necessary for smaller children, and high-calorie supplementation (PediaSure or Ensure) may be required for larger children. Frequent office or home health visits are indicated to ensure weight gain. In some instances, hospitalization of an FTT child is required; such infants often have rapid weight gain, supporting the diagnosis of nonorganic FTT.
Nonorganic FTT treatment requires not only the provision of increased calories but also attention to contributing psychosocial issues. Referral to community services (Women, Infants, and Children [WIC] Program, Food Stamp Program, and local food banks) may be required. Caregiver help in the form of job training, substance and physical abuse prevention, parenting classes, and psychotherapy may be available through community programs. Older children and their families may benefit from early childhood intervention and Head Start programs.
Some children with organic FTT also have nonorganic FTT. For instance, a poorly growing special-needs premature infant is at increased risk for superimposed nonorganic FTT because of psychosocial issues, such as poor bonding with the family during a prolonged hospital stay. In such cases, care for the organic causes is coordinated with attempts to preclude nonorganic FTT.
1.1 Parents bring their 6-month-old son to see you. He is symmetrically less than the 5th percentile for height, weight, and head circumference on routine growth curves. He was born at 30 weeks’ gestation and weighed 1000 g. He was a planned pregnancy, and his mother’s prenatal course was uneventful until an automobile accident initiated the labor. He was ventilated for 3 days in the intensive care unit (ICU) but otherwise did well without ongoing problems. He was discharged at 8 weeks of life. Which of the following is the mostly likely explanation for his small size?
A. Chromosomal abnormality
B. Protein-calorie malnutrition
C. Normal ex-premie infant growth
D. Malabsorption secondary to short gut syndrome
E. Congenital hypothyroidism
1.2 A 13-month-old child is noted to be at the 25th percentile for weight, the 10th percentile for height, and less than the 5th percentile for head circumference. She was born at term. She was noted to have a small head at birth, to be developmentally delayed throughout her life, and to have required cataract surgery shortly after birth. She currently takes phenobarbital for seizures. Which of the following would most likely explain this child’s small size?
A. Congenital cytomegalovirus (CMV) infection
B. Down syndrome
C. Glycogen storage disease type II
D. Congenital hypothyroidism
1.3 A 2-year-old boy had been slightly less than the 50th percentile for weight, height, and head circumference, but in the last 6 months he has fallen to slightly less than the 25th percentile for weight. The pregnancy was normal, his development is as expected, and the family reports no psychosocial problems. The mother says that he is now a finicky eater (wants only macaroni and cheese at all meals), but she insists that he eat a variety of foods. The meals are marked by much frustration for everyone. His examination is normal. Which of the following is the best next step in his care?
A. Sweat chloride testing
B. Ophthalmologic examination for retinal hemorrhages
C. Reassurance and counseling for family about childhood normal developmental stage
D. Testing of stool for parasites
E. Magnetic resonance imaging (MRI) of the brain
1.4 A 4-month-old child has poor weight gain. Her current weight is less than the 5th percentile, height about the 10th percentile, and head circumference at the 50th percentile. The planned pregnancy resulted in a normal, spontaneous, vaginal delivery; mother and child were discharged after a 48-hour hospitalization. Feeding is via breast and bottle; the quantity seems sufficient. The child has had no illness. The examination is unremarkable except for the child’s small size. Screening laboratory shows the hemoglobin and hematocrit are 11 mg/dL and 33%, respectively, with a platelet count of 198,000/mm3. Serum electrolyte levels are sodium 140, chloride 105, potassium 3.5, bicarbonate 17, blood urea nitrogen 15, and creatinine 0.3. Liver function tests are normal. Urinalysis reveals a pH of 8 with occasional epithelial cells but no white blood cells, bacteria, protein, ketones, or reducing substances. Which of the following is the most appropriate therapy for this child?
A. Transfusion with packed red blood cells (PRBCs)
B. Intravenous (IV) infusion of potassium chloride
C. Sweat chloride analysis
D. Growth hormone determination
E. Oral supplementation with bicarbonate
1.1 C. The expected weight versus age must be modified for a preterm infant. Similarly, growth for children with Down or Turner syndrome varies from that for other children. Thus, use of an appropriate growth curve is paramount. For the child in the question, weight gain should follow or exceed that of term infants. For this premature infant, when his parameters are plotted on a “premie growth chart,” normal growth is revealed.
1.2 A. The developmental delay, intrauterine growth retardation (including microcephaly), cataracts, seizures, hepatosplenomegaly, prolonged neonatal jaundice, and purpura at birth are consistent with a congenital cytomegalovirus (CMV) or toxoplasmosis infection. Calcified brain densities of CMV typically are found in a periventricular pattern; in toxoplasmosis, they are found scattered throughout the cortex.
1.3 C. Between 18 and 30 months of age children often become “picky eaters.” Their growth rate can plateau, and the period can be distressing for families. Calm counseling of parents to provide nutrition, avoid “force-feeding,” and avoid providing snacks is usually effective. Close follow-up is required.
1.4 E. The patient has evidence of renal tubular acidosis (probably distal tubular), a well-described cause of FTT. Upon confirmation of the findings, oral bicarbonate supplementation would be expected to correct the elevated chloride level, the low bicarbonate and potassium levels (although potassium supplements may be required), and poor growth.
In the United States, psychosocial failure to thrive is more common than organic failure to thrive; it often is associated with poverty or poor parent-child interaction.
Inexpensive laboratory screening tests, dietary counseling, and close observation of weight changes are appropriate first steps for most healthy-appearing infants with failure to thrive.
Organic failure to thrive can be associated with abnormalities of any organ system. Clues in history, examination, or screening laboratory tests help identify affected organ systems.
Up to one-third of patients with psychosocial failure to thrive have developmental delay as well as social and emotional problems.
Patients with renal tubular acidosis, a common cause of organic failure to thrive, can have proximal tubule defects (type 2) caused by impaired tubular bicarbonate reabsorption or distal tubule defects (type 1) caused by impaired hydrogen ion secretion. Type 4 is also a distal tubule problem associated with impaired ammoniagenesis.
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