Introduction

Failure to thrive is a descriptive term for those children less than 5 years of age who have poor weight gain.
Classically failure to thrive has been described as weight less than the 3rd centile on two or more separate occasions, or weight which crosses two centile lines over time.While such findings should alert clinicians to look for a significant problem, it is important to remember that at least 5% of healthy normal children will fulfill these criteria and that many healthy children don’t follow the apparent growth trajectories suggested by the lines on the charts.

It is common for there to be no specific cause found for a child’s apparent poor weight gain. A well looking child with normal neurodevelopmental progress, who shows apparent isolated poor weight gain, without specific cause evident from history, examination and some simple investigations, will have an excellent prognosis for future healthy wellbeing and development.

Notes:
•    Nutrition is the main driver for growth in the first two years of life.
•    Remember to correct for prematurity (gestation <37 weeks) until 24 months of age.
Average weight gain per week (not the minimally acceptable weight gain).
•    0-3 months                   180g/wk
•    3 to 6 months                 120g/wk
•    6 to 9 months                 80g/wk
•    9 to 12 months               70g/wk
•    Weight gain slows further after 12 months.
Causes of Failure to Thrive to Consider
Inadequate Caloric Intake/Retention
•    Inadequate amount of food provided
•    Poor breast feeding technique
•    Structural causes of poor feeding e.g. cleft palate
•    Persistent vomiting
•    Anorexia of chronic disease
Inadequate Absorption
•    Coeliac disease
•    Chronic Liver disease
•    Pancreatic insufficiency e.g. Cystic Fibrosis
•    Chronic diarrhea
Excessive Caloric Utilization
•    Urinary Tract Infection
•    Chronic Respiratory disease e.g. Cystic Fibrosis
•    Congenital Heart disease
•    Diabetes Mellitus
•    Hyperthyroidism
Other Medical Causes
•    Genetic syndromes
•    Inborn Errors of Metabolism
Psychosocial factors
•    Parental depression
•    Coercive feeding
•    Distractions at meal times.
•    Poverty
•    Behavioral disorders
•    Poor social support
•    Neglect
Evaluation
History
•   Perinatal and Birth History– antenatal complications and maternal health. Birth weight, length and head circumference.
•    Feeding History– most important aspect to elicit.
•    Infants: Breast feeding and attachment, formula feeding, timing of feeds, volumes, and presence or absence of vomiting. Timing of introduction of solids/carbohydrates.
•    Toddlers: Meal time battles, distractions, coercive feeding, food refusal, milk volume/24 hrs. Assess parental attitude towards foods and mess.
•    Medical History- significant intercurrent illnesses coinciding with onset of weight loss.
•    Developmental History- assess for any regression or syndromal causes of failure to gain weight.
•    Family History- including mid-parental height and childhood weight gain.
•    Social History- Neglect and poverty can impact on the child.
Examination
Measure height, weight and head circumference and plot on appropriate growth chart- include previous measurements to elicit a pattern over time.
•    Does the child appear sick, scrawny, irritable or lethargic.
•    Evidence of loss of subcutaneous fat stores; esp upper arm, buttocks and thighs.
•    Pallor
•    Facial dysmorphism
•    Jaundice / Bruising / Pruritis
•    Rashes / Hair and nails.
•    ENT
•    GI (especially abdominal distension)
•    Cardiac / Respiratory system
•    Neurodevelopmental
•    Endocrine – goiter
Investigation and Management
o    For an otherwise healthy and normally developing child with no suggestive features in history or examination: no investigations are necessary at first. Reassure the family.
o    For a child with clues in the history or examination that are suggestive of a particular diagnosis: investigate according to the features you have elicited.
o    For a child where there is significant concern but no specific pointers to a medical cause: simple first line investigations are appropriate. These include:
•    FBE/CRP
•    U&E, LFT, Ferritin
•    Urine for micro and culture
•    Coeliac screen if on solid feeds containing gluten.
•    Stool for fat globules and fatty acid crystals
For all groups, consider a general paediatric follow up appointment to confirm growth pattern and further investigation / reassurance.
Avoid weighing the child too frequently. Do not weigh more than once a week for babies <3months of age, and not more than fortnightly after that age. Excessive weighing can cause normal fluctuations in weight velocity to cause unnecessary anxiety.
Other Issues to Consider
•    Admission to hospital may be required to establish the cause if the FTT is significant.

•    Social factors may influence the decision to admit the child.

•   Addressing the cause- can be difficult if related to parenting styles rather than a medical issue in the child. Utilization of community based resources including general paediatrician, MCHN, General Practitioner, dietician, lactation consultant, speech pathologist and psychologist where appropriate.

http://www.rch.org.au/clinicalguide/cpg.cfm?doc_id=13848