Paediatrics: Faltering growth (failure to thrive)

2021-03-04 12:00 AM

Faltering growth, also known as failure to thrive (FTT), is when there is a failure to grow at the expected rate (i.e. growth ‘falls away’ from standardized weight or height centile).

Faltering growth (failure to thrive)

Faltering growth, also known as failure to thrive (FTT), is when there is a failure to grow at the expected rate (i.e. growth ‘falls away’ from stan-dardized weight or height centile). Weight is the most sensitive indicator in infants and young children, whilst height is a better in the older child. Under stress, head circumference growth is more preserved than linear growth, which in turn, is more than weight gain.

In infancy, birth weight reflects the intrauterine environment. It is a poor guide to the child’s correct ‘genetic potential’ and weight may naturally fall until the correct ‘level’ is attained. In a well, happy child consider constitu-tional small stature (characterized by normal growth velocity in a healthy child of small stature parents).


95% of true FTT is due to not enough food being offered or taken. In developing countries poverty is the main cause. In the UK, causes include socioeconomic difficulties, emotional deprivation, unskilled feeding, or a particular belief system regarding appropriate nutrition.

Organic causes include:

  • Decreased appetite, e.g. psychological or secondary to chronic illness.
  • Inability to ingest, e.g. GI structural or neurological problems.
  • Excessive food loss, e.g. severe vomiting (gastro-oesophageal reflux disease (GORD), pyloric stenosis, dysmotility), diabetes mellitus (urine).
  • Malabsorption.
  • Increased energy requirements, e.g. congenital heart disease, cystic fibrosis, malignancy, sepsis.
  • Impaired utilization, e.g. various syndromes, IEM, endocrinopathies.

Causes may overlap, e.g. in cystic fibrosis there is simultaneous malabsorp-tion, increased energy requirements, anorexia, and chronic infection.


  • Detailed history: including age of onset of FTT, and timing of weaning.Consider asking paediatric dietitian to perform detailed dietary history.
  • Full examination: including accurate measurement of growth.
  • If organic disease possible: basic investigations should include:
  • FBC, ESR/CRP, U&E, creatinine, total protein and albumin, Ca2+, PO43 –, LFT;
  • immunoglobulins;
  • coeliac antibody screen;
  • urinalysis, including M, C&S.
  • Further investigations: are indicated if there are suggestive symptoms or the faltering growth is severe, and include: IEM screen; karyotype; serum lead (pica); sweat test; upper endoscopy and small intestinal biopsy; CXR; bone age, skeletal survey (NAI); abdominal US; head CT/ MRI; oesophageal pH monitoring; ECG; faecal occult blood.
  • If non-organic disease: is likely, seek dietary advice, preferably by apaediatric dietitian:
  • If FTT resolves in the next few weeks, give positive reinforcement and supervise subsequent growth as an outpatient.
  • If FTT persists, admit to hospital for basic investigations and observe the response to supervised adequate dietary input. Adequate growth in hospital suggests a non-organic cause; explore and support family dynamics.
  • Should FTT occur again at home after improvement in hospital, and then refer to social services for family assessment and appropriate intervention.
  • If FTT continues in hospital despite adequate dietary input, occult organic disease is most likely and requires extensive investigation as above.
  • Provide dietetic input, whatever the cause, to support nutritional correction and education.
  • Identify and correct associated comorbidities, e.g. developmental delay or early presentation of a neurological disorder such as cerebral palsy; fall off in head growth is suggestive.


The prognosis depends on the severity of FTT. It is good if mild. Severe FTT, whatever the cause, may be associated with later developmental and behavioural impairment.