Faltering Growth

Introduction

Faltering growth describes a slower rate of weight gain than expected for a child's age and sex. NICE deliberately adopted the term in NG75 to replace failure to thrive, which carried an implication of parental fault that the evidence does not support and that made families defensive at exactly the point where their cooperation was needed.¹

It is common, it is usually a feeding problem rather than a disease, and it is one of the areas where over-investigation is a genuine hazard. A run of blood tests in a well child with a slightly disappointing weight gain rarely finds anything, but it does frighten the family and delay the feeding support that would actually help.

Equally, faltering growth is sometimes the first visible sign of coeliac disease, cystic fibrosis, congenital heart disease or neglect. The skill is in recognising which children need looking into, and the tools for that are an accurate growth chart, a detailed feeding history, a full examination and - more than anything - watching the child actually feed.

Defining and measuring it

NICE NG75 thresholds

The logic behind the sliding scale is that a small baby has less room to fall before entering a genuinely abnormal range, whereas a large baby crossing centiles is very often simply regressing towards their genetic potential.

Measuring properly

• Use the UK-WHO growth charts, weighing infants under 2 years naked and using calibrated scales³
• Measure length lying down under 2 years and height standing over 2 years - the two are not interchangeable, and a switch between them creates an artificial step on the chart
• Correct for prematurity: until 1 year of age for babies born at 32-36 weeks, and until 2 years for those born before 32 weeks
• Plot head circumference as well, since the relative pattern of the three measurements is diagnostically useful
• Calculate the mid-parental height and target centile range, which puts the child's growth in a familial context
• Take more than one measurement over time - a single point tells you almost nothing

Weight loss in the newborn period

Some weight loss after birth is normal, and most term babies regain their birthweight by about 3 weeks. A loss of more than 10% of birthweight should prompt a clinical assessment, a detailed feeding history, direct observation of a feed, and consideration of hypernatraemic dehydration - which occurs in inadequately fed breastfed babies and can be severe by the time the baby looks unwell.¹

Causes

It is worth organising the causes by mechanism, because the mechanism determines the assessment. In practice, inadequate intake accounts for the overwhelming majority.

Inadequate intake - the commonest by far

• Breastfeeding difficulties - poor latch or positioning, ineffective milk transfer, insufficient supply, infrequent feeds, maternal pain
• Formula feeding problems - incorrect reconstitution, inadequate volumes, or over-dilution to make a tin last
• Weaning and toddler feeding difficulties - restrictive or faddy eating, excessive milk or juice suppressing appetite, constant grazing, coercive mealtimes
• Oromotor and structural problems - cleft lip and palate, significant ankyloglossia, an unsafe swallow, hypotonia, cerebral palsy
• Psychosocial factors - maternal depression, poverty and food insecurity, parental learning disability or mental illness, chaotic households, and neglect
• Anorexia of chronic illness, in which any long-standing disease suppresses appetite

Inadequate retention

• Gastro-oesophageal reflux disease with significant vomiting
• Pyloric stenosis in the 2-8 week old
• Persistent vomiting from any cause, including raised intracranial pressure and metabolic disease

Malabsorption

• Coeliac disease - appearing after gluten is introduced at weaning, with diarrhoea, abdominal distension and irritability⁵
• Cystic fibrosis - steatorrhoea, recurrent chest infections, and a positive newborn screen⁶
• Cow's milk protein allergy and other food allergy⁷
• Chronic diarrhoea, post-gastroenteritis enteropathy, and short bowel syndrome
• Cholestatic liver disease and pancreatic insufficiency

Increased requirements

• Congenital heart disease - sweating with feeds, tachypnoea, a murmur, and breathlessness that limits feed volume
• Chronic lung disease of prematurity, where the work of breathing consumes the calories
• Chronic infection - recurrent urinary tract infection, tuberculosis, HIV
• Chronic inflammation - inflammatory bowel disease, juvenile idiopathic arthritis
• Malignancy, hyperthyroidism and chronic kidney disease

Inefficient utilisation

• Chromosomal disorders - Down syndrome, Turner syndrome and others
• Congenital infection - cytomegalovirus, toxoplasmosis, rubella
• Inborn errors of metabolism
• Endocrine disease - growth hormone deficiency, hypothyroidism and Cushing syndrome, which characteristically affect height more than weight

Assessment

History

• Pregnancy and birth - gestation, birthweight, antenatal concerns, maternal health, substance use
• A detailed feeding history - what, how much, how often, how long each feed takes, who feeds the child, and how formula is made up. Ask the family to keep a food and feeding diary.
• Symptoms by system - vomiting, stool frequency and consistency, cough, wheeze, sweating with feeds, recurrent infections, lethargy
• Development - is any skill loss or delay present alongside the growth problem?
• Past medical history, including hospital admissions and the newborn screening result
• Family history - parental heights, consanguinity, coeliac disease, cystic fibrosis, atopy, thyroid disease
• Social history - housing, income and food security, other children, support networks, parental mental health, and any involvement of children's social care

Direct observation of feeding

NICE recommends this explicitly, and it is the single most valuable part of the assessment.¹ Watching a breastfeed reveals latch, positioning, and whether milk is actually being transferred. Watching a bottle feed reveals volumes, teat flow, positioning and how the feed is terminated. Watching a toddler's mealtime reveals the atmosphere, the distractions, the pressure, the duration and the range of foods offered - and frequently makes the diagnosis in the room.

Examination

• Plot all three measurements and compare against previous values and the target centile range
• General appearance - wasting, loss of subcutaneous fat and buttock wasting, pallor, hair and skin quality, and whether the child is alert and engaged
• Dysmorphic features suggesting a syndromic cause
• Mouth - cleft palate, ankyloglossia, dental caries, oral thrush
• Cardiovascular - murmur, tachypnoea, hepatomegaly and other signs of heart failure
• Respiratory - chronic cough, wheeze, clubbing
• Abdomen - distension, organomegaly, palpable faecal loading
• Neurological - tone, posture, primitive reflexes and developmental level
• Signs of neglect or non-accidental injury - unexplained bruising, poor hygiene, unusual interaction with the carer, and a flat, watchful affect

Investigations

NICE advises against routine investigation in the absence of a clinical indication, because the yield in a well child is very low. Tests should be selected by what the history and examination suggest.

• FBC, ferritin, U&Es, LFTs, bone profile and CRP as a general screen where a systemic cause is suspected
• Coeliac serology - tissue transglutaminase IgA with a total IgA, and only once gluten has been in the diet for at least 6 weeks⁵
• Thyroid function
• Urine dipstick and culture - recurrent or occult urinary tract infection is easily missed
• Sweat test or CF genetics, and confirmation of the newborn blood spot result⁶
• Stool - microscopy and culture, faecal elastase for pancreatic insufficiency, and faecal calprotectin where inflammatory bowel disease is a possibility
• Karyotype or microarray where there are dysmorphic features or developmental delay
• IGF-1 and a bone age radiograph where short stature rather than low weight is the dominant problem
• Echocardiogram if a murmur or signs of heart failure are found

Management

Management is nutritional and behavioural first, and multidisciplinary throughout - health visitor, GP, infant feeding specialist, paediatric dietitian, speech and language therapy, paediatrician, and children's social care where there are safeguarding concerns.

Feeding support

• Breastfeeding support from a specialist - correcting latch and positioning, increasing feed frequency, and expressing where necessary
• Formula feeding advice - correct reconstitution, appropriate volumes and teat flow
• Regular mealtimes eaten together as a family, with the child in a supportive seated position
• Limit meals to around 30 minutes, and avoid prolonged grazing between them
• Avoid coercion, force-feeding and distraction techniques - pressure at mealtimes reliably makes feeding aversion worse
• Reduce excess milk and juice, which suppress appetite for solids in toddlers

Increasing intake

• Food fortification first - adding butter, cheese, cream, full-fat milk or oil to ordinary foods to raise energy density without increasing volume
• Oral nutritional supplements only under dietetic supervision, and as an addition to food rather than a substitute for it
• Enteral tube feeding reserved for children with severe faltering growth, an unsafe swallow, or where other approaches have genuinely failed - and only after a multidisciplinary decision with the family
• Treat the underlying cause wherever one is found, since nutritional support alone will not fix untreated coeliac disease or a large ventricular septal defect

Monitoring

Complications and prognosis

• Micronutrient deficiency - iron, zinc and vitamin D in particular, with iron deficiency anaemia further impairing appetite and development
• Impaired immune function with recurrent infection
• Developmental and cognitive effects - measurable but generally modest, and concentrated in severe and prolonged undernutrition
• Reduced final adult height where the problem is severe or persists through periods of rapid growth
• Entrenched feeding aversion and mealtime conflict, which can outlast the original problem by years
• Parental anxiety and guilt, which are considerable and are worsened by frequent weighing and by the older terminology

The prognosis for the great majority is good. Most children with faltering growth from inadequate intake gain weight and return towards their expected centile once feeding is addressed practically, and the developmental consequences in that group are small.²

The children who do badly are those whose underlying disease is missed, and those whose faltering growth is the visible part of neglect. Both are found by the same means: measure accurately, take a proper feeding history, examine the child fully, watch a feed, and be curious about the social circumstances rather than assuming the problem is purely nutritional.