Investigations
Investigations to consider
temporary exclusion of cows’ milk protein
Test
Cows’ milk should be excluded from the infant’s diet for 2 to 4 weeks. Extensively hydrolysed formula is used for formula-fed infants. The mother eliminates cows’ milk protein from her diet if the infant is breastfeeding.
Symptoms usually improve substantially within 2 weeks if the diagnosis is correct.
Failure to respond to dietary modification should prompt reconsideration of the original diagnosis.
Result
feed intolerance: improvement of symptoms on new feed, recurrence of symptoms when cows’ milk reintroduced
oesophageal 24-hour pH study
Test
Useful in correlating acid reflux with symptoms, although accuracy depends on parental reporting.[35] Should be considered in patients with associated neurological or neuromuscular problems, patients with severe symptoms, and patients who have not responded to anti-reflux medication.[36][35] As a test for GORD, it has a sensitivity of 50% and a specificity of 82%.[35]
Initial assessment should be performed while off anti-reflux medication.
Does not detect reflux episodes with pH >4, which are common in infants, particularly premature infants.[15][35]
Result
GORD: an episode of acid reflux occurs where oesophageal pH is <4 for 15-30 seconds; reflux index (percentage of time oesophageal pH <4) is <12% in normal infants
upper gastrointestinal contrast study
Test
Used to confirm or exclude anatomical abnormalities.[35]
Result
possible abnormal anatomy (e.g., fistula, pouch, stricture, hiatus hernia, extrinsic compression of oesophagus, malrotation); evidence of aspiration, evidence of reflux with retrograde flow into oesophagus from stomach
oesophageal impedance study
Test
Detects episodes of gaseous or liquid reflux by monitoring distension of distal oesophagus. Impedance monitoring can detect non-acidic reflux (pH ≥4).[35]
Should be considered in patients with associated neurological or neuromuscular problems.[36]
May be of particular use in detecting reflux in premature and very young infants where feeds are frequent and non-acidic reflux is more common.[15]
Available in specialised centres.
Result
GORD: episode of reflux corresponds to a drop in impedance to <50% baseline, starting in distal oesophagus and moving progressively towards mouth
CXR
videofluoroscopic swallow
Test
To provide dynamic imaging of oral, pharyngeal, and upper oesophageal swallowing phases.[8] Most useful for defining pharyngeal physiology.[25]
Can provide information about strength and coordination of muscles in oropharynx.
May detect aspiration, needs to be interpreted in relation to timing of swallow.[8]
Does not allow full study of oesophageal anatomy, which will be better seen with an upper gastrointestinal contrast study.[8]
Does involve radiation exposure.
Usually available only in tertiary centres or with consultant speech and language therapists.
Result
possible abnormal pharyngeal phase of swallowing
fibreoptic endoscopic evaluation of swallowing with sensory testing
Test
May be useful to determine swallowing function, particularly the events surrounding the pharyngeal part of swallowing.
There is no radiation exposure. Does not provide visualisation of the oral phase of swallowing because the endoscope is passed transnasally.[8][25]
Not available in all hospitals.
Result
possible abnormal masses or secretions in pharynx and laryngeal vestibule; presence of aspirated material may be seen below the vocal cords
upper gastrointestinal endoscopy with biopsy
Test
To assess presence of oesophagitis, oesophageal strictures, and webs.
Distinguishes between GORD and the less common eosinophilic oesophagitis (associated with atopy and food allergy).[8][35] Biopsies should be taken, because the endothelium may look normal macroscopically.[35][60]
Upper gastrointestinal endoscopy should be considered for children with GORD if there is feeding aversion and a history of regurgitation, or if there is persistent faltering weight.[36]
May diagnose coeliac disease following a positive tissue transglutaminase assay.
Result
eosinophilic oesophagitis: inflammatory changes of oesophageal mucosa, with predominantly eosinophilic infiltrate; GORD: vertical red lines in distal oesophagus; coeliac disease: villous atrophy and crypt hyperplasia
radio-allergosorbent testing (RAST) to cows' milk protein
Test
May support diagnosis of cows' milk protein allergy, but positive result does not necessarily mean that an infant will be symptomatic.[42]
Result
cows' milk protein allergy: a positive result supports the clinical diagnosis
trial of lactose-free diet
Test
Lactose intolerance is usually diagnosed by performing a therapeutic trial of lactose-free feeds.
Result
lactose intolerance: improvement of symptoms on diet
faecal-reducing substances
Test
A fresh stool sample will be positive for faecal-reducing sugars in patients with lactose intolerance. Requires a fresh stool sample, as sugars degrade after 2-4 hours.
Result
lactose intolerance: positive
tissue transglutaminase (TTG) antibodies and total immunoglobulin A
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