Tests
Tests 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 hydrolyzed 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
esophageal 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 neurologic or neuromuscular problems, patients with severe symptoms, and patients who have not responded to antireflux medication.[36][35] As a test for GERD, it has a sensitivity of 50% and a specificity of 82%.[35]
Initial assessment should be performed while off antireflux medication.
Does not detect reflux episodes with pH >4, which are common in infants, particularly premature infants.[15][35]
Result
GERD: an episode of acid reflux occurs where esophageal pH is <4 for 15-30 seconds; reflux index (percentage of time esophageal pH <4) is <12% in normal infants
upper gastrointestinal contrast study
Test
Used to confirm or exclude anatomic abnormalities.[35]
Result
possible abnormal anatomy (e.g., fistula, pouch, stricture, hiatus hernia, extrinsic compression of esophagus, malrotation); evidence of aspiration, evidence of reflux with retrograde flow into esophagus from stomach
esophageal impedance study
Test
Detects episodes of gaseous or liquid reflux by monitoring distension of distal esophagus. Impedance monitoring can detect nonacidic reflux (pH ≥4).[35]
Should be considered in patients with associated neurologic or neuromuscular problems.[36]
May be of particular use in detecting reflux in premature and very young infants where feeds are frequent and nonacidic reflux is more common.[15]
Available in specialized centers.
Result
GERD: episode of reflux corresponds to a drop in impedance to <50% baseline, starting in distal esophagus and moving progressively toward mouth
CXR
videofluoroscopic swallow
Test
To provide dynamic imaging of oral, pharyngeal, and upper esophageal 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 esophageal anatomy, which will be better seen with an upper gastrointestinal contrast study.[8]
Does involve radiation exposure.
Usually available only in tertiary centers or with specialist speech and language therapists.
Result
possible abnormal pharyngeal phase of swallowing
fiberoptic 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 visualization 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 esophagitis, esophageal strictures, and webs.
Distinguishes between GERD and the less common eosinophilic esophagitis (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 GERD if there is feeding aversion and a history of regurgitation, or if there is persistent faltering weight.[36]
May diagnose celiac disease following a positive tissue transglutaminase assay.
Result
eosinophilic esophagitis: inflammatory changes of esophageal mucosa, with predominantly eosinophilic infiltrate; GERD: vertical red lines in distal esophagus; celiac disease: villous atrophy and crypt hyperplasia
radioallergosorbent 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
Usually diagnosed by performing a therapeutic trial of lactose-free feeds.
Result
lactose intolerance: improvement of symptoms on diet
fecal-reducing substances
Test
A fresh stool sample will be positive for fecal-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 IgA
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