Approach

Most disorders are multifactorial in nature, and their evaluation is best approached by an interdisciplinary team, which may include a pediatrician for general and neurodevelopmental assessment, a pediatric gastroenterologist, a dietitian, a behavioral psychologist, a speech and language therapist, and an occupational therapist.[2]

Diagnosis is usually made on clinical grounds. In the presence of a normal clinical exam, with normal neurodevelopmental assessment and normal anthropometric measurements, diagnostic tests are rarely needed.

General history

Prenatal history should be reviewed, checking for results of the prenatal ultrasound scan and signs of possible neuromuscular problems (e.g., polyhydramnios, decreased fetal movements). Prematurity and intrauterine growth restriction increase the risk of subsequent feeding disorders, and the gestational age, birth weight, subsequent weight gain, and measurements of linear growth (length and head circumference) should be reviewed carefully. Perinatal events such as time taken to pass meconium and initial feeding regimen (type of milk, duration of feeding, feeding interval) should be elicited.

It is important to review growth from birth and relate this to any changes in feeding. For example, infants with celiac disease may not gain weight following weaning.

Evidence of previous illnesses and hospitalizations should be sought. Concurrent illness may impact on an infant's ability to feed (e.g., poor respiratory reserve in patients with congenital heart disease or chronic lung disease). Medical interventions such as tracheal intubation or nasogastric feeding are postulated to increase sensory aversion to feeding.[3] Problems with feeding may also be the presenting complaint of more complex conditions such as cerebral palsy, which become apparent only as the infant matures. Regular hospital attendance can also be evidence of stress within a family, which can result from or lead to difficulties with feeding.

Elicit the infant’s surgical history, to include correction of oropharyngeal and gastrointestinal (GI) tract abnormalities, GI tract resection, stoma formation, and neonatal cardiac surgery.

Enquire about symptoms of:

  • Vomiting

  • Abdominal pain, distension, or colic

  • Constipation or diarrhea

  • Postural changes during feeds

  • Respiratory problems

  • Atopy.

Recurrent vomiting with a normal physical exam and normal growth is common in uncomplicated GERD.[35] Vomiting associated with abdominal pain, colic, and constipation may be seen in both GERD and cows' milk protein allergy (CMPA). A sudden onset of vomiting in a previously well child may be a symptom of other conditions, notably infections such as meningitis and urinary tract infection, which should be considered and ruled out first. Bilious vomiting in a term infant indicates an upper GI obstruction usually requiring surgical intervention. However, this is a common finding during the establishment of enteral feeding in premature neonates, and is normally managed medically in this population. Simple regurgitation without any other symptoms is physiologic and does not require either investigation or treatment.[36][37]

Colic is defined as paroxysms of irritability or crying lasting >3 hours per day and occurring >3 days per week.[38] Colic can occur in isolation, or concomitantly with GERD or CMPA.[39] Infants who are reported to have symptoms of colic have more disorganised feeding behaviors, less rhythmic sucking, and lower responsiveness during feeds.[39] 

Coughing or retching at mealtimes may indicate difficulties with swallowing and possible aspiration.[8] Chronic aspiration can lead to recurrent pneumonia, even in the absence of these symptoms; this is particularly the case if the infant is neurologically impaired.[8][35][40][41] Recurrent cough, wheeze, stridor, or hoarseness of cry can be associated with GERD.[35] Apnea and bradycardia with feeds may reflect either a central problem with breathe-suck-swallow coordination, or may reflect GERD.[8] Increased respiratory rate and increased work of breathing at rest will impair ability to feed.[8] Poor coordination, weak suck, and short sucking bursts are described in infants with severe bronchopulmonary dysplasia.[24]

Posture changes during feeds may indicate discomfort.[2] Arching the neck and turning the head to one side may be seen in Sandifer syndrome, an uncommon manifestation of severe GERD. 

Rashes (especially eczema), rhinitis, diarrhea, and constipation may be symptoms of CMPA.[42] Watery stool, abdominal distension, and flatulence suggest lactose intolerance.

Family history of atopy or feeding problems should be sought. Families with atopy, particularly those with CMPA, are more likely to have children affected with conditions such as CMPA and eosinophilic esophagitis.[43] A familial pattern is seen in pyloric stenosis and in celiac disease.[44][45] The risk of feeding disorders is increased if an infant’s parents had feeding problems in their own infancy.[46] 

Feeding history and observation of feed

A detailed feeding history should be sought, ideally with the help of a pediatric dietitian. Feeding history should include:[8]

  • Diet since birth

  • Amount of feed (looking for excessive or inadequate intake, errors in the preparation of formula feeds)

  • Types of feed (including changes in formula, and introduction of solids)

  • Feeding interval

  • Time taken to feed. Efficient feeding usually takes <30 minutes per feed.

Where breastfeeding is the exclusive mode of feeding, details about latching on, awareness of milk supply, time spent feeding, and nipple pain should be elicited. Breastfeeds commonly take 15 to 20 minutes, although can range from 10 to 45 minutes on some occasions.

Age at weaning and amount of solids taken during a day should be ascertained in older infants, because decreased solid intake has been associated with faltering growth in this group.[47]

Feeding should be observed for a full 20 minutes to gain an accurate impression of the infant's feeding pattern.[8] The infant should be observed to assess response to cues, level of infant alertness, breathe-suck-swallow coordination, and quality of feed (length, quantity, associated symptoms). The interactions between the caregiver and the infant should be observed, looking for positive interactions (maintaining eye contact, offering praise for good behaviors, reciprocal vocalization, responding to satiety cues) and negative interactions (forced feeding, bribing, distracting).[40] 

Behavioral and social issues

A behavioral component is found in 80% of feeding disorders, and is the primary cause of the feeding disorder in 10% of cases.[3][4]

Diagnosis is primarily obtained from the history (food aversion, food refusal, stressful mealtimes). A feed diary documenting these symptoms may be extremely useful in the initial assessment of an infant with a feeding disorder.

An observed feed over 20 minutes to assess caregiver-infant interactions supports the diagnosis. Positive interactions include positive reinforcement for accepting food, good eye contact, and praise. Negative interactions include attempting to force the infant to feed, coaxing the infant, or using distraction techniques during mealtimes.[6][48] Overall responsiveness and temperament of the infant should be assessed as well.[8] Normal infants can cry up to an average of 2 hours per day, and the feed diary may be helpful to determine the length of irritability and any temporal association with feeds.

An understanding of any stresses or mental illness within the family will be helpful both in making the initial diagnosis and in optimizing its management. Feeding disorders in infants have been associated with depression in adult caregivers.[49] Caregivers may report stressful mealtimes due to the length of time taken to feed, behavior of the child during feeding, or difficulty in giving adequate amounts or variety of food.[7][8][41] An early feeding disorder can be compounded by abnormal learned behavioral responses to these stresses.[7]

Clinical exam

Careful measurements of weight, length, and head circumference should be plotted on appropriate charts and compared with growth from birth.

The symmetry of the infant's face and jaw, lips, and palate, and the rhythm and strength of non-nutritive and feeding suck should be assessed to rule out craniofacial abnormalities such as Pierre Robin sequence.[8] An open-mouthed posture may reflect nasal or pharyngeal obstruction.[8] Tonsillar hypertrophy should be considered if mouth breathing or stertorous (snoring) breathing is heard.[8] Tongue-tie has been associated with suckling difficulties in breastfed infants.[28]

[Figure caption and citation for the preceding image starts]: Infant with tongue-tie (ankyloglossia)Shutterstock [Citation ends].com.bmj.content.model.Caption@7f12e9de[Figure caption and citation for the preceding image starts]: An infant with Pierre Robin sequenceReproduced from https://pubmed.ncbi.nlm.nih.gov/22300418/ under a CC BY 2.0 license; no changes have been made to the image [Citation ends].com.bmj.content.model.Caption@4f566b54

Rashes (especially eczema) may be a sign of CMPA.[42]

Neurodevelopmental assessment is of particular importance. Feeding disorders are seen in up to 80% of children with neurodevelopmental delay.[3] Failure to achieve feeding milestones may be the presenting sign of more global developmental delay. Attention should be paid to the infant's posture, position during feeds, truncal tone, and movement. Drooling may be a sign of difficulty swallowing. The infant's response to sensory stimuli may also give more clues about developmental issues.[8]

Tests

Often feeding problems can be diagnosed from history, feeding assessment, and clinical exam, and no tests are required. Conditions that can be diagnosed clinically include simple overfeeding, prematurity, GERD, behavioral issues, and some craniofacial, neurologic, and genetic conditions. Investigations may be required to assess for complications and to guide management.

Trial of dietary changes

Diagnosis of CMPA is confirmed by exclusion of cows’ milk from the diet for 2 to 4 weeks, followed by a rechallenge with cows milk protein after resolution of symptoms. Recurrence of symptoms after the cows’ milk challenge confirms the diagnosis. If symptoms fail to improve with dietary modification, the original diagnosis should be reconsidered.[42] 

Lactose intolerance is diagnosed by performing a therapeutic trial of lactose-free feeds. Hypoallergenic formula preparations are available that are suitable for use in infants with either lactose or cows' milk intolerance, which is helpful given the overlap of symptoms in these disorders.

Laboratory tests

Symptomatic infants with suspected celiac disease should be screened by measuring immunoglobulin A (IgA) antibodies against tissue transglutaminase and total serum IgA.[50]

Radioallergosorbent testing to cows’ milk protein or skin prick testing can support the diagnosis of CMPA, but must be interpreted in the context of the patient’s history and cows’ milk challenge response. Negative test results do not exclude CMPA.[42] 

A fresh stool sample can be tested for fecal-reducing substances in suspected lactose intolerance. A positive result confirms the diagnosis.

Chest x-ray

Performed when aspiration is suspected. Chronic aspiration can lead to recurrent pneumonia, even in the absence of any symptoms of regurgitation or coughing; this is particularly the case if the infant is neurologically impaired.[8][35][40]

Upper GI contrast study

Used to confirm or exclude anatomic abnormalities.[35]

Videofluoroscopic swallowing assessment

This test provides dynamic imaging of oral, pharyngeal, and upper esophageal swallowing phases.[8] It can provide information about strength and coordination of muscles in the oropharynx, as well as presence and timing of aspiration. This information is useful to determine optimal feeding position, rate of feeding, and food texture.

Fiberoptic endoscopic evaluation of swallowing with sensory testing (FESST)

FESST may be useful to determine pharyngeal swallowing function. It does not provide visualization of the oral phase of swallowing, because the endoscope is passed transnasally.[8][25] FESST is radiation-free and is generally well tolerated, and can be repeated if needed. It is a highly specialized test, usually available only in tertiary centers. 

Upper GI endoscopy

Referral for upper GI endoscopy and biopsy should be considered for children with GERD if there is feeding aversion and a history of regurgitation.[36] This test can distinguish between GERD and eosinophilic esophagitis. Duodenal biopsy can confirm a diagnosis of celiac disease.

Esophageal 24-hour pH study/combined esophageal pH and impedance monitoring

Esophageal pH study or combined esophageal pH and impedance monitoring can be helpful to correlate symptoms with episodes of acid reflux.[35] Accurate parental reporting of symptoms is crucial.[35] Esophageal pH studies cannot detect reflux episodes with pH >4.[35]

Impedance monitoring detects episodes of gaseous or liquid reflux by monitoring distension of distal esophagus. This test should be considered in patients with associated neurologic or neuromuscular problems, suspected recurrent aspiration pneumonia, or unexplained apneas.[36] Impedance monitoring can detect nonacidic reflux (pH ≥4).[35] It may be particularly helpful to detect reflux in premature and very young infants where feeds are frequent and nonacidic reflux is more common.[15] 

Other specialized investigations

Other tests such as genetics assessment or echocardiography will be determined by the suspected clinical syndrome. Many patients with complex needs, such as infants with cleft lip and palate, will have been under the review of multidisciplinary teams since birth.[51]

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