and Spencer W. Beasley2
(1)
Department of Urology, Royal Children’s Hospital, Melbourne, Australia
(2)
Paediatric Surgery Department Otago, University Christchurch Hospital, Christchurch, New Zealand
Abstract
This chapter is a description of how to assess a baby with suspected pyloric stenosis.
The mechanical causes of non-bile-stained vomiting in children correlate closely with age (Fig. 7.1). Hypertrophic pyloric stenosis occurs between 3 and 12 weeks of age (most commonly between 4 and 7 weeks), while intussusception is most frequent in older infants between 3 months and 2 years. Gastro-oesophageal reflux, which is extremely common in the first few weeks of life, becomes progressively less so with time.
Fig. 7.1
Surgical causes of non-bile-stained vomiting
In pyloric stenosis, there is postnatal thickening of the circular muscle of the pylorus which results in gastric outlet obstruction. As the narrowing progresses, the stomach becomes hypertrophied, producing visible gastric peristalsis.
The vomitus contains no bile because the obstruction is proximal to the bile duct opening (Fig. 7.2).
Fig. 7.2
The pathology of pyloric stenosis (a) compared with gastro-oesophageal reflux (b). The hypertrophied pylorus causes outlet obstruction of the stomach and prevents bile from reaching the stomach
The cardia of the normal child acts as a sphincter to prevent retrograde flow of stomach contents up the oesophagus. In children with gastro-oesophageal reflux, there is no barrier to prevent this flow, with consequent free regurgitation of feeds.
Clinical Features
Non-bile-stained vomiting in an infant is caused most commonly by a feeding problem (Table 7.1). Where the mother is inexperienced or the baby is greedy, excessive feeding leads to gastric distension and vomiting. This problem is diagnosed by a careful history and observation of the feeding technique. The major challenge to the physician, however, is separating the trivial causes of vomiting (like excessive feeding) from more sinister diseases, such as systemic infection or mechanical obstruction and reflux. One simple way to approach the diagnosis is to follow the algorithm outlined in Fig. 7.3.
Table 7.1
Causes of non-bile-stained vomiting in infancy
Feeding problem | Greedy, ‘healthy’ baby and/or inexperienced mother |
‘Hidden’ infection | Systemic illness – vague systemic symptoms and signs in an ‘unwell’ baby |
Meningitis | |
Urinary tract infection | |
Gastroenteritis | |
Gastro-oesophageal reflux | Mechanical problem – ‘healthy’ baby with or without failure to thrive |
Pyloric stenosis | Mechanical problem – ‘healthy’ baby with or without failure to thrive |
Inguinal hernia | Intermittent pain and/or mechanical obstruction |
Fig.7.3
A simple algorithm which is useful in assessing any infant with non-bile-stained vomiting
The History
Knowledge of the patient’s age and a careful history usually will provide clues as to the correct diagnosis before the physical examination is commenced, since the commonest causes are strongly age-dependent (Fig. 7.1). The history should be aimed at answering the following questions:
1.
Is the infant well and active, and keen to take feeds? Reason: to separate mechanical or feeding problems from septic causes of vomiting.
2.
What is the duration, nature and timing of the vomiting? Reason: to separate gastro-oesophageal reflux from pyloric stenosis.
3.
Is the vomiting forceful? Reason: strongly projectile vomiting is suggestive of pyloric stenosis (with secondary gastric hypertrophy).
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