Value of ultrasound in differentiating causes of persistent vomiting in infants

A prospective study of abdominal ultrasound was undertaken in 100 consecutive infants who presented with a history of persistent vomiting aged 5 to 90 days. Each infant had a 'test feed' followed by an ultrasonographic scan of the pylorus at the cotside. On test feeding a palpable tumour was evident in 38 infants. On real time ultrasound using the criteria for diagnosing pyloric stenosis, these 38 infants as well as six others were documented as having pyloric stenosis. In the other 56 patients the vomiting settled in six and a barium examination was performed on the remaining 50. This confirmed gastro-oesophageal reflux in 46, two of whom had an associated hiatus hernia, one with a duodenal malrotation, and three were reported as normal. Ultrasound of the abdomen is an accurate, reliable, and rapid screening method to differentiate the causes of severe vomiting in infancy. examination except that it will confirm the diagnosis and document the size of the hypertrophied muscle. The group of patients that will, however, benefit from an ultrasound examination are young infants who present with severe vomiting but with no palpable mass on initial test feeding. The diagnosis may well be infantile hypertrophic pyloric stenosis but could be due to differing conditions associated with vomiting in infancy. Our aims in this prospective study were firstly to confirm that pyloric muscle dimensions are an accurate indicator of underlying pyloric stenosis with no evidence of false positive or false negative results. Secondly, to find whether by using this ultrasound technique one can rapidly and reliably exclude pyloric stenosis at the cotside before deciding whether radiological methods are required to identify other causes of vomiting in infancy. Department of Paediatrics, Altnagelvin Area Hospital, Londonderry, Northern Ireland M D Rollins M D Shields R J M Quinn M A W Wooldridge Correspondence to: DrM Rollins, Ulster Hospital, Dundonald, Belfast BT16 ORH, Northern Ireland. Accepted for publication 3 July 1990 Since the demonstration by Teele and Smith in 1977 of the ultrasonographic appearance of infantile hypertrophic pyloric stenosis on static B scan1 several papers have been published assessing the accuracy and predictive value of this technique. With the widespread use of high resolution real time equipment this technique has now proved much easier, with greater visualisation and assessment of the pyloric region. In the past many of the infants exposed to abdominal ultrasound will have presented with the classical history of projectile vomiting, visible gastric peristalsis, and a palpable tumour on test feeding thus indicating the presence of the underlying pyloric stenosis. These patients will not necessarily benefit from a sonographic Methods The study was carried out in the Paediatric Unit of Altnagelvin Area Hospital which serves the population of Londonderry and adjacent areas of Northern Ireland. Between 1 December 1986 and 30 June 1988 100 consecutive infants up to the age of 3 months were admitted to the infant unit with a history of severe persistent vomiting. None of these infants showed clinical evidence of associated infection or had a known metabolic disorder which may give rise to such vomiting. On admission a careful history was taken to establish the type and amount of feeds taken by each infant, the age of ofiset of vomiting, its frequency, and its relation to feeds. The baby's birth weight in relation to weight on admission was documented as well as a general assessment of the infant. Of the infants studied, there were