Can a conservative approach to the treatment of hypertrophic pyloric stenosis with atropine be considered a real alternative
to surgical pyloromyotomy?
- 1 The Hull York Medical School, University of York, York, UK
- 2 Centre for Reviews and Dissemination, University of York, York, UK
- Correspondence to Anita Erika Mercer, The Hull York Medical School, John Hughlings Jackson Building, University of York, York YO10 5DD, UK;
- Received 14 January 2013
- Revised 25 February 2013
- Accepted 26 February 2013
- Gastrointestinal system diseases
- Stomach diseases
- Gastric outlet obstruction
- Pyloric stenosis
- Pyloric stenosis hypertrophic
A 6-week-old boy with projectile non-bilious vomiting is diagnosed with infantile hypertrophic pyloric stenosis (IHPS). His parents are advised that surgical pyloromyotomy is the gold standard treatment for their son's condition, yet they are not keen for him to have an operation and a general anaesthetic. When looking for alternatives, you come across medical therapy of IHPS with atropine. You wonder if this treatment really works?
Structured clinical question
In a 3-week-old infant with hypertrophic pyloric stenosis [patient], does therapy with atropine [intervention] achieve sufficient resolution of the condition so as to avoid the need for surgical pyloromyotomy [outcome]?
We searched the Ovid MEDLINE and EMBASE databases, using the search criteria ‘pyloric stenosis’ and ‘atropine’, and limiting the results to ‘children’. These searches retrieved 41 individual articles, 14 of which were initially considered relevant. However, four studies were subsequently excluded from further analysis as they provided insufficient data on patient characteristics, treatment dosage or duration of treatment. The remaining 27 publications were excluded as they were review articles or concerned atropine use in an anaesthetics context. Further searches of SumSearch and TripDatabase did not retrieve any additional publications. The 10 selected articles are summarised in table 2.
Pyloric stenosis is a common condition in early infancy that presents with projectile non-bilious vomiting with a characteristic feature of hunger after vomiting, Pathophysiologically, there is hypertrophy of the pyloric muscle causing gastric outlet obstruction. Although there is some uncertainty as to the underlying mechanism, the pyloric muscle seems to be unable to relax. Following hydration and electrolyte imbalance correction, the most accepted treatment of this condition worldwide is by surgical pyloromyotomy. However, this involves a general anaesthetic in a small infant and carries certain surgical risks, including wound infection, mucosal perforation and adhesions. The operation can be performed either as an open procedure or laparoscopically, and postoperatively the child can usually be fed within 6 h and discharged within 2 days of surgery.
There are no randomised controlled trials addressing the question of whether therapy with atropine can achieve sufficient resolution of pyloric stenosis to avoid the need for surgical pyloromyotomy. Our search retrieved only a number of case series and a retrospective cohort study, both of which are low-level evidence. The risk of bias in these studies was assessed using criteria from a Health Technology Assessment report.11 All identified studies were small in participant numbers and methodologically had a potentially high risk of bias. (Six out of the 10 studies would be at least of ‘satisfactory’ quality if their authors had included confirmation of consecutive and prospective patient recruitment. In the absence of such information, the quality rating of this evidence had to be downgraded to ‘poor’, as no assumption could be made as to their actual risk of bias regarding patient selection.) This is significant, as a high risk of bias may inflate the reported success rates. The identified studies reported heterogeneous treatment regimens with wide ranges for treatment duration and dosing. It was therefore not possible to determine which exact regimen was the most effective option.
The data of all 10 studies were pooled in a meta-analysis, the results of which seemed to be that conservative therapy with atropine works in 88% of cases (see Figure 1). However, bearing in mind the poor quality of evidence, the meta-analysis was exploratory and probably less precise than the numbers suggest. Publication bias in favour of smaller, potentially more successful studies is unlikely, as figure 1 shows an even distribution of small and large studies with similar success rates. The study by Riccabona et al 10 reported only a 32% success rate with oral atropine therapy. However, this particular study was very unclear regarding the amount of atropine used, and the small success rate may have been due to dosages below a therapeutic level. Even the study most critical of conservative treatment of IHPS, whose authors would not recommend conservative therapy in settings where surgery is possible due to length of treatment and lower success rates when compared to surgery, reported a success rate for the conservative approach of 75%.5 Furthermore, known side effects of atropine therapy, such as mild facial flushing, increased alanine aminotransferase and tachycardia, appear to be rare and not serious.
However, the success rate of medical treatment with atropine is lower than that of surgery (which is at least 95%5), and it requires longer hospitalisation because of intravenous therapy and the need to continue oral atropine after discharge, the latter requiring a lot of parental effort. Additionally, due to the lower success rate, patients whose symptoms do not resolve with atropine therapy, may then have to undergo surgery when their health has deteriorated even further. Surgery, on the other hand, carries the usual risks of a general anaesthetic, a risk of mucosal perforation, wound infection and adhesions.2 At present, there are no studies comparing the long-term outcomes of surgery and atropine therapy in the treatment of IHPS.
The available evidence therefore indicates that a conservative approach to the treatment of hypertrophic pyloric stenosis with atropine should only be considered as an alternative to surgical pyloromyotomy where longer hospital stays and a reduced success rate are acceptable. This would apply to patients who are unsuitable or high risk for surgery and to areas of the world where surgery on small infants is unsafe.
Clinical bottom line
▸ Conservative management of infantile hypertrophic pyloric stenosis with atropine can be effective in approximately six out of seven cases but has a lower success rate and longer duration of therapy than surgery. (Grade B)
▸ In light of the available evidence, atropine therapy may only be a possible alternative to pyloromyotomy for patients unsuitable or at high risk for surgery, and in areas of the world where surgery on small infants is unsafe. (Grade B)
Contributors AEM conducted the database searches, appraised the identified evidence and wrote the draft for this submission. She is the guarantor. RP supervised her work and carried out the meta-analysis.
Competing interests None.
Provenance and peer review Commissioned; internally peer reviewed.