Elsevier

The Lancet

Volume 354, Issue 9196, 18–25 December 1999, Pages 2101-2105
The Lancet

Articles
Infantile hypertrophic pyloric stenosis after pertussis prophylaxis with erythromycin: a case review and cohort study

https://doi.org/10.1016/S0140-6736(99)10073-4Get rights and content

Summary

Background

In February, 1999, a local US health department identified a cluster of pertussis cases among neonates born at a community hospital and recommended oral erythromycin for post-exposure prophylaxis for about 200 neonates born at that hospital between Feb 1 and Feb 24, 1999. We investigated a cluster of seven cases of infantile hypertrophic pyloric stenosis (IHPS) that occurred the following month among the neonates who had received erythromycin.

Methods

We obtained a masked, independent review of the IHPS ultrasonography diagnoses, calculated the monthly IHPS incidence, and compared index and historical (1998–99) IHPS cases with respect to several characteristics including erythromycin exposure. We used a retrospective cohort of infants born in January and February, 1999, to investigate further erythromycin exposure and development of IHPS.

Findings

An independent review confirmed the ultrasonographic diagnoses of all seven index IHPS cases. All index cases versus none of the historical IHPS cases had been given erythromycin for pertussis prophylaxis. The IHPS rate for infants born in the hospital in February, 1999, was 32·3 per 1000 liveborn infants, representing nearly a seven-fold increase over 1997–98 (relative risk 6·8 [95% CI 3·0–15·7]). Among infants born in January and February, 1999, erythromycin was associated with IHPS (absolute risk 4·5%, relative risk ∞ [1·7–∞]).

Interpretation

Neonates receiving oral erythromycin may have an increased risk of IHPS. The risks and benefits of erythromycin for neonatal pertussis prophylaxis should be re-evaluated, and caution should be used in defining risk groups for prophylaxis.

Introduction

Infantile hypertrophic pyloric stenosis (IHPS) is hypertrophy of the pyloric muscle that usually results in non-bilious, projectile vomiting. Symptoms of IHPS begin in most cases at about 3·5 weeks of age,1 although in rare cases symptoms may occur shortly after birth.2 Premature infants develop IHPS symptoms later than term infants.3, 5 IHPS affects about one to three infants per 1000 liveborn infants and affects about four to five times as many boys as girls.3, 6 Surgical treatment for IHPS is safe and effective.7 Although some reports have suggested a possible link between erythromycin and IHPS,8, 9 the cause of the disorder remains unknown.

In February, 1999, physicians diagnosed pertussis in six infants who were about 2 weeks of age and had been born that month in a community hospital in the USA. The source of the infection was presumed to be a staff member working in the nursery at the hospital. On Feb 25, 1999, the local health department recommended erythromycin prophylaxis for all infants born at the hospital from Feb 1 to Feb 24, 1999, based on the current American Academy of Pediatrics recommendations.10 The recommendation was extended to infants born in the last 2 weeks of January at the hospital and who had any pertussis symptoms. The community hospital has about 215 births per month, and is one of six maternity units in a metropolitan area of about 350 000 people.

In late March, paediatric surgeons at another hospital recognised that they had operated on seven infants with pyloric stenosis within a 2-week period, that all seven infants had been born in the community hospital, and all had been treated prophylactically with erythromycin. The hospital in which the surgery was done is one of two hospitals in the metropolitan area that have paediatric surgery services.

The state health department requested assistance from the Centers for Disease Control and Prevention. The county health department and the Centers for Disease Control and Prevention launched this investigation to assess the possible association between erythromycin prophylaxis and subsequent surgery for pyloric stenosis.

Section snippets

Case review

To validate the diagnoses, we did a masked review of ultrasonography scans for the seven IHPS cases originally identified at surgery, as well as for seven negative ultrasonography scans of the pylorus from the same hospital during the same period. The 14 ultrasonography scans were reviewed by a paediatric radiologist in another state who was unaware of the original readings. The reviewing radiologist marked each scan as either positive or negative for IHPS. The degree of agreement between the

References (24)

  • JA San Filippo

    Infantile hypertrophic pyloric stenosis related to ingestion of erythromycine estolate: a report of five cases

    J Pediatr Surg

    (1976)
  • H Stang

    Pyloric stenosis associated with erythromycin ingested through breastmilk

    Minn Med

    (1986)
  • Cited by (0)

    View full text