Trends in the publication of infantile hypertrophic pyloric stenosis in Africa: A systematic review

INTRODUCTION

Infantile hypertrophic pyloric stenosis (IHPS) is an anomaly whose etiology is not clear, but there is global variation in its epidemiology. It is characterized by progressive hypertrophy of the circular muscles of the pylorus with consequent obstruction of the gastric outflow, mostly in neonates and infants under the age of 1 year.^[1] The resulting gastric outlet obstruction produces a clinical manifestation of postprandial, projectile, non-bilious vomiting with associated palpable epigastric abdominal mass.^[2-4] IHPS is highly prevalent in the Caucasian population with an incidence of 5/1000 newborns^[5-7] in comparison to the African population in which it is rarer.^[8] Other well-documented risk factors include a male preponderance (especially firstborn male) with a 4–5 times higher risk than females, young maternal age, and positive family history of IHPS.^[5,6] Clinical diagnosis is usually made following a palpable mass in the epigastrium during feeding; however, this may sometimes be difficult to appreciate. Ultrasonography of the abdomen and contrast study of the upper gastrointestinal tract have proved very valuable in identifying the olive-shaped mass in the epigastrium.^[1] Following adequate pre-operative resuscitation to correct fluid and electrolyte abnormalities, Ramstedt’s Pyloromyotomy^[9] is often the surgical treatment of choice with a good post-operative outcome.

The relatively rare nature of this anomaly in the African population has made literatures from Africa to be very limited on the epidemiology, etiopathogenesis, management, and clinical outcome of IHPS. This systematic review sought to evaluate the trends of reporting IHPS from all publications emanating from various centers in Africa.

MATERIAL AND METHODS

The guidelines provided by the 2009 statement of the Preferred Reporting Items for Systematic Reviews and Meta-analysis^[10] were used to carry out a systematic review of all literatures on IHPS emanating from Africa within the last seven decades from January 1951 to December 2018. Searches were conducted of all articles in the databases of African Index Medicus, OvidSP, PubMed, and African Journal Online added with Google Scholar Search using “Infantile hypertrophic pyloric stenosis” AND “Africa” OR “Congenital hypertrophic pyloric stenosis” AND “Africa.” Full evaluation of each article was performed to identify those that reported IHPS in Africa. The relevance of these articles was examined and inclusion criteria were case reports, case series, and original articles. Excluded were review articles, commentaries, letters to the editor, and any other publication that did not provide adequate patients’ information. Articles that were published in languages other than English language were translated to English language using Google translator. Recorded from these publications were information on the type of article, trend of reporting, the country of publication, demographic details of the patients, number of cases, clinical presentation, pre-operative management, type of surgical approach, and the outcome of management. The trend of reporting was examined by comparing the publications in the first 35 years of the study (1951–1985) with the ones published in the following 33 years of the study (1986–2018). Analysis of data was performed using Microsoft Excel Spreadsheet 2010. Categorical variables were summarized using frequencies and proportions, while continuous variables were summarized using the mean.

RESULTS

Following the database search for IHPS in Africa, a total of 62 publications were obtained with 59 publications meeting the criteria for the study after screening. A total of 40 articles were evaluated fully for the study after 19 duplicates were excluded [Figure 1]. Of these, 16 (40.0%) articles were published within the first three and a half decades of the study^[11-26] [Table 1a] from 1951 to 1982 (Group A) and 24 (60.0%) were published in the last three and a half decades [Table 1b] from 1983 to 2018 (Group B).^[9,27-49] There were 14 (35.0%) case reports^{,[12,14-17,19,21,24,32-34,43-45]} of which eight (20.0%) were published within the first three and a half decades^{[12,14-17,19,21,24]} and six (15.0%) articles were published later.^{[32-34,43-45]} Seven (17.5%) articles were case series^{,[11,18,20,22,23,36,41]} all but two (5.0%)^[36,41] were published within the first three and a half decades, 15 (37.5%) articles were retrospective studies^{[9,13,25-31,35,37,39,40,46,48]} with three (7.5%) published in the first three and a half decades^[13,25,26] of the study, and 11 (27.5%) in the last three and a half decades^{.[9,27-31,35,37,39,40,46,48]} There were four (10.0%) prospective studies,^{[38,42,47,49]} all of which were published in the last three and a half decades of the study. Eleven (27.5%) articles emanated from Nigeria^{,[11,20,23,26,31,33-35,43,45,48]} 6 (15.0%) from South Africa,^{[15,18,24,29,37,39]} 5 (12.5%) from Egypt,^{[32,38,42,47,49]} 4 (10.0%) each from Tanzania^[9,17,28,44] and Zimbabwe,^{[12,13,21,22]} 3 (7.5%) from Uganda,^[14,16,19] 2 (5.0%) each from Cameroon,^[41,46] and Ethiopia^[27,40] whereas 1 (2.5%) each were published from Republic of Benin,^[36] Ghana,^[30] and Sudan.^[25]

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Figure 1:

Flowchart for article selection for the study.

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A total of 811 patients diagnosed and managed for IHPS were reported with an age range of 1 day–1 year and an incidence that ranged from 1 in 550 to 12.9 in 1000. Sex incidence was reported by 35 studies (87.5%) and there were 621 boys and 114 girls (M:F – 5.5:1). All the patients were breastfed and the average birth rank incidence was 42.4% among firstborn, 19.5% in second, 15.2% in third, 13.2% among fourth, and 10.0% among fifth born and beyond. Vomiting was the most common clinical presentation reported by 20 (50.0%) articles, this is followed by visible peristalsis 19 (47.5%) and palpable tumor reported by 17 (42.5%) articles. Twelve (30.0%) articles reported electrolyte problems, of these, only one article (2.5%) had normal serum electrolytes. The reported electrolyte derangements included hypokalemia and metabolic acidosis reported by 7 (17.5%) articles each, hypochloremia by 6 (15.0%), and hyponatremia by 5 (12.5%).

Associated congenital anomalies were reported in five (12.5%) studies, with an incidence of 6.9–20% occurring in a total of 28 patients. Inguinal hernias were the most common associated anomalies (11 patients) reported by all the studies. Others included congenital heart defects (5 patients), neural tube defects, undescended testis, Down’s syndrome, and craniosynostosis in 2 patients each, rectovaginal fistula, cleft palate, and Meckel’s diverticulum in one patient each. Thirty-five (87.5%) studies reported the operative procedures performed on the patients. Of these, all but three (7.1%) studies reported that open surgery was adopted to perform the pyloromyotomy. The remaining three studies reported laparoscopic pyloromyotomy using endo umbilical approach.^[39,47,49] Of the open surgical approach, right upper transverse approach was most commonly used, other approaches included circumumbilical (3, 7.5%), supraumbilical (3, 7.5%), and upper midline (1, 2.5%). Mucosal perforation was reported by 8 (20.0%) studies with a range of 2.5–10.9%. Other post-operative complications reported included surgical site infection in 7 (17.5%) studies, gastroduodenal tear in 2 (5.0%), hemorrhage and incisional hernia in 1 (2.5%) study each.

Mortality was reported in 26 (65.0%) studies with a range of 1.8–50% and a mean mortality rate of 5.2%. The mean duration of hospital stay ranged from 2 to 13 days.

DISCUSSION

CONCLUSION

The studies indicate that there is a gradual departure of publications from descriptive studies to comparative studies on newer modality of management of IHPS after the awareness about IHPS had been established. There were no publications on the etiology of IHPS to evaluate the interplay of genetics and environmental factors in Africans. Therefore, adequate funding should be provided by stakeholders to intensify research in this area as it relates to Africans. There is also the need to introduce more recent methods of management and to assess the outcome of these in Africa. Emphasis should also be made to publish these articles in indexed journals for more visibility and accessibility.