Colonoscopy in Hong Kong Chinese children

Abstract

AIM: To investigate the safety and diagnostic yield of colonoscopy in Chinese children in whom the procedure is not often done.

METHODS: We conducted a retrospective review of all colonoscopies in consecutive children who underwent their first diagnostic colonoscopy from Jan 2003 to 2008.

RESULTS: Seventy-nine children (48 boys, 31 girls; mean age 9.2 ± 4.2 years) were identified and reviewed with a total of 82 colonoscopies performed. Successful caecal and ileal intubation rates were 97.6% and 75.6% respectively. Forty patients (50.6%) had a positive diagnosis made in colonoscopy and that included colonic polyps (23), Crohn’s disease (12), ulcerative colitis (1), and miscellaneous causes (4). 80% of polyps were in the rectosigmoid colon. All but one were juvenile hamartomatous polyps. The exception was an adenomatous polyp. The mean ages for children with inflammatory bowel disease (IBD) and polyps were 11.3 and 4.3 years respectively. There was no procedure-related complication.

CONCLUSION: Colonoscopy is a safe procedure in our Chinese children. The increasing diagnosis of IBD in recent decades may reflect a rising incidence of the disease in our children.

Key Words: Colonoscopy; Children; Inflammatory bowel disease; Colonic polyps

INTRODUCTION

The safety and effectiveness of colonoscopy in the investigation of lower gastrointestinal tract pathology in children has been established for more than 2 decades[1]. It remains to be a procedure that mandates highly specialized expertise and is usually performed in a tertiary referral center. Investigation of inflammatory bowel disease (IBD), whether for diagnosis or follow-up evaluation, and suspected colonic polyps are the most common indications for pediatric colonoscopy in European and North American society[2-5]. Population-based studies suggest the uneven distribution of IBD throughout the world with the highest disease rates in Caucasian countries[6]. It has been believed that the incidence of IBD in Chinese children is low and as a result pediatric colonoscopy is not as commonly done in the Chinese population as in Western countries. Recent reports suggested an increasing incidence of pediatric IBD in Western countries while it is unknown whether a similar increase happens in Chinese children as well[7-9]. In this study, we aimed to investigate the diagnostic yield and safety of colonoscopy, and the pathology pattern of our Chinese children who underwent this procedure.

MATERIALS AND METHODS

A retrospective review was conducted on all consecutive pediatric patients who underwent their first diagnostic colonoscopy during the period from January 2003 to 2008 in a tertiary referral center serving a population of 1.32 million. The data were collected from the hospital electronic database system which required prospective entry of all the patients who underwent endoscopic procedures. Our institution was the only center that provided a pediatric colonoscopy service in the region.

Demographic data, indications for colonoscopy, endoscopic findings, extent of the procedure and follow-up progress were analyzed. All the colonoscopy procedures were performed by a single endoscopist (Tam YH) using a pediatric videoscope (Olympus PCF 200, Tokyo, Japan) in the presence of an anesthetist. Each patient had bowel preparation of low residual diet for 3 d prior to examination followed by admission to our hospital one day before the procedure for anesthetic assessment and further bowel cleansing with either oral sodium phosphate or polyethylene glycol-based solution. The endoscopy suite was equipped with an anesthetic machine and the majority of pediatric patients had the procedure done under general anesthesia by orotracheal intubation with inhalation anesthetic agents. A few exceptions, usually being older children, were put under conscious sedation by anesthetists using a combination of agents including ketamine, midazolam and propofol. Mucosal biopsies were taken whenever indicated and polypectomy were performed by snare with electrocautery.

RESULTS

Seventy-nine children, being all ethnic Chinese, were identified and reviewed. These included 48 boys (61%) and 31 girls, aged from 21 mo to 16 years (mean = 9.2 ± 4.2 years, median = 10 years). The two most common indications were painless per rectal bleeding (n = 46, 58%) and suspected IBD (n = 23, 29.1%). Other miscellaneous indications included investigation for protein losing enteropathy, enteritis in immunocompromised patients, Graft-versus-host diseases after bone marrow transplant, iron deficiency anemia, change of bowel habit and strong family history of carcinoma of the colon with parental anxiety.

A total of 82 colonoscopies were performed in the 79 patients during the study period. All but 7 of the procedures were done under general anesthesia. Complete colonoscopy was successful in 80 procedures (97.6%). Ileal intubation was routinely attempted in patients with suspected IBD and was successfully performed in 22 out of 23 children (95.7%) investigated for IBD. Ileal intubation was attempted but failed in one patient with Crohn’s disease (CD) because of an edematous ileocaecal valve. Overall, ileal intubation was performed in 62 out of the total of 82 colonoscopies (75.6%). Three children had a repeat colonoscopy during the study period for recurrent colonic polyp, follow-up progress of CD and argon beam coagulation for multiple colonic haemangioma respectively.

Forty out of 79 patients (50.6%) had a positive diagnosis made in colonoscopy with or without biopsy. These included colonic polyps (n = 23), CD (n = 12), ulcerative colitis (UC) (n = 1) and other miscellaneous pathology (Table 1). Children diagnosed to have IBD were found to be significantly older than children with colonic polyps (11.3 ± 3.7 years vs 4.3 ± 1.9 years; mean age difference = 7.1 years; 95% CI: 5.2-9.0). Of the 12 patients diagnosed with CD, there were 7 girls and 5 boys. The only patient with UC was a girl.

Table 1 Indications and diagnoses of 79 children after colonoscopy.

Indications	Diagnoses	n
Painless per rectal bleeding (n = 46)	Colonic polyps	23
	Normal findings	23
Suspected IBD (n = 23)	Crohn’s disease	12
	Ulcerative colitis	1
	Normal findings	10
Miscellaneous (n = 10)	Eosinophilic enteritis	1
	CMV enteritis	1
	GVHD	1
	Multiple colonic haemangioma	1
	Normal findings	6

IBD: Inflammatory bowel disease; CMV: Cytomegalovirus; GVHD: Graft-versus-host disease.

Among the 23 children with polyps, there were 14 males and 9 females. Twenty two of them had solitary colonic polyp while 1 patient had 3 synchronous polyps at multiple sites. Of the 25 polyps, 20 (80%) were located in the rectosigmoid colon (Table 2). Therapeutic colonoscopic polypectomy was successful in all but 1 patient who had a huge polyp with a broad base at the transverse colon and partial resection was achieved during colonoscopy. The patient subsequently underwent elective laparoscopic-assisted bowel resection and pathology was confirmed to be juvenile polyp. Histological examination revealed all the polyps removed to be juvenile hamartomatous polyps except one which was tubular adenoma that developed in a child who presented with painless per rectal bleeding without any family history of colonic polyp or cancer. One child developed recurrent juvenile polyp 1 year afterwards and required a second colonoscopic polypectomy. There were no procedure-related complications including perforation, bleeding that required re-examination or checking of hemoglobin after procedure, and cardiopulmonary problems caused by general anesthesia or sedation. At a mean follow-up of 22 ± 16 mo, 2 patients died of complications after bone marrow transplant. None of the patients with normal colonoscopy findings had persistent symptoms that required a repeat colonoscopy or further radiological imaging to exclude any pathological conditions.

Table 2 Locations of the 25 colonic polyps in 23 children.

Locations	n (%)
Rectum	11 (44)
Sigmoid colon	9 (36)
Descending colon	3 (12)
Transverse colon	1 (4)
Ascending colon	1 (4)

DISCUSSION

Reports in Western countries have suggested a significant increase in the incidence of IBD in children over the last few decades[7-9]. The annual incidence rates in United Kingdom and North America were estimated to be 5.2 to 7.05 per 100 000 pediatric populations in recent reports[10,11]. IBD has been believed to occur rarely in Chinese children. However, a recent population-based study in North America did not find any difference in the incidence between Caucasian children and other racial groups including Asians[11]. The authors suggested changing environmental factors had played an increasingly important role in the pathogenesis of pediatric IBD.

Our institution serves a population of 1.32 million and is the only center to provide a pediatric colonoscopy service within the region. If we could assume all the newly diagnosed cases of childhood IBD in our region were captured by our study during the review period and based on the population census report of Hong Kong in 2006 that children aged 18 or less accounted for 20.3% population, we could estimate the annual incidence rate in our children to be 7- to 8-fold less than the figures in United Kingdom and North America. Epidemiological data of IBD in Chinese children is scarce. A study conducted two decades ago reported only 1 case of IBD out of 65 colonoscopies in our Chinese children over a six-year period[12]. We have previously reported 9 children (CD = 7; UC = 2) who were diagnosed and treated in our institution in 10 years from 1992 to 2002[13], while 13 cases (CD = 12; UC = 1) were diagnosed within 6 years in this study. The increase in diagnosis of childhood IBD in the most recent decade compared with our local data in the 80s and 90s may reflect a possible increase in incidence of the disease although attribution to changes in referral patterns cannot be excluded. A central register of pediatric IBD, which is lacking currently in our locality, is deemed necessary to accurately monitor the incidence of the disease in our children[14].

We reported a mean age of 11.3 years at the time of diagnosis and a higher incidence of CD over UC in our childhood IBD. The results are in keeping with data reported in Western countries[10,11,14-16]. Our finding of more instances of CD in female children was in contrast to the consistent findings of male predominance in Caucasian populations[10,11,14-16]. Female predominance of CD is noted in the adult population[17]. However, our small sample size does not allow us to make any conclusion about the gender predominance of IBD in Chinese children.

Our results of male predominance and mean age of 4.3 years in children with colonic polyps are in keeping with previous reports[18-22]. About 80% of the polyps were found in the rectosigmoid colon of our children and only 8% were proximal to splenic flexure. Our findings are similar to those reported from India and Netherlands[4,20,22]. Recent data in North America found more proximal polyps with 54% in the rectosigmoid colon and 32% proximal to the splenic flexure[21]. Genetic and environmental factors may likely account for the difference between races. Despite our small series, there was one case of adenomatous polyp in a child with a solitary polyp in the sigmoid colon. This finding agrees with others that adenomatous polyps do occur in children, though infrequently, and pancolonoscopy is indicated as the initial procedure for investigation of suspected colonic polyps in children in view of the neoplastic potential of an unidentified polyp[18,20,21].

Despite the small case volume, our reported rates of 97% and 75.6% in caecal and ileal intubation respectively compare well with other series[1-4]. We did not encounter any complications related to the procedure, in accordance with the universally low complication rates reported in pediatric colonoscopy[23]. All of our procedures were done by a single endoscopist. Concentration of expertise and experience helps to promote good clinical results. However, the small case volume remains to be a major limitation to training of next generations. In a prospective survey in United Kingdom, specialized pediatric centers perform a mean of 24 colonoscopies over a 4-mo period, which is over 5-fold of our volume[24]. Pediatric guidelines have been issued in North America to recommend the minimum number of procedures to be performed to acquire competency of skills[25]. Recommendations in Western countries may not be applicable in our locality. Rotation training in adult colonoscopy and virtual endoscopy training[26] may provide an alternative way of providing training in pediatric colonoscopy in Hong Kong.

COMMENTS

Background

Colonoscopy in children is a highly specialized endoscopic procedure that is not often performed in the Chinese population as inflammatory bowel disease (IBD), which is an important indication for this procedure, is quite rare in Chinese children. Data of the safety, indications and diagnostic yield of colonoscopy in Chinese children is rarely reported. In this study, the authors retrospectively reviewed all the Chinese children who underwent their first diagnostic colonoscopy in a tertiary referral center within a 6-year period.

Research frontiers

There were 79 children who underwent their first colonoscopy over 6 years in the authors’ institution that serves a population of 1.32 million and is the only center that provides this service in the region. The procedure was successfully completed in 97.6% of cases without any complications. Pathological conditions that could account for the symptoms were identified in 50% of cases by colonoscopy. The two most common positive diagnoses were colonic polyps in 23 children and IBD in another 13 patients.

Innovations and breakthroughs

The results found that there was an increase in the diagnosis of IBD by colonoscopy in the recent decade compared with our local data in the 1980s and 1990s. Data in Western countries have recently suggested an increase in the incidence of IBD in children. The authors’ findings suggest the possibility of a similar increase in the occurrence of this disease in Hong Kong Chinese children in whom the disease has been believed to be extremely uncommon for many years.

Applications

The findings suggested that establishment of a central registry for childhood IBD is strongly indicated to monitor its incidence in Chinese children.

Peer review

This is a retrospective cohort study of all pediatric patients undergoing colonoscopy at a tertiary centre over a 6 year period. Though it is a simple observational study of workload undertaken during this period, it does add background value with respect to identified pathologies in a predominantly Asian pediatric population.