EXPERIENCE WITH COLONOSCOPY IN THE RIVERINE SOUTHWESTERN NIGERIA

Abstract

Background

Colonoscopy is useful for diagnosis, treatment and surveillance of anal and colorectal lesions. It affords a good, less invasive and tolerable way to see and access the large intestine.

Aim and Objective

To determine the indications, finding and diagnosis at colonoscopy in a riverine setting in Southwestern Nigeria.

Type of study

Descriptive cross sectional study.

Patients and Methods

Patients who presented in the State Specialist Hospital, Okitipupa and requiring colonoscopy in their management between January 2011 to April 2013 were included in this study. They were reviewed and their demographic and clinical data, indications for colonoscopy, the findings and the pathological diagnosis were entered in a proforma.

Results

Colonoscopy was done in 100 patients out of which seventy seven (77%) were males and 23 (23%) were females. The indications were frank lower gastrointestinal bleeding 55 (55%) chronic diarrhea (11%), chronic constipation10(10%), occult gastrointestinal bleeding (7.0%), lower abdominal and anal pain 4 (4.0%), queried anorectal cancer 3 (3.0%) and enterocutaneous fistula 1(1%).

Colonoscopic findings, include, normal finding 24(24%) colitis 24 (24.0%), hemorrhoid 20(20.0%), Anal fissure 16 (16.0%) colonic cancer 5 (5.0%), anorectal cancer 4 (4.0%), caecal cancer 2 (2.0%) faecal impaction 2 (2.0%), anal wart 2 (2.0%) , polyps 1 (1.0%) and anal fistula 1 (1.0%). The diagnostic yield was 76%.

Conclusion

Bleeding from the lower gastrointestinal tract was the commonest indication for colonoscopy and the most frequent pathology was amoebic in the riverine Southwestern Nigeria.

Introduction

Treatment of some rectal and colonic pathologies could be effected even during a diagnostic colonoscopy and could be safely carried out on out-patient basis.1,2

Surveillance colonoscopy is recommended for early detection of colorectal cancer for those at risk and as a post-operative monitoring procedure in order to detect recurrence early.2,3

Despite the need for colonoscopy in Nigeria, it is still not in common use, so not much work has been reported using this diagnostic tool4. This could lead to missed diagnosis with the attendant high morbidity and mortality. .

In order to determine the indications and findings in this riverine area, we studied hundred colonoscopies over a two years and four months period at our endoscopy unit.

Reports

Materials and Methods

Following informed consent, all the patients referred for colonoscopy at the State Specialist Hospital Okitipupa, Ondo State, Nigeria between January 2011 and April 2013 formed the study group in this study. Their demographic and clinical data as well as the colonoscopic findings, treatment and outcome were recorded in a proforma.

All the colonoscopies were done with a Pentax video colonoscope with a light source color temperature: ≥3200k, color rending index :≥ 85%, illuminance:≥7x 104 Lux with a pump pressure of 40-60 kpa while the flux was ≥5 L / min.

Colonoscopy requires a full bowel preparation accompanied by fasting and sedation prior to commencing the procedure. Bowel preparation regimen consisted of ingestion of a total of 40pills of sodium phosphate (visicol), with 5 pills taken every hour with a full glass of water. When the pills are not available we used the liquid sodium phosphate solution (fleet’s phospho- soda) 45ml taken twice 8- 12 hours apart. Patient is placed on liquid diet during the period of this mechanical bowel preparation. After establishing an intravenous line, 10mg of diazepam and 30mg of pentazocine were administered to achieve sedation and analgesia respectively. Digital rectal examination is a sine qua non before starting the standard process of colonoscopy.

Results

Out of a total of 100 patients, 77 (77%) were males while 23 (23%) were females giving a male to female ratio of 3.5:1. Their age ranges from 15 to 86 years. The age distribution is as shown in Fig. 1.

The indications for colonoscopy include frank bleeding per rectum in 55 (55%) patients, chronic diarrhea in 11 (11%), chronic constipation in 10 (10%), suspicion of colonic cancer in 9 (9%) patients, tarry black stools in 7 (7%), lower abdominal /anal pain in 4 (4%),suspicion of anorectal cancer in 3(3%) and enterocutaneous fistula in one(1%) patient as shown in Fig. 2.

The following were the colonoscopic findings: normal mucosa in 24(24%) patients, colitis in 24 (24%), hemorrhoids in 20 (20%), anal fissure in 16 (16%), histologically confirmed colonic cancer in 5 (5%), anorectal cancer in 4 (4%), cancer of the caecum in 2 (2%), faecal impaction in 2 (2%) patients, anal wart in 1 (1%), polyps in 1 (1%) and anal fistula 1(1%) patient as shown in Fig. 3.

Amoebic colitis was histologically confirmed and accounted for 18 patients with colitis which is 75% of the cases of colitis while ascariasis was responsible for 4 (16%) cases of colitis, and intestinal schistosomiasis was responsible for 2 (8%) cases of colitis as shown in Fig. 4.The diagnostic yield is the ratio between the total number of cases with findings and the total number of colonoscopy done.

The diagnostic yield in this study was 76 (76%) patients out of 100(100%).

Figure 1:

Age and gender distribution of patients

Figure 2:

Indications for colonoscopy

Figure 3:

Endoscopic findings

Figure 4:

Causes of chronic colitis

Figure 5:

Colonoscopic appearance of familial adenomatous polyposis in one patient

Conclusions

Bleeding from the lower gastrointestinal tract was the commonest indication for colonoscopy and the most frequent pathology was amoebic in the riverine Southwestern Nigeria.

Discussion

There was a consistent increase in the age of the patients till the 5^th decade i.e. 41-50years,therafter, there was a decline. Our study has shown an overall diagnostic yield of 76.0% at colonoscopy. This figure is similar to the 79.0% diagnostic yield found by Ismaila et al in Jos, Nigeria7.

Studies in Ilorin, Nigeria also showed a similarly high diagnostic yield 8. This same pattern was also reported in various parts of the West African sub-region by Mbengue et al9 in Senegal and Dakubo et al10 in Ghana. Depending on the sample size, varieties of colonic disease and the different selection criteria and indications, the diagnostic yield may differ.

Worldwide, colonoscopy for frank lower gastrointestinal bleeding and positive faecal occult blood test, has an increased yield for cancer.

This study showed that the commonest indications for colonoscopy were lower gastrointestinal bleeding, alteration in bowel habit, and the suspicion for colorectal cancer. These were also the indications for colonoscopy in the study carried out by Berkowitz and Kaplan11, Sahu et al12 and Kassa13 in their South African, Indian and Ethiopian patients respectively.

The commonest pathologies seen at colonoscopy in this study were colitis 24%, hemorrhoids in 20% and anal fissure in 16%. These indications differ significantly from the work done in upland areas and developed countries where cancers of the colon and anorectal regions including diverticulosis were the predominant findings .

It is noteworthy that vegetable diets are staple in this environment and contributed to the low incidence of colorectal cancers and diverticulosis in this study. In nearly all symptomatic patients, heamatophagous trophozoites of E. histolytica were seen in their stool specimens and rectal biopsy specimens. Colonoscopy and biopsy even in patients with colitis is, however safe and affordable.14

Another cause of colitis in this study was heavy infestation with ascaris lumbricoides as a result of consumption of unsafe water and contaminated food. Dead and dying ascaris were visualized during the procedure. In some cases, bolus of dead worms was extracted from the large gut during the procedure and there was a marked hyperaemia of the gut mucosa due to the inflammation associated with the worms.

In this study, intestinal schistosomiasis (S. mansoni and S. Japonicum ) infestation was associated mainly with mucoid bloody diarrhea and abdominal pains. Anal fissure are characteristically located in the posterior midline at 6 o’clock position.

Sahu et al found ulcerative colitis to be the most frequent pathology in Indians but none was observed in this study in keeping with the low incidence of ulcerative colitis in African populations because of high vegetable content in most staple diets in the continent15,16,17 . A case of familial adenomatous polyposis was detected in this study. This was a 30-year old male who had appendicectomy but continued to have lower abdominal pain, waist pain and chronic constipation. The findings at colonoscopy including the result of biopsy were in keeping with familial adenomatous polyposis as shown in Fig. 5. Adenomatous poliposis coli is associated with cell cycle control by regulating the intracytoplasmic pool of B-catenin18,19,20,21,22,23,24,25.

Colonoscopy has the advantage of providing intervention in the natural history of colorectal cancer by facilitating endoscopic polypectomy. The disadvantages include colonic perforation (¹/₂₀₀₀ to ¹/₂₅₀₀ examinations) as well as significant bleeding (<1 % of examination) that could occur during colonoscopic interventions. The bleeding we recorded during the course of the procedure were minor and resolved after pressure packing at the site of bleeding.