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Comparative study of rapid urease test and histopathological examination for detection of H. pylori infection

Helicobacter pylori (H. pylori) infection is very common throughout the world, occurring in 40-50% of the population in developed countries and 80-90 % of population in developing regions. Since the discovery of H. pylori by Marshall and Warren in 1983, overwhelming evidence has accumulated to confirm that H. pylori infection plays a significant role in the development of chronic active gastritis and peptic ulcer. H. pylori is the etiologic agent of acute and chronic gastritis, peptic ulcer disease and two forms of gastric cancer. ABSTRACT


INTRODUCTION
Helicobacter pylori (H. pylori) infection is very common throughout the world, occurring in 40-50% of the population in developed countries and 80-90 % of population in developing regions. Since the discovery of H. pylori by Marshall and Warren in 1983, overwhelming evidence has accumulated to confirm that H. pylori infection plays a significant role in the development of chronic active gastritis and peptic ulcer. 1 H. pylori is the etiologic agent of acute and chronic gastritis, peptic ulcer disease and two forms of gastric cancer. 2 Up to 80% of gastric carcinomas and 92% of low grade gastric mucosa-associated lymphoid tissue lymphomas are H. pylori associated. 3 Every method for detection of H Pylori has its own inherent advantages and disadvantages. Rapid Urease Test (RUT), with its high sensitivity and specificity, is considered to be a quick and reliable test for the initial diagnosis of H. pylori infection and is simple and inexpensive. 4 The present study is done for evidence of H. pylori infection in our set up and detection of H. pylori from Gastric biopsy specimen using Rapid Urease Test and Histopathological examination and the efficacy of the anti H. pylori treatment by doing the follow up endoscopy and diagnostic test.
In this study, we aim: to study the incidence of H. pylori infection in our Hospital. And to find out the Sensitivity and Specificity of Rapid Urease Test and Histopathological Examination for the detection of H. pylori on gastric biopsy. Also, to study the effect of anti H. pylori drugs by performing follow-up Endoscopy in terms of positive or negative Rapid Urease Test and Histopathological Examination report.

METHODS
The study was conducted at Dr. D. Y. Patil Medical College and Hospital, DPU University, for a period of 2 months (from July 2012-September 2014) and is a prospective and comparative randomized type of study using 100 cases. The study was approved by the Institute's Ethics Committee.

Inclusion criteria
• Age-18-75 years • All patients with upper abdominal pain more than 6 month.
In our study, 100 patients with history of epigastric pain for more than 6 months, burning sensation in epigastric region, were admitted and evaluated. Patients taking NSAIDS and PPIs were advised to stop taking the drugs at least 5 days prior to endoscopy. HIV and HbSAg status was done.
Patients were kept Nil by Mouth (NBM) 4-6 hrs. prior to Endoscopy. Four biopsies were taken from different sites (Antrum and Pylorus). Two biopsies were sent to the Pathology department in plain bulb containing 1:10 mixture of distilled water and formalin after the endoscopy for examination, and other two biopsies were subjected to RUT and result was seen within 1-2 hrs.

Specific preparation
Patients were instructed not to eat or drink for 4-6 hours before endoscopy. Patients with gastric outlet or oesophageal obstruction were kept NBM for a longer period.

Pre-endoscopy preparation
IV access was obtained for giving IV fluids and SOS Injectable Antispasmodics.

Premedication
Premedication consists of local oral anaesthesia by lidocaine topical aerosol (LOX 10% oral spray).

Examination
All patients were kept NBM for 6 hrs prior to endoscopy and after bringing the patient to endoscopy room LOX 10% spray was sprayed on the both tonsillar pillars, posterior pharyngeal wall and after waiting for 5 minutes, patient was kept in left lateral position with the head on a small pillow flexed forward and mouth tilting downward to facilitate drainage of saliva and a pulse oximeter was attached to the patient and endoscope was introduced after placing a mouth gag.
The scope was passed through the oropharynx and nudged through cricopharynx under vision with the voluntary swallowing movement of the patient. The scope was rapidly passed through the esophagus doing a rough scanning and leaving the detailed mucosal examination to be done during withdrawal.
As per the endoscopic finding a total of 4 biopsies were taken. 2 of the biopsy samples were taken for the RUT and rest for the Histopathological Examination. After confirming haemostasis, the scope was removed after deflating the stomach.
2 biopsies were placed on yellow paper of RUT kit after removing the plastic cover and a single drop of distilled water was placed on yellow paper and then plastic cover was again sealed with its own adhesive and results were observed after 1-2 hrs. Change of colour of yellow paper to pink indicates an H. pylori infection.
2 biopsies were sent for histopathological examination, in a plain bulb containing 1:10 of formalin and water mixture to the pathology department, for Giemsa stain.
The patient was advised to start oral diet after 1 hour of procedure. Negative PPI Started immediately. The anti H. pylori therapy included: a Lansoprazole (PPI) 30 mg,

RESULTS
The Table 2 showing that 84 patients out of 100 are RUT positive and 16 patients are RUT negative. The Table 3 showing that Total 83 patients shows presence of H. pylori positive in HPE.  This Table 4 showing total no. of cases positive for both RUT and HPE positive is 80 RUT positive and HPE negative is 4 and HPE positive and RUT negative is 3 and both negative is 13. The Table 5 showing that 87 patients were treated with anti h pylori treatment and rest with PPI. This Table 6 showing that 9.20% cases were positive RUT at the time of follow up after treatment and rest that is 90.80 % were RUT negative.  Table 7 shows that 10.34 % cases were positive in HPE at the time of follow up and rest were negative.
This Table 8 showing total number of cases positive for both RUT and HPE were 8 and RUT positive and HPE negative were 0 and both RUT and HPE negative were 78 and HPE positive and RUT negative were 1.

RUT results at first presentation
In our study 84 patients were detected positive by RUT method. This is comparable with study conducted by Jemilohun et al found RUT is accurate for the diagnosis of H. pylori infection. Its use will serve as a good alternative to histology in management of patients with dyspepsia in resource poor environments, except in patients who need histology for reasons other than H. Pylori diagnosis. 6

HPE results at first presentation
In our study 83 patients (83 %) were detected positive by HPE method. This is comparable with study conducted by MDU Islam, SHZ Rahman et al found culture, RUT and HPE all are high sensitive and specific to diagnose H. pylori infection. 7

Association between RUT and HPE finding in study group
The sensitivity was 96.38 % and specificity was 74.47 %, PPV was 95.24% and NPV was 81.25%. This is comparable with study conducted by Jemilohun et al found sensitivity, specificity, PPV and NPV was 93.33%, 75.6 %, 80.76 % and 91.17 % respectively. 6

Treatment for H. pylori infection
We have given triple drug therapy (Lansoprazole 30mg, Clarithromycin 250 mg, Tinidazole 500mg or Metronidazole 400mg) for 14 days with patients with H. pylori gastritis and PPI for nonspecific gastritis. This is comparable with study conducted by Yesim Ozen Alahdab et al and found that triple drug therapy remains an appropriate first line therapy in areas of low clarithromycin resistance. 8

RUT results at the time of follow up
At the time of follow up after taking anti H. pylori treatment, 79 patients are RUT negative and 8 are RUT positive which are defaulters (not taken complete dose) and again started on treatment with the accuracy of the drug being 98.85 %.

HPE results at the time of follow up
At the time of follow up after taking anti H. pylori treatment, 78 patients are HPE negative and 9 are HPE positive which are defaulters (not taken complete dose) and again started on treatment.

Association between RUT and HPE finding at follow up
The sensitivity was 88.89 % and specificity was 100%, PPV was 100% and NPV was 98.73%. This is comparable with study conducted by Megraud F. found sensitivity, specificity, PPV and NPV was 93.33%, 100 %, 80.76 % and 91.17 % respectively. 9 According to Islam MDU, Shamsuzzaman SHZ et al, a comparative study among different invasive methods for the diagnosis of H. pylori was done and it was concluded that comparing among culture, rapid urease test, and histopathology methods all are highly sensitive and specific to diagnose H. pylori infection.10

CONCLUSION
The results support the view that RUT is accurate for the diagnosis of H. pylori infection as it is as sensitive to HPE examination. Main disadvantage of this procedure is that it is an invasive procedure. In our population the OMA regimen shows 99 % sensitivity which was proven by follow up biopsy with RUT and HPE. To conclude, our study reveals that RUT is accurate for the diagnosis of H. pylori infection and its use will serve as a good alternative to histology in management of patients with dyspepsia in resource poor environments, except in patients who need histology for reasons other than H. pylori diagnosis.