Virtual colonoscopy includes CT Colonography (CTC) and MR (magnetic resonance) colonography. MR colonography is very much in the developmental phase and is not available in Australia and therefore, will not be discussed here.
Technique: CTC involves
a) bowel cleansing,
b) air or CO2 insufflation of the co- lon,
c) CT scanning and
d) image processing and interpretation.
Introduction: Irritable bowel syndrome (IBS) is the most common referral to a gastroenterologist.The prevalence is between 14% to 24% in women and 5% to 19% in men in the US and Britain. It cost US $1.6 billion in 1998 mostly in medication and diagnostic tests.
While volumes have been written, which make stimulating reading, on the pathogenesis of IBS namely brain gut neural dysfunction, visceral hypersensitivity, sympathetic and parasympathetic imbalance, role of gut infection etc., purpose of this review is to focus on practical management of IBS.
We have a barrage of tests such as faecal occult blood(FOB), faecalDNA, flexible sigmoidoscopy, colonoscopy and virtual CT colonography (CTC) to address the possibility of significant colorectal neoplasia. Where do these tests fit and when should these be used individually or in combination? Before we can address this question, we need to understand the demographics of CRC.
Vast majority (65-85%) of CRC occur in people who have no family history and they are referred to as average risk category patients. Some 10-30% of CRC occur in patients who have a family history of CRC and they are referred to as moderate risk category. Remaining 5-6% of CRC occur in high risk patients such as those with non-polyposis colorectal cancer syndrome (HNPCC) and rarely in adenoma- tous polyposis coli or similar rare syndromes.
Helicobacter Pylori (HP) eradication continues to pose some challenges as “standard” treatment fails. Treatment failure is said to be due to resistance of HP to the antibiotics used in this regimen. Before we examine the advances in treatment options, let us briefly review treatment indications.
The prevalence of HP infection in the Australian community is approximately 20% or less. Only a small minority of the infected population get symptoms. Also we need to be cognizant of the probable beneficial effect of HP in reflux oesophagitis, Barrett’s oesophagus, asthma, atopic diseases and side effects of eradication therapy.
Prevalence of constipation is reported to be 20%. In the U.S.A, $800 million are spent yearly on laxatives. Constipation in the U.S.A account for 20,000 hospitaliza- tions and 2.5 million out-patient consultations per year.
Definitions: Stool frequency 2 or less per week, straining, hard stools and a feel- ing of incomplete evacuation are all features used by the Rome consensus criteria to define constipation.
We have a barrage of tests such as faecal occult blood (FOB), faecal DNA, flexible sigmoidoscopy, colonoscopy and virtual CT colonography (CTC) to address the possibility of significant colorectal neoplasia. Where do these tests fit and when should these be used individually or in combination? Before we can address this question, we need to understand the demographics of CRC.
Vast majority (65-85%) of CRC occur in people who have no family history and they are referred to as average risk category patients.
There is increasing use of warfarin and antiplatelet agents in the aging population for various indications. These patients are often referred for endoscopy for investigation of abdominal pain, dyspepsia, change of bowel habit, family history of bowel cancer, positive faecal occult blood, anaemia, polyp surveillance etc.
While colonoscopy and polypectomy reduced incidence of bowel cancer in 76% and reduced bowel cancer related mortality in 53% in a cohort of post-polypectomy pa- tients ( National bowel cancer study), the magnitude of such prevention depends on your colonoscopist’s adenoma detection rate (ADR). Colonoscopist’s ADR is de- fined as the percentage of consecutive screening (asymptomatic) patients who had at least one adenoma removed. A colonoscopist’s ADR is inversely proportional to post-colonoscopy missed cancers and adenomas. Higher the ADR less the missed colorectal cancers (CRC) and polyps (adenomas) for these patients in the post – polypectomy years.