bsg guidelines (2003) for the investigation of chronic diarrhoea
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BSG Guidelines (2003) for the Investigation of Chronic Diarrhoea
Definition
Chronic diarrhoea may be defined as the abnormal passage of three or more loose or liquid stools per day for more than four weeks and/or a daily stool weight greater than 200 g/day.
Prevalence Talley et al reported a prevalence of “chronic
diarrhoea” of between 7% and 14% in an elderly population
estimates of the prevalence of chronic diarrhoea in a Western population are of the order of 4–5%
Algorithm for investigation of chronic diarrhoea
Causes of chronic diarrhoea
Colonic Colonic neoplasia Ulcerative and Crohn’s
colitis Microscopic colitis
Small bowel Coeliac disease Crohn’s disease
Other small bowel enteropathies (for example, Whipple’s disease,
tropical sprue, amyloid, intestinal lymphangiectasia)
Bile acid malabsorption
Disaccharidase deficiency
Small bowel bacterial overgrowth
Mesenteric ischaemia Radiation enteritis Lymphoma Giardiasis (and other
chronic infection)
Causes of Chronic Diarhoea Pancreatic Chronic pancreatitis Pancreatic carcinoma Cystic fibrosis Endocrine Hyperthyroidism Diabetes Hypoparathyroidism Addison’s disease Hormone secreting
tumours (VIPoma, gastrinoma, carcinoid)
Other Factitious diarrhoea “Surgical” causes (e.g.
small bowel resections, internal fistulae)
Drugs Alcohol Autonomic neuropathy
Initial investigations History and Examination Aim to establish: (a) organic vs functional,
(b) malabsorptive vs colonic/inflammatory forms of diarrhoea
(c) to assess for specific causes of diarrhoea.
Symptoms of Organic Diseaseless than three months’ duration,
Predominantly nocturnal or continuous (as opposed to intermittent) diarrhoea,
significant weight loss.
Functional Disease The absence of symptoms of organic disease,
in conjunction with positive symptoms such as those defined in the Manning or Rome criteria and a normal physical examination, are suggestive of a functional bowel disturbance, but only with a specificity of approximately 52–74%.
Unfortunately, these criteria do not reliably exclude inflammatory bowel disease.
Malabsorption
Colonic/Inflammtory
steatorrhoea liquid loose stools with blood
bulky malodorous pale stools
mucous discharge
Inspection of the stool may be helpful indistinguishing these two
Risk Factors for Organic Disease Family history. Particularly of neoplastic,
inflammatory bowel, or coeliac disease. Previous surgery. Previous Pancreatic disease Systemic disease i.e.
Thyrotoxicosis/parathyroid disease Alcohol Drugs Recent overseas travel or other potential
sources of infectious gastrointestinal pathogens
Recent antibiotic therapy and Clostridium difficile infection
Lactase deficiency
Basic Investigations FBC U and Es liver function tests, including albumin vitamin B12 and folate, calcium, ferritin, ESR and CRP TFTs Coeliac screen- EMA (anti endomysial
antibodies),Anti TTG (anti tissue tranglutaminase)
Stool Tests Inspection of stool Stool collection - 24-48hrsIf less than 200g/day, no further investigations
may be warranted
Stool cultures Protozoan, giardasis and amoebiasis ELISA for giardiasis
Stool osmolality – limited use may help in differentiating secretory and osmotic diarrhoea
Functional Disease Symptoms suggestive of Functional disease
< 45 years
Normal basic investigations
Diagnosis = Irritable bowel syndrome
Factitious Diarrhoea a common cause of reported chronic
diarrhoeal symptoms in Western populations.Due to laxative abuse adding of water or urine to stool specimens
Up to 20% of patients that are seen in tertiary centres.
Often underlying psychiatric hx such as eating disorders
High index of suspicion
Colonic/Terminal Ileal Disease Flexible SigmoidoscopyRecommended in patients under 45
because covers most pathology in this age group
Allows assessment and sampling of sigmoid and descending colon
In a study (n=809) of non HIV Non bloody chronic diarrhoea it was demonstrated that 15% of patients had colonic pathology
99.7% of these diagnoses could have been made from biopsies of the distal colon using a flexible sigmoidoscope,
primary diagnoses being microscopic colitis, Crohn’s disease, melanosis coli, and ulcerative colitis.
Colonic/Terminal Ileal Disease
Colonoscopy Recommended in patients over 45 years old Diarrhoea may be caused by colorectal neoplasia One study showed prevalence of colonic
neoplasms of 27% in those patients undergoing colonoscopy for a change in bowel habit
50% of neoplasms are proximal to splenic flexture Higher diagnostic yield with ileoscopy particularly
in IBD preferred modality to exclude or confirm
microscopic colitis Barium Enemas useful in complementing
colonoscopy but has lower sensitivity in detecting neoplasms
Colonic/Terminal Ileal Disease If colonoscopy and barium enema negative:
Barium follow through – further imaging of terminal ileum and proximal colon in patients with negative findings on colonoscopy and biopsy
Enteroclysis/Technetium scan?Superseded by CT with contrast and video
endoscopy
Malabsorption- Small Bowel Upper GI endoscopy with duodenal biopsies
even in absence of EMA/TTG antibodies
Small bowel imaging (barium follow through or enteroclysis) should be reserved for cases where small bowel malabsorption is suspected and distal duodenal histology is normal (C).
Malabsorption- Small Bowel If enteropathy (e.g. Whipple’s , tropical sprue
amyloid)-
Fat malabsorption – faecal elastase and EMA is superior to 3 day
stool samples for fat measurement.Breath tests 14C-triolein absorption to measure
fat absorption in high faecal fat content
Malabsorption- Pancreatic Severe pancreatic insufficiency with
malabsorption is normally associated with pancreatic duct abnormalities. ERCP offers the greatest sensitivity for the diagnosis of ductal changes- (however since the publication of this guideline in 2003 practice has changed as mentioned below MRCP has replaced ERCP as diagnostic option)
MRCP has the potential to replace ERCP as the imaging modality of choice and has the advantage of avoiding the risks associated with ERCP
Malabsorption- Pancreatic Urine tests such as the Pancreolauryl test and
stool tests such as faecal elastase or chymotrypsin –poor sensitivity in mild/moderate pancreatic dysfunction
Serum levels of pancreatic dysfunction are only affected in severe pancreatic dysfunction
Small bowel bacterial overgrowth Culture of small bowel aspirates is the most
sensitive test for SBBO but methods are poorly standardised and positive results may not reflect clinically significant SBBO (B).
Hydrogen breath tests have poor sensitivity but acceptable specificity, and are of value when a positive result is obtained.
The glucose hydrogen breath test is recommended
Bile Acid Malabsorption Bile acid malabsorption (BAM) may occur
when there isterminal ileal disease or resection. Measurement of serum 7α hydroxy-4-cholesten-3-one is an effective test for this but is seldom performed.
75Se homotaurocholate (75Se-HCAT) testing is more widely available and is a sensitive measure
In the absence of these tests a therapeutic trial of cholestyramine is sometimes employed as a test for the presence of BAM, but the validity of this approach has not been subject to study
Hormone Secreting Tumours Diarrhoea due to hormone secreting tumours
is extremely rare and
testing for the presence of excess vasoactive intestinal peptide, gastrin, or glucagon in plasma is recommended only in the presence of high volume watery diarrhoea when other causes of diarrhoea have been excluded
Summary History and examination extremely important Important to exclude ‘functional’ diarrhoea
with basic investigations and thorough history Coeliac serology tests should be done early in
investigation In patients under the age of 45, flexible
sigmoidoscopy is recommended In patients with one first degree relative with
bowel neoplasm and above age of 45 warrant a colonoscopy
Summary Obvious deficiencies in the investigation of
SBBO, pancreatic insufficiency, BAM Empirical therapy is often employed
Gut. 2003 July; 52(Suppl 5): v1–v15.Guidelines for the investigation of chronic diarrhoea, 2nd edition P Thomas, A Forbes, J Green, P Howdle, R Long, R Playford, M Sheridan, R Stevens, R Valori, J Walters, G Addison, P Hill, and G Brydon