AMC 2 Flashcards
Commonest GIT malignancy: mainly adenocarcinoma
Colorectal cancer
Second most common cause of death from cancer in Western society
Colorectal cancer
Generally men over 50 years (90% of all cases)
Colorectal cancer
Two-thirds in descending colon and rectum
Colorectal cancer
Colorectal cancer Predisposing factors
Ulcerative colitis (longstanding)
Familial: familial adenomatous polyposis (FAP), hereditary non-polyposis colorectal cancer
Colonic adenomata
Decreased dietary fibre
Age >50 years
Alternating constipation with spurious diarrhoea
Colorectal cancer
Unsatisfactory defecation
Colorectal cancer
Rectal examination—this is appropriate because many cancers are found in the lowest 12 cm
and most can be reached by the examining finger
Colorectal cancer
If obstructing, there is a risk of rupture of the caecum.
Colorectal cancer
Spread
Lymphatics → epigastric and para-aortic nodes
Direct → peritoneum
Blood → portal circulation
Colorectal cancer
FOBT: immunochemical tests (e.g. Inform and InSure) do not require dietary or medication
restriction
Colorectal cancer
Colonoscopy ± biopsy
CT colonography (investigation of choice)
Serum CEA level
Colorectal cancer
Ultrasonography and CT scanning not useful in primary diagnosis; valuable in detecting
spread, especially hepatic metastases
Colorectal cancer
PET-CT scanning (if available) is useful for follow-up
Colorectal cancer
If FOBT is positive—investigate by colonoscopy or by flexible sigmoidoscopy.
Colorectal cancer
An FOBT every 2 years is now recommended for all people from 50–74 years
Colorectal cancer
FOBT is safer, cheaper and more convenient than colonoscopy.
Colorectal cancer
Do not use the
CEA blood test as a screening tool.
Colorectal cancer
Colonoscopy as screening is only recommended in 2% of the population
Colorectal cancer
Moderate risk (family history category 2): 2 yearly FOBT from 40–49, then colonoscopy
every five years from 50–74 years.
Colorectal cancer
High risk (family history category 3): 2 yearly FOBT from 35–44, then colonoscopy every 5
years from 45–74 years
Colorectal cancer
flexible sigmoidoscopy and rectal biopsy for those with ulcerative colitis
Colorectal cancer
Refer to a bowel cancer specialist to plan appropriate surveillance
Colorectal cancer
Early surgical excision is the treatment, with the method depending on the site and extent of the
cancer
Colorectal cancer
Dukes classification gives a guide to prognosis
Colorectal cancer
The survival rates for
Dukes C cancer have improved with more effective chemotherapy.
Colorectal cancer
Follow-up includes:
CEA antigen
colonoscopy
abdominal imaging: ultrasound or CT scan of liver
Colorectal cancer
Patients with constipation or change in bowel habit of recent onset without obvious cause need
further investigation.
Colorectal cancer
intestinal disorder characterised by abnormal frequency and liquidity
of faecal evacuations.
Diarrhoea
In Australia most infective
cases are viral.
Diarrhoea
vomiting and diarrhoea =
gastroenteritis
diarrhoea (only) =
enteritis
The characteristics of the stool provide a useful guide to the site of the bowel
disorder.
Diarrhoea
Disorders of the upper GIT tend to produce diarrhoea stools that are copious,
watery or fatty, pale yellow or green.
Diarrhoea
Colonic disorder tends to produce stools that are small, of variable consistency,
brown and may contain blood or mucus
Diarrhoea
Acute gastroenteritis should be regarded as a diagnosis of exclusion.
Diarrhoea
is more likely to be due to protozoal infection (e.g. amoebiasis,
giardiasis or Cryptosporidium) than bacillary dysentery.
Chronic diarrhoea
Certain antibiotics can cause an overgrowth of Clostridium difficile, which produces
pseudomembranous colitis.
Diarrhoea
Coeliac disease, although a cause of failure to thrive in children, can present at any
age
Diarrhoea
In disorders of the colon, the patient experiences frequency and urgency but
passes only small amounts of faeces.
Diarrhoea
can be classified broadly into four types:
acute watery diarrhoea
bloody diarrhoea (acute or chronic)
chronic watery diarrhoea
steatorrhoea
Diarrhoea
Common causes are:
gastroenteritis/enteritis:
bacterial: Salmonella sp., Campylobacter jejuni, Shigella sp., enteropathic Escherichia coli,
Staphylococcus aureus (food poisoning)
viral: rotavirus (50% of child hospital admissions),1 norovirus, astrovirus, adenovirus
Acute diarrhoea
Unexpected weight loss
Persistent/unresolved
Blood in stool
Fever
Overseas travel
Severe abdominal pain
Family history: bowel cancer, Crohn disease
Red flag pointers for diarrhoea
Irritable bowel syndrome was the commonest cause of
Chronic diarrhoea
In children, coeliac disease and cystic fibrosis can present as
chronic diarrhoea
although not causing true diarrhoea, can present as loose, redcurrant jelly-like
stools and should not be misdiagnosed (as gastroenteritis).
intussusception
must also be considered
in the onset of acute diarrhoea and vomiting
Appendicitis
may lead to the
haemolytic uraemic syndrome or thrombotic thrombocytopenic purpura, particularly in children
Infection with enterohaemorrhagic strains of E. coli (e.g. O157:H7, O111:H8)
Clue: Think of it with atypical gastroenteritis and bloody diarrhoea
Avoid antibiotics
This potentially fatal colitis can be caused by the use of any antibiotic, especially clindamycin,Page 413
lincomycin, ampicillin and the cephalosporins (an exception is vancomycin).
Pseudomembranous colitis
It is usually due to
an overgrowth of C. difficile, which produces a toxin that causes specific inflammatory lesions,
sometimes with a pseudomembrane.
Pseudomembranous colitis
Clinical features
Profuse, watery diarrhoea
Abdominal cramping and tenesmus ± fever
Within 2 days of taking antibiotic (can start up to 4 to 6 weeks after usage)
Persists 2 weeks (up to 6) after ceasing antibiotic
Pseudomembranous colitis
Diagnosed by characteristic lesions on sigmoidoscopy and a tissue culture assay and/or PCR for
C. difficile toxin
Pseudomembranous colitis
Treatment2
Cease antibiotic
Hygiene measures to prevent spread
Pseudomembranous colitis
Mild to moderate: metronidazole 400 mg (o) tds for 10 days
Severe: vancomycin 125 mg (o) qid for 10 days
Consult with specialist. Beware of toxic megacolon.
Pseudomembranous colitis
Central colicky abdominal pain indicates involvement of the
small bowel
while lower
abdominal pain points to the
large bowel
profuse bright red bleeding, consider
diverticulitis or carcinoma of colon
small
amounts with mucus or mucopus, consider
inflammatory bowel disorder
Diarrhoea at night suggests
organic disease
the stools are distinctively pale, greasy, offensive, floating and difficult to flush.
steatorrhoea
‘Rice water’ stool is characteristic of
cholera
inflammatory bowel disease, colonic polyps, carcinoma, infective especially Shigella,
Salmonella, Campylobacter, E. coli, amoebiasis, colitis (pseudomembranous, ischaemic).
Bloody diarrhoea
Antibody tests, total IgA (e.g. IgA transglutaminase for
coeliac disease
Haemagglutination tests for
amoebiasis
Fluid loss with dehydration, electrolyte loss (Na+, K+, Mg+, Cl-)
Vascular collapse
Hypokalaemia
Complications of diarrhoea
DxT acute diarrhoea + colicky abdominal pain ± vomiting →
gastroenteritis
DxT (young adult) diarrhoea ± blood and mucus + abdominal cramps
→
inflammatory bowel disease (UC/Crohn)
DxT as above + constitutional symptoms ± eyes/joints →
Crohn disease
DxT altered bowel habit: diarrhoea ± constipation ± rectal bleeding ±
abdominal discomfort →
colorectal carcinoma
DxT profuse watery diarrhoea + abdominal cramps and increasing
distension (on antibiotics) →
pseudomembranous colitis (Girotra’s
triad)
DxT variable diarrhoea/constipation + abdominal discomfort + mucus
PR + flatulence →
irritable bowel syndrome
The common causes are coeliac disease, chronic pancreatitis and postgastrectomy.
malabsorption
Bulky, pale, offensive, frothy, greasy stools
Stools difficult to flush down toilet
Weight loss
Prominent abdomen
Failure to thrive (in infants)
Increased faecal fat
Signs of multiple vitamin deficiencies (e.g. A, D, E, K)
malabsorption
It is widely underdiagnosed because most patients present with non-GIT symptoms, such as
tiredness.
Coeliac disease
Classic tetrad: diarrhoea, weight loss, iron/folate deficiency, abdominal bloating
Coeliac disease
Characteristic duodenal biopsy: villous atrophy (key test)
Coeliac disease
IgA transglutaminase antibodies (>90% sensitivity and specificity)
Coeliac disease
Associations
Iron-deficiency anaemia
Malignancy, especially lymphoma, GIT
Type 1 diabetes
Coeliac disease
Dermatitis herpetiformis
Coeliac disease
Diet control: high complex carbohydrate and protein, low fat, lifelong gluten-free (no wheat,
barley, rye and oats)
Coeliac disease
Give pneumococcal vaccination (increased risk of pneumococcus sepsis)
Coeliac disease
This is due to atheromatous occlusion of mesenteric vessels (low blood flow)
Ischaemic colitis
sharp abdominal pain in an elderly person with bloody diarrhoea (low blood flow)
or
periumbilical pain and diarrhoea about 15–30 minutes after eating
Ischaemic colitis
associated with fever, diarrhoea
and/or vomiting,
Acute gastroenteritis
Mainly rotavirus (developed countries) and adenovirus: viruses account for about 80%
Acute gastroenteritis
Bacterial: C. jejuni and Salmonella sp. (two commonest), E. coli and Shigella sp.
Protozoal: G. lamblia, E. histolytica, Cryptosporidium
Food poisoning—staphylococcal toxin
Acute gastroenteritis
correction of fluid and electrolyte loss.
Acute gastroenteritis
The most accurate way to monitor dehydration is to weigh the child, preferably without
clothes, on the same scale each time.
Acute gastroenteritis
If acute invasive or persistent Salmonella are present, give antibiotics (ciprofloxacin or
azithromycin)
Acute gastroenteritis
Avoid
Drugs: antidiarrhoeals, anti-emetics and antibiotics
Acute gastroenteritis
Fluid loss (mL) = % dehydration × body weight (kg) × 10
Acute gastroenteritis
Aim to give more (replace fluid loss) in the first 6 hours.
Rule of thumb: give 100 mL/kg (infants) and 50 mL/kg (older children) in first 6 hours.
Acute gastroenteritis
Diarrhoea often follows acute gastroenteritis when milk is reintroduced into the diet (some
recommend waiting for 2 weeks).
Sugar intolerance
Stools may be watery, frothy, smell like vinegar and tend to
excoriate the buttocks. They contain sugar.
Sugar intolerance
Remove the offending sugar from the diet.
Use milk preparations in which the lactose has been split to glucose and galactose by enzymes,
or use soy protein.
Sugar intolerance
A clinical syndrome of loose, bulky, non-offensive stools with fragments of undigested food in a
well, thriving child.
Toddler’s diarrhoea (‘cradle crap’)
Diagnosis: duodenal biopsy (definitive).
Treatment: remove gluten from diet.
Coeliac disease
severe diarrhoea, especially if associated with
blood or mucus, may be a feature of a more serious bowel infection such as amoebiasis.
Traveller’s diarrhoea
is caused
by E. coli, which produces a watery diarrhoea within 14 days of arrival in a foreign country.
Most traveller’s diarrhoea
If moderate to severe, azithromycin is
recommended for 2–3 days.
traveller’s diarrhoea
Any traveller with persistent diarrhoea after visiting less developed countries, especially India
and China, may have a
protozoal infection such as amoebiasis or giardiasis
If there is a fever and blood or mucus in the stools, suspect
amoebiasis
is
characterised by abdominal cramps, flatulence and bubbly, foul-smelling diarrhoea
Giardiasis
anti-emetic injection (for severe vomiting) prochlorperazine IM, statim
or
metoclopramide IV, statim
Antidiarrhoeal preparations:
(avoid if possible, but loperamide preferred) loperamide (Imodium) 2 caps statim then 1 after
each unformed stool (max. 8 caps/day)
treatment of diarrhoea
diarrhoea in adults and older children is usually self-limiting and does not require
antibiotic treatment
Bacterial
Campylobacter, Salmonella, Shigella and E. coli are the most common causes.
Bacterial diarrhoea
use oral
rehydration solution 2–3 L orally over 24 hours if mild to moderate dehydration.
Bacterial diarrhoea
If severe,
intravenous rehydration with N saline is recommended.
Bacterial diarrhoea
Only treat if symptoms have persisted for more than 48
hours.
Bacterial diarrhoea
Recommended empirical therapy is ciprofloxacin or norfloxacin.
Bacterial diarrhoea
cotrimoxazole (double strength) 1 tab (o) 12 hourly for 5 days: use in children (children’s
doses)
or
norfloxacin 400 mg (o) 12 hourly for 5 days (preferred for adults)
or
ciprofloxacin 500 mg (o) bd for 5 days
Shigella dysentery (moderate to severe)
tinidazole 2 g (o), single dose (may need repeat)
or
metronidazole 400 mg (o) tds for 7 days
Giardiasis
Antibiotics are not generally advisable, but if severe or prolonged, use:
ciprofloxacin 500 mg (o) bd for 5–7 days
or
azithromycin 1 g (o) day, then 500 mg for 6 days
or
ceftriaxone IV or ciprofloxacin IV if oral therapy not tolerated
Salmonella enteritis
Salmonella is a notifiable disease; infants under 15 months are at risk of
invasive
Salmonella infection.
metronidazole 600–800 mg (o) tds for 6–10 days
plus
diloxanide furoate 500 mg (o) tds for 10 days
Amoebiasis (intestinal)
bloody diarrhoea and mucus
colonic pain and fever
urgency to visit toilet and feeling of incomplete defecation
constitutional symptoms including weight loss and malaise
Inflammatory bowel disease3
extra-abdominal manifestations such as arthralgia, low back pain (spondyloarthropathy), eye
problems (iridocyclitis), liver disease and skin lesions (pyoderma gangrenosum, erythema
nodosum)
Inflammatory bowel disease3
Investigations include FBE, vitamin B12 and folate, LFTs (abnormal enzymes), HLA-B27, faecal
calprotectin (if normal, no intestinal inflammation; if abnormal, needs colonoscopy) and
lactoferrin
Inflammatory bowel disease
Mainly a disease of Western societies
Mainly in young adults (15–40 years)
High-risk factors—family history, previous attacks, low-fibre diet
Recurrent attacks of loose stools
Ulcerative colitis
Begins in rectum (continues proximally)—affects only the colon: it usually does not spread
beyond the ileocaecal valve
An increased risk of carcinoma after 7–10 years
Ulcerative colitis
Diagnosis
Faecal calprotectin: a sensitive test
Proctosigmoidoscopy: a granular red proctitis with contact bleeding
Barium enema: characteristic changes
Ulcerative colitis
regional enteritis, granulomatous colitis
Crohn disease
Recurrent diarrhoea in a young person (15–40 years)
Blood and mucus in stools (less than UC)
Colicky abdominal pain (small bowel colic)
Crohn disease
Right iliac fossa pain (confused with appendicitis)
Constitutional symptoms (e.g. fever, weight loss, malaise, anorexia, nausea)
Crohn disease
Signs include perianal disorders (e.g. anal fissure, fistula, ischiorectal abscess), mouth ulcers
Crohn disease
Skip areas in bowel: ½ ileocolic, ¼ confined to small bowel, ¼ confined to colon, 4% in upper
GIT
Crohn disease
Sigmoidoscopy: ‘cobblestone’ appearance (patchy mucosal oedema)
Crohn disease
Colonoscopy: useful to differentiate from UC
Biopsy with endoscopy
Crohn disease
5-aminosalicylic acid derivatives (mainly UC): sulfasalazine (mainstay), olsalazine,
mesalazine. Usually start with these agents
Ulcerative colitis
corticosteroids (mainly for acute flares): oral, parenteral, topical (rectal foam, suppositories
or enemas)
for severe disease, immunomodifying drugs (e.g. azathioprine, cyclosporin, methotrexate)
and anti-TNF and biological agents (e.g. adalimumab, vedolizumab, infliximab)
Ulcerative colitis
Surgical treatment: reserve for complications; avoid surgery if possible
Ulcerative colitis
Typically in younger women (21–40 years)
Any age or sex can be affected
May follow attack of gastroenteritis/traveller’s diarrhoea
Cramping abdominal pain (central or iliac fossa)
Irritable bowel syndrome (IBS)
Pain usually relieved by passing flatus or by defecation
Variable bowel habit (constipation more common)
Diarrhoea usually worse in morning—several loose, explosive bowel actions with urgency
Irritable bowel syndrome (IBS)
Often precipitated by eating
Faeces sometimes like small hard pellets or ribbon-like
Irritable bowel syndrome (IBS)
relieved by defecation
onset associated with a change in stool frequency
onset associated with a change in form (appearance) of stool (loose, watery or
pellet-like)
Rome III diagnostic criteria for irritable bowel syndrome
Age of onset >50 years
Fever
Unexplained weight loss
Rectal bleeding
Pain waking at night
Persistent daily diarrhoea/steatorrhoea
Recurrent vomiting
Red flag pointers for non-IBS disease
Major change in symptoms
Mouth ulcers
↑ CRP, ESR
Anaemia
Family history of bowel cancer or IBD
Red flag pointers for non-IBS disease
is a problem of the colon (90% in descending colon) and is related to lack
of fibre in the diet. It is usually symptomless.
Diverticular disorder
Present in one in three people over 60 years (Western world)
Diverticular disorder
infected diverticula and symptomatic
Diverticulitis
Intermittent cramping lower abdominal pain in LIF
Tenderness in LIF
Rectal bleeding—may be profuse (± faeces)
Diverticular disorder
Bleeding—may cause massive lower GIT bleeding
Abscess
Perforation
Diverticular disorder
Peritonitis
Obstruction (refer CHAPTER 24 )
Fistula—bladder, vagina
Diverticular disorder
WBC and ESR—to determine inflammation
Sigmoidoscopy
Barium enema
Investigations Diverticular disorder
Management
It usually responds to a high-fibre diet.
Avoidance of constipation.
Diverticular disorder
Oral antidiarrhoeal drugs are contraindicated in
children
can readily provoke dystonic reactions in children, especially if young
and dehydrated
Anti-emetics
is invariably self-limiting (lasts 2–5 days). If it lasts longer than 7
days, investigate with culture and microscopy of the stools.
Acute diarrhoea
If diarrhoea is associated with episodes of facial flushing or wheezing, consider
carcinoid syndrome
Recurrent pain in the right hypochondrium is usually a feature of
IBS (not gall
bladder disease).
Recurrent pain in the right iliac fossa is more likely to be
IBS than appendicitis.
if a patient’s diarrhoea resolves spontaneously on hospital
admission.
Consider alcohol abuse
diarrhoea 30 minutes after meal →
mesenteric ischaemia
It is enterically
transmitted and arises from the ingestion of contaminated food, such as shellfish, or water.
Hepatitis A
