SA Large Intestinal Disease Flashcards
Define tenesmus
a continual or recurent inclination to evacuate the bowels
painful/ineffectual straining
What is the function of the LI with regards to fluid/electrolyte balance?
- Resorption of water: colon esp asc & TV
- Step in for what the LI hasn’t done
- Segmented contractions
- Retrograde peristalsis
What is the function of the large intestine with regards to population of bacteria? What do the bacteria do?
Large population of bacteria:
- Fibre fermentation àSCFA production
- Reduces risk of colonisation by pathogenic bacteria
What is the function of the rectum?
Faecal storage
Define:
- Diarrhoea
- Tenesmus
- Constipation
- Dyschezia
- Haematochezia
- Diarrhoea
- increased fluidity, volume or frequency of defecation
- Tenesmus
- painful/ineffectual straining
- Constipation
- decreased frequency/difficult defecation
- Dyschezia
- difficult/painful defecation
- Haematochezia
- fresh blood in faeces
If the clinical feature is weight loss,
is the problem more likely SI or LI?
Small intestine problem - commonly causes weight loss
Large intestine problem - rarely does
What would the faecal consistency be like if there was:
- A problem with the SI
- A problem with the LI
SI - watery/soft/bulky/undigested food/variable colour
LI - variable/colour ususally unchanged
How does the faecal volume change with a SI problem or a LI problem?
SI - volume increased
LI - normal or decreased volume
How does borborygmi/flatulence change with a SI problem and a LI problem?
SI problem - not uncommon to have these
LI - borborygmi/flatulence absence
How does the frequency of defecation change with a SI problem and a LI problem?
SI - 1-3x a day, increased urgency if acute or severe
LI - >6x a day, increased urgency
Is tenesmum absent or present with a SI problem or a LI problem?
SI - absent
LI - present
Is mucus present with a SI problem or a LI problem?
SI - mucus absent
LI - mucus present
Is there any blood with a SI problem or a LI problem?
SI - usually as melaena i.e. black, tarry stools *fresh blood might be seen if massive bleed and/or increase rate of transit e.g. AHDS (acute haemorrhagic diarrhoea syndrome.)
LI - fresh blood can be seen
Give some differential diagnoses of LI diarrhoea
- Inflammatory/colitis (IBD)
- Lymphoplasmacytic*
- Eosinophilic
- Granulomatous/histiocytic
- Inflammatory infiltrates in the mucosal lining
- Dietary indiscretion…especially dogs!
•This is actually more common than IBD
- Infections: think about signalment, immune compromise, environment
- Bacterial: salmonella, campylobacter, clostridia
- Salmonella and clostridia are rarely seen in SA
- Protozoal: giardia, isospora, tritrichomonas (cats)
- Parasitic: trichuris, hookworm
- Easy to overlook!!!!!! DO NOT FORGET ABOUT THESE.
- Secondary to fat maldigestion in SI*:
•EPI, SIBO/ARD, IBD, lymphangiectasia, liver disease, pancreatitis
- Secondary to portal hypertension: liver Dx
•Anything that reduces perfusion to the LI
- Local irritation: pancreatitis*, prostatitis, mass
•Not only vomiting signs but colitis signs too
- Colonic polyps- proximal cats, distal dogs
- Colonic neoplasia-adenocarcinoma, lymphoma
- Motility disorder: ‘irritable bowel syndrome’
•Normally diagnosis when we cannot think of anything else. Motility disorder. Not inflammatory (which is IBD)
Give some examples of inflammatory/colitis (IBD) that can be a differential diagnosis for LI diarrhoea
- Lymphoplasmacytic*
- Eosinophilic
- Granulomatous/histiocytic
- Inflammatory infiltrates in the mucosal lining
What are some eamples of infections that can be a differential diagnosis for LI diarrhoea?
- Bacterial: salmonella, campylobacter, clostridia
- Salmonella and clostridia are rarely seen in SA
- Protozoal: giardia, isospora, tritrichomonas (cats)
- Parasitic: trichuris, hookworm
- Easy to overlook!!!!!! DO NOT FORGET ABOUT THESE.
With regards to the investigation for LI disease, what kind of things should you ask about in the history?
What is the aim of taking a thorough history in these cases?
- Vaccination- less relevant to LI disease…
- Worming
- Diet history – any change, any scavenging
- Medication- anything we have given? anything the owner has given?
- In contact animals (or people) affected
- Previous or concurrent illnesses?
- Questions relating to other body systems?
- Is your patient vomiting?
- vomiting is often associated with SI disease but~10- 30% of dogs with colitis may vomit
- Is your patient generally well?
- most cases with LI diarrhoea are systemically well
Aim: determine if the diarrhoea is SI or LI if possible
When investigating potential LI disease, what should you do on your physical exam?
- Full physical examination:
- Assess possible causes and consequences
- Consequences less likely than in SI diarrhoea
- Caudal abdominal palpation is important but often unrewarding
- Any evidence of concurrent disease
- One example….Any petechiation/ecchymoses?
- Perineal exam: is there any evidence of
- Perineal rupture
- Wounds/swelling/mass
- Faecal incontinence (tritrichomonas infection in cats)
- Anal sac disease
- Palpate and empty and palpate again! Assess the anal tone?
- Self trauma
- Anal furunculosis
- Link between this and IBD of the LI
As part of investigating LI disease, you should perform a rectal exam. What should you be looking/feeling for?
- Provides a faecal sample/evidence to support LI disease
- Rectal mucosa:
- Smooth or roughened?
- Any mass lesions?
- Any evidence of a stricture?
- Can you feel the lumbar (medial iliac) LN
- In a male dog can you feel the prostate?
- Would you expect to?
- Palpate the pelvic urethra ventrally
- Could there be tenesmus due to a urethral calculus?
Why might you take rectal cytology as a diagnostic test for investigation LI disease?
- Might document inflammatory or neoplastic cells?
- Often not helpful but some clinicians advocate this for completeness
- Collect sample with a gloved finger as part of the rectal exam or with a cytology brush?
How should you analysis a faecal sample when investigation LI disease?
- Visual assessment of the sample
- does it support the clinical history you have taken?
- Microbiology: what do you expect to find in faeces?
- beware of over diagnosing bacterial infection
- think about commensals
- enteropathogens only suspected
- in severe disease
- if there are worrying systemic signs
- Parasitology: young dog/cat? (immunocompromised)
- Nematodes-T.vulpis
- Giardia – multiple or pooled samples?
- faecal flotation, faecal antigen SNAP test, PCR
- Tritrichomonas (cats)-PCR (see notes for links on more info)
- Chronic LI disease history especially in young cats. Can be self limited. Leak mucoid stool.
- Do a PCR if the history matches
Why might you do biochemistry and urinalysis when investigating LI disease?
Often very unhelpful but something to consider if your patient is unwell:
- Could there be a concurrent disease? Ie are these 2ry GI signs?
- Consider underlying causes such as liver disease, pancreatitis
- Is this part of AHDS or more generalised IBD?
- Are there any significant consequences of the li problem:
- Signs of fluid and electrolyte imbalance?
- Azotaemia (high creatinine and urea) + concentrated urine sgà dehydration
- High urea only –> GI bleed
Why might you use haematology as part of the diagnostic tests for investigating LI disease?
Often very unhelpful but occasionally is something to consider?
Neutrophillia – stress reponse? Or is it inflammatory???
Might see supporting evidence for
- Inflammation
- Parasitism (or hypoadrenocorticism…)
- Anaemia
- Blood loss - just a colitis this is not enough to cause anaemia. Have you got a polyp or tumour which is bleeding more than you think.
- Chronic disease
How useful is radiography for investigating LI disease?
When would you consider them?
Often unhelpful….
- Consider plain abdominal radiographs if there is anything suggesting systemic illness
- Abdominal pain
- Weight loss
- Contrast studies might be more useful but rarely done:
- Barium enema may be helpful
- Pneumocolon
Why might you consider thoracic radiographs? Which views would you want?
Met check if you think you have neoplasia!! Always do before surgery.
How useful is abdominal radiography for investigating LI disease?
What would you be looking for if you chose to do it?
Often unhelpful…. Air and U/S are not a good match!! But air and radiographs work well
- Look for mass lesions
- Any evidence of
- Increased wall thickness
- Loss of layering
- Disease elsewhere?
- Lymph nodes
- Prostate – good for U/S
- Pancreas
- SI….
- More to go on – know what to do next
How useful is endoscopy/proctoscopy for investigating LI disease?
- Can be very helpful but most cases do not need this level of investigation
- Can be very useful but Bowel preparation is crucial to the likely value of this investigation
- “if a job’s worth doing, it’s worth doing well”
- Colonoscopy is not as common as in humans –you can tell a human to have laxatives and not eat etc.. Hard to create an empty colon in a dog/cat. Can starve for 48 hours or give laxative..
- Appearance will vary but won’t predict the diagnosis
- normal?
- cobblestone appearance?
- focal mass?
- lost visibility of mucosal vessels?
- Cant find anything but have a high clinical suspicion?? Repeat again tomorrow!!
What is the rationale for high fibre diets for colonic disease?
- Colonocytes use volatile fatty acids (butyrate and proprionate) for energy metabolism
- VFAs are derived from fibre fermentation
- “Fibre –> improved colonic health” (needed)
Plant polysaccarides and lignins are resistant to digestion.
What happens if they are fermentable or unfermentable?
- Fermentable:
- fermented by bacteria to short chain fatty acids (SCFAs)
- binds bile acids to reduce colonic irritation and bind water
- lower colonic pH:
- encourages beneficial bacterial
- reduces NH3 absorption
- Unfermentable: passes through unchanged
- increased faecal bulk –> stretches colon –> normalises motility
How can you use diet to manage acute colitis?
Manage with a highly digestible, low fat diet
Fibre
Would you use fenbendazole and anti-bacterials for the management of acute colitis?
- Fenbendazole treatment trial? – can be very useful
- Consider treatment for trichuris vulpis?
- Intermittent shedding of eggs –> false –ve faecal flotation tests
- Rule out giardia?
- More commonly a si problem
- Anti-bacterials: less easy to justify
- Enteropathogens or commensals?
- Except maybe metronidazole – as can help dampen down inflammation in colon
What is the most common cause of CHRONIC LI disease?
- Inflammatory bowel disease
- Lymphocytic-plasmacytic-commonest cause of chronic colitis in dogs
- any age but esp 6mths- 4 yrs
- any breed but esp GSDs, rough collies, labs
- Eosinophilic
- Histiocytic/granulomatous
Try to find/rule out an underlying cause before calling this idiopathic or assuming you need to treat for immune mediated disease
With the management of chronic colitis, where should you start every time?
Give some examples of this and what it should contain
Start with diet every time
- Most intestinal disease diets
- are highly digestible and low fat
- low residue –> reduced faecal bulk
- Consider need to increase fibre
- Like SI IBD there can be a dietary intolerance component
- “Hypoallergenic diets”
- single source, novel or hydrolysed protein
- Low fat
When trying to manage CHRONIC colitis, if management as for acute colitis & diet alone are not successful, what next?
Drugs
- Corticosteroids (prednisolone)
- 1st line treatment in dogs and cats
- Don’t give out on day 1. Mass number of side effects
- +/- Other immunosuppressive drugs
- Ciclosporin
- Azathioprine (not cats-ever!)
- Chlorambucil (cats)
- Metronidazole
- For immune modulating effects?
- Sulphasalazines- uncommonly used
- Side effects include KCS
- May be useful in colitis cases – but there are better things like diet etc
- Antibiotics: controversial if not unwell?
- Anerobes especially therefore tend to choose metronidazole
- Amoxicillin, ampicillin?
What is granulomatous colitis?
Which dogs have a genetic predisposition to it?
- Granulomatous colitis = histiocytic ulcerative colitis
- Aggressive!!!
- Young Boxers and French Bulldogs (anything that looks like a boxer on small legs)
- genetic predisposition therefore potential in other breeds
- Originally thought to be severe idiopathic IBD
- very severe and progressive disease
- weight loss common (unusual for LI!) – very active and the colon is so inflamed! Dog is so sad they go off their food L
- many dogs PTS
- poor response to management for IBD
What is granulomatous colitis now recognised to be associated with?
- Now recognised to be associated with adherent and invasive Escherichia coli (AIEC) burrows into mucosa of the gut!! So wont pick up on the faeces. Need a mucosal biopsy.
- Dogs may have an underlying problem with neutrophil function
What is the diagnosis for granulomatous colitis?
What is the treatment?
- Diagnosis:
- biopsies
- granulomatous inflammation
- accumulation of PAS stain +ve macrophages
- FISH technique identifies colonic mucosal invasion by EColi
- Treatment: must be sure of your diagnosis!
- 8 weeks of enrofloxacin –? cure
- We need to be certain why we are using this and for this period of time!!!
- May relapse
- poor response might mean resistance?
Where do 40-60% of all GI tumours occur in dogs?
What are the most common ones seen?
- Dogs: 40-60% of all GI tumours occur in the LI
- Commonest are benign adenomatous polyps
- Also see adenocarcinoma, lymphoma, leiomyoma, others
- Usually found in the distal colon/rectum
Where do 10-15% of all GI tumours occur in cats?
What are the most common ones seen?
Where is the most common place?
- Cats: 10-15% of all gi tumours occur in the LI
- Lymphoma, adenonoma and others
- Usually found in the proximal colon
- Ileocaecal junction is fave place of a cat tumour
What is the diagnosis for LI neoplasia?
- Diagnosis
- History- flattened stool? surface blood?
- Rectal examination, especially dogs
- Radiography, including met check (sub-lumbar LN and thorax)
- Ultrasonography
- Endoscopy and biopsy
What is the treatment for LI neoplasia?
- Treatment
- Surgery
- Control with NSAIDs such as piroxicam. Meloxicam is often used too
- chemo protocols for lymphoma
- prognosis can be reasonable
What is constipation?
What are some causes?
- Decreased frequency and/or difficult defecation
- Many different causes and often multifactorial especially in cats
- may develop into irreversible megacolon – esp. cats
- Problem is it gets left and left then needs surgery
- Very often these cats are also dehydrated – obese, lazy, kidney cats!!
Give a DAMNIT-V list of causes of constipation?
What things do you need to try and get from the history when trying to diagnose a constipation case?
- History
- Ask the right questions
- Differentiate from colitis + cystitis
- Previous episodes and response to therapy
- Any history of RTAs
- Any degree of pelvic narrowing… We now attend to the width of the pelvic canal of an RTA cat
- Any change in diet, behaviour
- Think about concurrent disease
Give a diagnostic plan for a possible constipation case
- Radiography
- Ultrasound
- Blood samples
- for underlying diseases e.g. kidneys in the older cat
- Proctoscopy
Note that evacuation of colon may be difficult: rehydrate your patient first (maybe 24 hours) if there is nay doubt about hydration status!
What is primary and secondary feline megacolon?
Primary “dilated” (60%)
•Primary smooth muscle defect?
Secondary “hypertrophic” 40% due to
- Multiple causes including…
- Pelvic malunion
- Dietary
- Spinal
- Dysautonomia
- Manx sacrum
- Initially reversible- important to treat effectively if possible
- Some cats have it removed????????????
What are some causes of secondary hypertrohic feline megacolon?
Multiple causes including…
- Pelvic malunion
- Dietary
- Spinal
- Dysautonomia
- Manx sacrum
What is the management of constipation?
- Treat underlying cause
- Rehydration
- Enemas water ± soap (lubricate is much better as soap is an irritant to the mucosal lining) ± lactulose (act as an osmotic and draw water into the colon)
- Dietary fibre (eg RC Satiety Support)
- Laxatives
- Prokinetics?
- Surgical colectomy
Give some examples of laxatives that are used for the management of constipation?
Laxatives:
- Dietary fibre supplements: bulk-producing agents
- poorly digestible polysaccharides/celluloses
- psyllium (1–4 tsp per meal)
- pumpkin (1–4 tblsp per meal)
- Sterculia granules (Peridale 98 % w/w Granules)
- takes up ~60 times its own volume of water –> gelatinous mass (softer)
- increased bulk promotes peristalsis
- Stool softeners / surfactants
- anionic detergents
- enhance lipid absorption and impair water absorption
- Lubricants / emollient
- White soft paraffin e.G. Katalax
- Impede colonic water absorption à easy passage of faeces
- Only beneficial if mild constipation
- Hydrating agents (osmotic action)
- Poorly absorbed polysaccharides
- E.G. Lactulose 0.5 ml/kg q8–12h
- Traps water
- Stimulate colonic fluid secretion
- Stimulate propulsive motility
Give some examples of prokinetics for the management of constipation
Prokinetics – not particularly helpful
- Cisapride
- Serotonin 5-HT4 receptor agonist
- Not always available
- Ranitidine?
- Stimulates GI muscarinic receptors, esp colon
- May help but wont help if the colon is concrete full
