PATHOLOGY - Large Intestinal Disease Flashcards
What are the key clinical signs of large intestinal disease?
Faecal tenesmus
Dyschezia
Large intestinal diarrhoea
Constipation
Faecal incontinence
What is faecal tenesmus?
Faecus tenesmus is straining to defaecate
What is dyschezia?
Dyschezia is pain associated with defaecation
What are the features of large intestinal diarrhoea?
Small volumes of diarrhoea
Increased frequency of defaecation (usually associated with urgency)
Mucus
Haematochezia
What are the general differential diagnoses for tenesmus and dyschezia?
Colorectal disease
Perineal/perianal disease
Prostatic disease
Urogenital disease
Which targeted history questions are beneficial to ask when investigating tenesmus and/or dyschezia?
- Is there concurrent diarrhoea? Describe it?
- Is there haematochezia? Is there mucus?
- Is there constipation?
- When does the dyschezia occur (before, during or after defaecation)?
- When does the tenesmus occur (before, during or after defaecation)?
- Is there concurrent urinary tract signs?
- Is there evidence of pelvic limb weakness or difficulty on posturing to defaecate?
Which additional steps should you take when doing a clinical examination on a patient with suspected large intestinal disease?
Rectal examination
Careful assessment of the perineal and perianal area
Patients may require sedation for this
What are the differential diagnoses for faecal tenesmus, dyschezia and large intestinal diarrhoea?
Parasitic colitis
Idiopathic colitis
Granulomatous colitis
Idiopathic large intestinal diarrhoea
Intussusception
What are some of the parasitic causes of colitis?
Giardia
Trichuris
Tritrichomonas foetus
Which specific form of intusussception can cause faecal tenesmus, dyschezia and large intestinal diarrhoea?
Intussusception where a portion of the small intestine becomes invaginated within the large intestine
Which diagnostic tests can be useful when investigating faecal tenesmus and dyschezia combined with large intestinal diarrhoea?
Faecal analysis
Rectal cytology
Diagnostic imaging
Colonoscopy and mucosal biopsy
Which differentials are you ruling out with faecal analysis?
Faecal analysis can be used to rule out parasitic and infectious causes of large intestinal disease
What are the benefits of faecal cytology?
Faecal cytology can be used to indicate fungal disease or algae diseases such as prototheca (rare)
Which differentials are you ruling out diagnostic imaging?
Diagnostic imaging can be used to rule out some extramural disease, intussusception, lymphadenopathy (which could indicate neoplasia), intestinal wall thickening, as well as help determine if colonoscopy is appropriate for further diagnostics
What is tritrichomonas foetus?
Tritrichomonas foetus is a protozoal infection which is an important cause of colitis in cats
Which signalement is most prone to tritrichomonas foetus?
Young pedigree cats
What are the clinical signs of tritrichomonas foetus?
Asymptomatic
Large intestinal diarrhoea
Faecal tenesmus
Faecal incontinence
How can you diagnose tritrichomonas foetus?
Faecal wet preparation
In-pouch culture
PCR
What is a faecal wet preparation?
A faecal wet preparation is where you mix a faecal sample with saline and assess it under a microscope
Which diagnostic method is the most specific to tritrichomonas foetus?
PCR
How do you treat tritrichomonas foetus?
Ronidazole
High fibre diet
Probiotics
What should you be aware of when using ronidazole to treat tritrichomonas foetus?
Ronidazole is not licensed in the UK and can have severe neurological side affects if dosed incorrectly
What is idiopathic colitis?
Idiopathic colitis is idiopathic, potentially immune mediated, inflammation of the colon
Which disease is idiopathic colitis often concurrent with?
Chronic idiopathic enteropathies/inflammatory bowel disease (IBD)
How do you diagnose idiopathic colitis?
Idiopathic colitis is diagnosed through the exclusion of other causes of faecal tenesmus and dyschezia combined with large intestinal diarrhoea, along with a colonoscopy guided biopsy with changes compatible with idiopathic colitis on histopathology
How do you manage idiopathic colitis?
Dietary modification
Antibiotics
Anti-inflammatory drugs
Immunosuppressive therapy
Often requires a lot of trial and error, make owners aware of this
Start with diet and antibiotics
What dietary modifcations are recommended for idiopathic colitis?
Fibre supplementation (e.g. psyllium)
Hydrolysed protein diet
Hypoallergenic diet
What is the mechanism of action of psyllium fibre?
Colonic bacteria ferment the psyllium fibre which results in the production of short chain fatty avids which can provide an energy substrate for colonocytes, maintain intestine electrolyte and fluid balance, maintain normal colonic motility, prevent pathogenic bacterial overgrowth and ameliorate intestinal inflammation
Why are hydrolysed protein diets recommended for idiopathic colitis?
Idiopathic inflammation may result as a consequence of an abnormal immune response to dietary antigens. The hydrolysis of proteins removes allergens that a patient may have been sensitised to and may also remove potential allergens in a naive patient, thereby preventing sensitisation
Which antibiotic is recommended for the management of idiopathic colitis?
Metronidazole
Why is metronidazole recommended in the management of idiopathic colitis?
Metronidazole has spectrum of activity against clostridium perfringens which has been implicated as a potential cause of idiopathic colitis
Which anti-inflammatory drug can be used for managing idiopathic colitis?
However this drug is falling out of favour
Sulfasalazine
What is the mechanism of action of sulfasalazine?
Sulfasalazine is an anti-inflammatory drug which is broken down into its active ingredients by bacteria in the colon, which inhibit the production of proinflammatory mediators, allowing for local anti-inflammatory effects in the colon
What is a potential side effect of sulphasalazine?
Keratoconjunctivitis sicca
What is the first line drug for immunosupporessive therapy when managing idiopathic colitis?
Prednisiolone. However if this is ineffective you can also administer cyclosporin
Which dogs breeds are prone to granulomatous colitis?
Boxers
French Bulldogs
Which age-group is more prone to granulomatous colitis?
Young dogs (less than 4 years of age)
Which bacteria is the most likely cause of granulomatous colitis?
Escherichia coli (E. coli)
What are the clinical signs of granulomatous colitis?
Large intestinal diarrhoea (haemorrhagic and mucoid)
Faecal tenesmus
Dyschezia
Anaemia
Hypoproteinaemia
Weight loss
How do you treat granulomatous colitis?
Treat granulomatous colitis with fluoroquinolones
Why is it so important to get a mucosal biopsy before beginning treatment of granulomatous colitis?
You should do a colonoscopy guided mucosal biopsy to allow you to do culture and sensitivity to determine which fluroquinolones the E.coli are resistant to so you choose the correct antibiotic for treatment
What is idiopathic large intestinal diarrhoea?
Idiopathic large intestinal diarrhoea is intermittent large intestinal diarrhoea characterised by increased frequency of diarrhoea and faecal tenesmus. In patients with this condition, haematology, biochemistry, faecal analysis, colonoscopy evaluation and histopathology of colonic mucosa will all come back normal
How do you manage idiopathic large intestinal diarrhoea?
Dietary modification with supplementary dietary fibre, specifically psyllium fibre
What are the differential diagnoses for faecal tenesmus, dyschezia and constipation?
Mechanical obstruction
Neuromuscular dysfunction
Metabolic disease
Endocrine disease
Perineal disease
List some examples of mechanical obstruction which can cause constipation
Foreign body impactions
Colorectal stricture
Colorectal neoplasia
Rectal polyp
Perineal hernia
Pelvic fracture
Pelvic stenosis
Prostatic disease
What can be used to shrink colorectal neoplasms?
Topical peroxicam suppositories have an anti-inflammatory effect and can be used to shrink colorectal neoplasms which can improve clinical signs
List some examples of neurological dysfunction which can cause constipation
Lumbosacral disease
Hypogastric or pelvic nerve dysfunction
Colonic smooth muscle dysfunction
List some examples of metabolic diseases which can cause constipation
Dehydration
Hypokalaemia
Hypercalcaemia
Obesity
List some examples of endocrine disease which can cause constipation
Hypothyroidism
Not a common cause of constipation
Which diagnostic tests can be useful when investigating faecal tenesmus and dyschezia due to constipation?
Rectal examination
Biochemistry
Thyroid function tests (T4/TSH)
Diagnostic imaging
Barium contrast enema (good for assessing for strictures)
Colonoscopy
What is megacolon?
Megacolon is the abnormal dilatation of the colon due to abnormal function of the muscles in the colon wall, resulting in faecal material accumulating within the distended colon rather than being pushed into the rectum
Which species is most prone to megacolon?
Cats
What is the most common cause of megacolon?
The most common cause of megacolon is unrelieved or recurrent constipation resulting in obstipation and megacolon. The megacolon will then exacerbate the constipation and obstipation as the faecal material will accumulate within the distended colon
What is obstipation?
Obstipation is intractable constipation
What are the most common causes of obstipation in cats?
Idiopathic megacolon
Pelvic stenosis
Sacral deformaties
Nerve damage
Note a few of these can be caused by road traffic accidents
What is the typical history associated with feline constipation, obstipation and megacolon?
Chronic history of reduced faecal output ± faecal tenesmus and dyschezia. There may be a history of road traffic accident/pelvic trauma
What are the potential clinical signs of feline constipation, obstipation and megacolon?
Constipation
Obstipation
Intermittent haematochezia
Intermittent mucoid diarrhoea
Vomiting
Weight loss
Inappetence
How do you manage constipation, obstipation and megacolon in cats?
Achieve and maintain normal hydration
Remove impacted faeces
Dietary modification
Laxatives
Prokinetic drugs
Which methods can be used to remove impacted faeces?
Enema
Manual evacuation of faeces
Which dietary modifications are recommended for cats with constipation, obstipation and megacolon?
Dietary fibre supplementation, specifically psyllium fibre
Which laxatives can be used in cats with constipation, obstipation and megacolon?
Psyllium fibre
Movicol
Lactulose
Which prokinetics can be used in cats with constipation, obstipation and megacolon?
Cisapride
Ranitidine
What should be done if medical management of constipation, obstipation and megacolon in unsuccessful?
Subtotal colectomy
What are the potential consequences of megacolon in cats?
Colitis
Colonic ulceration
Colonic perforation
List some examples of perineal and perianal disease (which can cause faecal tenesmus and dyschezia)
Anal sacculitis
Anal impaction
Anal neoplasia
Anal furunculosis
Perineal hernia
What is anal furunculosis?
Anal furunculosis is a chronic inflammatory, immune mediated disease resulting in ulceration and fistulous tracts in the anal and perineal area
Which disease can anal furunculosis commonly occur concurrently with?
Idiopathic colitis
Which dog breed is prone to anal furunculosis?
German Shepherds
How do you manage anal furunculosis?
Clean the area to reduce secondary bacterial infections
Antibiotics to treat secondary bacterial infections
Analgesia
Stool softener
Immunosuppressive therapy
Make owners aware that due to being an immune mediated conditon, can recur
Which immunosuppressive drug is recommended for treating anal furunculosis?
Ciclesporin
What is the main disadvantage of ciclesporin?
Ciclesporin is very expensive for long term management of anal furunculosis
What can be used to reduce the cost of ciclesporin when treating anal furunculosis?
Ciclesporin can be combined with ketoconazole as ciclesporin is metabolised in the liver by cytocrome P450 enzymes, and ketoconazole inhibits cytochrome p450 enzymes, reducing the dose of ciclesporin required
Which immunosuppressive drug should be used to treat severe or refractory anal furunculosis?
Topical tacrolimus
What are some of the potential consequences of anal furunculosis?
Anal strictures
Faecal incontinence
What is a perineal hernia?
A perineal hernia is where the muscles in the pelvic diaphragm weaken causing a loss in lateral support of the rectum causing subcutaneous herniation of the rectum. Faecal material and even the urinary bladder can become entrapped in this herniated area resulting in perineal swelling
Which signalement is prone to perineal hernias?
Older male, intact dogs
How do you treat perineal hernias?
Surgical repair
This is not a day one skill
What are the two classifications of faecal incontinence?
Sphincter incontinence
Reservoir incontinence
What are the three main causes of sphincter incontinence?
Neurological dysfunction
Trauma to the internal or external anal sphincter
Aging
What are the two most common neurological causes of sphincter incontinence?
Lumbosacral disease
Degenerative myelopathy in German Shepherds
What are the two most common causes of trauma to the anal sphincter resulting in feacal incontinence?
Anal furunculosis
Surgical trauma
Which surgeries can result in sphincter incontinence?
Owners should be made aware of this risk
Anal sacculitis surgery
Perineal hernia surgery
How do you treat sphincter incontinence?
Sphincter incontinence is usually permanent and irreversible
What is reservoir incontinence?
Reservoir incontinence is failure of the large intestine to accomadate faecal content due to colorectal irritation (i.e. colitis), decreased capacity/compliance of the large intestine or increased volume of faeces
How do you treat reservoir incontinence?
To treat reservoir incontinence, treat the underlying disease and the incontinence should resolve
