16. Diseases of the large intestines in dogs and cats. Perineal/perianal diseases Flashcards
Diseases of the Large Intestine and Acute Colitis?
Diseases Of The Large Intestine
ACUTE COLITIS
Usually self-limiting; Cause is rarely identified
Potential causes
Diet: Fibre deficiency; Food intolerance; Indiscretion
Parasitic
§ Trichuris vulpis § Giardia spp.
§ Tritrichomonas spp. § Cryptosporidium spp.
Bacteria and their toxins
§ Salmonella typhimurium § C. difficile
§ Campylobacter jejuni § C. perfringens
§ Yersinia enterocolitica § Brachyspira pilosicoli
Fungal & Algal
§ Histoplasma spp.
§ Pythium insidosum
General treatment
Diet
24 hours of fasting
Low-fat; Hypoallergenic
Highly-digestible food
Fibre supplement
Metronidazole; Tylosin
Trichuris vulpis (Whipworm)
§ CSx: Intermittent diarrhoea;
§ Dx: Eggs in faeces; Colonoscopy; Intermittent evacuation
§ Tx: Fenbendazole
Tritrichomonas spp.
§ T. foetus; Distal ileum → Colon; Seen in young cats
§ Similar to Giardia spp. → Misdiagnosis is common
§ CSx: Intermittent, cow-pat-like & sticky faeces
§ Dx: Faecal smear; PCR & culture; Biopsy
§ Tx: Ronidazole
Cryptosporidium spp. [Zoonotic]
May be present in low numbers, physiologically
§ Seen mostly in young animals
§ CSx: Diarrhoea
§ May be associated with other parasites e.g worms &
Giardia spp.
§ Tx: Treat underlying diseases; Symptomatic treatment
C. perfringens
§ CSx: Acute haemorrhagic diarrhoea syndrome (HGE)
§ Dx: Faecal smear (spores in faeces); Culture; ELISA; PCR
§ Tx: Tylosine; Amoxiclav; Metronidazole; Ampicillin
Chronic Colitis?
CHRONIC COLITIS
Middle-aged; Dog or cat
§ Lymphocytic-plasmocytic colitis (LPC)
§ Plasmocytic colitis (PCC)
§ Eosinophilic colitis (EC)
§ Chronic histiocytic ulcerative colitis (CHUC)
Diagnosis in general: Based on histological evidence of mucosal
inflammation
Differential diagnosis
§ Systemic diseases § Infectious diseases
§ Chronic parasitism § Neoplasia
§ Dietary sensitivity
Causes (multifactorial)
§ Defective mucosal barrier function
§ Abnormal immune response e.g to luminal pathogen; TLR
mutation
§ Dysbiosis
§ Genetics
§ Dietary antigens
Lymphocytic-plasmocytic colitis (LPC)
Where inflammatory cells infiltrate the lining of the GIT due to an
abnormal immune response
§ The most common form of chronic colitis
§ Middle/older-aged
§ CSx (usually intermittent/cyclical): Tenesmus; Mucoid
faeces; Haematochezia
§ Dx: ↑ Mucosal friability; Granularity; Loss of submucosal
vascularity; Erosions
Eosinophilic colitis (EC)
Eosinophils gather in the colon → Injury & irritation
§ Middle-aged animals
§ CSx: Like LPC; Roughened irregular mucosa
§ Dx: Colonoscopy – More friable & ulcerated than LPC
Chronic histiocytic ulcerative colitis (CHUC)
Disease with unknown aetiology, causing inflammation & ulceration
of the GIT mucosa
§ Predisposed: Boxer; French bulldog; Young males
§ Causes: Adherent-invasive-E.coli (AIEC) +
Aberrant immunosystem or
Mutant TLR or
Genetic defect
§ CSx: L. bowel diarrhoea; Lethargy; Anorexia
§ Diagnosis
Histopathology: PAS + Macrophages in mucosa
Friable mucosa; Thicker; Granular; Erosions; Ulcers
§ Tx: Enrofloxacin
Irritable bowel syndrome (IBS)
Uncommon; Non-inflammatory large bowel disease
Abnormal colonic myoelectrical function
§ Large-breed dogs; Stress-induced
§ CSx: Chronic, intermittent l. bowel diarrhoea; Tenesmus;
Mucoid faeces; Haematochezia
§ Dx: By exclusion – Diet, parasitic, Infectious, IBD;
Colonoscope biopsy = Normal
§ Tx: To correct abnormal motility – Dietary fibre;
Anxiolytics; Loperamide
Colonic neoplasia
Dogs: Adenocarcinoma; Lymphosarcoma; Leiomyosarcoma
Cats: Adenocarcinoma; Lymphosarcoma; Mast cell tumour
Generic treatment
GENERIC TREATMENT OF LARGE BOWEL DISEASE
Dietary
§ Novel protein (hypoallergenic)
§ High digestibility
§ High fibre
NSAIDS (Ø cats):
§ Mesalazine (or mesalamine)
§ Balsalazide
§ Olsalazine
Anti-inflammatories/Immunosuppressants
§ Prednisolone
§ Budesonide
§ Chlorambucil
§ Cyclosporin
Antibiotics
§ Metronidazole
§ Tylosin
§ Amoxiclav
§ Ampicillin
§ Enrofloxacin
Perineal/Perianal diseases Incontinency?
Perineal/Perianal diseases
INCONTINENCY
Loss of the ability to control bowel movements
Two subtypes:
§ Reservoir incontinence: Disease of the rectum preventing
the storage of stools in a normal manner
§ Sphincter incontinence: Inability of the anal sphincter to
remain in a closed position → Leakage of faeces; Usually
associated with nerve damage
Clinical signs
These vary depending on the severity and underlying cause
§ Leaking of small volumes of stool without awareness
Sphincter incontinence: Redness; Inflammation; Drainage from
the rectum; Licking of the anal region
Because this may be nerve-related, changes in how the tail is
carried may be seen.
Reservoir incontinence: Dog is aware of defecation, but cannot
control it; Defecation in strange places;
Faeces – Soft, bloody, or mucoid
Diagnosis
§ Thorough physical exam; RDP
§ Thorough neurological exam
§ Suspected neurological cause: Radiology of spine
§ Suspected intestinal cause: Faecal floatation; Blood test;
US; Endoscopy; Surgical biopsy
Treatment
Depends on the underlying cause; Identify the cause first
Perianal fistula?
PERIANAL FISTULA
Abnormal connection between the anal canal and the perianal region
AKA anal furunculosis; Serious medical condition
Intact males; Middle aged; German Shepherd
Possible causes:
Not fully understood
§ Anal gland impaction/ infection
§ Poor air circulation around the anal region
§ Auto-immune disease
§ Genetic disposition
Clinical signs
§ Early stages: Few CSx
§ Straining during defecation
§ Blood in faeces
§ Anorexia
§ Behaviour: Licking of tail/anal region; Aggressiveness;
Depressed
Characterised by chronic, purulent, smelly, ulcerating sinus tracts
in the anal region
Treatment
§ Immune-modulating drugs – Divided into an induction
phase and then a maintenance phase → Tacrolimus (top.);
Cyclosporine (PO)
§ Antibiotics
§ Hypoallergenic diet
§ ↑ Ventilation of the perianal region (clipping; bathing)
§ Severe: Surgery (+ cryotherapy)
Anal sac disease?
ANAL SAC DISEASE (BRIEF)
Predisposed: Overweight dogs
§ Impaction
§ Inflammation (Sacculitis/proctisis)
§ Abscessation: Painful; Red; Hot; Swollen; May produce
pus if burst
Clinical signs
§ Malodorous, oily fluid from the perianal region
§ Scooting; Dragging; Excessive licking; Biting of perianal
region
§ Pain
§ Blood; Pus drainage from the rectum
Treatment
§ Impaction: Expressing the anal sacs (+ flushing if
necessary); Sedation/Anaesthetic
§ Antibiotics: Clindamycin
§ Pain relief: Meloxicam
§ Surgery in rare cases
§ High fibre diet
§ Treat any underlying cause
Anal Prolapse?
ANAL PROLAPSE
Rectum becomes everted and protrudes out of the anus
Appears red/pink, tubular, crusty, oozy or dark
Causes
§ Straining to defecate for a prolonged time
§ Intestinal worms
§ Dehydration
§ Constipation
§ Diarrhoea
§ Ileus
Over time, these may lead to weakening of the structures that
secure the rectum in place.
Clinical signs
§ Tenesmus
§ More frequent defecation than usual
§ Change in the faecal consistency – Dry; Small; Worms
Diagnosis: Physical exam; RDP
Treatment
§ Clean the area → Replace back into original position
§ Sedation; Anaesthesia
§ Purse-string suture
§ Antibiotics
§ Analgesia
§ Collar
§ Treatment of the underlying cause
If the rectum cannot be replaced, surgery may be required
Removal of damaged tissue
Colpopexy
ANAL SAC ADENOCARCINOMA
