16. Diseases of the large intestines in dogs and cats. Perineal/perianal diseases Flashcards

1
Q

Diseases of the Large Intestine and Acute Colitis?

A

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

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2
Q

Chronic Colitis?

A

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

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3
Q

Generic treatment

A

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

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4
Q

Perineal/Perianal diseases Incontinency?

A

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

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5
Q

Perianal fistula?

A

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)

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6
Q

Anal sac disease?

A

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

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7
Q

Anal Prolapse?

A

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

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