Page 771 - Problem-Based Feline Medicine

34 – THE CAT WITH SIGNS OF LARGE BOWEL DIARRHEA 763

QUICK REFERENCE SUMMARY
Diseases causing signs of large bowel diarrhea
ANOMALY

● Congenital malformations (e.g. diverticulum, short colon syndrome, vascular ectasia) (p 779)
All are rare conditions that are observed in young cats or kittens, with the severity depending on
the anomaly (e.g. short colon syndrome causes severe signs, while vascular ectasia and diverticular
formations may initially be clinically silent.

MECHANICAL
● Irritant (foreign body) colitis** (p 765)
This is the acute development of colitis manifest by the presence of mucoid- to blood-streaked
feces resulting from ingestion of hair, bones, string, feathers or other foreign material.
● Perineal hernia (p 776)
Perineal hernias cause perineal swelling associated with a mucoid- or blood-streaked fecal mass
and straining to defecate. In long-standing cases, constipation may occur.
● Perianal tumors (p 777)
The tumor mass may cause straining to defecate and other signs of large bowel disease, or it may
obstruct the passage of feces and cause constipation.

METABOLIC
● Hyperthyroidism* (p 771)
Hyperthyroidism may cause voluminous, soft and mucoid feces due to increased intake and reduced
GI transit time, changes in metabolism (malassimilation of food) and motility disturbances.
● Pseudomembraneous colitis (antibiotic-induced colitis) (p 777)
Acute or chronic large bowel diarrhea may be caused by the use of anaerobic antibiotics
resulting in overgrowth of pathogenic species that may be resistant to many or most antibiotics.
Severe forms of this disease are rare in cats, but diarrhea due to antibiotic use is not
uncommon.
NEOPLASTIC

● Colonic adenocarcinoma* (p 774)
This is the most common non-hematopoietic tumor of the GI tract and the most common colonic
tumor in cats. It typically affects old cats (>10 years) and vomiting, weight loss and lethargy are
more common signs than diarrhea.
● Lymphosarcoma* (p 773)
Lymphosarcoma tends to cause infiltrative disease that affects both the large and small intestine,
but may be localized to the colon in some cases causing only signs of large bowel disease.
● Colorectal polyps (p 778)
These are benign growths that are clinically silent until they grow large enough to prevent normal
fecal passage and cause large bowel diarrhea or constipation. Most cases reported in Siamese
cats.

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