Constipation (dyschezia) is defined as fecal passing less than three bowel movements per week. This condition is relatively common in dogs and in most cases caused by dietary (high-protein, low fibre) or age-related problems (back pain), dehydration and inactivity.
Although constipation is a symptom, rather than a disease, it may be the cause of severe secondary diseases resulting from enteral fermentation, inducing toxic gas, and therefore requires active prevention and proper treatment.
Uncommon causes include:
- Peripheral neuropathy - hypertrophic megacolon, chronic progressive autonomic dysfunction
- Obstructive disease (pelvic fractures, pelvic granulomas, intestinal lymphoma, benign prostatomegaly, hernia, intestinal stricture, foreign body obstruction, longitudinal intestinal torsion, postoperative ileus, intestinal pseudo-obstruction)
- Endocrine disease - hypothyroidism, diabetes mellitus or hypokalemia
- Drugs - morphine, buprenorphine, anticholinergic compounds or excess dietary calcium
- Idiopathic factors
- Anal sacculitis, anal sac adenocarcinoma, anal melanoma
- Atresia ani, rectovestibular fistula
- Mucocutaneous systemic lupus erythematosus
Most dogs present clinically with delayed fecal movements, considerable straining and often intermittent attempts at defecation. In prolonged bouts, blood may be evident on the surface of feces.
In intractable cases, a distended abdomen is evident wand the dog is usually anorexic, lethargic and reluctant to eat. Rare cases of hepatic encephalopathy have been reported due to fermentation of ammonia-producing colonic bacteria.
The most common functional food remedy for constipation is dietary fiber, but prokinetic drugs such as cisapride, dioctyl sodium sulfosuccinate (Coloxyl) and lactulose are frequently used in intractable cases.
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