Motility disorders

Intestinal motility disorders are not very well characterized as a primary cause of small intestinal disease in dogs and cats. However, secondary alterations in the motility of the small intestine occur in many diseases.

Most often, hypomotility of the intestines and ileus are seen after abdominal surgery, or during ischemic or inflammatory conditions, such as peritonitis, pancreatitis, or parvovirus infection. In malabsorptive disorders, undigested and osmotically active particles in the intestinal lumen can decrease the transit time. Dietary management should be attempted at first. Small amounts of a low-fat, low- protein diet given at frequent intervals can help reduce the symptoms of delayed gastric emptying. Medical therapy can be attempted if dietary management alone is unsuccessful (Table 5.6). Metoclopramide or domperidone act peripherally at

Table 5.6: Prokinetic agents. This table shows a list of commonly used gastric and small intestinal prokinetic agents.⁷⁹

Compound	Commonly used dose
Cisapride	0.1-0.5 mg/kg PO q 8-12 h
Erythromycin	0.5-1 mg/kg PO q 8 h
Metoclopramide	0.2-0.5 mg/kg PO or SC q 8 h 0.01-0.02 mg/kg/h as a CRI
Nizatidine	2.5-5 mg/kg PO q 24 h
Ranitidine	1-2 mg/kg PO or IV q 12 h

dopaminergic receptors and promote antral contractions. These compounds are contraindicated if an intestinal obstruction is suspected. Cisapride has also been successfully used for the treatment of delayed gastric emptying. While this drug has been withdrawn from the market, it can still be acquired through compounding pharmacies and can be used at dosages of 0.1-0.5 mg/kg PO q 8 h.

Erythromycin at lower dosages than those recommended for antibacterial treatment regimens (1 mg/kg PO q 12 h) can also stimulate gastric emptying by inducing an interdigestive motor pattern. This causes larger particles to pass into the duodenum faster than with normal antral contractions and may lead to a worsening of the symptoms if the motility disorder is primarily located in the small intestine as erythromycin also stimulates small intestinal motility. Newer prokinetic agents are ranitidine and nizatidine, which act as acetylcholinesterase inhibitors in the stomach and the small intestine. Hypothyroidism in dogs and hyperthyroidism in cats may also alter intestinal transit time and cause diarrhea.

Feline dysautonomia is caused by a degeneration of autonomic ganglia and can cause constipation and decreased anal tone among other signs of sympathetic and parasympathetic dysfunction, such as dysuria, mydriasis, vomiting, regurgitation, and diarrhea.⁷⁷ Treatment is largely supportive and the overall prognosis is poor.

Key Facts

■ Important viral infections that can cause primary intestinal disease are canine parvovirosis and canine distemper in unvaccinated puppies. Supportive care, including antibiotic therapy for the prevention of septicemia, is the treatment of choice.

■ Helminthic parasite infections are common in both dogs and cats. Ancylostoma and ascarids can cause significant disease in small animals.

■ Many enteropathogenic bacteria can be isolated from the feces of healthy dogs and cats and when such pathogens are found in the feces in animals with diarrhea, it is often difficult to distinguish primary infections from opportunistic secondary infections.

■ Many bacterial infections in the gut are self-limiting and the indiscriminate use of antibiotics is not advised.

■ Although dogs and cats do not appear to play a central role in the epidemiology of gastrointestinal infections in humans, caution is warranted when pets, shedding potential bacterial or protozoal pathogens, have close contact with immune-compromised individuals.

■ The diagnosis of gastrointestinal protozoal infections may be challenging and requires the examination of several fecal samples and /or using immunoassays or PCR-based assays on fecal material.

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Source: Steiner J.M. (ed.). Small Animal Gastroenterology. Schluetersche,2008. — 387 p.. 2008

Motility disorders

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