It is essential to identify the underlying cause of feline diarrhea before an appropriate and effective treatment protocol can be developed. In many cases, the source of the problem can simply be removed or avoided – such as removing dietary ingredients that are not well tolerated by a particular cat – and the diarrhea will quickly resolve. If the cause is not readily apparent, the attending veterinarian has a number of diagnostic and management tools available to treat affected cats. Cats become dehydrated very quickly when they lose water through prolonged bouts of diarrhea. If the problem persists for more than 24 hours, the cat should see a veterinarian. The owner should bring along a fresh fecal sample, if at all possible.
The goals of treating diarrhea are to restore hydration, prevent further fluid volume depletion, identify and remove the underlying cause of the condition if possible and prevent passage of infectious microorganisms to other pets and to people.
When presented with a cat suffering from diarrhea, the veterinarian will perform a thorough physical examination, take a complete history and most likely take a fecal sample to check for the presence of internal parasites, protozoa and abnormally high numbers of bacteria in the stool. A number of different techniques are available for fecal evaluation. Other diagnostic tools include a complete blood count and serum chemistry panel, urinalysis, abdominal radiographs, abdominal ultrasonography, fecal culture, urine protein-to-creatinine ratio, serum bile acid levels, serum folate and cobalamin levels, endoscopy, intestinal biopsy and assessment of serum T4 levels (for hyperthyroidism).
If parasites are present, several broad spectrum oral de-wormers are available to remove the adults and their eggs and larva from the cat’s digestive tract. It can be difficult to identify protozoa during a fecal assessment, although there are techniques such as iodine staining, centrifugal flotation with zinc sulfate and enzyme-linked immunosorbent assay (ELISA) that improve the chances of finding protozoal organisms in a stool sample.
Most cats with diarrhea will be fasted for 24 to 36 hours, depending upon the severity of their condition and their overall health. They should have access to small amounts of water or crushed ice during this period. They typically will then be started on a bland, low-fat, highly digestible diet with small, frequent meals. Common ingredients include rice, potatoes, tofu, strained meat baby food, yoghurt and/or low-fat cottage cheese. Gradually, the cat’s normal diet (or a new one, if recommended by the veterinarian) will be reintroduced over the course of several days. Specific prescription diets are available for cats with diarrhea. These diets are low in fat and contain a moderate amount of fiber. Veterinarians may recommend an elimination diet, if a food allergy is suspected. Novel protein sources - such as venison, fish, duck, rabbit and bison - are increasingly available in commercial feline diets. Dehydrated cats can be given intravenous or subcutaneous fluids to restore normal electrolyte and volume balance.
If the bacterial count in the cat’s stool is abnormally high, the veterinarian can prescribe broad-spectrum antibiotics to restore balance of the normal intestinal flora. Metronidazole is a common drug used to treat bacterial diarrhea. Other medications are available to help reduce inflammation, relieve intestinal irritation and pain, soothe the intestinal lining, reduce intestinal spasms, relieve nausea and vomiting, firm up the feces and add bulk to loose stool.
The outlook for cats suffering from diarrhea depends almost entirely upon the cause of their condition, although owner compliance and individual variation in response to treatment can also play a role. Diarrhea associated with an underlying systemic disease, and that caused by ingested toxins, intestinal obstruction or torsion, can rapidly become life-threatening and carries a guarded to fair prognosis. The prognosis for cats with diarrhea caused by cancer depends upon the type of cancer involved. Diarrhea caused by internal parasites, most infectious organisms, dietary indiscretion (“garbage gut”; less common in cats than in dogs), food allergies or bacterial overgrowth from long-term antibiotic use usually is less serious and relatively easy to treat. The prognosis for cats with diarrhea from one of those conditions is good to excellent.