Clinical problem and differentials.
Vomiting is the forceful ejection of stomach and proximal duodenal contents through the mouth. Vomiting can be induced by
vestibular, vagal, chemoreceptor trigger zone, or direct input to the emetic center. Diarrhea is a characterized by increased
frequency of defecation, increased fluid content of the stool, or increased volume of stool. Markedly increased frequency
of defecation, small volume stools, tenesmus, urgency, hematochezia, and mucus are consistent with large bowel diarrhea. Slight
increase in frequency of defecation, large volume, melena, steatorrhea, and polysystemic clinical signs are more consistent
with small bowel diarrhea. Mixed bowel diarrhea is a combination of characteristics or clinical signs. Gastrointestinal (GI)
signs can be the result of primary diseases of the GI system or secondary GI diseases. The secondary GI diseases are generally
those of the kidneys, liver, pancreas (pancreatitis or exocrine pancreatic insufficiency), endocrine system (hypoadrenocorticism;
diabetic ketoacidosis; hyperthyroidism), or central nervous system. Differential diagnoses for primary GI diseases are often
grouped into obstruction (masses, foreign body, and intussusception), dietary intolerance, drugs/toxins (garbage gut), inflammatory
gastric and bowel diseases, neoplasia, infectious diseases, and parasites. The primary bacteria associated with gastrointestinal
tract disease in cats include Salmonella spp., Campylobacter jejuni, Clostridium perfringens, Helicobacter spp., bacterial overgrowth syndrome, bacterial peritonitis, and bacterial cholangiohepatitis. The primary viral agents include
feline coronaviruses, feline leukemia virus, feline immunodeficiency virus, and feline panleukopenia virus. The primary nematodes
are Ancylostoma/Uncinaria, Strongyloides cati, Dirofilaria immitis (vomiting), Toxocara cati, Toxascaris leonina, Ollulanus tricuspis, and Physaloptera spp. Enteric protozoans include Giardia spp., Cystoisospora spp., Cryptosporidium spp., Entamoeba histolytica, and Tritrichomonas foetus. The cestodes Taenia, Dipylidium, and Echinococcus generally cause subclinical infection.
Diagnostic procedures for infectious diseases
Liquid feces or feces that contains large quantities of mucus should be microscopically examined immediately for the presence
of protozoal trophozoites, including those of Giardia spp. and Tritrichomonas foetus. A direct saline smear can be made to potentiate observation of these motile organisms. The amount of feces required to cover
the head of a match is mixed thoroughly with one drop of 0.9% NaCl. Following application of a coverslip, the smear is evaluated
for motile organisms by examining it under 100X magnification. The sample should be fresh. The material for evaluation should
be collected from the surface of the fecal material, preferably mucous if present. Alternately, a rectal scraping can be used.