The veterinarian will take a thorough history and perform a physical examination in order to determine the severity of the illness, how long it has been occurring, and to differentiate vomiting from regurgitation. Although uncommon in cats, regurgitation is a passive act in which food flows back up the esophagus, the tube connecting the mouth and stomach. Shortly after eating, at the time when this occurs, the food usually will appear undigested and shaped like a tube. Regurgitation carries different possible diagnoses than vomiting and should be addressed accordingly.
Vomiting is a reflex action in which material is expelled from the stomach and/or intestines through the mouth. It is usually preceded by nausea and involves retching. Cats with acute vomiting that are not very ill may be treated symptomatically for a short time before diagnostic tests are pursued. Testing is appropriate when the vomiting is severe, the cat seems very ill and fails to respond to appropriate therapy, or when the vomiting is chronic.
Common tests include fecal examination, urinalysis, and routine bloodwork, such as a complete blood count and chemistry panel. Other relevant blood tests include thyroid hormone level and viral serology for feline leukemia virus and feline immunodeficiency virus. Abdominal x-rays commonly are needed.
Sometimes the veterinarian may perform a barium contrast study. Liquid barium outlines the gastrointestinal tract on x-rays and helps determine if there are any abnormalities. Other diagnostic tools include ultrasonography, which uses high frequency sound waves to outline the details of the abdomen. Another procedure, endoscopy, involves placing a tiny camera down the mouth and into the stomach and intestines to look for disease. Also, tissue samples can be taken and sent to a pathologist for assessment. In other cases, exploratory surgery is needed to diagnose the problem.
Depending on the underlying cause, some cases of chronic vomiting in cats are very difficult and frustrating to diagnose and treat. A referral to an internal medicine specialist for further diagnostics and treatment may be indicated in some cases.
