Vomiting is often preceded by restlessness, salivation, and retching, and requires forceful abdominal contractions to expel the stomach contents. One must differentiate acute from chronic vomiting. One must also differentiate vomiting from regurgitation, which is the effortless evacuation of fluid, food, or mucus from the esophagus. The causes, diagnostic tests, and treatments for regurgitation are quite different from those for chronic vomiting.
Chronic vomiting generally does not respond to symptomatic therapy, and most often necessitates a full diagnostic work-up to determine the underlying cause. If the patient continues vomiting despite being kept off food, if the vomiting is recurrent, and/or if blood is present in the vomitus, your veterinarian should examine the animal. In addition, if your pet appears to be in distress, seems painful, lethargic, or sick in any other way, you should contact your veterinarian at once.
Chronic vomiting can be caused by diseases of the gastrointestinal tract or can occur secondary to other systemic diseases. It is important to try to establish the cause of chronic vomiting. If the underlying cause is not removed or treated, it is unlikely the vomiting will resolve. Chronic, recurrent dietary indiscretion can include eating spoiled food, overeating, ingesting foreign material, and sudden dietary changes.
Dietary intolerance is a reaction to some normal food component. It is most often a response to a particular protein, but can be associated with lactose, diets high in fat, and certain food additives.
Bacterial causes of chronic vomiting include Salmonella and Helicobacter.
Fungal causes of chronic vomiting include histoplasmosis, aspergillosis and phycomycosis
Parasitic causes of chronic vomiting include roundworms, hookworms, and Giardia.
Administration of certain drugs and/or exposure to toxins can cause chronic vomiting by directly irritating the lining of the gastrointestinal tract. Examples include nonsteroidal anti-inflammatory drugs, corticosteroids, certain antibiotics, insecticides, heavy metals, and lawn and garden products, etc.
Slowly developing obstruction or blockage of the gastrointestinal tract may cause chronic vomiting. Obstruction may be secondary to foreign bodies, tumors, intussusceptions (telescoping of the bowel into itself), parasites, and other structural abnormalities.
Metabolic diseases, such as kidney and liver diseases, uncontrolled diabetes mellitus, and hyperthyroidism may cause vomiting, although it is more common for these diseases to cause acute episodes of vomiting.
Some abdominal disorders may result in chronic vomiting. Examples include chronic pancreatitis (inflammation of the pancreas), kidney infections, tumors in other abdominal organs, adhesions of the abdominal organs, etc.
Motility disorders of the stomach and small intestines are an important cause of chronic vomiting. With these diseases food does not leave the stomach and intestines as it normally does and builds up in the stomach where it induces vomiting.
Inflammatory bowel disease (IBD) is an inflammation of the walls of the gastrointestinal tract, and may be an immune disorder in some animals. Chronic vomiting with IBD may be accompanied by diarrhea, weight loss, and a change in appetite.
Certain maldigestion and malabsorption problems, such as lymphangiectasia cause chronic vomiting, diarrhea, and weight loss.
Gastrointestinal ulcers associated with intestinal diseases and tumors, liver disease, and kidney disease may result in chronic vomiting, but such ulcers are uncommon.
Constipation is infrequent, incomplete, or difficult defecation with the passage of hard, dry feces. Vomiting may occur secondary to constipation.
Slow growing tumors of the gastrointestinal tract may produce intermittent vomiting that tends to get worse with time.