Acute Vomiting in Dogs

Vomiting is defined as the forceful discharge of ingested material from the stomach and sometimes part of the small intestines (yellow bile), which is initiated by the central nervous system. It is a common clinical sign in small animals. It is a protective mechanism developed to remove potentially damaging ingested substances. Vomiting is associated with many pathologic conditions, gastrointestinal disease, bowel obstruction, systemic or metabolic disease, and toxicity (poisons, drugs). Severe vomiting can result in serious consequences, including volume depletion (dehydration), acid-base and electrolyte disturbance, esophagitis, aspiration pneumonia and malnutrition.

Vomiting is a protective reflex initiated by the central nervous system consisting of three stages: nausea, retching, and subsequently expulsion of the gastric content. Specific signs of animals with acute vomiting will depend on the underlying cause, however, most animals will present:

• Continuous vomiting
• Dehydration
• Pain and distress
• Weakness

There are several possible etiologies for acute vomiting; some of the most common causes are:

Dietary problems

• Intoxication (poisonous plants, insecticides, rodenticides, among others)
• Indiscretion (ingestion of table scraps, garbage, foreign bodies)
• Food allergy or dietary sensitivity

Parasites

• Intestinal (Giardia, roundsworms, hookworms, tapeworms, whipworm)
• Gastric (Physaloptera)

Drug-related Problems

• Non-steroidal anti-inflammatory drugs (analgesics)
• Cardiac glycosides
• Certain antibiotics
• Chemotherapeutic agents

Metabolic Disorders

• Renal disease
• Liver disease
• Electrolyte abnormalities
• Addison's disease
• Diabetic ketoacidosis

Gathering a complete history of the patient is the first and most important step in the diagnosis of acute vomiting. It is crucial to provide the veterinarian with as much information as possible about the signs, history and a thorough description of the vomiting episodes.

The veterinarian needs to differentiate the owner's report of vomiting from gagging, coughing, dysphagia, or regurgitation. Vaccination status, travel history, previous medical problems, and current and previous medication should be provided. Many drugs, such as non-steroidal anti-inflammatory drugs (NSAIDs), can result in vomiting. The possibility of an intoxication, foreign body ingestion and metabolic disease should be considered. For example, frequent urination, increased water intake and weight loss are typical of vomiting associated with diabetes or chronic kidney failure.

A complete physical description of the vomited material and a dietary history are needed because vomiting may be associated with an adverse reaction to food. Vomiting of an undigested or a partly digested meal more than 6 to 8 hours after eating, a time at which the stomach should normally be empty, suggests a gastric problem. On the other hand, vomit-containing bile (yellow vomit) makes a gastric obstruction unlikely. Vomit having a fecal odor suggests problem in the small intestine. Presence of blood can indicate a gastric ulcer, which can be related to metabolic conditions, reaction to certain drugs, clotting abnormalities, gastritis, or neoplasia.

After a complete history and physical examination lab work including an intestinal parasite screen and radiographs will aid in the diagnosis.

• Maropitant (CereniaTM) - Most commonly used antiemetic and very effective. Can be administered orally or injected. At higher doses it is also effective in preventing motion sickness. Maropitant does not appear to affect the gastrointestinal system but it should be used with caution in patients that have hepatic dysfunction.
• Metoclopramide - This is a very effective drugs to control vomiting. It is more effective in dogs than in cats. Can be given orally and by injection. It also affects the gastrointestinal system and should be avoided in epileptics and should not be combined with chlorpromazine.
• Diphenhydramine (an antihistaminic drug) - This drug acts by blocking the vomiting signal in the nervous system. It will also cause some sedation.
• Chlorpromazine (ThorazineTM) - This drug is administered through injection. The potential side effects are hypotension, sedation and, possibly, seizures by lowering the seizure threshold.
• Isopropamide and Propantheline - Also blocks the vomiting signal in the nervous system. May cause adverse gastrointestinal effects.
• Ondansetrol HCL (Zofran) - Can be give orally and injectably. Mainly used for severe vomiting and when associated with chemotherapy or other drug therapy. Caution when using in hepatic patients and herding breeds. Heart arrhythmia and hypotension is possible.
• Correcting dehydration with fluid therapy, and reducing stomach acid production with Famotidine (Pepcid) or Omeprazole (Prilosec) allow the patient to recover.

The gastro intestinal tract is very resilient and there are many cases of pets with clinical signs of acute vomiting and/or diarrhea that resolve spontaneously. However, in some cases acute vomiting can be a sign of a life-threatening disorder, which if not identified and treated, could lead to death of the pet. Depending on the final diagnosis, your pet may need a special or prescription diet (bland easily digestable). Patients that present vomiting due to renal failure may need a prescription diet with specific amounts of calcium, phosphorus and high quality protein. In cases of vomiting due to food allergy or dietary sensitivity, it is important to identify which ingredient is causing the problem and eliminate it from the diet.