Dog Health by LowchensAustralia.com

Carnivores in the wild are formidable predators who are perfectly adapted to the hunt. They are capable of eating phenomenal quantities of meat in a single meal. Upon their return, they can regurgitate this food without the slightest effort in order to feed their young. This ability requires not only a stomach that is capable of holding large quantities, but also a reflex mechanism that facilitates regurgitation of food and therefore vomit. 

Dogs, who are domestic carnivores par excellence, have not lost any of this ability. How many dog owners in fact have witnessed their favourite animal regurgitate a meal that was a little too copious? Most of the time, there is nothing alarming in this behaviour. Sometimes, however, vomiting is the first sign of an underlying disease.

Stages of vomiting
In general, a vomiting episode is preceded by a state of nausea in which the dog appears uncomfortable, turns in circles and sometimes tries to eat grass. It is almost as if the dog is trying to "purge" himself, though this term does not accurately reflect reality. The dog then vomits. Violent heaving of the flank and thorax is observed. The dog lowers his head and appears to be smiling. Then after a final effort, the contents of the stomach are ejected. Given the violence of the phenomenon and the muscle fatigue that ensues, it may take the dog a few minutes to recuperate. In cases where only the contents of the esophageus are regurgitated, there is no noticeable effort. The food easily ejected by means of a simple reflex. 

Physiological mechanisms in vomiting
Like any reflex, vomiting involves nerve mechanisms. They may originate in the central nervous system, in other words, directly from the brain (disruption of normal central nervous system functions, inflow of particle substances into the blood, even olfactory stimulus, cause the vomit centre to react). The origin may also be peripheral, which involves receptors located in abdominal or thoracic organs. Information received is transmitted through a system of neurotransmitters to the vomit centre in the brain. In both cases, this centre responds by triggering the muscular action that causes vomiting. 

Causes of vomiting
Vomiting is usually an indication of inflammation or excessive distension of organs, namely those of the digestive tract: esophageus, stomach, intestines and liver. The causes are numerous. Classic causes include poisoning, gastritis, ulcers, gastroenteritis, foreign objects, intestinal obstructions, gastric dilation-torsion or spoiled food. 

Vomiting may also be a symptom of an infectious or viral disease (canine distemper, canine parvovirus and leptospirosis are among the most notable, in addition to uterine infections, peritonitis, etc.). Absorbing excessive quantities of food, foreign objects or substances that prevent the stomach from emptying its contents into the small intestine also causes gastric distension and consequently, vomiting. Finally, vomiting can also be an indication of diseases that affect other organs, especially renal or hepatic insufficiencies or even nervous system disorders, such as motion sickness. 

Vomiting is a very common problem in dogs and cats. There are many causes of vomiting. Primary or gastric causes of vomiting are those that are due to diseases of the stomach and upper intestinal tract. Secondary or non-gastric causes of vomiting are caused by diseases of other organs that cause an accumulation of toxic substances in the blood. These toxic substances stimulate the vomiting center in the brain causing the animal to vomit. (Anatomy of the digestive system: dog / cat)

Vomiting must be differentiated from regurgitation which is caused by diseases of the esophagus. A problem that can be confused with vomiting is regurgitation. Vomiting is the ejection of contents of the stomach and upper intestine; regurgitation is the ejection of contents of the esophagus. The esophagus is a narrow, muscular tube that food passes through on its way to the stomach. In health, food moves quickly through the esophagus to the stomach. If the muscle of the esophagus loses tone, the esophagus dilates, a condition called megaesophagus. A dilated esophagus does not effectively move food to the stomach and the animal will regurgitate food usually shortly after eating. The food may also be inhaled into the airways causing pneumonia and cough.

When you present your pet to the veterinarian because he or she is vomiting, the veterinarian will ask questions in attempt to differentiate between vomiting and regurgitation and to try to determine if your pet is vomiting due to gastric or non gastric disease. Vomiting is an active process. The pet is apprehensive and heaves and retches to vomit. If food is present in vomit, it is partially digested and a yellow fluid, bile may be present. Regurgitation is fairly passive. The animal lowers its head and food is expelled without effort. The food brought up by regurgitation is usually undigested, may have a tubular shape, and is often covered with a slimy mucus. The pet will often try to eat the regurgitated material. You may bring a fresh sample of "vomit" for the veterinarian to examine. The pH of vomit containing food is acid, the pH of regurgitated materials is higher. 

If blood is seen in the vomit, ulcers, stomach cancer, kidney disease or mast cell cancer must be considered. Your ability to answer questions about your pet's activity, habits and environment will help the veterinarian decide which causes of vomiting are most likely in your pet. A history of any drugs your pet is receiving is important. Over-the-counter pain medications such as aspirin and ibuprofen can cause severe stomach ulcers in dogs depending upon the dose and duration of treatment. The veterinarian may ask you to describe the appearance of the vomit, as well as describe how your pet looks when it vomits and the relation ship of vomiting to eating. If the vomit contains blood it may be fresh, red blood or look like coffee grounds if the blood is digested. Blood is most often seen with stomach ulcers, stomach cancer or uremia (a collection of signs including vomiting seen in pets with kidney failure). Stomach ulcers can be caused by drugs or the presence of a mast cell cancer in the skin. Mast cell cancers release histamine that leads to stomach ulcers. Regurgitation often, but not always, happens right after eating and the pet will try to eat the regurgitated food. Vomiting occurs a variable time after eating or may occur in a pet who is off food. Animals with a twisted stomach, gastric dilation-torsion, may make frequent attempts to vomit without producing anything. Pets with a hacking cough may retch and sometime vomit at the end of an episode of forceful coughing. An accurate description in this case would lead to an investigation of the causes of coughing, rather than vomiting. 
If your pet vomits just occasionally and has a specific series of actions associated with vomiting, you may consider video taping an episode of vomiting to help describe the episodes to the veterinarian. 

The physical examination of the vomiting pet can also provide information to narrow the list of possible causes. The presence of fever, abdominal pain, jaundice, anemia or abnormal masses in the abdomen will help the veterinarian make a more specific diagnosis. The mouth should be carefully examined as some foreign objects such as string can wind around the base of the tongue with the rest of the object extending into the stomach or small intestine. A nodule may be palpated in the neck of cats with hyperthyroidism. 

The list of non-gastric causes of vomiting is long. 

Pancreatitis in the dog causes vomiting that is sudden in onset and often severe. The dog may have a painful belly. Pets with pancreatitis often have a history of eating garbage or fatty table scraps. Tumors of the pancreas can cause similar signs to pancreatitis. Pancreatitis occurs in the cat but the signs are subtle and non specific and often don't include vomiting

Kidney failure is a common cause of vomiting in dogs and cats. The kidneys can be acutely (suddenly) damaged by poisons such as antifreeze or by severe dehydration. Waste products that the kidneys normally get rid of, rise to high levels in just a few days. The kidneys can also gradually lose their ability to remove waste products from the body as the pet ages. Early signs of kidney failure include drinking and urinating large amounts called polyuria and polydipsia or PU-PD. PU-PD may be present for months to years before the kidney failure is severe enough to lead to waste product accumulation and vomiting. Vomiting in chronic kidney failure may began as occasional episodes and progress to severe, frequent vomiting. The pet with chronic kidney failure will often lose body condition and may have pale gums due to anemia. 

Non-spayed, middle aged female pets can develop a uterine infection called pyometra. Pyometra occurs within 2 months after a heat cycle and often results in discharge of pus from the vagina. The pet may frequently lick the vagina so discharge may not be seen. Dogs develop pyometra more often than cats. Other signs may include PU-PD and depression. 

Liver failure causes vomiting as well as other signs depending on the type of liver disease. Other signs of liver disease may include seizures, jaundice (a yellow discoloration of the areas of skin not covered by fur), PU-PD and fluid accumulation in the belly or legs. 

Bladder obstruction will cause a sudden onset of vomiting. Bladder obstruction is fatal in just a few days. Bladder obstruction or rupture will cause a sudden onset of vomiting. The urethra that leads from the bladder to the outside can get plugged by stones or tumors. The animal will strain and pass just a free drops of urine or none at all. They will also have a painful belly. Bladder obstruction if not corrected, is fatal in just a few days. The bladder can be ruptured by blunt trauma such as being hit by a car or kicked. 
A form of diabetes called ketoacidosis will cause vomiting along with depression and PU-PD. 

Addison's disease is a deficiency of hormones from the adrenal gland and causes vomiting, diarrhea and weakness. Addison's disease occurs most commonly in young to middle aged dogs, most of which are female. Addison's is rare in the cat. The signs of Addison's disease may be intermittent or may be very severe and constant. 

Diseases of the inner ear can cause vomiting accompanied by incoordination, circling and tilting of the head to the side. Motion during car rides stimulates the inner ear and can cause vomiting. 

A sudden onset of vomiting in young, poorly vaccinated pets may be caused by infectious agents including canine distemper, canine parvovirus and feline panleukopenia virus.

There are many toxins including lead, insecticides, antifreeze and other chemicals that can cause vomiting. 

Cats with elevated thyroid function, hyperthyroidism, may vomit in addition to other signs including, increased appetite, weight loss, hyperactivity and a poorly kept coat. Heartworm disease in cats may cause vomiting in addition to coughing, respiratory distress, weight loss and depression. 

Primary causes of vomiting include acute gastritis often due to eating garbage or other types of dietary indiscretions; the ingestion of large amounts of hair during grooming; ulcers of the stomach; stomach or upper intestinal cancer; parasites; food allergies; the presence of a foreign body stuck in the stomach or upper intestine; twisting and dilation of the stomach; and intussusception which is a telescoping of one part of the intestine into another piece of intestine. 

The stomach is usually empty 6 to 8 hours after eating. Vomiting of food when the stomach should be empty suggests an obstruction of the stomach or abnormal motion of the stomach muscles that normally grind food and push the ground food out of the stomach. 

Tests to differentiate primary causes of vomiting include x-rays or ultrasound of the abdomen and endoscopy. Endoscopy is the technique of passing a flexible scope into the stomach and upper intestine to examine the inside of these structures. It may be possible to remove a foreign body with endoscopy and small biopsies of the lining of the stomach and intestine can be taken for microscopic evaluation. Endoscopy requires general anesthesia.

If the pet vomits sporadically, the results of all tests may be normal. Many healthy dogs and cats vomit occasionally without identifying a cause. Sometimes the cause of vomiting is as simple as the pet eating too fast. 

Consult a veterinarian before treating a vomiting pet at home. The treatment for vomiting depends upon the cause. Nonspecific treatment for vomiting includes fasting, and fluids to correct or prevent dehydration. In episodes of sudden onset of vomiting, food is withheld for 24 - 48 hours and water for 24 hours. Water should never be withheld from an animal with known or suspected kidney disease without replacing fluids intravenously or subcutaneously (under the skin). If vomiting stops, small amounts of a bland low-fat food are fed 3 to 6 times daily for a few days, with a gradual increase in the amount fed and a gradual transition to the pet's normal diet. Water is also reintroduced in small amounts on the second day. You may start with ice cubes and then gradually increase the amount of water over the day if vomiting does not reoccur. 
If the pet is bright and alert and has had no previous health problems, episodes of acute vomiting may be managed at home, although veterinary consultation prior to home treatment is advised. Consultation with a veterinarian in your region may reveal a recent outbreak of an infectious disease causing vomiting or identify a cluster of recent poisonings. With this type of knowledge you will want to have your pet evaluated rather than waiting a few days. Dogs and cats who vomit for longer than a few days or are depressed or dehydrated should be presented for veterinary evaluation. 


College of Veterinary Medicine
Washington State University
Web Page

• Vomiting in Dogs, Cats & Ferrets
• Vomiting Problems in Dogs
• The Vomiting Dog - Diagnosis
• Causes & Treatment of Diarrhea & Vomiting in Dogs
• Vomiting and Diarrhea
• Vomiting in the Canine
• Chronic Vomiting in Dogs
• Vomiting and Diarrhea
• Vomiting and Regurgitation in Dogs and Cats
• Cat And Dog Vomit
• Vomiting in Dogs and Cats
• Megaoesophagus