The Digestive system - Healthy Dog Experts

The digestive tract begins at the mouth and ends at the anus. The lips, teeth, tongue, salivary glands, mouth and pharynx are considered to be part of the digestive system. Other important digestive tract organs are the esophagus, stomach, duodenum (the first part of the small intestine), jejunum and ileum (also parts of the small intestine), (the large intestine is divided into four segments), the cecum, colon, rectum and the anal canal. The organs that aid in digesting and absorbing foodstuffs are the pancreas, gall bladder and liver. The pancreas is located next to the duodenum. The pancreatic enzymes drain into the pancreatic duct, which joins the bile duct from the liver: both ducts empty into the duodenum. The esophagus is a muscular tube that carries food down to the stomach through a series of rythmic contractions. The esophagus runs along the neck and into and through the chest cavity, on its way to the stomach. The lower esophagus enters the stomach at a sharp angle, which prevents food and liquids from refluxing back up into the esophagus. Food can remain in the stomach for up to eight hours before passing through the pylorus into the duodenum and the rest of the small intestine. Digestive juices from the pancreas and small intestine break the food down into amino acids, fatty acids and carbohydrates. The products of the meal are absorbed into the intestinal circulation and are carried to the liver, where they are converted to stored energy. Fiber and undigested food continue on through the small intestine into the colon. The function of the colon is to remove water and store waste material as feces.

The Esophagus

The esophagus is a muscular tube that propels food and water into the stomach. This is accomplished by a series of rhythmic contractions called peristaltic waves, which are coordinated with the act of swallowing. Signs of esophageal disease include regurgitation, painful swallowing (dysphagia), drooling and weight loss.

Regurgitation

Regurgitation is the relatively effortless expulsion of undigested food, without retching. It occurs because the esophagus is physically blocked or because it lacks peristaltic activity. In either case, the food accumulates until the esophagus is overloaded, after which the food is passively expelled. Regurgitation should not be confused with vomiting. Vomiting is the forceful expulsion of stomach contents, preceding by drooling and retching. The material vomited is usually sour-smelling, partly digested and stained with yellow bile. The sudden onset of regurgitation in a previously healthy dog is almost certainly due to a foreign body caught in the esophagus. Constant drooling indicates that the dog cannot swallow saliva. Chronic regurgitation (the kind that comes and goes but seems to be getting worse) suggests a partial obstruction caused by megaesophagus, stricture or tumor. A serious complication of regurgitation is aspiration pneumonia, in which the lungs become infected as a result in food being aspirated into them. When regurgitated food ends up in the lungs, aspiration pneumonia is the result. Another potentially serious complication is nasal cavity infection. This occurs when food is regurgitated into the nose.

Dysphagia (difficult, painful swallowing)

A dog with a painful esophagus eats slowly, stretches his neck and makes repeated efforts to swallow the same mouthful. As the condition becomes more painful, the dog stops eating and begins to lose weight. Difficult, painful swallowing, indicates a partial blockage caused by an esophageal foreign body, stricture or tumor. Pain on swallowing also occurs with mouth infections, sore throat and tonsillitis.

Megaespohagus means enlarged esophagus. When the esophagus is partially obstructed over a period of time, it gradually enlarges like a balloon and becomes a storage organ. This process, called megaesophagus, is accompanied by regurgitation, loss of weight and recurrent episodes of aspiration pneumonia. There are two causes of megaesophagus. The first is a failure of the esophagus to contract and propel food into the stomach. This impaired motility occurs as a hereditary disorder in puppies and as an aquired disease in adults. The second cause of megaesophagus is a physical blockage, such as a foreign body or a developmental problem with abnormal blood vessels that encircle the esophagus.

Congenital megaesophagus is a hereditary form of the disease that occurs in puppies. It is caused by a developmental disorder involving the nerve plexus in the lower esophagus. Peristaltic activity stops at the level where the esophagus is paralyzed, and food can go no further. In time, the esophagus above the inert segment enlarges and balloons out. This can been seen by lifting the puppy by his back legs and looking for a bulging out of the esophagus at the side of the neck. Congenital megaesophagus has been described in German Shepherd Dogs, Golden Retrievers, Great Danes, Irish Setters, Greyhounds, Labrador Retrievers, Newfoundlands, Miniature Schnauzers, Chinese Shar-Pei and Wire Fox Terriers. Hereditary myopathies are other causes of congenital megaesophagus. Puppies with congenital megaesophagus show signs of weaning, when they begin to eat solid foods. Characteristically, they approach the food dish with enthusiasm but back away after a few bites. They often regurgitate small amounts of food, which they eat again. After repeatedly eating the food, it becomes quite liquid and passes into the stomach. Repeated inhalation of food causes bouts of aspiration pneumonia. Another type of congenital megaesophagus is caused by retained fetal arteries in the chest. The arteries produce a constriction around the esophagus (known as vascular ring anomoly) that prevents swallowing. The most common anomoly is a persistent right aortic arch. Regurgitation and difficulty swallowing appear at 4 to 10 months of age. These puppies are stunted and malnourished.

Adult-onset megaesophagus is an aquired condition that occurs with several rare neuromuscular diseases, including myasthenia gravis. Other known causes are hypothyroidism, hypoadrenocorticism, esophagitis, autoimmune diseases and heavy metal poisoning. In most cases the cause is unknown. A chest X-ray may show an enlarged esophagus, opaque material in the esophagus or aspiration pneumonia. The diagnoses can be confirmed by administering a barium meal and then taking an X-ray of the chest. Ultrasound will also detect megaesophagus.

Foreign bodies in the esophagus are common. Bones and bone splinters are seen most often. Other objects that obstruct a dog's esophagus include string, fishhooks, needles, wood splinters and small toys. Suspect a foreign body in esophagus when a dog suddenly begins to gag, retch, drool and regurgitate. A history of regurgitation and difficulty swallowing for several days or longer suggests a partial obstruction. Sharp foreign bodies are particularly dangerous, because they can perforate the esophagus. A dog with a perforated esophagus exhibits fever, cough rapid breathing, difficulty swallowing and a rigid stance. The diagnoses can usually be made by taking X-rays of the neck and chest. Ingesting a contrast material such as Gastrografin, followed by an X-ray of the esophagus, may be required.

Esophagitis

A mucosal injury caused by a foreign body, or a burn caused by ingesting a caustic liquid can cause inflammation of the esophagus, known as esophagitis. Gastroesophageal reflux (similar to acid reflux in humans) is the other possible cause. Gastroesophageal reflux is the process in which stomach acid backs up into the esophagus, resulting in chemical burns of the mucosal lining. This can occur when a dog is tilted in a head-down position during general anesthesia. It may also occur with the use of of stomach tube, after chronic vomiting, and with a hiatal hernia. With this type of hernia, the stomach protrudes through an abnormally large esophageal opening in the diagram. The opening allows part or all of the stomach to slide up into the chest. Hiatal hernias are not common in dogs. Most of them are congenital, with an increased incidence among Chinese Shar-Pei. The major concern with hiatal hernia is that it causes gastroesophageal reflux. Signs to moderate to severe esophagitis are dysphagia, repeated swallowing, regurgitation and drooling. With chronic esophagitis the dog loses his appetite and weight. The diagnoses is made by gastroscopy, which he reveals an inflamed, swollen esophageal mucosa.

A stricture is a circular scar that forms after an injury to the wall of the esophagus. Most injuries are caused by esopageal foreign bodies, swallowed caustic liquids and gastroesophageal reflux and other causes. Tumors of the esophagus can produce a stricturelike narrowing. The principal sign of esophageal stricture is regurgitation. The dianoses can be made by X-ray after the dog has been given a barium solution, or by an esophageal endoscopy. The stricture appears as a fibrous ring that narrows the esophagus.

Primary tumors of the esophagus are rare and most are malignant. A common benign tumor is a leiomyoma. Tumors that have spread to lymph nodes around the esophagus can also press on the esophagus, creating a physical obstruction. Growth on the esophagus caused by a worm parasite (spirocerca lupi) occur in the southwestern United States. The disease is uncommon. A few of these growths can transform into cancer.

Stomach and duodenal ulcers are being diagnosed more frequently in dogs due to the wider use of gastroscopy. Seen through the endoscope, superficial ulcers are patches of inflamed and eroded mucosa covered by white or yellow pus. Deep ulcers are punched out areas involving all layers of the stomach wall. Ulcers can be single or multiple, and can range in size from less than one inch (2.5cm) to several inches in diameter. Ulcers occur more often in the stomach than in the duodenum. Bacteria are often the cause of ulcers in humans, but ulcers in dogs are not generally believed to be caused by stomach bacteria-although helicobacter species have been found in dogs. The usual cause in dogs is corticosteroids or nonsteroidal anti-inflammatory drugs (NSAIDs), such as aspirin and ibuprofen. Dogs are even more suseptible than people to the ulcer-producing affects of these drugs. Other conditions that predispose a dog to ulcers include all forms of liver disease, kidney failure, extreme stress (from severe illness or major surgery), chronic gastritis (particularly the eosinophilic type) and shock. Mast cell tumors of the skin can cause ulcers. This is because these tumors produce and release histimine, which is a powerful stimulant to acid secretion. In fact, ulcers occur in up to 80 percent of dogs with mast cell tumors. The principal sign of an ulcer is sporadic or chronic vomiting. Dogs may also lose weight and be anemic. In dogs with non-specific signs, such as chronic vomiting, the diagnoses is made by gastroscopy. Occasionally the vomitus contains old blood (which looks like coffee grounds) or fresh blood and blood clots, although the bleeding in many ulcers is microscopic. With rapid breathing the dog goes into shock and passes black, tarry stools. Stomach and duodenal ulcers can rupture into the adbomen, causing peritonitis.

At the outlet of the stomach is the pyloric canal. Scarring and contraction of the pyloric canal prevents the stomach from emptying. Stomach and duodenal ulcers close to the pyloric canal are the most common causes of inflammation and scarring. Other causes of scarring and contraction include hypertrophic and eosinophilic gastritis and gastric tumors. Foreign bodies and bezoars are other causes of gastric outflow obstruction. Gastric outflow obstruction can be partial or complete. Dogs with partial obstruction vomit intermittently, often 12 to 16 hours after eating. The vomitus usually contains undigested food and occasionally, blood. When obstruction is complete, vomiting occurs immediately after eating and is often projectile. Other signs of gastric outflow obstruction include obstruction include loss of appetite, weight loss and bloating. The diagnosis can sometimes be made by an X-ray of the abdomen or an ultrasound showing an enlarged, fliud-filled stomach. Gastroscopy or an upper GI series may be required for more complete dianosis.

A stomach tumor should be considered in an older dog with sporadic vomiting. The vomitus often contains old, partially digested blood. Enemia and weight loss are frequently found. Tumors in the pyloric canal region often cause gastric outflow obstruction. Adenocarcinoma is the most common malignant tumor of the stomach. Benign tumors, such as leiomyomas and polyps also occur. The diagnosis is made by gastroscopy and biopsy of the tumor.

Bloat is a life-threatening emergency that affects dogs in the prime of life. The mortality rate for gastric volvulus approaches about 50 percent. Early recognition and treatment are the keys to survival.

Bloat actually refers to two conditions. The first is gastric dilatation, in which the stomach distends with gas and fliud. The second is volvulus, in which the distended stomach rotates on its long axis. The spleen is attached to the wall of the stomach, and therefore rotates with the stomach. Gastric dilatation may or may not be complicated by volvulus. If volvulus occurs the stomach may twist 180 degrees or less (technically called a torsion). An actual volvulus is a twist of a 180 degrees to 360 degrees or more. During volvulus, the pylorus is pulled out of position and becomes displaced to the left of the gastroesophageal junction. This pinches off the duodenum and prevents fliud and air from escaping from the stomach through the pyloric canal. Simultaneously, the gastroesophageal junction becomes twisted and obstructed, preventing the dog from belching and vomiting. Gas and fliud are trapped in the closed-off stomach, which becomes hugely distended as the material ferments. Interference with blood circulation results in necrosis of the wall of the stomach. This sequence produces a number of other problems, including acute dehydration, bacterial septicemia, circulatory shock, cardiac arrhythmias, gastric perforation, peritonitis and death. Bloat can occur in any dog at any age, but typically occurs in middle-aged to older dogs. There may be a familiar association. Large breed dogs with deep chest are anotomically predisposed. These breeds include the Great Dane, German Shepherd Dog, Saint Bernard, Labrador Retriever, Irish Wolfhound, Great Pyrenees, Boxer, Weimaraner, Old English Sheepdog, Irish Setter, Collie, Bloodhound and Standard Poodle. Chinese Shar-Pei and Basset Hounds have the highest incidence among midsized dogs. Small dogs are rarely affected, with the exception of Dachshunds, who are also deep-chested. Bloat develops suddenly, usually in a healthy, active dog. The dog may have just eaten a large meal, excercised vigorously before or after eating, or drank a large amount of water immediately after eating. There is no evidence that the protein or soy content in the diet contributes to bloat: research has shown that the majority of gas associated with bloat is due to swallowed air.

The classic signs of bloat are restlessness and pacing, salivation, retching, unproductive attempts to vomit and enlargement of the abdomen. The dog may whine or groan when you press on his belly. Thumping the abdomen produces a hollow sound. Unfortunately, not all cases of bloat present with typical signs. In early bloat the dog may not appear distended, but the abdomen usually feels slightly tight. The dog appears lathargic, obviously uncomfortable, walks in a stiff legged fashion, hangs his head, but may not look extremely anxious or distressed. Early on, it is possible to distinguish dilatation from volvulus. Late signs (those of impending shock) include pale gums and tongue, delayed capillary refill time, rapid heart rate, weak pulse, rapid and labored breathing , weakness and collapse. If the dog is able to vomit or belch, quite likely the problem is not due to a volvulus, but this can only be determined by an examination.

In all cases where there is the slightest suspicion of bloat, take your dog to an animal hospital immediately. Time is of the essence. Gastric dilatation without torsion or volvulus is relieved by passing a long rubber or plastic tube through the dog's mouth into the stomach. This is also the quickest way to confirm a diagnosis of bloat. As the tube enters the dog's stomach, there should be a rush of air and fliud from the tube, bringing relief. The stomach is then washed out. The dog should not be allowed to eat or drink for at least 36 hours and will need to be supported with intravenous fliuds. If the symptoms do not return, the diet can be gradually restored. Passing a stomach tube is a procedure normally done by a trained professional (doggy doctor). In extreme circumstances when professional help is not available, you may be asked to perform the procedure at home. If you live in a remote location where fast access to animal services is limited, you may wish to aquire a stomach tube and add it to your home emergency medical kit. To pass a stomach tube , first mark the tube by measuring the distance from the dog's nose to his last rib Then lubricate the tube with K-Y or petroleum jelly. It is helpful to put a roll of adhesive tape in the dog's mouth to pass the tube through, so the dog cannot bite down on the tube. Insert the tube behind one of the canine teeth and advance it into the throat until the dog begins to swallow. If the dog gags, continue to advance the tube. If the dog coughs, the tube has entered the trachea. Withdraw the tube a few inches and start again. If the tube will not pass into the stomach, discontinue further attempts, as it is possible to harm the dog. If you do not have a tube available, a fairly large gauge sterile needle, such as an 18-gauge needle from a syringe may be used to poke directly through the body wall into the distended area to release gas and relieve pressure on the abdominal tissues. This is only a stopgap measure to buy you time to reach an animal hospital and only be done in a serious emergency in which there are no trained professionals available; because the needle could damage other tissue as it is pushed through the body wall. If you can pass a tube through, you should still take your dog to an animal hospital for follow-up treatment to prevent a recurrence. Being able to pass a tube through does not always rule out volvulus. Occasionally the tube passes even though the stomach is twisted. A diagnosis of dilatation or volvulus is best confirmed by X-rays of the abdomen. Dogs with simple dilatation have a large volume of gas in the stomach., but the gas pattern is normal. Dogs with volvulus have a "double bubble" gas pattern on the X-ray, with gas in two sections separated by the twisted tissue. Emergency therapy is directed toward correcting shock and dehydration with intravenous fluids and corticosteroids. Antibiotics may be needed to control infection. Ventricular arrhythmias are common. They require heart monitoring and the use of anti-arrhythmic drugs. If a dog has a volvulus, emergency surgery is required as soon as the dog is able to tolerate the anesthesia. The goals are to reposition the stomach and spleen, or to remove the spleen and part of the stomach if these organs have undergone necrosis. Future recurrence can often be prevented by suturing the wall of the stomach to the abdominal wall (a procedure called gastropexy). This important step keeps the stomach in position and prevents it from twisting.

Dogs who respond to nonsurgical treatment have about a 70 percent chance of having another episode of bloat. Some of these episodes can be prevented by following these practices:

4 Beware of the early signs and seek prompt professional help whenever you suspect bloat.

The adrenal glands, found in the abdomen above the kidneys, are important in the production of corticosteroids and other hormones that regulate body functions. Addison's Disease is caused by inadequate production of corticosteroids and mineralocorticoids. In some cases this uncommon condition arises after other illnesses; including infections, tumors and toxic drugs, which destroy the adrenal glands. An autoimmune reaction, in which antibodies are directed against the cells of the adrenal cortex (the part of the adrenal gland that produces corticosteroids), may be responsible for cases in which the cause is not known. There may be a genetic predisposition in Bearded Collies, Portagese Water Dogs and Standard Poodles. An iatrogenic form of Addison's Disease occurs after corticosteroids are administered to treat a medical condition. The corticosteroids have the side affect of putting the adrenal glands at rest. An abrupt withdrawal of the drug can produce a temporary deficit of hydrocortisone and cause an acute Addisonian crisis with shock and circulatory collapse. The signs of Addison's disease are lethargy, muscle weakness, intermittent vomiting and diarrhea, and a slow pulse. This disease should be considered when a dog unaccountably collapses. The diagnosis is made by an ACTH stimulation test. In a positive test, the adrenal cortex does not respond to an injection of ACTH by increasing the concentration of cortisol in the serum.

Acute gastritis is an irritation of the lining of the stomach that comes on suddenly. The principal sign is severe and continuous vomiting. Keep in mind that persistant vomiting is also associated with life-threatening diseases such as intestinal obstruction and peritonitis. Seek professional consultation in all cases where the cause of persistant vomiting is not known. Common stomach irritants include spoiled food and garbage, stools, grass, plastic wrappings, hair and bones. Certain drugs (notably aspirin, virtually all NSAIDs, cortisone, butazolidine and some antibiotics) produce gastric irritation. Common poisons that may cause vomiting are antifreeze, fertilizers, plant toxins and crabgrass killers. If poisoning is suspected, contact your nearest emergency animal hospital. A dog with acute gastritis vomits shortly after eating. Later the dog appears lathargic and sits with his head hanging over the water bowl. The dog's temperature remains normal unless he is suffering from acute infectious enteritis, a disease that also causes diarrhea.

Dogs with chronic gastritis vomit from time to time over a period of days or weeks. These dogs would appear lathargic, have a dull hair coat and lose weight. The vomitus sometimes contains foreign material and food eaten the day before. A common cause of chronic gastritis is a food allergy. Other causes are persistent grass eating, repeated consumption of drugs, chemicals or toxins and ingesting cellulose, plastic, paper or rubber products. Also consider the possibility of hairballs. Hair is shed more heavily in the springtime and is swallowed as the dog licks and pulls it out. Hair and other foreign materials can be incorporated into a hard mass called a bezoar. Bezoars may grow to a size that makes it impossible for them to pass out of the stomach. Note that in many cases of chronic vomiting the cause is not known.

Hypertrophic gastropathy is a thickening of the mucous membranes of the lower half of the stomach, which can lead to gastric obstruction and food retention. Vomiting occurs three to four hours after eating. Hypertrophic gastropathy occurs most in middle-aged dogs of the small breeds. It may also be seen as a congenital problem called pyloric stenosis in brachycephalic breeds such as Bulldogs and Boston Terriers. The cause is unknown in older dogs, but may be related to histimine release from mast cell tumors in some dogs.

Chronic atrophic gastritis involves a thinning of the stomach wall. This is primarily seen in Norwegian elkhounds, and may develop from an immune problem

Eosinophilic gastritis is a chronic condition characterized by the accumulation of eosinophils (a type of white blood cell) in the mucous lining of the stomach, along with thickening and scarring of the stomach wall. The cause is unknown, although a food allergy or parasites have been proposed. Eosinophilic gastritis is more likely than other types of gastritis to be associated with ulcers and bleeding. Stomach and duodenal ulcers also produce sporadic vomiting. Finally, if there is no obvious explanation for the sporadic vomiting, the dog may be suffering from a systemic disease, such as liver or kidney failure, which can be diagnosed by blood tests.

Many young dogs become sick when traveling by car, boat or air. The signs are restlessness followed by salivation, yawning, nausea and then vomiting. Motion sickness is caused by over-stimulation of the labyrinth in the inner ear.

Vomiting is common in dogs. All vomiting is the result of activating the vomiting center in the brain. The vomiting center is well developed in dogs, so dogs vomit more readily than most other animals. As a dog perceives a need to vomit, he becomes anxious and may seek attention and reassurance. He then begins to salivate and swallow repeatedly. Vomiting begins with simultaneous contraction of the muscles of the stomach and abdominal wall. There is an abrupt increase in intra-abdominal pressure. The lower esophagus relaxes, allowing the stomach contents to travel up the esophagus and out the mouth. The dog extends his neck and makes harsh gagging sounds. This sequence should be distinguished from the passive act of regurgitation.

The most common cause of vomiting is eating indigestible substances, such as grass, that irritate the lining of the stomach. Another cause of vomiting is overeating - dogs who eat more than their daily amount of food, perhaps because they have gotten into the dog food supply. Also puppies who gobble their food and exercise immediately after are likely to vomit. This after-meal vomiting is frequently caused by feeding a group of puppies from a common food pan. Since they are all competing for food, each one eats as much as he possibly can. Separating puppies, or feeding them frequent small meals, eliminates the problem of gorging. Dogs may vomit when they are upset, excited or suffering from a phobia (for example; during a thunderstorm). Phobic dogs also drool, whine, paw and tremble. Puppies with heavy loads of ringworms may vomit up some worms. Vomiting occurs with most acute infectious diseases. It also occurs with many chronic diseases, including kidney and liver failure, Cushing's syndrome, Addison's disease and diabetes mellitus. To determine the cause of vomiting, note whether it is repeated, and if so, whether it is sporadic or persistent. How soon after eating does it occur ? Is it projectile ? Inspect the vomitus for blood, fecal material and foreign objects.

If the dog vomits or retches repeatedly, bringing up a frothy, clear fluid, this suggests a stomach irritation such as acute gastritis. However, persistent vomiting also occurs with life-threatening diseases such as acute pancreatitis, gastric outflow obstruction, intestinal obstruction and peritonitis. Persistent retching without bringing up any vomitus is typical of bloat. Repeated vomiting along with diarrhea suggests acute infectious enteritis.

Sometimes a dog vomits off and on over a period of a few days or weeks. There is no relationship to meals. The appetite is poor. The dog has a haggered look and appears listless. Suspect liver or kidney disease or an illness such as chronic gastritis, stomach or duodenal ulcer, a heavy worm infestation or diabetes mellitus. A foreign body in the stomach is another possiblity. In an older dog, suspect a gastric or intestinal tumor. A check-up is in order.

Red blood in the vomitus indicates active bleeding somewhere between the mouth and the upper small bowel. (Blood from the nasopharynx and esophagus may be swallowed). Common causes are stomach and duodenal ulcers, gastrointestinal foreign bodies and gastric tumors. Material that looks like coffee grounds is old, partially digested blood. This also indicates a bleeding point between the mouth and the upper small bowel. Any dog who vomits blood should be seen by a trained professional.

A dog who vomits foul material that looks and smells like feces is most likely suffering from intestinal obstruction or peritonitis. Seek immediate professional treatment. Dogs who eat feces may also do this, but it will be an isolated incident.

Projectile vomiting is forceful vomiting in which the stomach contents are ejected a considerable distance. Typically it occurs in a dog with gastric outflow obstruction. Diseases that cause pressure on the brain (tumors, encephalitis, blood clots) also cause projectile vomiting.

Dogs may also vomit foreign objects, including rubber balls, pieces of toys, sticks and stones. Puppies with a heavy roundworm infestation may vomit adult worms.

If there is any question about the cause or seriousness of the vomiting, seek professional help. Vomiting dogs can rapidly become dehydrated as they lose body fluid and electrolytes. Home treatment is appropriate only for normal, healthy adult dogs who show no signs other than vomiting. Puppies, dogs with preexisting health conditions and old dogs are less able to tolerate dehydration and should be treated by a professional. An important initial step is to rest the stomach by withholding food and water for a minimum of 12 hours. If the vomiting stops with stomach rest, the dog can be permitted to lick a few ice chips every three to four hours if the vomiting has stopped, offer 1/4 to 1/2 cup of water (63 to 125 ml), depending on the size of the dog, every two to three hours. A pediatric electrolyte solution can be given in small amounts, in addition to the water. After 12 hours with no vomiting, start the dog on a bland diet such as two parts boiled rice mixed with one part ground beef or chicken and a little bit of cottage cheese. Begin offering small amounts (1 or 2 tablespoons, 15 to 30 ml, at a time) every two to three hours. Increase the volume over the next few days and gradually return the dog to his customary diet.

Small and Large Bowels

Problems in the small and large bowels are associated with three common symptoms: diarrhea, constipation and passing blood. Diarrhea is by far the most common.

This is a group of small and large intestines, characterized by chronic and protracted diarrhea, malabsorption, weight loss, anemia and malnutrition. They are all treatable, but are seldom cured. In each specific disease, a different type of inflammatory cell is found in large numbers in the lining of the small and/or large intestines. These cells distinguish the specific diseases. Diagnosis is made by endoscopy and biopsy of the intestine wall or by exploratory surgery.

This is the most common inflammatory bowel disease in dogs. Lymphocytic-plasmacytic enterocolitis has been associated with giardiasis, food allergy and overgrowth of intestinal bacteria. . Lymphocytes and plasma cells are the target cells seen on biopsy. Certain breeds are predisposed, suggesting a genetic influence. They are the Basenji, Soft Coated Wheaten Terrier, German Shepherd Dog and Chinese Shar-Pei. In the Basenji, the disease is known to be related to an autoimmune disorder. While signs can show up in younger dogs, most dogs are middle-aged when diarrhea starts. Lymphocytic-plasmacytic enterocolitis produces a small bowel type of diarrhea. Vomiting is common. Involvement of the colon produces signs of colitis.

This is a relatively uncommon form of inflammatory bowel disease in dogs. On biopsy, eosinophils may be found in the stomach, small intestine or colon, and the eosinophil count in the blood may be elevated. Some cases are thought to be associated with food allergy or the tissue migration and roundworms and hookworms.

This is a rare disease, similar to Crohn's disease in humans. There is thickening and narrowing of the terminal of the small bowel due to inflammation of surrounding fat and lymph nodes. Macrophages, which are cells found in tissues that fight infections, are found on biopsy of the colon. The diarrhea is the chronic large bowel type containing mucus and blood. Biopsies are processed with special stains to exclude histoplasmosis and intestinal tuberculosis.

This inflammatory bowel disease produces acute and chronic large bowel diarrhea. The inflammatory infiltrate is composed of mature white cells in the tissues and blood vessels. Diagnosis is based on a colon biopsy and stool cultures to exclude bacterial infection.

This inflammatory bowel disease occurs almost exclusively in Boxers. Signs usually appear before age 2. Affected dogs develop severe, unrelenting diarrhea that contains mucus and blood, and corresponding weight loss. The diagnosis is based on a colon biopsy.

Enteritis is an infection of the gastrointestinal tract characterized by the sudden onset of vomiting and diarrhea, rapid pulse, fever, apathy and depression. The vomitus and diarrhea may contain blood. Dehydration occurs rapidly. Dogs under 1 year of age and those over 10 are particularly susceptible to the effects of dehydration and shock. The most common cause of infectious enteritis in