Dogs: Health, Disease and Physiology: Digestive system, including liver, diabetes, poisoning and obesity


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Study of 253 dogs in the United Kingdom with diabetes mellitus

Prevalence and treatment of canine diabetes in the UK

source: L.J. Davison, M.E. Herrtage, and B. Catchpole Veterinary Record
vol 156 no 15, April 9 2005 starts p467, 5 pages long

Diabetes is common in dogs, and is linked to both genetic and environmental factors, like infections and diet. The study sample used information on 253 diabetic dogs, supplied by vets after an appeal in a vet journal. The dogs were from 37 breeds, with over 50% of them being labradors, collies and Yorkshire terriers. Diagnosis was more common in winter, especially January.

Large numbers of some breeds, like labradors, may simply be because they are popular. There is no compulsory registration of dogs in the UK, so it is difficult to work out the percentages of different dog breeds in the population as a whole. However, some idea can be obtained from a database of 46,593 insured dogs, of which 151, or 0.32%, had been diagnosed with diabetes. Some breeds, like Cavalier King Charles spaniels, samoyeds, Tibetan terriers and Cairn terriers, appear to be at higher risk for diabetes, whereas golden retrievers, boxers and German shepherds appear to be at lower risk.

Most dogs in the sample of 253 were between five and twelve years old when diagnosed. Few entire females were found compared to previous studies, and this may explain why diagnosis was more common in winter, because certain hormonal factors are less important once bitches are spayed. Most of the dogs received insultin once daily, though there appeared to be better glycaemic control for dogs receiving insulin twice daily.



Monitoring the diabetic dog: 1) Clinical signs, goals of therapy and techniques

Diagnosing and treating canine diabetes

source: Grant Petrie
In Practice vol 26 no 8, September 2004
starts p 411, 6 pages long

Diabetes mellitus is due to lack of insulin. Insulin helps with the synthesis of proteins, fatty acids and glycogen. Some hormones, such as cortisol, adrenaline, and progesterone, counteract insulin. High levels of blood glucose mean that the kidneys cannot cope, and glucose appears in urine, leading both to increased urination and increased thirst.

Dogs with diabetes tend to lose weight, despite being hungry. Owners can inject insulin and keep a diary to record weight, exercise and water consumption. Spaying bitches can help, as can tackling diseases that affect insulin levels. Owner diaries can be more important than tests. Water consumption of under 60 ml per kg daily is normal. When insulin levels are too high, dogs may be weak or overexcitable, and collapse into a coma. Dogs can also develop cataracts if glycaemic control is poor, and they can develop urine infections, or ketoacidosis with symptoms such as vomiting and weakness. Urine glucose testing has limitations, for example, different timing of tests in relation to insulin injections gives different results. Furthermore, glucose levels in urine are a poor indicator of levels in blood, so blood tests as measures of blood glucose concentration are important for taking decisions on how much insulin to give a dog, and to monitor glycaemic control.

The same dose can have different effects on individual dogs, so it is helpful to take serial glucose estimations to find out how a dose of a particular product affects a particular dog.


Monitoring the diabetic dog: 2) restoring good diabetic control in problem cases

Six cases of diabetic dogs illustrating ways to tackle problem cases

source: Grant Petrie
In Practice vol 26 no 8, September 2004
starts p 421, 8 pages long

Dogs with diabetes have hyperglaecamia, or high glucose levels, which result from a deficiency of, or insensitivity to insulin. At high levels, glucose appears in urine, leading to frequent urination and thirst. Calorie loss from excretion of glucose leads to weight loss and hunger. Vets and owners need to monitor dogs to resolve clinical signs and prevent complications. Urine tests, glycated blood protein measurement, and estimations of serial blood glucose all help with management.

Six cases show how management can be improved in problem cases with poor control. A ten-year-old keeshond, reassessed after three weeks with twice daily insulin therapy, appears stabilised, with a glucose curve showing good absorption of insulin, and a safe glucose nadir. He needs follow-up reassessments, and owners need to report symptoms such as increased thirst or weight loss. A six-year-old boxer appeared resistant to insulin, not responding after she was rehomed. Infections, or poor storage of insulin are among possible causes of dogs not responding. In this case, it emerged that the owner had not been taught how to inject insulin, and was squirting it onto the dog's skin. A third dog, an eight-year-old crossbreed, became lethargic and thirsty. Her dose of insulin was increased, and her condition improved and stabilised. An eight-year-old beagle given insulin once a day was also lethargic, and serial glucose measurements showed that the insulin dose was only lasting 10 hours. He improved after moving to twice-daily injections. The case of a five-year-old labrador was more complex. Her symptoms persisted, and a glucose curve showed a dramatic drop in levels followed by a rise as a reaction. Her insulin dosage was too high, leading to a too-steep drop in glucose levels, followed by a rise to abnormally high levels. After a reduction in her dosage, her condition improved. Urine tests alone would not have revealed the problem. The last case was a seven-year-old male Irish wolfhound, who was lethargic, thirsty, and urinating excessively. He appeared to have insulin resistance. He was diagnosed with discospondylitis, and a urinary tract infection. He was treated with painkillers, intravenous fluids, and an antibiotic. His insulin dose was reduced, and his diabetes stabilised. His disc disease was also resolved, and his quality of life returned to normal.



Investigation and differential diagnosis of vomiting in the dog

Diagnosis of conditions leading to dogs vomiting

source: Clive Elwood
In Practice vol 25 no 7, July/August 2003
starts p374, 9 pages long

Some vomiting in dogs is normal. They are omnivorous, and sometimes need to get rid of indigestible objects that they have eaten. Bitches also vomit frequently when they are feeding pups.

The reasons for dogs vomiting are likely to vary according to age, breed and gender. Pups are likely to have eaten something that disagrees with them, or may have infections, or anatomical abnormalities. Some breeds, such as golden retrievers and boxers, tend to be especially sensitive to their diets. Large breeds are more prone to gastic dilation-volvulus, while rough collies and Belgian shepherds are prone to gastric neoplasia. Prostate problems in dogs and pyometra in bitches can also cause vomiting.

The length of time a dog has been vomiting can give some clues as to the cause. Dogs that suddenly start vomiting may, for example, have an infection, have eaten something they cannot digest, suffered poisoning, or have an acute abdominal problem, like pancreatitis. Dogs that have been vomiting over a longer period, and just intermittently may have inflammatory bowel disease, or chronic gastritis, or both. What the dogs produce when they vomit can also give clues. Dogs suffering from gastric irritation may vomit bile in the morning. Pyloric obstruction is linked to vomiting undigested meals. Intestinal obstruction is linked to vomiting watery matter. When a dog vomits dark blood, looking like coffee grounds, there could be intestinal inflammation, neoplasma, or benign ulcers, though fresh blood may just be linked to the action of vomiting.

Diarrhoea tends not to be associated with pure gastric, renal, splenic or hepatic disease. Signs of a dog being in pain may also give clues as to the cause. Dogs may react for example if they are touched, or show they are in pain by being restless, or taking up a posture as though they were praying. Their bellies may also be swollen. Less serious conditions tend not to affect dogs' appetites and the way they behave.

Dogs that stop vomiting when they are not allowed food may be suffering from an obstruction. Certain diseases, such as diabetes, kidney failure, and pyometra, are linked to drinking a lot of water.

Dogs that suddenly start vomiting and do not produce anything, and also have swollen bellies may be suffering from gastric dilation-volvulus, and need immediate attention.

Owners can be asked about whether any objects have gone missing in the house, or whether dogs might have eaten corn cobs or other objects at a social event. Another avenue of investigation is dogs' access to toxins, such as glycol, ethylene, or lead, and any medicines they might be taking. Rupture of internal organs, for example due to previous accidents in which dogs have been injured, can also lead to vomiting.

Diagnosis includes checking for signs of dehydration, such as sunken eyes, dry membranes, and skin tenting. The heart rate and temperature should also be assessed. A high temperature is linked to inflammation and infections. Physical examinations also include palpating the abdomen and rectal examinations. Blood tests, diagnostic imaging such as radiography and ultrasound, and endoscopy may be needed. Exploratory surgery is a further option, which should only be undertaken when non-surgical diseases have been excluded, and the dog has been stabilised. The article examines the different reasons why dogs vomit, and how to diagnose the cause, in further detail.


Rational selection of gastrointestinal drugs for cats and dogs

Choosing the right drugs for cats and dogs with gastrointestinal problems

source Edward Hall
In Practice vol 24 no 5, May 2002
starts p 242, 6 pages long

An accurate diagnosis of gastrointestinal disease in cats and dogs is needed in order to choose the most appropriate drugs. Sometimes tackling the symptoms of a disease can cause more problems than it solves, by delaying treatment of the cause of the problem. Diets should be good quality and highly digestible. Antibiotics should be used only when clearly needed, due to the risks of antibiotic resistance, though risks of inducing abnormal flora through usage of antibiotics have probably been exaggerated. Antibiotics can be used where there are specific, culture-proven infections with systemic signs, in the case of haemorrhagic diahorrea, and in the case of bacterial overgrowth in the small intestine.

Other drugs used to treat gastrointestinal disease include mucosal (cyto)protectants. Sucralfate is one such drug, and, though not licensed to be used in cats and dogs, the only side effect reported is constipation. There is concern that it could interact with other drugs, such as acid blockers and tetracycline, so it is safer to time doses of the different drugs with an hour at least between them.

Acid blockers are used to help healing of gastric and oesophageal ulcers. They include antacids, H2-antagonists, and proton pump inhibitors. Antiemetics can be helpful, though they may have side-effects, such as drowsiness. Prokinetics and antidiarrhoeals are other drug types that may be indicated.

Another class of drugs used to tackle gastrointestinal problems are immunosuppressive drugs, which should be used with caution. They should only be used where a biopsy has confirmed that there is significant inflammation, and where known reasons for the inflammation have been excluded. The article examines the selection of gastrointestinal drugs in further detail.


Capillaria hepatica (Calodium hepaticum) infection in a British dog

Dog may have caught liver infection from rats

Source: S. Lloyd et al
Veterinary Record vol 151 no 14, October 5 2002
starts p419, 2 pages long

Capillaria hepatica has been found in rats and mice in the UK. This case concerns a West Highland White cross bitch, which had always stayed in the UK, and which developed the disease. The bitch was neutered, and at 15-years-old, developed urinary incontinence and drank more than usual, as well as appearing to be senile. She was being treated for atrioventruclar block and hypradrenocorticism. She was euthanased, and her liver was found to be enlarged, pale and mottled on the outside, with internal lesions. The lesions contained eggs which appeared to be those of C hepatica.

Rats are the most common hosts of C hepatica. Infection is most common in urban areas and in the spring time, possibly due to cannibalism in rat nests. There is a need to carry out more investigations into the prevalence of C hepatica in the rat population. Dogs which hunt rats could become infected, as could humans, and the disease can be serious.


Essentials of nutrition in dogs and cats with gastrointestinal disease

Dietary therapy for cats and dogs with gastrointestinal problems

source: Marge Chandler
In Practice vol 24 no 9, October 2002
starts p528, 5 pages long

Diet is important for cats and dogs with gastrointestinal problems, and sometimes dietary therapy is enough to solve the problem.

Protein deficiencies can be caused by protein not being absorbed properly, and poor quality protein fed to pets. Effects of protein deficiency include weight loss, weakness, and decreased immune function, as well as lower levels of nutrient absorption, and a higher risk of overgrowth of bacteria in the small intestine. Protein sources should be highly digestible if pets suffer from intestinal problems. The average protein digestibility for commercial pets foods is from 78% to 81%, while pets with gastric disease should have a diet with protein digestibility of 87% minimum.

Proteins account for almost all food allergens, and the common allergens vary according to which protein sources are most commonly used in a particular country. Pets with food sensitivity may have gastrointestinal problems, or skin disease, or both. The pet can be fed a protein source not previously eaten. Pets with inflammatory bowel disease may benefit from being fed one novel protein just after treatment has been started., then a different novel protein once the intestinal inflammation has eased, since the pet may develop sensitivity to the initial protein.

White rice and cottage cheese is very digestible and unlikely to trigger allergic responses. The pet should be given twice as much rice as cottage cheese. Cats may refuse to eat cottage cheese, so boiled minced chicken could be used, so long as the cat has not previously eaten much chicken. Fish, rabbit, lamb or tofu can also be used, so long as the pet has not eaten the particular protein for at least six months. There are also special commercial pet foods which use hydrolysed protein sources for pets with allergies. Glutamine is an amino acid that pets may need if stressed, and it seems to be more effective if fed as an intact protein, rather than hydrolysed.

Cats and dogs are less likely to be sensitive to carbohydrates, though they should be fed gluten-free, highly digestible carbohydrate sources if they suffer from small intestine and stomach problems. Gluten sensitivity has been noted in Irish setters as well as in some other dog breeds, and in cats. Affected pets may suffer from gas, diarrhoea, and overgrowth of intestinal bacteria. Boiled rice is commonly used, and barley and corn may be tried. Tapioca and potatoes tend not to be digested as well, especially if not cooked properly. Cats with intestinal disease may have trouble digesting carbohydrates. Extruded dry food for dogs tends to be very digestible. Milk and yoghurt can trigger diarrhoea, since they contain more lactose than cottage cheese, and older dogs in particular may have trouble digesting lactose. Tapioca, bananas and raw potato contain resistant starches that may cause problems since they are not fully digested.

Elimination diets using easily digestible novel proteins and carbohydrates can be used to test for food sensitivities. The pet is started on one novel protein and one carbohydrate source, with small amounts of previously fed foods added to see if any of these trigger problems. Skin problems caused by food sensitivity tend to take longer to clear up than gastrointestinal problems. Elimination diets should be used with care, since they are not complete, so they are unsuitable for immature pets, and should not be fed for long periods without supplements. Ingredients in commercial foods other than proteins and carbohydrates, such as preservatives, may cause problems for some cats and dogs. Fibre may provide some benefits such as maintaining colonic motility, but is not recommended for pets with small intestine problems since it may damage small intestines that are inflamed. Diets with more fibre are also less digestible, and pancreatic enzyme activity is impaired by fibre.

Fats have a high calorie content, so slow gastric emptying. Pets with gastrointestinal problems may not digest fats well, and this can cause diarrhoea. Dogs with gastrointestinal disease should have between 12% and 15% dry matter basis fat levels, while cats should have between 15% and 22%. omega-3 fatty acids, found in fish oil and some plant oils like canola and flaxseed oil, may benefit some cats and dogs with intestinal problems.

Vitamin loss may result from diarrhoea, which leads to water-soluble vitamins being excreted at a higher rate, while pets that have problems absorbing fats may suffer from deficiencies in fat-soluble vitamins. Cats need high levels of B vitamins, so are especially at risk. Vomiting and anorexia are among signs of thiamine deficiency in cats. Supplements can be given in intravenous fluids. Vitamin E may help pets with gastrointestinal problems, given at between 10 and 100 iu/kg per day, though prothrombin activity may be impaired if doses of vitamin E are too high. Cats may also suffer from potassium deficiency. Most pets with gastrointestinal problems should have highly digestible, frequent, small meals with novel or hydrolysed proteins, gluten free carbohydrates, moderate fat restriction, and increased levels of water-soluble vitamins. Pets with colonic disease may also benefit from fibre increases.



Two pointers die after eating pesticide on potato field

source: Veterinary Record vol 151 no 4, July 27 2002 p104

Two pointers have died following a walk on a potato field. Both dogs were found to have traces of a pesticide, aldicarb, in their stomachs. The field had just been sown, and it is possible that some of the pesticide had spilled onto the surface, and was eaten by the dogs. Other notable cases of canine illness seen by vets include the death of five puppies from canine herpesvirus infection, and coccidiosis affecting two puppies in separate incidents. It is rare for coccidiosis to affect dogs.


Advances in dietary management of obesity in dogs and cats

Different effects of diet changes in cats and dogs

source: Richard F. Butterwick and Amanda J. Hawthorne
Journal of Nutrition vol 128 no12, December 1998
starts p2771S, 5 pages long

The reasons why animals are obese are not always clear, and there may be breed dispositions in dogs, but the direct cause os a higher intake of energy than is being spent. Activity levels are also important, and activity levels for dogs can vary greatly. A survey of border collies has found that most pet collies exercise for less than three hours a day. Recommendations for the calorie intake of dogs may be excessive, give the evidence of this survey of food intake and exercise levels of collies. If these recommendations are too high, they will contribute to obesity.

Cats subjected to rapid weight loss may lose too much lean tissue. They lose weight faster if they are only allowed to eat 45% of their maintenance diet at the desired body weight, but loss of lean tissue is faster than if they are only restricted to 60% of the diet they should have at their desired weight. Dogs appear to lose less lean tissue on high fibre diets, according to one study, but not enough is known about how dogs use fibre, and how far it may contribute to energy intake.

A high fibre diet does not appear to cause dogs to eat less due to feeling full. It may be better to assess whether diets for companion animals undergoing slimming programmes are nutritionally adequate, rather than focus on fibre as a slimming aid, since evidence for high fibre diets being effective as slimming aids is doubtful, and more research is needed.


Dog loses 427 stones

Springer spaniel bitch operated on after swallowing patio stones

source: Guardian February 1 2001 p8

Vets in the West Midlands, England, have removed 427 patio pebbles with a total weight of over one kilogram from a springer spaniel bitch. She had already vomited some 200 of the stones, prior to being operated on, according to her owner.


Chocolate can kill your dog

National Canine Defence League warns against giving chocolate to dogs

source: Independent April 20 2000 p9

The National Canine Defence League in Britain has warned against the dangers of feeding chocolate to dogs. Chocolate contains theobromine which can trigger convulsions and vomiting in dogs.


Diabetes mellitus in the dog, part 1.

Causes and diagnosis of diabetes mellitus in dogs

source: B. Holm
European Journal of Companion Animal Practice, vol VII (1) April 1997
starts p61, six pages long

Diabetes is cause by problems with insulin production, release or usage, affecting the way that glucose is metabolised, since insulin lowers glucose production. Growth hormone, adrenaline, cortisol and glucagon are insulin antagonists. A reduction in insulin production can occur for a number of reasons such as elevated insulin antagonist levels and pancreatitis. Around one percent of dogs with diabetes suffer an hereditary condition causing primary juvenile diabetes. This can affect Old English Sheepdogs, Labrador and Golden Retrievers, German Shepherds, Dobermann Pinchers and keeshonds. Secondary diabetes may also be linked to inherited tendencies, and can be triggered by high progesterone levels in oestrus and pregnancy, and Cushings syndrome. Contraceptive injections can also trigger diabetes between six and 12 weeks after the injections. Neutering, and treating animals suffering from Cushings syndrome may be enough to solve the problem. Obesity and high levels of stress hormones due to heart disease, trauma or other reasons may trigger diabetes, as can some drugs like thiazides, frusemide, and beta blockers.

Older and middle aged dogs are more likely to be affected, as are bitches and smaller breeds, such as some terriers, Poodles and Dachsunds, though German Shepherds, Irish Setters and Labrador Retrievers are also vulnerable. Affected dogs may urinate and drink a lot, and lose weight, and their blood glucose levels are high. They may also have cataracts and cystitis and swollen livers, and will have a high urine sugar content.


Treatment of diabetes mellitus in the dog, part 2

Treating dogs with diabetes mellitus

source: B. Holm
Eurpean Journal of Companion Animal Practice, vol VII(1) April 1997
starts p68, 10 pages long

Treatment of diabetic dogs involves a life-long commitment from owners, and may not be possible for some dogs, for example if they have severe ketoacidosis. The aim is to keep blood glucose levels as stable and near normal as possible. Spaying, diet and exercise can all be helpful. Oestrus suppression using proligestone is an alternative to spaying, for example with aged bitches.

Non-digestible fibre and complex calories can help avoid blood glucose peaks. Small dogs aged less than eight-years-old, and large dogs under six-years-old need between 60 and 80 kcal for each kilo in weight, dropping to between 40 and 60 kcal per kilo for older dogs. Fibre can slow absorption rates for glucose and limit fat and cholesterol absorption, and reduces blood glucose fluctuation levels, so less insulin is needed. Fibre is best baked into foods. Complex carbohydrates should account for a minimum 50% of the diet's energy content, and fat levels should not be above 30% of energy content. Blood glucose fluctuations can also be lowered through feeding several small meals. Chicken, egg, cottage cheese, rice and pasta, with calcium supplements from eggshells or elsewhere can be used for home-cooked diets, together with oat or bran fibre and a vitamin supplement. Regular commercial dog food should not be used, since it may have simple sugars not displayed in ingredients lists, and some extruded foods may also be unsuitable due to having a higher simple carbohydrate percentage than baked foods. A sample diet is provided in the article.

Exercise benefits diabetic dogs, though several short walks are better than fewer and longer walks. Owners should give dogs biscuits if walks turn out to be long, and always have glucose in case of hypoglycaemia. Feed meals before exercise to help reduce blood glucose peaks after meals.

Dogs can be treated with human or porcine insulin, and bovine/porcine insulin if this is not effective. Insulin is usually given twice a day through injections in the neck, with food given at the time of injections and four hours after if needed. Dogs take three or four days to adjust to dosages, with initial evaluations from four to seven days following initial treatment. Dogs should be walked frequently before urine tests, and tests should not be carried out using morning urine. Injections can be delayed for an hour, but should be omitted if there is a delay of several hours, with the following injection as scheduled. Insulin doses should be reduced when dogs are off their food or have diarrhoea. Dogs need more food and less insulin if their exercise levels increase significantly. Insulin should be kept in a fridge.

Too high insulin doses can lead to hypoglycaemia after some six hours, leading to a hormonal reaction that then pushes up blood glucose after 12 hours to hyperglycaemia. Hypoglycaemia is characterised by weakness, restlessness and hunger, and can be treated with glucose, honey or other food, rubbed under the tongue if the dog cannot eat. Owners should then contact the vet to have the treatment adjusted.


Heaviest dog

Bull mastiff entered in Guinness Book of Records as heaviest living dog

source: Guardian September 22 2000 p9

A bull mastiff called Kell has been entered in the Guinness Book of Records as the heaviest living dog. Kell comes from Loughborough, England, and weighs 19 stones.



Fifteen inch knife found in eighteen inch puppy

Staffordshire bull terrier swallows knife

Source: Independent January 26 2001 p6

Kyle, a puppy cross between a Staffordshire bull terrier and a collie, was found to have swallowed a breadknife 15 inches long, when he was X-rayed because he had been vomiting. Kyle comes from Leeds, England, and is only 18 inches long. He is recovering after surgery.