When dogs get mopey, possible reasons range from nothing in particular to the onset of serious health problems. But if uncharacteristic lethargy is combined with such symptoms as increased thirst and funny-smelling breath, something's definitely amiss. Many conditions can be responsible for impairing kidney function, but when urinalysis detects the presence of glucose, it suggests that those hard-working organs have been struggling to filter sugar out of the blood. That's a classic sign of diabetes mellitus.
Kidneys, Urine and Health
People can't get along without good kidney function, and neither can dogs. The kidneys are the bloodstream's bouncers, filtering out undesirable elements in urine, moving them to the bladder and expelling them from the body. Kidneys also help maintain the correct balance of salt and water, play a role in controlling blood pressure, and keep levels of essential minerals such as phosphorus and calcium in healthy balance. When kidneys don't function properly, wastes build up in the blood and cause sickness. That's why urinalysis can tell vets so much about a dog's health, both generally and in relation to specific conditions. Older dogs are more susceptible to kidney disease than younger ones. If left untreated, kidney disease can be fatal.
What Glucose in the Urine Suggests
When vets test glucose levels in dogs' urine, the reading should be negative. If it's positive, it means that the kidneys have been struggling to filter glucose out of the blood but were overwhelmed by the quantity. Insulin, a hormone produced by the pancreas and released into the bloodstream, is necessary to metabolize sugars, fats and proteins; if the pancreas is underperforming, the balance of everything else in the blood will be knocked out of kilter. Though diabetes mellitus isn't the only possible diagnosis, it will head the list of suspects. To confirm it or rule it out, the vet will order a blood glucose test and possibly other tests to get a better idea of the severity of the illness.
Breeds and Other Factors
Glucose in a dog's urine can sometimes be the result of stress or conditions other than diabetes, including bleeding in the urinary tract and Cushing's disease, which causes the adrenal glands on top of the kidneys to overproduce the hormone cortisol. Some breeds appear to be more susceptible to kidney problems than others, namely samoyeds, bull terriers, cairn terriers, German shepherds and English cocker spaniels. Elevated glucose levels not attributable to diabetes have been identified in a few breeds and mixed breeds, including basenjis, Norwegian elkhounds, Shetland sheepdogs, miniature schnauzers and Scottish terriers.
Kidney Disease and Dental Decay
Teeth and kidneys are a long way apart, but for the toxins that cause dental decay, it's an easy commute via the bloodstream. According to the ASPCA, dental disease is a primary cause of kidney failure in dogs. These bacteria can damage other organs, such as the heart and liver. The American Veterinary Dental Society reports that 80 percent of dogs suffer from some form of oral or dental disease by the age of 3.
Symptoms of Kidney Disease
Whatever the cause, loss of kidney function in dogs is a serious matter that needs a vet's attention with all possible haste. Common symptoms listed by the ASPCA include changes in drinking habits or the amount of urine produced, listlessness, chemical odors on the breath, pale gums or mouth ulcers, decreased appetite or weight loss, vomiting and loss of coordination.
Medical and Nutritional Management of Canine Diabetes
If your vet has diagnosed diabetes mellitus, the next step is to determine the best course of treatment. In milder cases, changes in diet may suffice to keep the disease in check. If your dog is overweight, shedding excess pounds might work wonders. If your dog needs insulin, sometimes it can be administered orally. However, there's no one-size-fits-all solution. A change in diet won't help your dog if he refuses to eat because he doesn't care for the new menu. With an insulin-dependent dog, your careful monitoring of food intake becomes the new normal -- taken on an empty stomach, insulin can be deadly.
By Rebecca Bragg
The Whole Dog Journal: Canine Urinalysis
ASPCA: Pet Care: Kidney Problems
UC Davis: William R. Pritchard Veterinary Medical Teaching Hospital: Nutritional Management of Diabetes Mellitus
VCA Animal Hospitals: Diabetes in Dogs – Testing and Monitoring
Pet MD: Kidney Failure (Long-Term) in Dogs
Washington State University: Pet Health Topics: Diabetes Mellitus
North Carolina State University: College of Veterinary Medicine: Remember Pet's Dental Health
U.S. Food and Drug Adminstration: Treating Cushing's Disease in Dogs
About the Author
Rebecca Bragg has been a writer since 1979. From 1988 to 2000, she was a reporter for Canada's largest newspaper, the "Toronto Star," specializing in travel. She holds a Master of Arts in English literature and creative writing and has lived in India and Nepal, volunteering in animal rescue organizations in both countries.