Diabetes in Dogs – Lack of Insulin Production in the Body

Diabetes in dogs is an increasingly recognized and diagnosed health problem. Typically occurring in the later years of life, previously healthy dogs begin to show an array of symptoms that can suggest diabetes.  As in human medicine, diabetes in dogs can be completely treatable, and with good management it will not affect quality of life or the life span of your dog.  However, if the symptoms of diabetes go unnoticed and the disease is left untreated, it can lead to malnutrition, dehydration, and death.

In humans, as well as animals, diabetes is caused by a decrease in, or complete lack of insulin production in the body. Ever cell within our bodies requires energy to live. The food we ingest is converted into glucose, which travels throughout the bloodstream, feeding cells and creating energy. Insulin in the body is the vehicle that allows cells to get their energy from the bloodstream.

In normal, healthy animals, cells in the pancreas release insulin automatically when a rise in glucose in the blood is detected. The insulin is distributed to cells in the body, allowing them to capture the glucose from within the bloodstream.

Almost all diabetes in dogs is caused by type 1, or insulin dependent diabetes. In these animals the pancreas stops producing insulin. Many factors can affect and destroy insulin production by the pancreas, including Cushing’s disease, steroid and immune system problems, pancreatic infection or stress- but often times a precipitating factor will never be identified for why the pancreas suddenly cease to produce insulin.  Regardless of the cause, without insulin, cells throughout the body cannot take in the glucose from the blood, effectively starving them of energy.

In response to the cells distress, the brain begins to send signals to eat more, so the body can take in more glucose.  The glucose level in the blood steadily rises, unable to be utilized, while the cells in the body continue to demand glucose, breaking down fat and muscle protein to be converted by the liver. An unending cycle is quickly created, with more glucose being taken in and created, the body unable to utilize it as energy because the lack of insulin prevents transfer of the glucose into the cells.

As the cycle progresses, glucose continues to build up in the body, leaking into the urine and drawing water from cells in the body into the urinary tract, leading to constant dehydration despite increased water intake.

If diabetes is allowed to progress unchecked, dogs will begin to suffer from severe malnutrition (as the body is unable to use the food that is eaten), muscle wasting (as the body feeds on it’s own tissue for energy) and dehydration (from the glucose drawing water from the body). In addition, diabetic ketoacidosis can develop. As the body begins to break down fat as a source of energy, by-products called ketones are created.  As these byproducts continue to accumulate in the blood, it can cause a very serious and potentially fatal illness.

Symptoms of diabetes in dogs are similar to those in people. The early signs most commonly noticed include :

  • Drastically increased appetite
  • Significant weight loss, even while eating more
  • Increased Thirst (polydipsia)
  • Increased Urination (polyuria)
  • Lethargy

In diagnosing and treating diabetes, the knowledge and skill of your veterinarian is absolutely essential. After a complete physical exam of your dog, your vet will perform laboratory tests. Because the symptoms of diabetes can often mimic those of other diseases, such as Cushing’s disease and hypothyroidism, only by a combination of symptoms and laboratory tests can a definitive diagnosis of diabetes be made.

Complete blood work and chemistries, as well as a urinary analysis will be performed to establish the amount of glucose present in the dogs blood and urine. A positive result in the urine, and a value of over 200 in the blood is indicative of diabetes. In addition, the level of ketones will be measured to ensure that they are not abnormally high.

Once a diagnosis of diabetes has been made, your veterinarian can begin to work with you and your dog to get control over your the disease. Treatment of diabetes has many facets, and may include insulin injections, dietary adjustments and even lifestyle changes.

Almost all dogs with insulin dependent diabetes will require insulin injections to regulate their blood glucose. The most commonly used type of insulin, Vetsulin, is made specifically for dogs. However there are many types of insulin available, and your vet will decide which will work best for your pet. Although many owners are initially afraid to give their dog injections, your veterinarian will help you to get comfortable with the procedure, and it can soon become second-hand to you.

The initial regulation phase of treatment may include several “glucose curves” where a starting dose of insulin is given, and the blood glucose is checked immediately after eating, as well as 4-6 more times at 2-hour intervals to monitor the dogs blood glucose levels throughout the day.

Glucose levels in the blood between 90-180mg/dL are the optimum and target range of diabetes control. Levels from 180-300mg/dL are too high, and symptoms of diabetes will begin to manifest. Over 300mg/dL the blood glucose is dangerously high, and serious side effects can occur.

It may take several weeks of adjusting the dosage of insulin, as well as several glucose curves to establish the correct dosage for your dog. At home, you may be asked to get a glucose meter so that you can monitor your dogs glucose levels, insuring they do not get too high, or too low. Hypoglycemia, or blood sugar levels below 50 mg/dL, is a life threatening emergency, most often caused by giving a diabetic dog an incorrect dose of insulin, or giving a dose of insulin when the dog has not eaten prior. Symptoms of hypoglycemia include severe lethargy, dizziness, loss of bladder control, loss of consciousness and seizures. If your diabetic pet begins to exhibit these symptoms, immediately try to get him to eat something, or spread honey or corn syrup in the mouth for the body to absorb the glucose, and seek immediate veterinary attention.

Because keeping a constant, well-regulated blood sugar level is the goal of diabetes treatment, your veterinarian may recommend switching your dog to a high-fiber, lowered-carbohydrate diet to help maintain their blood sugar levels.

Through a combination of insulin and dietary changes, initial regulation of your diabetic dog will help to control their disease, and you should see positive changes in their energy, body condition and other symptoms within a few weeks. After good regulation has been established, monitoring bloodwork every 3-6 months will be needed to ensure your pets insulin requirements are not changing, and regulation of glucose is still good.

Dogs and Cataracts

The most common “side effect” of diabetes seen in dogs is progressive blindness caused by cataracts. Prolonged high amounts of glucose in the blood lead to cataract (a white pigmentation of the lens) formation in the eye, which causes blindness. Unfortunately, many dogs that develop diabetes will also develop cataracts and blindness as a result, even with excellent treatment and control. Surgery is available in some cases to remove the cataract and restore vision, but is not an option in every case.



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