Diabetes Mellitus in Dogs - Symptoms and Treatment

 

Diabetes mellitus is one of the common endocrine diseases in dogs, being common in females and in adult dogs (with an average age of 7-9 years). Despite the fact that it is an incurable disease, with the commitment of dog owners and proper treatment management, diabetic dogs can enjoy a good quality of life. If you are interested in learning more about diabetes mellitus in dogs, its symptoms, and treatment, then read on. Because in this article we will explain everything you need to know about diabetesmellitus in dogs.

What is diabetes mellitus in dogs?

Diabetes mellitus is an endocrine disease characterized by a state of persistent hyperglycemia (high blood glucose levels), which is caused by a deficiency in insulin production or by factors that prevent its action. To better understand how this disease develops, we will briefly explain its pathogenesis. Insulin is a hormone secreted by the pancreas in response to the presence of glucose in the blood.

When blood glucose levels rise, the pancreas releases insulin to allow glucose to enter cells and be used for energy. But, when for reasons that we will see below there is a deficiency in the production of insulin or there are factors that prevent its action, glucose accumulates in the blood-producing a state of hyperglycemia.

When the blood glucose concentration exceeds the so-called “renal threshold”, glucose is excreted in the urine (glycosuria). At the same time, the absolute or relative lack of insulin means that the tissues have limited access to glucose, and so, they need to break down the body's protein and fat reserves to get the energy they need.

Causes of diabetes mellitus in dogs

Diabetes is usually a multifactorial disease, that is, it is usually a process conditioned by various factors. Specifically, the causes of diabetes mellitus in dogs can be primary or secondary. Primary causes: those that affect the pancreas itself. This group includes pancreatitis, exocrine pancreatic insufficiency, and immune-mediated insulitis, among others. Secondary causes: those that do not directly affect the pancreas, such as glucocorticoid treatment, high levels of progesterone, obesity, chronic infections or inflammation, and azotemia.

Types of diabetes mellitus in dogs

Type I diabetes mellitus: also known as insulin-dependent diabetes is the most common form of diabetes mellitus in dogs. It occurs as a result of a primary injury to the pancreas that destroys the pancreatic cells responsible for insulin synthesis. As a consequence, there is an absolute deficiency of insulin in the body. This type of diabetes is irreversible, which means that patients require lifelong insulin treatment.

Type II diabetes mellitus: also known as non-insulin-dependent diabetes. Although it can occur in dogs, it is more common in cats. In this case, the animal is capable of producing insulin, but there are factors (fundamentally obesity) that induce insulin resistance in the tissues, which prevents the hormone from exerting its effect. The advantage of this type of diabetes is that it is reversible.

Type III or secondary diabetes mellitus: is a type of diabetes that occurs when certain diseases (such as pancreatitis, Cushing's syndrome and acromegaly) are combined with certain drugs (such as glucocorticoids or progestins).

Symptoms of diabetes mellitus in dogs

The symptoms associated with diabetes mellitus in dogs are quite evident, which allows dog owners to easily detect the signs and go to the veterinarian in the early stages of the disease. We explain these clinical signs in more detail below.

Polyuria: increased volume of urine. As we explained at the beginning of the article, when the blood glucose level exceeds the "renal threshold", glucose is eliminated through the urine. Glucose acts as an osmotic diuretic, drawing large amounts of water with it and increasing the volume of urine.

Polydipsia: increased water intake. The polyuria produced by the presence of glucose in the urine gives rise to compensatory polydipsia, in order to prevent dehydration of the animal.

Polyphagia: increased appetite. As the tissues are not capable of capturing glucose, a negative energy balance is produced that the animal tries to compensate by increasing food consumption.

Weight loss: the lack of intracellular glucose leads the body to break down fat and protein reserves for energy, which results in weight loss.

Cataracts: opacity of the lens. It is the most common complication of diabetes mellitus in dogs. They are irreversible and can evolve rapidly.

Bacterial infections: oral, urinary, and skin infections are very common in diabetic dogs.

Hepatic lipidosis: accumulation of fat in the liver that occurs as a result of the mobilization of reserves to obtain energy.

Pancreatitis: Although pancreatitis is a cause of diabetes, it can also be a complication. This is because the mobilization of fat reserves gives rise to a state of hyperlipemia that can predispose to the appearance of acute pancreatitis.

Glomerulopathies: this is a group of diseases that cause a loss of the glomerular filtration membrane and its integrity.

Diabetic ketoacidosis: it is the most serious complication of diabetes mellitus. If not treated quickly, the death of the patient occurs since it implies an absolute deficiency of insulin.

Diagnosis of diabetes mellitus in dogs

The diagnostic plan for diabetes mellitus in dogs is based on the following points: Clinical history: as we have mentioned, the most common signs of diabetes in dogs are polyuria, polydipsia, polyphagia, and weight loss.

Blood tests: hyperglycemia (>200 mg/dl) is detected in all diabetic dogs. In the event that it is in a doubtful phase (180-200 mg/dl), the animal is considered to be prediabetic. In prediabetic or potentially diabetic animals, it is recommended to measure the levels of glycated proteins (fructosamine and glycated haemoglobin) that indicate glycemia in recent weeks. In addition to hyperglycemia, hyperlipidemic fasting plasma, as well as increased liver enzymes GPT and alkaline phosphatase, can be seen in many diabetic dogs.

Urinalysis: When the renal threshold is exceeded, glucose will be detected in the urine (glycosuria). Although the animal has polyuria (increased urine volume), urine density is normal or even increased because the presence of glucose in the urine increases its osmolarity. In addition, ketonuria (presence of ketone bodies in the urine) and proteinuria (presence of protein in the urine) may be observed in some patients.

Imaging diagnosis: given the large number of complications that can develop in diabetic patients, it is advisable to perform imaging tests (mainly X-rays and ultrasound) to detect these complications early.

Treatment of diabetes mellitus in dogs

Diabetes mellitus is a chronic disease for which there is no curative treatment. However, with proper management of the pathology, diabetic dogs can live a good quality of life. Therefore, it is essential to diagnose and control the disease as soon as possible, to reduce or eliminate clinical signs and delay the onset of complications. In any case, it is essential that owners of diabetic dogs understand the disease, its risks, and its treatment, since their collaboration will be essential to control the pathology.

In fact, the involvement of dog owners is one of the most important factors determining the success or failure of treatment. Specifically, the treatment of diabetic dogs is based on four fundamental pillars:

Insulin: Diabetic dogs require lifelong insulin treatment, and unlike what happens in people, insulin cannot be replaced by any other compound. There are several types of insulin depending on their potency and the duration of their effect. In dogs, the first option is Caninsulin, slow-acting insulin of porcine origin and structurally identical to canine insulin. It is administered subcutaneously, 2 times a day. To administer the dose, it is essential to use specific insulin syringes for veterinary medicine, because if syringes for human medicine are used, important dosing errors can be made.

Diet and regular exercise: diabetic dogs must have a special diet that helps, on the other hand, to regain lost weight and, to reduce postprandial hypoglycemia. Specifically, a diet low in fat (<15% fat), high in fiber (15-22% fiber), and with normal protein levels (20% protein) should be administered.

The ideal is to divide the ratio into 2 meals a day and use a specific feed for diabetic dogs. It should be noted that food should always be administered first and then insulin and the insulin dose should be adjusted according to what the animal eats (for example, if it only eats half of the ration, only half should be administered).

Control of other diseases and concurrent processes: any pathological or even physiological process (such as heat or pregnancy) can cause a diabetic dog to decompensate since these phenomena can produce insulin resistance. Therefore, it is important to detect and treat these processes in time to keep diabetes under control.

Regulation of treatment (revisions): the treatment of diabetes mellitus is dynamic and requires adjustment of the insulin dose throughout the life of the animal. For this reason, the diabetic dog needs to attend regular check-ups in which a glycemia curve will be performed and weight, polyuria, polydipsia, and polyphagia will be controlled. Based on the results of these check-ups, the insulin dose will be adjusted.

How to prevent diabetes mellitus in dogs?

The prevention of diabetes mellitus in dogs is not a simple matter, since in most cases the pathology is caused by processes that cannot be avoided. But, there are certain risk factors that must be taken into consideration to prevent the onset of diabetes mellitus as much as possible.

Castration: High levels of progesterone can lead to insulin resistance. For this reason, castration is especially recommended in female dogs as a preventive measure for diabetes mellitus. In addition, in bitches in which the disease has already been diagnosed, castration is always indicated since it can reverse diabetes.

Obesity: preventing obesity through a balanced diet and regular physical exercise will prevent some of the causes of diabetes, such as pancreatitis.

Periodic veterinary check-ups: through these check-ups, prediabetic dogs that require specific management can be detected to prevent diabetes from finally developing. These reviews are especially recommended in breeds predisposed to diabetes mellitus such as terriers (particularly the West Highland terrier), poodle, dachshund, schnauzer, and golden retriever.