Diabetes in dogs is the correct medical term for diabetes (diabetes mellitus) by the house dog. In everyday language, the terms "dog diabetes" for the disease and "Sugar Dog" for a sick dog can be used. The initial symptoms include increased thirst and increased food intake with regard to increased urination and loss of weight. Diabetes in dogs almost always requires a lifelong administration of insulin, but is easy to control.
Frequency
As in humans, it increases the number of diabetics in the dog. It is unclear, however, whether the disease incidence increases real or whether the disease is detected only common in veterinary practice by the improved diagnostics. It is estimated that about 0.3 to 1% of the total population of the domestic dog is suffering from diabetes mellitus. Diabetes is now constitute the second most common hormonal disorder in dogs. In eight out of ten it is in the diseased animals to adult, castrated bitches.
Shape
The classification of canine diabetes mellitus is handled differently in the literature. In principle, the disease in insulin-dependent and non-insulin-dependent divided. The current human medical WHO classification is not common in veterinary medicine. Basically, all forms of diabetes can occur in dogs. In practice, however, almost exclusively of insulin-dependent diabetes mellitus observed the non-insulin-dependent (type II diabetes) - ie insulin resistance of peripheral insulin target cells - in contrast to humans and the cat almost never.
In primary diabetes mellitus with absolute insulin deficiency (type I diabetes) work the insulin-producing beta cells of the pancreas no longer or not sufficiently, either due to genetic predisposition, infection or antibodies against the beta cells. He makes the dog for about half of the cases, but evolved, in contrast to humans, predominantly in adult animals.
The so-called secondary diabetes mellitus (type III diabetes in humans) arises as a result of disease. This can be an inflammation of the pancreas (pancreatitis), a pancreatic tumor, adrenal hyperfunction (Cushing's syndrome), an underactive thyroid (hypothyroidism) or an exaggerated secretion of growth hormone (Hypersomatotropismus). In addition, a secondary diabetes mellitus by administration of diabetic medications (steroids, GH, progestogens) are triggered.
Both primary and secondary diabetes mellitus in dogs are irreversible, in contrast to the cat, as a rule.
As a special feature, a diabetes mellitus due to the diestrus occur in intact bitches. Here, the distributed from the ovaries progesterone stimulates the production of growth hormone, which acts as an antagonist of insulin. If the progestin distribution does not eliminate by means of a castration, a life-long therapy requiring diabetes is inevitable. Although this form of diabetes after removal of the gonads is initially reversible, instruct the affected females before the onset of symptoms a reduced content of beta cells and are thus susceptible as castrated animals for the disease.
Pathogenesis
Risk Factors
There are several genetic and environmental factors that may favor the occurrence of diabetes in dogs. Being overweight increases the risk of disease. The walk frequency and duration does not affect the risk; however, it can be reduced by regular physical activity. When feeding, increase self-prepared diets compared with dry food risk; the same is true for frequent administration of treats. Next have dogs under 22.7 kg of body weight compared to larger dogs at increased risk, older dogs are more frequently affected than females young and more frequently than males.
Pathophysiology
In contrast to the diabetes of man is the canine diabetes primarily due to insulin deficiency (type I) diabetes by insulin resistance (type II) is very rare in dogs. With the lack of insulin can dextrose (glucose) can not be utilized in the cells. In addition, disturbances occur in fat and amino acid metabolism. As a result of the disturbed usability of glucose that occurs through dietary intake and synthesis in the liver in the body, it accumulates first in the blood (hyperglycemia). At a certain limit (about 180 mg / dl, renal threshold) is exceeded, the recovery capacity in the renal tubules of the kidney, and it comes to sugar excretion in the urine (glycosuria). Due to the osmotic effect of glucose water is also increasingly excreted in the urine, so the amount of urine increases (polyuria). The increased water loss is compensated by an increased water intake (polydipsia). The lack of glucose in the brain, especially in the satiety center in the hypothalamus, leading to increased hunger and food intake (polyphagia). As a result of impaired glucose utilization the body tries to compensate for the lack of energy by breaking down proteins (mainly muscle) and fat. This leads to emaciation (inanition, cachexia).
Longer periods of insulin deficiency may lead to a further metabolic imbalance, the so-called ketoacidosis. As a result of the increased fat loss fatty acids are increasingly being released, which can not be recycled in the citric acid cycle by the body and converted to ketone bodies. Since ketone bodies have an acidic pH, there is an over-acidification (acidosis). The excess ketone bodies can also be excreted in the urine (ketonuria) and increase as a result of its osmotic effect, the polyuria. A pronounced ketoacidosis is a life threatening condition.
Clinical manifestations
A diabetes initially remains often unnoticed, unless an elevated blood sugar levels is discovered during a routine examination. Clinical symptoms only occur if there is a glucose excretion in the urine (glycosuria) or ketoacidosis. Typical symptoms of clinically manifest diabetes include excessive fluid intake (polydipsia), increased urination (polyuria), greatly increased feed intake (polyphagia), and weight loss.
If these early symptoms may be overlooked, secondary symptoms may predominate. Often a declining eyesight is determined by the owner as the first symptom, which is due to the diabetes-induced lens opacity. The well-emerging in the aqueous humor glucose is converted into the lens by the enzyme aldose reductase to sorbitol, which accumulates there and due to the osmotic water influx to cataracts (cataract) results. Diabetes mellitus is not infrequently observed only in manifest ketoacidosis. Here the general condition is greatly disturbed, the animals can be chipped or even comatose.
Diagnostics
The diagnosis by a veterinarian is performed through a measurement of blood glucose levels. As evidence of the disease from diabetes mellitus, a sustained blood sugar levels in dogs in fasted animals applies, ie without prior food intake of about 150 mg / dl (8.3 mmol / l). Physiologically (ie as a healthy carrier), are fasting levels in the blood plasma of 70 to 120 mg / dL (3.9 to 6.7 mmol / l).
A detection of glucose in the urine is not conclusive, since it can also occur in dogs with kidney disease. An indication of diabetes mellitus is the detection of glucose in the urine, however, when at the same time, the specific gravity of the urine is high (> 1.035).
The determination of fructosamine plays in the dog, as opposed to diabetes mellitus of the Cat, only a minor role. Values above 340 micromol / l speak for diabetes mellitus.
Treats for diabetic dogs
Replacement of insulin-producing islets of Langerhans by islet cell transplantation in dogs is not in question, although this procedure was first performed in 1891 by Oskar Minkowski in a dog. This method is used in human medicine is still in the experimental stage and is unlikely to establish in veterinary medicine because of the immense costs. The canine diabetes mellitus is treated by supplying insulin.
In intact bitches castration (ovariohysterectomy) is recommended as a first measure, since the formation of progesterone during the metestrus or diestrus leads to destabilization of the disease and proper adjustment to insulin is not possible due to the induced insulin opponent somatotropin. Ideally, however, the only rarely occurs, the symptoms of the disease disappear with the removal of the ovaries and there is no further need of treatment.
When insulin treatment two phases can be distinguished:
-The stabilization of the dog by setting the correct insulin dose and
-The preservation of the dog by regular monitoring of blood sugar levels.
The goal of treatment is always to minimize the clinical symptoms, the risk of hypoglycemia and the development of consequential damages. Cataracts as a result of diabetes (diabetic cataract) can be medically not affected, but remedied by removing the lens.
Insulin substitution
Because of diabetes mellitus in dogs is almost invariably insulin-dependent and irreversible, a lifelong administration of a correct amount of insulin by subcutaneous injection is necessary. To determine the correct amount of insulin is done by setting the patient using the blood sugar value, best illustrated with an daily profile, by the veterinarian. Here is initiated with a dose in the lower range of doses and the dose adjusted for several weeks on the basis of the sugar content in the blood individually.
The only currently approved in Germany for the dog insulin preparation is a medium-long-acting, so-called intermediary porcine insulin (porcine lente insulin, Caninsulin® of intervet). After the pharmaceutical legislation other preparations may be used only for the purposes of a therapeutic emergency, so there be no or insufficient effect or intolerance. In these cases, human insulin can be used. In a complicated disease course as individually tailored combinations of long-acting and short-acting insulins can be used. Oral administration of antidiabetic drugs is not indicated in the dog. The dose of insulin twice a day at intermediate or specifically after feeding. This eliminates the dog gets into a life-threatening hypoglycemia because he had received insulin, but then not the appropriate amount of carbohydrates receives
Other measures
Essential accompanying measures in the treatment of the affected dog are:
-Setting on the ideal body weight (weight loss, weight gain)
-Adherence to a strict feeding concept (food type, amount of feed and feeding time should always be consistent). The approved for dogs insulin consists of an amorphous and a crystalline insulin insulin with a maximum effect on the one shortly after injection, occur on the other by about 7 to 8 hours a property that must be considered when feeding. For a good attitude of the patient is a fiber rich diet beneficial. There are special commercial diet feed. Home-cooked food should consist of one third meat, one third of carbohydrate sources and one third vegetables.
-Minimization of physical and psychological stress (eg. As no unusual physical exertion)
In addition, the presence of any other underlying diseases must be excluded or treated. Also accompanying disease must be diagnosed and treated, as they may reduce the efficacy of the administered insulin. 21% of people suffering from diabetes mellitus dogs develop a usually subclinical cystitis.
Insulin resistance
When insulin resistance is called the state if it can not be reduced below 300 mg / dl by a twice-daily dose of 1.5 IU / kg body mass of blood sugar levels. This must first be ruled out due to other diseases treatment errors (incorrect injection technique, wrong dose, insulin has become ineffective, feeding) and administration diabetes-inducing drugs (glucocorticoids, megestrol). Most common causes of insulin resistance are other diseases such as Cushing's syndrome, bacterial infections, hypothyroidism, heart, liver and kidney disease or chronic pancreatitis, and obesity. Only about 5% of cases autoimmune antibodies against the administered insulin to be developed, then another insulin should be used.
Home Monitoring
As in human medicine can also be in the dog a home monitoring, ie the control of sugar levels at home using a blood glucose meter performed. The procedure in dogs is not as essential as in cats in insulin adjustment phase but definitely recommended.
For a simple blood sample, there are special devices. Am so produced drops of blood glucose level can be measured using a commercially available blood glucose meter. This home monitoring has the great advantage that hypoglycaemia is detected early. In addition, insulin treatment can be better tailored to the individual life. The home monitoring is simple and can be learned by every dog owner. It should be performed at well-adjusted dogs once every two weeks. A veterinary inspection is recommended every three months.
The long-term monitoring can be done by the dog owners themselves. This fluid intake, Harnabsatzmenge and at least once a week, the sugar content in the urine (test strips) or blood should be controlled.
Hypoglycaemia
Even a dog well set there may be a hypo (hypoglycaemic shock), that lead to a low blood sugar levels. The signs include severe hunger, restlessness, tremor, movement disorders (twitching) to coma. A hypo is always an emergency and must be corrected immediately.
As a countermeasure, is recommended:
-Provision of food
-Instilling a sugar solution (glucose, honey or glucose syrup) into the mouth,
-Transfer of a sugar cube or grape sugar under the tongue,
If these measures are not successful, an immediate idea to the vet is essential.