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The adjustment does not work without castration

Diabetes Mellitus in the Female Dog 9

Flora was 4 1⁄2 years old when she suddenly started drinking more 4 weeks after her heat last spring. Symptoms of pseudopregnancy appeared two weeks later and improved with veterinary care. But she kept getting weaker. When she presented to the clinic, she could barely walk and had lost 14% of her body weight. Blood and urine tests revealed that large amounts of glucose and ketones were detectable in the urine, the blood glucose was 412 mg/dl and the fructosamine was 449 μmol/. Flora was energetically better off for a short time with old insulin and quickly castrated. Due to the high degree of acidosis, the metabolism was continuously monitored during the inhalation anesthesia, which was carried out with a high concentration of oxygen. Within the first few days after the operation, the sugar rose to 742 mg/dl despite the start of insulin therapy. However, after 2 weeks it was already below 200 mg/dl, 4 months after the operation the insulin treatment was stopped. Flora was lucky: she had overcome stress-related diabetes and was no longer insulin-dependent.

Frequency of the disease

Diabetes Mellitus in the Female Dog 10

Diabetes mellitus is not uncommon in pets. In dogs, the incidence is about 1:200. Small breeds, especially dachshunds, poodles, and small terriers are affected more often, among large breeds there is a predisposition to rottweilers and Samoyeds. Older dogs get sick more often than young ones. After puberty, bitches are affected twice as often as males.

Origin of diabetes

Dogs are almost always diagnosed with insulin deficiency diabetes or type 1 diabetes. Due to the destroyed or missing ß-cells of the islets of Langerhans in the pancreas, insulin production is reduced or completely absent. There is either congenital islet hypoplasia (Keeshond – ß-cells per islet significantly reduced) or a loss of islet cells, e.g. due to a viral infection (parvo) or in old age due to amyloidosis. However, secondary changes in the pancreas often also occur in dogs. These include necrosis, fibrosis, tumors or inflammation. The involvement of immunological processes that destroy the pancreas has not yet been definitively elucidated. However, the excessive secretion of insulin-antagonistic hormones or their external supply can also lead to diabetes. Mention should be made here of glucagon, somatotropin (e.g. in the case of acromegaly in cats), glucocorticoids, progesterone, estrogens, androgens, catecholamines or thyroxine. In the case of long-term heat suppression, the development of diabetes must also be expected. Obesity favors the development of the disease. Finally, diabetes can also result from the development of insulin resistance. With insulin production still normal at the beginning, the response of the somatic cells to insulin decreases continuously.

Since the publication of Eigenmann’s results, the pathomechanism of diabetes in bitches has also been clarified. Due to the antagonistic hormones, in particular the progesterone formed after heat, the need for insulin increases so much that the pancreas can no longer synthesize the required amount, production at maximum metabolic output is maintained for as long as possible, and the islet cells can burn out. Island atrophy occurs. Eventually no more insulin will be made available. Early diagnosis and the immediate removal of the ovary, which carries out progesterone synthesis in its functional bodies, can significantly reduce the strain on the pancreas. The faster the cause can be eliminated, the sooner the metabolic load will decrease. The islands can be protected from burning out.

Therapy options

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The therapy of the disease is correspondingly difficult: First, castration has to be carried out on patients who are often already ketoacidotic. In this metabolic state, the anesthesia does not pose a small risk, because the acidosis is increased by the respiratory depression caused by the anesthesia. With the help of short-acting old insulins, the energy supply to the body tissues for the operation can be significantly improved. 2-4 IU are used for a small dog and 5-10 IU for large bitches. Forced ventilation during inhalation anesthesia simultaneously exhales more CO2 and improves the oxygen supply. Breathing out the anesthetic gas reduces respiratory depression and the risk of acidosis.

Postoperatively, the convalescence phase represents a particular burden for the metabolism. This correlates with the glucose level, which usually rises above the preoperative values, despite the use of an intermediate insulin such as caninsulin. However, by increasing the insulin dose, the glucose level can be stabilized within a few days. Following this, close therapy monitoring should ensure that the injected insulin dose is adjusted to the pancreas function, which is hopefully slowly recovering. If the islet cells recover quickly, they quickly make significant amounts of the body’s own insulin available again. If the injected insulin is not adequately reduced, hypoglycemia will result. The insulin is gradually reduced as the glucose level decreases.

The values ​​of glucose and fructosamine measured preoperatively can already give an indication of whether the bitch is more likely to recover and have a physiological metabolic state or permanent insulin-dependent diabetes. For this purpose, the glucose-fructosamine correlation was determined on a large number of dogs.

This graphic is also easy to use under practical conditions: To do this, you enter the glucose value in mmol/l on the x-axis and the fructosamine value in mmol/l on the y-axis. If the correlation defined with this is below the lower limit line, the patient has a 90% chance of not having to be treated with insulin permanently later on. If the point determined in this way is above the upper limit straight line, there is a 90% probability that long-term treatment will be necessary. Unfortunately, it is not possible to make a reliable statement between the two boundary lines.

This correlation can also be established for other forms of secondary diabetes. According to preliminary results so far, the boundary lines are close to the functions shown below. Until more extensive data material is available, the assessment in practice can probably be based on the same limit values ​​as soon as other, primary causes have been ruled out.

Even bitches that do not require lifelong insulin therapy do not have a fully functioning endocrine pancreas for the rest of their lives. They are much more sensitive to diabetogenic noxae than normal dogs. Owners must be made aware that, for example, the use of glucocorticoids in their dogs must be reasonable in relation to the problems it may cause in the pancreas.

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If the blood sugar level does not fall adequately after castration under insulin therapy, daily profiles will usually have to be drawn up, as is the case with other forms of diabetes. The same applies to animals that have constantly changing blood sugar levels or a Somogy reaction. Fluctuations in the blood sugar level that occur after a long period of good adjustment should be readjusted if necessary after a daily profile has been drawn up. In this way, animals with diabetes mellitus can live well in their surroundings for a long time.