If you have nausea, vomiting, fever, diarrhea, or any other symptoms of an infectious disease, you should immediately consult a doctor. These infections and type 1 or 2 diabetes is a killer combination.  
Why are infections for people with diabetes especially dangerous With type 1 or type 2 diabetes?
Infectious diseases cause dehydration, and this is deadly, many times more dangerous than for adults and children who do not have diabetes. Do not hesitate to call an ambulance every time, as soon as a diabetic patient begins nausea, vomiting, fever or diarrhea. 
Why are infectious diseases with diabetes so dangerous?
Because they cause dehydration. And why dehydration is deadly dangerous? Because dehydration and elevated blood sugar form a vicious circle. This quickly - within a few hours - can lead to kidney failure, coma, death or disability.
There is also a danger that after an infectious disease if it is later treated, the remaining beta cells of your pancreas will die. From this, the course of diabetes will worsen. In the most severe scenario, type 2 diabetes can turn into a cruel and incurable type 1 diabetes.
What are the vicious circle of dehydration and high sugar
 If there is vomiting or diarrhea, then you are most likely an infectious disease. The cause may be poisoning with some poisons or heavy metals, but this is unlikely. Next, we will assume that the reason is an infection. Wherever there is an infection in the body - in the mouth, in the gastrointestinal tract, finger swelling or something else - blood sugar is likely to go up. So, the starting point: the infection itself increases blood sugar. Because of vomiting and diarrhea, the body loses its water reserves. The fluid contained in the gastrointestinal tract drops below normal. The lost liquid must be urgently replaced, and for this purpose, the body uses water from the bloodstream. This does not mean that internal bleeding occurs in the stomach or intestine. Simply cells suck in water from the blood and back give it much less. But when this happens, the additional glucose cells from the blood do not suck. As a result, the blood becomes less water, and the glucose remains the same. Thus, sugar in the blood even more increases. If vomiting or diarrhea occurs several times in a row, then because of high sugar and dehydration, the blood of a person with diabetes becomes viscous, like sugar syrup. The human body is permeated with a dense network of blood vessels. The farther these vessels from the center, the narrower their diameter. The farthest and closest ships are called "peripheral," i.e., distant from the center. At any time, a lot of blood is in the peripheral vessels. Unfortunately, if the blood becomes denser, then it becomes more difficult for her to squeeze into the narrow peripheral vessels.   
   
As a result, peripheral tissues are worse supplied with oxygen and nutrients, including insulin and glucose. This is even though the concentration of glucose in the blood rises. In fact, because glucose and insulin from the dense blood do not penetrate into the peripheral vessels, strong insulin resistance develops. Peripheral tissues begin to absorb less glucose, because of which its concentration in the blood is even higher. The more the blood sugar, the higher the insulin resistance. And insulin resistance, in turn, increases blood sugar. Also, the kidneys try to remove excess glucose in the urine, which causes the frequent urge to urinate, and this increases dehydration. This is one of the scenarios for the development of a vicious cycle of dehydration and high blood sugar, and another one is connected to this scenario.

 Glucose and insulin from the blood do not reach the peripheral tissues. Cells have a hard choice - to starve or to digest fats. They altogether choose the second option. However, in the process of the metabolism of fat inevitably appear by-products, which are called ketones (ketone bodies). When the concentration of ketones in the blood increases dangerously, the urge to urinate is further intensified, and dehydration goes to a higher level. The vicious double circle ends with the patient losing consciousness, and his kidneys are being denied. The main thing is that the events that we described above can develop very quickly, as a result of coma and kidney failure come in a few hours. The example with the woman-diabetic, which we resulted at the beginning of the article, is typical. For doctors of emergency care, there is nothing unusual in it. Unfortunately, in such cases, it is difficult for physicians to restore the average life of the patient. Mortality reaches 6-15%, and the subsequent disability - even more often. Muscular dehydration is treated only in the hospital with the help of intravenous drippers. To put these droppers begin in the ambulance. But we can do a lot to prevent such an extreme development of events. Suppose you woke up in the middle of the night or early in the morning because you have vomiting or diarrhea. 

 What should be done?
 Firstly, if you have a "doctor" of your own, call him and tell him, even at 2 am. Vomiting or diarrhea in a diabetic patient is how severe the event is, that you can upset the decorum. Secondly, if there is an infection in the body, you may temporarily need injections of insulin, even if you do not usually treat your type 2 diabetes with insulin. Infectious diseases typically increase blood sugar in diabetic patients. Also if you do not usually rub insulin, then when the body struggles with infection, it is advisable to start to do it temporarily. The goal is to reduce the load on the beta cells of your pancreas that are still working and keep them alive. Also, injections of insulin help keep blood sugar under control and thus prevent the development of a vicious circle of dehydration and high sugar. Beta-cells of the pancreas massively die as a result of elevated blood sugar, this is called glucose toxicity. If during an infectious disease to admit their death, then type 2 diabetes can turn into type 1 diabetes, or the course of type 1 diabetes will worsen. Therefore, all (!) Patients with diabetes need to master the technique of painless injections of insulin and be ready to use it when you are treated for an infection. 

 Here is the list of leading causes of dehydration in diabetes: diarrhea or vomiting several times in a row at short intervals;
Very high sugar in the blood; a high temperature, a person sweats profusely; forgot to drink enough liquid in hot weather or during physical exertion; the center of thirst in the brain is affected by atherosclerosis - in elderly diabetics. One of the main symptoms of the fact that sugar in the blood is very elevated is a definite thirst along with frequent urge to urinate. In this situation, problems arise, even if a person drinks water because he loses electrolytes. Nevertheless, there are simple measures that can be taken at home to prevent the development of a vicious circle of dehydration and high blood sugar.