Illness is a stressful condition that can increase insulin resistance and may raise your blood sugar levels. In addition, if you vomit and have diarrhea, you may become dehydrated, which can also cause insulin resistance. Therefore, you should never stop your diabetes treatment when you are sick. In fact, if you are very sick, you may need to use insulin temporarily to keep your blood sugar levels from rising too high. But if you have trouble eating, you should also be aware of the risk of hypoglycemia from insulin or sulfonylureas. In this case, it’s important to be able to take precautions and know what foods you usually feel comfortable with and how much you can eat to keep your blood sugar levels from getting too low. Keep these foods stocked in your room and warn your family members not to eat them because they are important to you in an emergency. It is a good idea to keep these foods in a specific place so that they can be found in time for use. People with type 1 diabetes also have to worry about the development of diabetic ketoacidosis (DKA). If you have type 2 diabetes, you are not predisposed to ketoacidosis, although you will produce some ketone bodies when you fast, eat too much fat, or go on a low-carbohydrate diet. But in most cases enough insulin is produced to stop ketoacidosis from developing. In patients with type 2 diabetes, however, a related acute complication, hyperosmolar hyperglycemic nonketotic syndrome (HHNS), may occur. Although rare, it has a high mortality rate when it occurs, so it is important that you know and are familiar with some of its symptoms. HHNS can occur when your blood sugar levels are very high. Your body tries to excrete too much glucose from your urine through a regulatory mechanism. This causes you to lose a lot of water, resulting in dehydration and thirst. So the initial presentation of HHNS is very similar to some of the presentations you had before your diabetes diagnosis. The problem is that if you have other discomforts, especially vomiting and diarrhea, it may be difficult to drink a lot of water to relieve the dehydration. You may feel very tired or have difficulty reaching for water. As a result, your blood sugar level rises even higher and your dehydration gets worse, and so on. The end result is that the patient becomes unconscious or even comatose. If not treated in time, HHNS can be fatal. Unlike DKA, HHNS usually starts slowly, over a period of several days, mostly in the elderly, especially if they are not being cared for by others and are not paying enough attention to their condition. If you feel unwell, watch for changes in your blood sugar levels. If you are too sick to take your own blood glucose, ask someone to do it for you. If your blood glucose level exceeds 16.7 mmol/L (300 mg/dl) and does not drop, go to the hospital promptly.