High blood sugar is caused by the body's inability to make its own insulin or use it effectively. When your cat eats he digests fats, proteins and carbohydrates for his body to use. Sugar, or glucose, is an important substance because it provides him with the energy he needs to live. His body should also produce insulin to regulate the flow of glucose. If he isn't producing insulin, his body will use other sources for energy and his blood sugar will be high.

Keeping your cat healthy requires being in tune with his body. It is important to learn his behavior, so you will know if he isn't at his best. While most cats are generally healthy, some develop medical conditions similar to humans, including hyperglycemia, or high blood sugar. Diabetes mellitus is a condition that occurs in cats which is characterized by high blood sugar.

Cats with high blood sugar will exhibit certain symptoms that will let you know something isn't right. Below is a list of the most common symptoms seen in cats with diabetes:

There are two types of diabetes mellitus that can occur in cats and cause hyperglycemia:

Cats with this type of diabetes do not need daily doses of insulin to regulate their blood sugar. It is controlled with diet alone. 

This form of diabetes requires daily insulin injections to control fluctuating blood sugar. Most cats diagnosed with high blood sugar will need insulin to stay healthy. 

While the exact cause of diabetes in cats is unknown, there are some factors veterinarians believe contribute to its development.

Temporary increases in blood sugar that are not linked to diabetes may be caused by:

Your doctor will do a thorough examination of your cat to reach a diagnosis. First, he will ask you some questions regarding your cat's health and medical history. He will also perform a physical examination and take his vital signs such as temperature, weight, heart rate and respiration rate. Diagnostic tests are a critical part of diagnosing high blood sugar in cats. Your veterinarian will draw blood from your cat and run a CBC, biochemical profile and blood sugar analysis. A urine sample will also be taken to determine the level of sugar in his urine.

How your cat will be treated for high blood sugar depends on the nature and severity of his condition. Cats that are not seriously ill or in grave danger, are typically treated with daily insulin injections, dietary changes, and oral medication. Lifestyle and dietary changes, along with treatment of underlying conditions may be recommended. If your cat is in immediate danger, he may be admitted to the hospital for IV fluids and medications to stabilize his blood sugar. 

If your cat has high blood sugar, you must learn how to care for him so that he does not have serious complications that could threaten his life. Cats with diabetes often do not want to eat, but they need regular nourishment to keep blood sugar steady. Your doctor may prescribe special food and it is important that he eats regularly. He may also require oral medications and insulin injections on a daily basis. Most injections are given twice a day. Your doctor will teach you the best way to give insulin injections. It is important to be comfortable with this, as it is necessary to prevent a health crisis. You may also need to check your cat’s glucose levels each day at home. This is very important because when your cat's blood sugar is high, it spills into his urine. Once it has done so, his sugar levels are most likely very high. You can check his urine output for sugar by placing a detector in his litter box, but this can be a bit unreliable. Your doctor will most likely advise you to check his blood sugar with a blood sample obtained from his ear or foot. There are special units designed to check your cat's blood sugar.

If not treated, high blood sugar can shorten your cat's life. Diabetes in cats can lead to unhealthy looking coats, liver problems and chronic bacterial infections. Cats with uncontrolled blood sugar can develop a fatal condition known as ketoacidosis. If this occurs, he must be seen by a veterinarian immediately. Diabetes can also cause cats to develop hind-leg weakness. 

While it is challenging to care for cats with high blood sugar, it can be managed with medication and dietary changes. Developing a good relationship with your veterinarian is key to helping your cat stay healthy while managing his disease.