Cushing syndrome can cause changes in how the body regulates blood sugar levels. This can result in hyperglycemia or diabetes.

Cushing syndrome is a condition that increases the levels of a hormone called cortisol, which is known as the stress hormone. Your body raises cortisol levels to keep you on alert and ready if you need to react quickly.

This is helpful if you’re actually in a dangerous situation, but over time, high levels of cortisol can cause high blood sugar and other health problems.

Cortisol is a hormone that’s involved in many systems in your body.

One possible complication of Cushing syndrome is high blood sugar (hyperglycemia), which can sometimes lead to type 2 diabetes.

Typically, your body wants to keep the amount of sugar in your blood in a steady range. Cushing syndrome makes this much more difficult. It’s estimated that between 43–84% of people with Cushing syndrome develop high blood sugar.

Two hormones are involved in blood sugar management: glucagon and insulin.

Glucagon increases blood sugar levels when you need a boost. If you’re in a situation where you might need to run or fight for your life, you’re going to need some extra energy. One of cortisol’s jobs is to raise glucagon levels. Glucagon triggers the release of stored sugar into your bloodstream. This makes the sugar available for that fight-or-flight response.

Insulin is another hormone involved in blood sugar management. Normally, when blood sugar starts to rise, your body will release insulin. Insulin takes extra sugar in your bloodstream and brings it into your body’s cells, where it’s used for energy.

Cortisol increases the amount of glucagon in the body and raises blood sugar levels. Cortisol also prevents insulin from working normally.

Insulin works to lower blood sugar levels. When insulin is blocked from doing its job, blood sugar levels stay high.

Hyperkalemia is when potassium levels in the body are high.

Just like blood sugar, the body needs to control potassium levels in the blood. Potassium plays a role in regulating the amount of fluid in your body. It also helps with nerves and muscle function. Cushing syndrome does not tend to cause high potassium levels. It’s more likely to result in low potassium levels. This is known as hypokalemia.

High levels of cortisol can cause your body to lose more potassium. Some medications used for Cushing syndrome can also cause potassium levels to drop too low. If you take any of those medications, your healthcare professional might require regular bloodwork to monitor your potassium levels.

Hypoglycemia is when blood sugar levels are too low. Cushing syndrome on its own is not likely to cause hypoglycemia. More often, Cushing syndrome causes blood sugar to be too high.

Some medications used to manage diabetes can cause low blood sugar. Ask your healthcare professional whether you need to watch for symptoms of low blood sugar. Low blood sugar can make you feel sweaty, shaky, dizzy, or lightheaded.

Not everyone with Cushing syndrome will develop diabetes.

High cortisol levels interfere with normal blood sugar regulation. This makes it harder for your body to keep blood sugar in a normal range.

In some cases, a person with Cushing syndrome might have high blood sugar levels, but levels are not high enough to be diagnosed with diabetes.

Anyone with Cushing syndrome should get regular blood work to monitor blood sugar levels. This way, any changes in blood sugar levels can be caught and treated early.

Treatments for Cushing syndrome help lower cortisol levels. They often lower blood sugar levels too.

There are different treatments for Cushing syndrome and high blood sugar. Usually, the priority is treating Cushing syndrome, as this will often lower blood sugar too.

Treatments for Cushing syndrome typically include:

  • surgery or radiation to remove or shrink a pituitary tumor
  • medications that reduce cortisol production

If you’ve also been diagnosed with diabetes, your healthcare professional may discuss treatment options with you. For some people, treating Cushing syndrome is enough to reduce blood sugar levels to within a normal range.

Other people may need to treat their high blood sugar. Treatment for hyperglycemia due to Cushing syndrome is similar to how anyone with type 2 diabetes would manage this condition.

This typically includes:

  • taking medication, insulin, or a combination of the two
  • eating nutritious foods like fruits, vegetables, and lean proteins
  • limiting low nutrient foods
  • monitoring food portions
  • staying physically active, such as exercising

Cushing syndrome causes high cortisol levels. This results in various changes in the body, including increasing the risk of high blood sugar, a condition known as hyperglycemia. High cortisol levels affect the action of glucagon and insulin, two hormones involved in managing blood sugar levels.

Treating Cushing syndrome helps lower cortisol levels, which often also helps to lower blood sugar levels to within a normal range.

For some people, additional treatment is needed for blood sugar management. It’s a good idea for anyone with Cushing syndrome to have regular blood work to help monitor blood sugar levels.