Patient Resources

Hyperglycemia

June 09, 2022

Hyperglycemia is the medical term for blood glucose (sugar) that is too high. High blood glucose (HBG) is a common problem for people with diabetes. Blood glucose can also rise too high for patients in the hospital, even if they do not have diabetes.   Hyperglycemia in a hospitalized patient is very common.  Infections, certain medications (e.g.  prednisone (steroid medication) and the body's stress response to an illness can all increase the likelihood of developing hyperglycemia in the hospital. 

Approximately 1 out of every 4 patients admitted to the hospital have diabetes. Another 25% of patients who do not have diabetes experience hyperglycemia when they are sick and in the hospital.      

Endocrine Connection

Insulin is a hormone made by the pancreas. Insulin unlocks cells so that glucose can enter.  When glucose enters cells, the body has energy.  Energy is needed to perform normal daily activities and for our heart to beat and lungs to breathe.  Without insulin or enough insulin, glucose levels rise.  If glucose levels go too high, it is called hyperglycemia.   

When someone is sick the body makes extra amounts of stress hormones.  Stress hormones include cortisol, glucagon, growth hormone, and epinephrine.  They help the body handle the stress of illness by making extra glucose to fuel the increased energy needs.  Sometimes, however, extra hormones can cause insulin resistance which prevents insulin from doing its job.  Glucose builds up in the blood, as a result, which leads to hyperglycemia.   

Many conditions can cause or worsen HBG in hospital patients. These include: 

  • Physical stress of illness, trauma, or surgery 
  • Infections such as urinary tract infection, pneumonia, flu or COVID-19 
  • Decrease in physical activity 
  • Steroids like prednisone and some other medicines 
  • Withholding or missed diabetes medicines 
  • Liquid food given through a feeding tube or nutrition given intravenously 
  • Certain rare endocrine conditions such as Cushing disease or tumor making too much of the stress hormones such as growth hormone or glucagon 
  • Many times, patients with diabetes have higher blood sugars when in the hospital, and patients who do not have diabetes may have high blood sugars while in the hospital. 

Sliding Scale Insulin (SSI): Historically SSI has been a common way to treat blood sugars in the hospital. SSI uses short-acting  insulin and the “sliding” term refers to the increasing amounts of insulin given based on glucose levels (e.g., Give 4 units if BG 140-80; Give 6 units if BG 180-220, etc.).  Used alone, SSI is not usually an effective way to manage diabetes in the hospital setting. 

Correction Insulin Therapy: Correction Insulin refers to insulin given to bring high blood glucose readings down to target levels. Rapid acting insulins are usually used.  

Basal Bolus Insulin Therapy: This therapy involves the use of both long-acting (basal) and rapid-acting (bolus) insulins.  The long-acting insulin (taken once or twice a day) provides consistent 24-hour coverage of blood glucose and rapidly acting insulins are given 2-4 times a day with food intake to help avoid hyperglycemia after eating.  

Carbohydrate Counting (CC): CC involves calculation of the amount of carbohydrates consumed in a particular meal.  Carbohydrates are generally measured in grams.  For example, a slice of bread has between 10 to 15 grams of carbs.  The amount of rapid insulin needed with a meal is determined by how many grams of carbohydrates will be consumed.  For example, a patient may need 1 unit of insulin for every 10 grams of carbohydrates they consume. 

Prandial/Nutritional/Mealtime Insulin: fast-acting insulin given before or after meals to minimize the increase in blood glucose after meals 

DKA or Diabetic Ketoacidosis: a buildup of acids in your blood as a result of  not having enough insulin.  Insulin helps cells use glucose for energy. Without enough insulin the body uses fat for energy and the liver is making ketones from fat causing acids to build up in the blood. 

HHS or Hyperosmolar Hyperglycemic State: a metabolic complication of diabetes linked to severe hyperglycemia. This hyperglycemia leads to severe dehydration and confusion. 

IV Insulin Infusion (Intravenous Insulin): giving insulin continuously in a vein to lower high blood sugar in the hospital 

Fingerstick Blood Test: Blood sugar is measured by pricking the finger and testing a drop of blood with a glucose meter. The glucose meters used in hospitals are calibrated on a regular basis leading to more reliability and accuracy of results compared to home glucometers. 

Venous Blood Test: Your blood sugar can also be determined through testing blood drawn from your veins when you are admitted to the hospital. 

Your health care providers will decide how often to check your blood glucose depending on your risk for HBG. For example, you have a higher risk for HBG if you have diabetes, are treated with medications that increase your blood sugar, or are receiving tube feeding or intravenous (IV) feeding. Detecting hyperglycemia early allows prompt treatment. 

Fingerstick blood glucose testing is usually performed before meals and at bedtime if eating.  They are tested every 4-6 hours for those who are not eating. 

HBG during hospital stay is defined as a blood sugar above 140 milligrams per deciliter (mg/dL) before eating a meal. After finding HBG, your care providers will continue to monitor your blood sugar before meals and at bedtime. You may need more testing in some cases. This includes if you develop symptoms of low blood sugar, are not eating, are receiving intravenous (IV) insulin, have a medication change that could affect blood sugar, or have frequent bouts of low blood sugar (hypoglycemia). 

While in the hospital, health care providers aim to keep blood sugar between 100 and 140 mg/dl before meals and below 180 mg/dl at other times.  However, your care team might decide that different targets are best in your particular case. For very ill patients in intensive care unit (ICU), blood glucose should stay below 180 mg/dL but not below 140 mg/dL.  

Common signs and symptoms of hyperglycemia include:  

  • Fatigue 
  • Hunger  
  • Thirst 
  • Frequent urination 
  • Trouble Focusing Vision 

Severe hyperglycemia can result in HHS with dehydration, confusion and coma. If your body does not make enough insulin and/or you are not given enough insulin, it can lead to the buildup of acids (ketones) in the blood and urine which can cause: 

  • Nausea and vomiting 
  • Abdominal pain 
  • Fast breathing 
  • Confusion 
  • Coma 

Long term hyperglycemia (uncontrolled diabetes) can lead to many serious complications including: 

  • Risk of vision changes and/or blindness (retinopathy) 
  • Risk of chronic kidney disease (nephropathy) 
  • Risk of neuropathy – problems with the peripheral nerves 
  • Increased risk of heart disease and strokes 
  • Increased risk of foot amputations 

Until recent years, doctors thought that HBG in hospitalized patients was not harmful if the blood glucose levels stayed at or below 200 mg/dL. Recent research studies show that HBG above 180 mg/dL increases the risk of complications in hospital patients. Keeping blood sugar below this level with insulin treatment lowers the risk for these problems. 

Patients with HBG may have more problems in the hospital, including: 

  • Delayed or cancellation of scheduled testing or surgery 
  • Longer hospital stays 
  • Slower wound healing 
  • Increased risk of developing an infection 
  • More disability after discharge from the hospital 
  • Higher risk of death 
  • Increased risk of getting readmitted to the hospital 

For all patients with HBG, good nutrition is important to help control blood sugar. A dietitian should work with you to plan your meals. The point is to make sure you get enough calories to heal, eat healthy food choices, and the right amount and types of sugars or carbohydrates. These include whole grains, fruits, vegetables, and low-fat milk. Some hospitals may base your premeal insulin based on the amount of carbohydrates you will consume. 

Insulin 

Insulin is the most reliable treatment for HBG in the hospital. This is true even if you do not have diabetes or if you do not use insulin at home. Insulin injection is the most effective way to control blood sugar. 

Hospital patients with HBG usually receive insulin shots under the skin (subcutaneous injections). Basal (long- or intermediate-acting) insulin is given once or twice a day to keep blood sugar levels steady between meals or if not eating. The effect of these injections tends to be over 24 hours and should not be skipped if you do not eat, although doses may need to be adjusted if you are not eating. Before meals, getting bolus (rapid-acting) insulin helps prevent blood sugar levels from going too high after eating. Besides mealtime insulin, some patients with HBG may need additional insulin injections. This scheduled insulin treatment prevents HBG, or, in some patients, a dangerous health problem called diabetic ketoacidosis (when acids and substances called ketones build up in the blood due to lack of insulin). 
 
Intravenous insulin is another way that HBG is treated in the hospital. This is used when the blood sugar is too high or unstable, not responding to subcutaneous injections, or if you have DKA. IV insulin is most frequently used for very sick patients who are not able to eat. This is a temporary way of treating HBG and is usually replaced by subcutaneous insulin when blood glucose levels are better or hospital discharge is anticipated. 
 
For people who are on insulin pumps, you and your health care provider may decide to continue using your insulin pump during the hospital stay if you are admitted to a hospital that has a policy for this in place. Please inform your nurse and physician that you use an insulin pump so they can work with you to manage your blood sugar in the hospital. You will be fully responsible for the mechanics of managing the insulin pump. If you think you are unable to do so, let your team know. If you wear a continuous glucose monitor (CGM), check with your team if you are allowed to wear it in the hospital. You may  have to remove your insulin pump and CGM devices for certain tests, for example MRI scans.  

There are situations when your health care team may decide to stop pumps or CGM devices. In this case, you will be started on standard subcutaneous insulin injections. 

Low blood sugar (defined as blood sugar below 70 mg/dL) can occur with insulin treatment, if you are not eating, or after a sudden stop to tube or IV feedings. If you receive insulin or other diabetes medicines, your care providers will check your blood sugar often to make sure it does not drop too low. They may need to change the dose or timing of your insulin to prevent low blood sugar. Low blood sugar is treated with juice or glucose gels or tablets if you can take food by mouth. If not, you might need to get injections of glucose or glucagon. 

Non-Insulin Therapies 

Some non-insulin therapies that are used in the outpatient setting for diabetes treatment can cause low blood sugar or other health problems while you are sick. For these reasons, you may have to stop taking your non-insulin diabetes medicines during your hospital stay. 

Pre-surgical Treatments 

Before surgery, patients who take insulin should continue to receive insulin. If you do not take insulin, your care providers will sometimes stop or adjust non-insulin medicines and may advise you to receive insulin if you develop HBG while in the hospital. 
 
Before and after surgery, all patients with type 1 diabetes and most patients with type 2 diabetes should receive insulin, especially basal insulin to prevent HBG (and DKA for those with type 1 diabetes). Insulin can be given through an IV or by multiple injections under the skin. When you can eat again, you should get mealtime (bolus or rapid-acting) insulin before meals. 

If you have diabetes, let your nurse and doctor know this information when you go into the hospital. If possible, bring your medications and insulin (or a detailed list of all your medications and insulin dose) to the hospital. Ask your doctor to make sure this information goes into your patient chart. You will need to have your blood sugar checked at least four times a day (before each meal and at bedtime if you are eating regular meals or every six hours if you are not eating). So that your care providers know your usual blood sugar control, you should have a hemoglobin A1c test (a blood test that shows your average blood sugar over the past three months). If you do not have diabetes but your blood sugar is above 140 mg/dL, you will need to have this test to determine if you have previously undiagnosed diabetes or are at risk for this in the future. 

If your hospital provider diagnoses you with diabetes, you may need to learn how to do home glucose testing and how to recognize and treat high and low blood glucose levels. In some cases, you may also need to learn how to inject insulin. You may receive education while you are in the hospital and will likely need to arrange for additional diabetes education through your primary care provider following discharge. 

When you leave the hospital, you will receive a written care plan for home diabetes management. It is important to fill in the medications prescribed at the time of your discharge. Please check back with your team if you have difficulty in filling medications at your pharmacy or if you have questions about the diabetes plan you were given.  If you had HBG or low blood sugar in the hospital, your care plan should include how to control your blood sugar and when to see your doctor next. It also should explain how and when to take your diabetes medications. By following this advice, you will have the best chance of a good recovery after your hospital stay. 

  • Does having hyperlycemia in the hospital mean that I have diabetes? 
  • What is plan to manage my diabetes while I am in the hospital? 
  • What home diabetes medications are you keeping me on when I’m in the hospital?   If you are stopping any of my home medications what is the reason? 
  • Are you planning to add any new diabetes medications while I’m in the hospital? 
  • What diabetes medication and/or insulin will I need to take after I am discharged from the hospital?   
  • How often do I need to check my blood sugar when I go home?  
  • Who should I contact if my blood sugar is too high or too low when I go home? 
  • Who should I see for follow-up when I’m discharged from the hospital? 

Developed For Patients Based on Management of Hyperglycemia in Hospitalized Patients in Non-Critical Care Settings: An Endocrine Society Clinical Practice Guideline 

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