DRG Category: 640
Mean LOS: 4.5 days
Description: Medical: Miscellaneous Disorders of Nutrition, Metabolism, Fluids, and Electrolytes With Major Complication or Comorbidity
Hyperglycemia exists when the fasting blood glucose level is greater than 110 mg/dL or the 2-hour postprandial level is above 140 mg/dL. Prediabetes occurs when blood glucose levels are higher than normal but not high enough for a diagnosis of diabetes. This condition is sometimes called impaired fasting glucose or impaired glucose tolerance. About one in three U.S. adults aged 20 years or older—or 88 million people—have prediabetes according to the Centers for Disease Control and Prevention.
Normal blood glucose levels can be maintained between 70 and 100 mg/dL when there is an adequate balance between insulin supply and demand. In acutely ill individuals, hyperglycemia is usually not diagnosed until a random test of serum glucose level shows an increase above the 150 to 200 mg/dL range. Glucose is the most important carbohydrate in body metabolism. It is formed from the breakdown of polysaccharides, especially starch and is absorbed from the intestines into the blood of the portal vein. As it passes through the liver, glucose is converted into glycogen for storage, but the body maintains a blood level for tissue needs.
Insulin is produced by the beta cells of the pancreas, which are stimulated to release it when the blood glucose level rises. Insulin transports glucose, amino acids, potassium, and phosphate across the cell membrane. Insufficient production or ineffective use of insulin causes an elevated blood glucose level (hyperglycemia), which promotes water movement into the bloodstream from the interstitial space and intracellular fluid compartments. As blood glucose levels increase, the renal threshold for glucose reabsorption is exceeded, and glycosuria (loss of glucose in the urine) occurs. Glucose in the urine acts as an osmotic diuretic, and the patient has an increased urinary output in response that can lead to a serious fluid volume deficit. As glucose levels climb, the blood becomes more viscous, and the patient is also at risk for thromboembolic phenomena.
Insulin resistance and hyperglycemia have been linked with any critical illness or traumatic injury, and the condition has been named the “diabetes of injury.” Current research has found links between hyperglycemia and poor outcomes from acute illnesses and trauma. Current thinking is that with better control of hyperglycemia, patient outcomes may improve during an acute illness. Complications of hyperglycemia include neuropathy, nephropathy, vascular damage, dehydration, and coma.
The two primary causes of hyperglycemia are diabetes mellitus (DM) and hyperosmolar nonketotic syndrome (HNKS). Other conditions that can lead to hyperglycemia include glucocorticoid imbalances (Cushing syndrome), increased epinephrine levels during times of extreme stress (multiple trauma, surgery), excess growth hormone secretion, excessive ingestion or administration of glucose by total parenteral nutrition or enteral feedings, and pregnancy. In patients with extreme physiological stress, such as thermal injuries, multiple trauma, or shock, a serum glucose of approximately 200 to 250 mg/dL is expected, considering the release of epinephrine that accompanies the stress response.
Hyperglycemia is a prominent feature of DM, which has a significant genetic component. Polymorphisms in the adiponectin gene have also been associated with elevated blood sugar levels as well as increased body mass index, insulin sensitivity, and type 2 diabetes in some cross-sectional studies. Glucokinase mutations are also associated with hyperglycemia and non-insulin-dependent type 2 diabetes.
Children and young adults of both sexes who are at risk for type 1 DM are between the ages of 6 months and 30 years, whereas adults older than 35 years are more at risk for type 2 DM. Older people are at highest risk for HNKS.
While there are no racial or ethnic considerations or sexual and gender minority health issues for hyperglycemia itself, there are different patterns of types 1 and 2 DM across populations (see Diabetes Mellitus).
The prevalence of DM is increasing dramatically. DM is a global epidemic, with the number of people with DM exceeding 422 million. The International Diabetes Federation states that by 2045, the number will exceed 700 million, and the countries with the most cases include the most populous countries of the world as well as Western Europe. Some experts note that type 1 DM is increasing by up to 5% each year in the Middle East, Western Europe, and Australia. Scandinavian countries have the highest prevalence rates for type 1 DM, while China and Japan have the lowest prevalence.
Type 2 DM is more common in developed countries than in developing countries. Experts suggest that in developing countries, and particularly in Africa, people ingest fewer calories and have higher levels of activity (less sedentary) than in North America and Western Europe. As countries become more developed, however, the prevalence of weight gain and type 2 DM increases dramatically. Africa will likely be the location for the largest increase in people with type 2 DM in the next decade.
PLANNING AND IMPLEMENTATION
Collaborative
If the serum glucose level is above 250 mg/dL and the fluid balance is adequate, insulin is usually prescribed either as a subcutaneous (SC) injection or as an IV push injection. Often patients are placed on a “sliding scale” of insulin every 6 hours. If a patient has an elevated serum glucose along with a fluid volume deficit, the fluid volume deficit is corrected first, often with normal saline solution (0.9% sodium chloride), before the glucose excess. If glucose is reduced on a fluid volume–depleted patient before volume resuscitation, the vascular volume decreases, and the patient can develop hypovolemic shock.
If the patient has hyperglycemia because of DM or HNKS, management is based on the severity of symptoms. Because HNKS is associated with extraordinarily high levels of glucose (some reports describe levels higher than 1,000 mg/dL), the patient usually requires volume resuscitation followed by an insulin infusion. Often patients receive intermittent SC or IV doses of insulin as well. This should be done cautiously, however, because if the serum glucose level is reduced too rapidly, fluid shifts into the central nervous system, leading to cerebral edema and death. No matter what the diagnosis, once the glucose level and the patient are stabilized, a full work-up to determine the cause and long-term treatment is needed to prevent recurrences of hyperglycemia.
Current thinking with acutely and critically ill patients, particularly surgical patients, is that patient outcomes can be improved with more stringent control of hyperglycemia than in the past. The goal of control during the critical illness is a glucose level in the range of 80 to 125 mg/dL. Serial glucose monitoring at the bedside as frequently as every 30 minutes with point-of-care technology may be necessary during the administration of insulin through continuous insulin infusions.
| Medication or Drug Class | Dosage | Description | Rationale |
|---|
| Insulin | Varies with severity of disease; adjusted to maintain blood glucose of 80–125 mg/dL | Hormone; hypoglycemic | Replaces deficient or absent levels of insulin |
Independent
The first priority is to maintain adequate fluid balance. The action of glucose as an osmotic diuretic places the patient at risk for severe fluid volume deficits. If the patient is awake, encourage the patient to drink water and sugar-free drinks without caffeine. Because patients are usually tachycardic, caffeinated beverages are contraindicated, and they also cause increased urine output. Because severe hyperglycemia is accompanied by increased serum osmolarity and accompanying decreases in mental status, fluid replacement is accomplished by the IV route in most cases. If rapid fluid resuscitation is needed, use a large-gauge peripheral IV site with a short length to provide for rapid fluid replacement. Keep the tubing as short as possible from the IV bag or bottle and avoid long loops of tubing at a level below the patient's heart. Monitor for signs of underhydration (mental status that remains depressed, dry mucous membranes, soft eyeballs) and overhydration (pulmonary congestion, neck vein distention, shortness of breath, frothy sputum, cough).
Patients with the most severe cases of hyperglycemia have a risk of ineffective airway clearance because of decreased mental status and airway obstruction by the tongue. Have airway equipment, including an oral and nasal airway, an endotracheal tube, and a laryngoscope, near the patient's bedside at all times. If the patient develops snoring, slow respirations, or apnea, maintain the patient's airway and breathing with a manual resuscitator bag and notify the physician immediately.
If the patient has hyperglycemia because of DM or HNKS, provide appropriate patient teaching. Discuss the administration of insulin; a consistent and appropriate technique of insulin administration is critical for optimal blood glucose control. Whenever possible, have patient self-administer insulin. Encourage exercise. Instruct the patient about self-monitoring to recognize the signs and symptoms of hyperglycemia and hypoglycemia. Teach the patient and significant others how to prevent skin and lower-extremity infection, ulcers, and poor wound healing.
Evidence-Based Practice and Health Policy
Chatzi, G., Mason, T., Chandola, T., Whittaker, W., Howarth, E., Cotterill, S., Ravindrarajah, R., McManus, E., Sutton, M., & Bower, P. (2020). Sociodemographic disparities in non-diabetic hyperglycaemia and the transition to type 2 diabetes: Evidence from the English Longitudinal Study of Ageing. Diabetic Medicine, 37, 1536–1544.
- The authors explored whether there are social inequalities in nondiabetic hyperglycemia (NDH) and in transitions to type 2 diabetes mellitus. The authors used the English Longitudinal Study of Ageing (ELSA) from 2004 to 2016 to study patients (N = 9,143) in three groupings: low risk, NDH, and type 2 diabetes.
- NDH was more prevalent in older participants, those reporting a disability, those living in deprived areas, and those with more disadvantaged social classes. Older participants with NDH were less likely to progress to undiagnosed type 2 diabetes. Individuals with NDH with limiting long-standing illness who were from disadvantaged social classes were more likely to progress to type 2 diabetes. Disparities included the greater likelihood of disadvantaged social groups with NDH developing type 2 diabetes and greater likelihood of advantaged social groups with NDH becoming low risk.