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Diabetic hyperglycemic hyperosmolar coma

Definition

Diabetic hyperglycemic hyperosmolar coma is a complication of type 2 diabetes that involves extremely high blood sugar (glucose) levels without the presence of ketones. Ketones are a by-product of fat breakdown.

Alternative Names

Nonketotic hyperglycemic hyperosmolar coma; NKHHC; HONK - hyperosmolar non-ketotic coma

Causes, incidence, and risk factors

Diabetic hyperglycemic hyperosmolar coma is a condition of decreased consciousness, extreme dehydration (lack of water), and extremely high blood glucose (sugar) levels, which is not accompanied by ketoacidosis.

The condition is usually seen in people with non-insulin-dependent diabetes (type 2 diabetes). It may occur in those previously undiagnosed with diabetes, or in people who have not been able to control their diabetes with diet and medications. The condition may be brought on by an infection, or by certain medications that lower glucose tolerance or increase fluid loss.

Normally, the kidneys make up for high glucose levels in the blood by allowing the extra glucose to leave the body in the urine. However, when water is scarce, the kidneys conserve (save) fluid, and glucose levels become higher. This results in greater need for water.

Hyperosmolarity is a condition in which the blood has a high concentration of sodium, glucose, and other molecules that normally attract water into the bloodstream. When the kidneys are conserving water, however, this creates a vicious cycle of increasing blood-glucose levels and increasing dehydration.

Risk factors include:

• Older age
• Underlying kidney insufficiency (the kidneys do not work well)
• Congestive heart failure
• Stopping insulin or other medications that lower glucose levels
• Improper management of diabetes -- not following the treatment plan as directed
• A stressful event such as infection, heart attack, stroke, or recent surgery

Symptoms

• Weakness
• Increased thirst
• Nausea
• Lethargy
• Confusion
• Convulsions
• Coma

Symptoms may progress over a period of days or weeks.

Additional symptoms that may be associated with this disease:

• Speech impairment
• Loss of feeling or function of muscles
• Dysfunctional movement

Signs and tests

Vital signs (temperature, pulse, rate of breathing, blood pressure):

• Temperature -- higher than 38 degrees Centigrade (100.4 degrees Fahrenheit)
• Heart rate -- greater than 100
• Systolic blood pressure -- low (less than 100)

Tests:

• Blood glucose -- severely higher than normal (from 600 to 2,400 mg/dL)
• Higher than normal serum osmolarity
• Higher than normal serum sodium
• Evaluation for possible underlying causes
  • Chest x-ray
  • Blood cultures
  • Urinalysis
  • Electrocardiogram (ECG)

Treatment

The goal of treatment is to correct the dehydration, which will improve the blood pressure, urine output, and poor circulation. Fluids and potassium are replaced by intravenous treatment. High glucose levels are treated with intravenous insulin.

Expectations (prognosis)

The death rate associated with this condition is as high as 40%.

Complications

• Acute circulatory collapse (shock)
• Blood clot formation
• Brain swelling (cerebral edema)
• Increased blood acid levels (lactic acidosis)

Calling your health care provider

This condition is a MEDICAL EMERGENCY! Go to the emergency room or call the local emergency number (such as 911) if signs or symptoms of diabetic hyperglycemic hyperosmolar coma develop.

Prevention

Good control of type 2 diabetes, coupled with recognition of early signs of dehydration and infection, can help prevent this condition.

Review Date:8/8/2006
Reviewed By:Robert Hurd, MD, Department of Biology, College of Arts and Sciences, Xavier University, Cincinnati, OH. Review provided by VeriMed Healthcare Network

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