DKA vs. HHNK: What's the difference?

Lets First Define Each Acronym

• DKA - diabetic ketoacidosis

• HHNK - Hyperosmolar Hyperglycemic Non-ketonic Coma (Now called HHS or Hyperosmolar Hyperglycemic State).

Pathophysiology

DKA is typically associated with insulin dependent patients - but not always- , whereas HHNK is generally associated with non-insulin dependent patients.

Think about what is going metabolically in a patient who is insulin dependent with elevated blood sugar.

Their cells are starving for glucose and thus they enter a catabolic state where they start breaking down fatty acids for energy.

The byproduct of this catabolic process is ketones. Ketones, of which there are three primary types, are acids and build up in the blood.

As the levels of ketones increase, the blood pH drops. This is what triggers Kussmaul respiration. It's the bodies attempt to blow off the excess hydrogen.

This increase in respirations, along with profound diuresis, leads to dehydration, hypotension, and if not corrected coma.

Glucose levels associate with DKA generally don't exceed 350mg/dl.

If you recall, in NIDDM the body is still producing insulin, its just that the cells have become desensitized to the insulin.

Because the cells are still able to use some, albeit very little, glucose their metabolic process does not switch to burning fatty acids.

Because cells are not consuming fatty acids, little if any ketone bodies are produced and thus pH is generally normal and pts don't develop Kussmaul breathing.

Unlike DKA where both dehydration and acidosis will kill your patient, in HHNK the chief problem is MASSIVE cellular dehydration, and organ failure, resulting from fluid shifts and diuresis.

In HHNK, blood sugars are typically well above 350mg/dl, usually more like 650mg/dl. I've even seen one as high as 900 in a 17 year old female.

Treatment

In both cases treatment is complicated and must be closly monitored.

The initial approach to managing these patients involves rehydration to prevent circulatory collapse.

Often this is the only care that can be performed outside of a hospital aside of standard supporative care.

Additional treatments will involved the careful and controlled administration of insulin and Glucose to slowly bring blood glucose levels back to normal.

Additional testing may be conducted to try and determine a precipitating cause for the elevated blood sugars such as infection, noncompliance with medications, stress, or trauma.

Alright! I hope this was helpful. I'd love to hear your thoughts so please leave your comments below.

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