For last week’s practice question, we quizzed participants on which feature most strongly supports a diagnosis of hyperosmolar hyperglycemic state (HHS) rather than diabetes ketoacidosis (DKA). 59.77% of respondents chose the best answer. We want to clarify and share this important information, so you can pass it on to people living with diabetes and your colleagues, plus prepare for exam success!
Before we start though, if you don’t want any spoilers and haven’t tried the question yet, you can answer it below: Answer Question
A 32-year-old with newly discovered diabetes is brought to the emergency department with polyuria and lethargy. They have been sleeping more than usual.
Initial labs show:
- Plasma glucose: 680 mg/dL
- Potassium 3.7 mEq/L
- Serum osmolality: 335 mOsm/kg
Based on the following labs, which feature most strongly supports a diagnosis of hyperosmolar hyperglycemic state (HHS) rather than diabetes ketoacidosis (DKA)?
- Markedly elevated plasma glucose
- Absence of significant metabolic acidosis
- Out of range potassium level
- Elevated effective serum osmolality
Getting to the Best Answer
Answer A is incorrect: 14.21% chose this answer, “Markedly elevated plasma glucose.” This answer is tempting, because glucose levels do become markedly elevated with HHS. However, very high glucose levels can also occur with DKA. So this answer doesn’t differentiate between these two hyperglycemic crises.
Answer B is incorrect: 21.38% chose this answer, “Absence of significant metabolic acidosis.” This juicy answer is tempting, since with HHS there is the absence of metabolic acidosis. However, based on the question details, there is no information on pH or ketone status, so we can’t make that assumption.
Answer C is incorrect: 4.64% chose this answer, “Out of range potassium level.” The potassium level of 3.7 is within normal range and doesn’t help us differentiate between HHS and DKA.
Answer D is correct: 59.77% chose this answer, “Elevated effective serum osmolality.” YES, this is the BEST Answer. Great Job! One of the main features of HHS, is increased serum osmolality (greater than 300), due to a combination of elevated glucose and dehydration.
We hope you appreciate this week’s rationale! Thank you so much for taking the time to answer our Question of the Week and participate in this fun learning activity!
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