A 70-year-old man is brought to the emergency department after his daughter found him lethargic and confused in his home. He has had a "cold" for the past 2 days. The patient lives alone and ambulates with a walker after a stroke 5 years ago. His daughter lives nearby and helps him with his daily activities of living. On arrival, temperature is 38 C (100.4 F), blood pressure is 90/65 mm Hg, pulse is 112/min, and respirations are 24/min. Mucous membranes are dry. The airway is maintained, and oxygen is administered. Intravenous access is secured, and blood and urine samples are drawn. Laboratory results are as follows:
| Serum chemistry | |
| Sodium | 134 mEq/L |
| Potassium | 5.9 mEq/L |
| Chloride | 101 mEq/L |
| Bicarbonate | 22 mEq/L |
| Blood urea nitrogen | 110 mg/dL |
| Glucose | 1,000 mg/dL |
| Arterial blood gases | |
| pH | 7.40 |
| PaCO2 | 38 mm Hg |
| PaO2 | 90 mm Hg |
Which of the following is the best immediate treatment for this patient?
Hyperosmolar hyperglycemic state | |
Patient |
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Clinical |
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Laboratory |
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Initial |
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*Normal saline for the first hour regardless of sodium levels; fluid choice may change thereafter. | |
This patient has severe hyperglycemia and mental status changes (lethargy, confusion), findings consistent with hyperosmolar hyperglycemic state (HHS). He also has prominent evidence of dehydration, with hypotension, tachycardia, and dry mucous membranes, likely due to osmotic diuresis from severely elevated plasma osmolality (eg, >320 mOsm/kg). Therefore, the best immediate step in treatment is aggressive fluid replacement with isotonic normal saline (NS), which replenishes extracellular volume, lowers plasma osmolality, and increases tissue perfusion and responsiveness to insulin.
HHS often occurs in a setting of type 2 diabetes. Compared with diabetic ketoacidosis (DKA), HHS is associated with higher glucose levels (often >1,000 mg/dL in HHS, 300-500 mg/dL in DKA), normal anion gap and pH, and absent ketoacids. Dehydration is more severe in HHS (up to 8-10 L of total body water losses) due to higher plasma osmolality and resulting osmotic diuresis.
In the first hour of treatment, NS should be used for resuscitation regardless of sodium levels. The fluid can be changed to 0.45% NS after the second or third hour if the corrected serum sodium is normal or high on repeat laboratory testing (Choice A).
(Choices B and F) Insulin therapy is a mainstay in the management of HHS. However, intravenous regular insulin is preferred because hypovolemia and systemic vasoconstriction in HHS can lead to erratic absorption of long-acting insulin. Although subcutaneous insulin can sometimes be administered in patients with mild DKA, it would not be appropriate for this patient with HHS and marked hypovolemia.
(Choice D) Despite demonstrating elevated potassium levels on laboratory testing, many patients with HHS actually have a total body potassium deficit (due to hyperosmolarity and urinary losses generated by osmotic diuresis). Insulin administration drives potassium into cells; therefore, such patients need supplemental potassium to prevent rapid unmasking of hypokalemia. However, potassium repletion is only indicated if the initial serum potassium level is less than 5.3 mEq/L. This patient's potassium is 5.9 mEq/L; therefore, supplemental potassium is not indicated.
(Choice E) Infusion of sodium bicarbonate is sometimes used in patients with DKA and severe acidosis (pH <6.9). Because ketoacid accumulation or acidosis is not present in this patient with HHS, bicarbonate supplementation is not required.
Educational objective:
Hyperosmolar hyperglycemic state is characterized by severe hyperglycemia and hyperosmolarity, mental status changes, and normal anion gap. Osmotic diuresis leads to marked deficits in total body water; therefore, treatment should begin with immediate intravenous fluid resuscitation with normal saline.