A 74-year-old male is brought from his nursing home to the emergency department for evaluation of confusion and right hemiparalysis. The patient was recently transferred from the hospital to nursing home for inpatient rehabilitation after suffering a stroke complicated by residual right-sided weakness. Over the past 48 hours, the patient has grown progressively more confused and complained of thirst. Staff observed right-sided paralysis the morning of transfer. History is notable for type 2 diabetes, hypertension, and dyslipidemia. A thiazide diuretic was added to the patient's blood pressure regimen during hospital admission. Diabetes is managed with glyburide, but hemoglobin A1c (HbA1c) is unknown. CBG from the nursing home is reported as >400 mg/dL. Tachycardia and hypotension (BP 86/54 mm Hg) are noted. The patient is disoriented to place and time, has limited ability to follow commands, and does not spontaneously move his right extremities.
Admission electrolyte panel revealed serum sodium 124 mEq/L, chloride 92 mEq/L, bicarbonate 22 mEq/L, BUN 62 mg/dL, Cr 1.6 mg/dL, and glucose 820 mg/dL. Other serologies and CBC were unremarkable. Urinalysis was notable for large glucose and small ketones. No acute hemorrhages, ischemic changes, or masses were observed on computed tomography of the head. No infiltrates or effusions were visible on plain films of the chest. EKG showed sinus tachycardia and nonspecific ST segment changes.
1. What are the diagnostic criteria for hyperglycemic hyperosmolar syndrome (HHS)?
2. What are important risk factors for HHS?
3. How should HHS patients be evaluated and managed?
HHS is diagnosed when patients present with altered mental status of some degree in the setting of severe hyperglycemia (plasma glucose ≥600 mg/dL) and hyperosmolarity (≥320 mOsm/L). Unlike DKA, there is no metabolic acidemia.
Key risk factors are listed in Figure 22-1. Advanced age, residence in an institutional setting, infections, and cardiovascular events are all potential risk factors for HHS. Some patients may have undiagnosed type 2 diabetes at presentation. Occasionally, patients have been started on medications such as glucocorticoids that significantly exacerbate hyperglycemia.
Prompt fluid resuscitation, parenteral insulin, and potassium repletion are the most important factors in management. Specific dosing instructions are summarized in Table 22-1. Since patients are not in ketoacidosis, insulin infusion rates are typically lowered as plasma glucose falls below 250 to 300 mg/dL to slow the rate of improvement and limit the possibility of cerebral edema.
Table 22-1. Recommendations for Insulin, Fluids, and Potassium Management |Favorite Table|Download (.pdf)
Table 22-1. Recommendations for Insulin, Fluids, and Potassium Management
- 0.1 U/kg bolus, and then 0.1 U/kg/h infusion
- 0.14 U/kg/h infusion w/o bolus
- 0.14 U/kg bolus if CBG fails to fall by ...