40: Hyperglycemic Emergency

INTRODUCTION

Diabetic ketoacidosis (DKA) and hyperosmolar hyperglycemic state (HHS) encompass two severe complications of diabetes mellitus (DM). The incidence is steadily increasing in the United States despite efforts at prevention and education, with 140,000 hospitalizations for DKA in 2009, which was approximately a 75% increase over two decades.¹ Care has become more efficient, and the average length of stay (LOS) for DKA has decreased by about 2 days in the same period, with a mean time in the hospital of about 3.4 days in 2009.¹ In 2009, the hospital discharge rates for DKA per 1,000 individuals with diabetes were 32.4, 3.3, and 1.4 for people aged 44 and younger, for those between 45 and 64 years, and those aged 65 years and older, respectively.¹ Although the rate of hospitalizations for hyperglycemic crises continues to rise, mortality from DKA and HHS combined has been declining. In particular, mortality rates for those aged 75 years and older have precipitously declined in the last 2 decades (Figure 40-1). In 2009, there were 2,417 deaths caused by one of these two entities, which was nearly 20% lower than that in 1980.¹ In general, HHS has a lower rate of hospitalization but a higher mortality at a rate of 5% to 20%.^2,3 The cost of DKA is profound and the aggregate cost of its hospitalizations is approximately $850 million.⁴

DEFINITION OF DKA AND HHS

DKA is defined by the following criteria (Table 40-1): plasma glucose >250 mg/dL, arterial pH ≤7.30, serum bicarbonate ≥18 mEq/L, presence of urinary and serum ketones, and an anion gap >10 mEq/L.² It is further divided into mild, moderate, and severe based on the degree of acidemia and serum bicarbonate level.² HHS is defined by the following criteria: plasma glucose >600 mg/dL, an arterial pH >7.30, serum bicarbonate >18 mEq/L, an effective serum osmolality >320 mOsm/kg (for which effective serum osmolality = 2 [measured Na⁺ (mEq/L)] + glucose [mg/dL]/18).^2,5 Although HHS was previously called hyperglycemic hyperosmolar nonketotic state (HHNKS), small urinary and serum ketones may be seen in this condition; thus, their presence does not exclude the diagnosis of HHS.² In reality, DKA and HHS lie along a continuum; up to 33% of patients may have a clinical presentation in which features of both ...