Hyperglycemic Crisis: DKA & HHS – Key Vocabulary

These vocabulary flashcards summarize the essential terms, laboratory markers, pathophysiology, treatment components, and monitoring endpoints for managing hyperglycemic crises—Diabetic Ketoacidosis (DKA) and Hyperosmolar-Hyperglycemic State (HHS).

Diabetic Ketoacidosis (DKA)

An absolute or near-absolute insulin deficiency that produces hyperglycemia (≥200 mg/dL), dehydration, ketone body formation, and metabolic acidosis.

Hyperosmolar-Hyperglycemic State (HHS)

A severe relative insulin deficiency causing extreme hyperglycemia (≥600 mg/dL), dehydration, hyperosmolarity, with little or no ketone production or acidosis.

Hyperglycemic Crisis

Umbrella term for acute, life-threatening metabolic emergencies in diabetes—primarily DKA and HHS.

β-Hydroxybutyrate (BHB)

The predominant serum ketone; ≥3.0 mmol/L supports DKA, <3.0 mmol/L helps rule in HHS.

Euglycemic DKA

DKA that occurs with normal or mildly elevated blood glucose, often seen in patients using SGLT-2 inhibitors.

6 I’s (Precipitating Factors)

Insulin deficiency, Infection, Inflammation, Intoxication, Infarction, Iatrogenic causes that trigger DKA/HHS.

Effective Serum Osmolality

Calculated as (2 × Na⁺ mEq/L) + Glucose (mmol/L); reflects tonicity without BUN contribution.

Total Serum Osmolality

Calculated as (2 × Na⁺ mEq/L) + Glucose (mmol/L) + BUN (mmol/L); includes all major osmoles.

Hyperosmolarity

Elevated serum osmolality (>300 mOsm/kg effective or >320 mOsm/kg total) leading to neurologic changes in HHS.

Kussmaul Respirations

Deep, rapid, labored breathing characteristic of severe metabolic acidosis in DKA.

Fruity Breath Odor

Acetone exhalation associated with ketone accumulation in DKA.

Polyuria

Excessive urination resulting from osmotic diuresis in hyperglycemia.

Polydipsia

Excessive thirst due to dehydration and high plasma osmolality.

Normal Saline (NS)

0.9 % sodium chloride solution; first-line crystalloid for fluid resuscitation in DKA/HHS.

Half-Normal Saline (½NS)

0.45 % sodium chloride; may be used once intravascular volume is restored or serum sodium is high.

Lactated Ringer’s (LR)

Balanced crystalloid containing Na⁺, K⁺, Ca²⁺, Cl⁻, and lactate; alternative to NS for initial fluids.

D5W / D5

Dextrose 5 % in water; added when BG falls <250 mg/dL to prevent hypoglycemia while insulin continues.

Potassium Chloride (KCl) Replacement

10–20 mEq K⁺ added per liter of IV fluid to maintain serum K⁺ 4–5 mEq/L and avoid hypokalemia during insulin therapy.

Insulin Infusion (IV)

Regular insulin started at 0.1 units/kg/h for DKA or 0.05 units/kg/h for HHS to suppress ketogenesis and lower glucose/osmolality.

Subcutaneous (SC) Rapid-Acting Insulin

Alternative treatment for mild DKA: 0.1 units/kg q1h or 0.2 units/kg q2h until BG <250 mg/dL.

Resolution Criteria – DKA

Venous pH > 7.3 or bicarbonate > 18 mmol/L AND BHB < 0.6 mmol/L.

Resolution Criteria – HHS

Serum osmolality < 300 mOsm/kg, urine output > 0.5 mL/kg/h, and BG < 250 mg/dL.

Sick-Day Management

Patient education on adjusting insulin, monitoring glucose/ketones, and maintaining hydration during illness to prevent DKA/HHS.

Osmotic Diuresis

Glucose-driven urinary water and electrolyte loss leading to dehydration and total body K⁺ deficit.

Fluid Deficit

Estimated volume depletion in DKA/HHS corrected with crystalloid resuscitation—goal: replace ~50 % within first 8–12 h.

Cerebral Edema

Rare but serious complication of overly rapid glucose/osmolality correction; avoided by gradual BG lowering and adding dextrose.

Overlap Period

1–2 h continuation of IV insulin after first SC insulin dose to ensure adequate insulin levels during transition.

Premixed D5-NS + KCl

Commercially available bags containing dextrose, saline, and potassium that streamline therapy and reduce compounding delays.

Nurse-Driven Insulin Drip Protocol

Hospital guideline allowing nursing staff to titrate insulin and fluids based on bedside glucose and lab results.

Initial Fluid Replacement in DKA/HHS

Administer 500-1000 mL/hr of Normal Saline (NS) or Lactated Ringer’s (LR) for the first 2-4 hours, adjusting for cardiac compromise, CKD, older adults, or pregnancy.

When to Add Dextrose to IV Fluids

Add Dextrose 5% (D5) or Dextrose 10% (D10) to IV crystalloid once blood glucose (BG) reaches < 250 \text{ mg/dL} during DKA/HHS treatment.

Target Blood Glucose during Hyperglycemic Crisis Treatment

Maintain blood glucose (BG) at 150-200 mg/dL for DKA and 200-250 mg/dL for HHS during treatment.

Potassium Management and Insulin Initiation

If serum potassium (K⁺) is < 3.5 \text{ mEq/L}, hold insulin therapy and administer IV KCl infusion until K⁺ \ge 3.5 \text{ mEq/L}, then start or resume insulin.

IV Insulin Adjustment in DKA

When blood glucose (BG) falls below 250 mg/dL in DKA, decrease intravenous regular insulin infusion to 0.05 units/kg/hr. An optional 0.1 units/kg IV bolus can precede the initial infusion.

Key Monitoring Parameters in Hyperglycemic Crisis

Monitor blood pressure (BP), heart rate (HR), serum sodium (Na⁺), blood glucose (BG), intake and output (I&Os), and signs of fluid overload frequently.

Resolution Criteria – DKA

Acidosis resolved (pH \ge 7.3 or bicarbonate \ge 18 \text{ mmol/L}) AND minimal ketones (BHB < 0.6 \text{ mmol/L}).

Resolution Criteria – HHS

Serum osmolality < 300 \text{ mOsm/kg}, urine output > 0.5 \text{ mL/kg/hr}, and BG < 250 \text{ mg/dL}.

Transition from IV to SC Insulin

After resolution criteria are met and the patient can eat/drink, begin the subcutaneous (SC) insulin regimen. Continue IV insulin for 1-2 hours after the first SC insulin dose to ensure an overlap. Restart previous regimen for known diabetes; start a new regimen for insulin-naïve patients.