DKA Triad
Hyperglycemia (> 250), Ketosis (beta-hydroxybutyrate), Anion gap acidosis
HHS Hallmark
Glucose > 600 mg/dL and Serum Osmolality > 320 mOsm/kg without ketoacidosis
Potassium Rule
NEVER start insulin if K+ < 3.3 mEq/L (replete K+ first to prevent fatal arrhythmias)
Cerebral Edema Risk
Avoid dropping glucose > 75–100 mg/dL per hour; add D5W when glucose reaches 200
DKA vs. HHS Comparison Table
Contrasting the two severe acute metabolic complications of diabetes mellitus:
| Feature | Diabetic Ketoacidosis (DKA) | Hyperosmolar Hyperglycemic State (HHS) |
|---|---|---|
| Patient Population | Typically Type 1 Diabetes (younger) | Typically Type 2 Diabetes (elderly, nursing homes) |
| Serum Glucose | 250 to 600 mg/dL | > 600 mg/dL (often > 1000 mg/dL) |
| Arterial pH | ≤ 7.30 (severe metabolic acidosis) | > 7.30 (mild or normal pH) |
| Serum Bicarbonate | ≤ 18 mEq/L | > 18 mEq/L |
| Urine/Serum Ketones | Strongly positive (beta-hydroxybutyrate) | Absent or trace |
| Effective Serum Osmolality | Variable (< 320 mOsm/kg) | > 320 mOsm/kg |
| Mental Status | Alert to drowsy; Kussmaul respirations, fruity breath | Profound stupor or coma, focal neurologic deficits |
| Fluid Deficit | Moderate (3 to 6 Liters) | Severe (8 to 10+ Liters) |
Master DKA/HHS Management Algorithm
Execute therapy according to the 4 sequential priorities: Fluids → Potassium → Insulin → Glucose:
1. Fluid Resuscitation
First-line: 0.9% Normal Saline 1000–1500 mL/hr during hour 1. Then switch to 0.45% NaCl if corrected serum sodium is normal or high.
2. Potassium Management (CRUCIAL)
Acidosis shifts K+ out of cells, so serum K+ may look normal/high despite profound total body potassium depletion. Insulin drives K+ into cells. If K+ < 3.3 mEq/L: HOLD insulin and infuse IV KCl 20–40 mEq/hr until K+ > 3.3. If K+ 3.3–5.2: Give 20–30 mEq K+ per liter of IV fluids alongside insulin. If K+ > 5.2: Start insulin without K+, recheck every 2 hours.
3. Insulin Titration
Regular insulin IV infusion (0.1 units/kg/hr). Goal is to lower glucose by 50–75 mg/dL per hour.
4. Preventing Cerebral Edema & Hypoglycemia
When serum glucose drops to 200 mg/dL in DKA (or 300 mg/dL in HHS), ADD 5% Dextrose (D5W) to IV fluids while continuing the insulin drip until the anion gap closes.
COMLEX / OMM Integration
NBOME High-Yield Correlate
Endocrine Viscerosomatic Reflexes
- Pancreas: Sympathetics originate from
- Adrenals: Sympathetics from
- Clinical Pearl: Severe autonomic facilitation at T5–T9 and Chapman point at the 7th intercostal space on the right adjacent to the sternum.
T5–T9 (celiac and superior mesenteric ganglia).- Adrenals: Sympathetics from
T10–T11.- Clinical Pearl: Severe autonomic facilitation at T5–T9 and Chapman point at the 7th intercostal space on the right adjacent to the sternum.
Board Traps & Common Distractors
- Trap: Stopping the insulin drip as soon as glucose reaches 200 mg/dL. The insulin drip must continue until the anion gap has normalized and serum bicarbonate is ≥ 18 mEq/L! Add dextrose to the fluids to keep glucose around 150–200 mg/dL while closing the gap.
- Trap: Administering routine IV sodium bicarbonate. Bicarbonate does not improve outcomes and increases risk of hypokalemia and paradoxical CSF acidosis (indicated only if pH < 6.9).