Diabetic Ketoacidosis (DKA) – Study Notes

Diabetic Ketoacidosis (DKA) – Study Notes

1. Diagnosis: DKA vs. HHS

Key labs: Glucose, Bicarbonate, Anion Gap, Ketones, pH

• Glucose:

  • Elevated in both DKA & HHS.

  • HHS → typically much higher (600–1000).

  • Note: Euglycemic DKA may occur with SGLT2 inhibitors.

• Bicarbonate:

  • DKA → <18 (often <10 in severe cases).

  • HHS → >18.

• Anion Gap:

  • DKA → elevated.

  • HHS → variable, but generally lower than DKA.

• Ketones:

  • DKA → positive (urine & serum).

  • HHS → minimal/absent.

• pH:

  • DKA → usually <7.3 (but not required for diagnosis).

  • HHS → typically normal.

  • ⚠️ Beware: metabolic alkalosis (e.g., GI losses) may skew pH upward.

Required for DKA diagnosis:

• Hyperglycemia

• Anion gap metabolic acidosis

• Positive ketones

Initial labs to order:

• Basic metabolic panel (BMP)

• Urinalysis

• Serum beta-hydroxybutyrate

• Venous blood gas (VBG)

2. Causes of DKA – The 5 I’s

Framework credited to Dr. Mark Kearns.

1. Insulinopenia – new diagnosis or missed doses.

2. Infection – exam, CBC, imaging, cultures.

3. Ischemia/Infarction/Inflammation – EKG, troponin, other workup.

4. Intoxication/ingestion – drug screen, ethanol level.

5. Impregnation – pregnancy test (β-hCG).

3. DKA Treatment Protocol

Three phases: Immediate, Maintenance, End-point transition

Immediate

• Fluids:

  • DKA patients = ~5–6 L net negative.

  • Start: 2–3 L Lactated Ringer’s (LR) bolus.

  • Evidence: LR associated with faster resolution vs. NS (JAMA, 2020).

  • Effect: IV fluids alone ↓ glucose by 50–70 mg/dL before insulin.

• Insulin:

  • Give 0.1 units/kg IV regular insulin (≈10 units for most).

  • Hold if K⁺ < 3.3 (risk of life-threatening hypokalemia).

• Electrolytes:

  • K⁺ and Phosphate shift extracellularly → labs may look high, but total body stores are low.

  • Replete as needed before starting insulin.

Maintenance

• Fluids:

  • 250–500 mL/hr LR, adjust for ongoing losses.

  • Add D5W when glucose <250–300 mg/dL (to prevent hypoglycemia).

• Insulin infusion:

  • 0.1 units/kg/hr IV, titrate to lower glucose 50–70 mg/dL per hr.

  • Avoid rapid drop (>70 mg/dL/hr) → risk of cerebral edema.

• Potassium:

  • Replete ~10–20 mEq/hr to maintain K⁺ ≈ 5.0.

• Phosphate:

  • Replete if critically low.

Ending Protocol

Criteria to stop infusion:

1. Stable insulin infusion rate.

2. Closed anion gap.

3. Bicarbonate >17–18.

4. Patient tolerating PO.

Transition to basal insulin:

• Give basal insulin 2 hrs before stopping infusion to avoid rebound hyperglycemia.

• New diabetes: use 24-hr insulin requirement → split 50% basal / 50% mealtime.

• Established diabetes: resume home basal dose.

4. Monitoring

• BMP + beta-hydroxybutyrate: q4h

• POC glucose: q1h

5. Summary

• Diagnosis: Glucose, Bicarb, AG, Ketones, pH.

• Causes: 5 I’s.

• Treatment: Fluids + Insulin + Electrolytes → Maintenance → Transition to basal insulin.