Diabetic ketoacidosis
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"diabetic ketoacidosis"[MeSH Terms] AND management
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diabetic ketoacidosis pathophysiology mechanism diagram
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Diabetic Ketoacidosis (DKA)
Definition
DKA is characterized by three fundamental biochemical features (the "DKA triad"):
- D — Hyperglycemia (or known diabetes)
- K — Ketonemia/ketonuria (urine ketones ≥ 2+, or ≥ 3.0 mmol/L)
- A — Acidosis (arterial or venous pH < 7.3, bicarbonate < 18 mmol/L)
Goldman-Cecil Medicine, p. 2483
Pathophysiology
The core defect is insulin deficiency combined with excess counter-regulatory hormones (glucagon, cortisol, catecholamines, growth hormone). This leads to three parallel catastrophes:
1. Hyperglycemia
- Decreased glucose uptake by peripheral tissues
- Hepatic glycogenolysis and gluconeogenesis accelerate (using amino acids, lactate, pyruvate from muscle)
- Glucose enters circulation faster than it is utilized
- Osmotic diuresis → dehydration, electrolyte loss, hemoconcentration → further worsens hyperglycemia
2. Ketogenesis
- Insulin deficiency activates hormone-sensitive lipase → ↑ circulating free fatty acids (FFAs)
- Long-chain FFAs are partially oxidized in the liver → acetoacetate and β-hydroxybutyrate (and acetone)
- Peripheral ketone utilization also decreases (starvation-like state)
- Net result: ketone accumulation → anion-gap metabolic acidosis
3. Fluid and Electrolyte Depletion
Typical deficits in severe DKA (per kg body weight):
| Substance | Deficit |
|---|---|
| Water | 70–120 mL/kg |
| Sodium | 8–10 mEq/kg |
| Potassium | 5–7 mEq/kg |
| Chloride | 6–8 mEq/kg |
| Phosphorus | ~3 mEq/kg |
Important: Despite total-body potassium depletion, the serum K⁺ on presentation is typically normal or elevated due to acidosis-driven intracellular-to-extracellular K⁺ shift. It plummets rapidly with insulin and fluid therapy.
Rosen's Emergency Medicine, pp. 2542–2543
Precipitants
Most Common
- Infection (most frequent)
- Inadequate insulin / non-adherence
- New-onset type 1 diabetes
- Acute coronary syndrome
- Unknown
Other Precipitants
- Stroke, PE, acute pancreatitis, mesenteric thrombosis
- Alcohol intoxication
- Endocrinopathies: Cushing syndrome, thyrotoxicosis, acromegaly
- Drugs: Corticosteroids, SGLT-2 inhibitors (euglycemic DKA), clozapine, olanzapine, cocaine, sympathomimetics, thiazide diuretics
Goldman-Cecil Medicine, Table 210-11
Clinical Features
Symptoms (evolve over hours to days)
- Polyuria, polydipsia, polyphagia
- Weakness, lethargy, nausea, vomiting
- Abdominal pain (mimics acute abdomen; more often idiopathic in children, more often organic in adults)
- Weight loss, visual blurring
Signs
- Kussmaul breathing — deep, rapid respirations (compensatory respiratory alkalosis)
- Fruity/acetone odor on breath
- Tachycardia, orthostatic hypotension or frank hypotension
- Dry skin and mucous membranes (dehydration)
- Depressed sensorium, up to frank coma (driven by hyperosmolality)
- Elevated temperature → suggests an infectious precipitant (DKA itself rarely causes fever)
Rosen's Emergency Medicine, p. 2542
Diagnosis
Laboratory Findings
| Test | Typical Finding |
|---|---|
| Glucose | >350 mg/dL (euglycemic DKA in ~18%, especially with SGLT-2i) |
| pH | <7.3 (mild: 7.20–7.30; severe: <7.00) |
| HCO₃⁻ | <18 mmol/L |
| Anion gap | Elevated (AG = Na − [Cl + HCO₃]) |
| Sodium | Often low (dilutional; correct for hyperglycemia) |
| Potassium | Normal/high on presentation; drops with treatment |
| BUN/Creatinine | Elevated (prerenal) |
| Ketones | Present (β-hydroxybutyrate predominates) |
| WBC | Often elevated (metabolic stress, not necessarily infection) |
DKA vs. HHS comparison:
| DKA | HHS | |
|---|---|---|
| Glucose | >350 mg/dL | >700 mg/dL |
| Bicarbonate | <10 mEq/L | >15 mEq/L |
| Ketones | Present | Absent |
| pH | <7.3 | >7.3 |
Ketone Testing Pitfall
Bedside nitroprusside strips detect acetoacetate, not β-hydroxybutyrate. Since β-hydroxybutyrate predominates in DKA, strip testing can underestimate severity. As treatment begins, β-hydroxybutyrate converts to acetoacetate → strips may paradoxically suggest worsening ketosis. Bedside capillary ketone monitors (measuring β-hydroxybutyrate directly) are now preferred.
Goldman-Cecil Medicine, p. 2484
Acid-Base Pitfalls
- Concomitant metabolic alkalosis (vomiting) may mask acidosis; the anion gap will be elevated out of proportion to the bicarbonate drop
- Delta gap (ΔAG − ΔHCO₃): >+6 → coexisting metabolic alkalosis; <−6 → coexisting hyperchloremic acidosis
- Winter's formula: Expected PaCO₂ = (1.5 × HCO₃⁻) + 8 ± 2
Treatment
1. Fluid Resuscitation (First Priority)
- Initial: 0.9% NaCl — 2–4 L in the first 2–4 hours; or 1 L in the first hour for adults with marked dehydration but no shock
- If in hypovolemic shock: bolus isotonic crystalloid as rapidly as possible (20 mL/kg in children until SBP >80 mmHg)
- Transition to 0.45% NaCl after initial resuscitation
- When glucose drops to 250–300 mg/dL, add dextrose to IV fluids (prevents hypoglycemia and rapid osmolarity shifts)
- Recent evidence: Balanced electrolyte solutions (e.g., Plasmalyte) may achieve faster DKA resolution than 0.9% saline [PMID: 38925619 — meta-analysis, 2024]
2. Potassium Replacement (Critical)
| Serum K⁺ | Action |
|---|---|
| <3.3 mEq/L | Replace K⁺ first; hold insulin until ≥3.3 mEq/L |
| 3.3–5.5 mEq/L | Add 20–40 mEq/L K⁺ to IV fluids; start insulin |
| >5.5 mEq/L | No K⁺ supplementation; monitor closely |
ECG can rapidly identify hypo- or hyperkalemia if point-of-care potassium is unavailable.
3. Insulin
- Route: IV infusion preferred in sicker patients (short half-life 3–10 min; erratic SC/IM absorption with poor perfusion)
- IV bolus is no longer recommended
- Dose: Regular insulin at 0.1 units/kg/h (up to 5–10 units/h)
- For mild DKA in selected well-hydrated patients: SC or IM insulin is safe and effective
- Recent evidence: Subcutaneous insulin is comparable to continuous IV infusion for appropriate DKA patients [PMID: 39090718]; early subcutaneous basal insulin alongside IV infusion reduces rebound hyperglycemia [PMID: 41208563]
4. Phosphorus
Replace only if serum phosphorus <1.0 mEq/L (use potassium phosphate); routine replacement not supported by evidence.
5. Magnesium
Often depleted; replace 1–3 g IV if hypomagnesemia suspected (can cause refractory hypokalemia, dysrhythmias, altered mental status).
6. Sodium Bicarbonate
- Not routinely recommended, even at pH <7.0
- Associated with: paradoxical CSF acidosis, worsening hypokalemia, delayed ketosis clearance, worse outcomes
- Only considered in extreme acidosis (pH <6.9) or life-threatening hyperkalemia
7. Treat the Precipitant
Identify and treat the underlying cause — antibiotics for infection, ACS workup if indicated.
Complications
| Complication | Notes |
|---|---|
| Cerebral edema | Primarily in children (~1%); accounts for 60–90% of DKA mortality in pediatrics; treat with mannitol at earliest suspicion; degree of acidosis/uremia is a better predictor than fluid volume |
| Hypokalemia | Life-threatening with insulin therapy; prevent with K⁺ supplementation |
| Hypoglycemia | Over-treated insulin; prevent with dextrose when glucose <250–300 |
| Hypophosphatemia | Usually self-limiting; replace if severe |
| ARDS | From fluid overload or underlying infection |
| Aspiration | From gastroparesis/ileus; intubation if GCS impaired |
Monitoring
- Vital signs, fluid balance (I&O), urine output (target 1–2 mL/kg/h)
- Serum glucose every 1–2 hours
- Electrolytes, pH every 2–4 hours
- Meticulous flow sheets are essential
Resolution criteria (ADA):
- Glucose <200–250 mg/dL
- Bicarbonate ≥15 mEq/L
- pH >7.3
- Anion gap closing
Recent Evidence Updates (2024–2026)
Three high-quality meta-analyses may update standard practice:
- Balanced crystalloids vs. normal saline [PMID 38925619, Diabetes Metab Res Rev, 2024]: Balanced electrolyte solutions achieve faster DKA resolution than 0.9% saline in adults.
- SC vs. IV insulin [PMID 39090718, BMC Endocr Disord, 2024]: Subcutaneous insulin is safe and effective vs. continuous IV infusion for selected patients.
- Early basal SC insulin + IV infusion [PMID 41208563, Diabetes Obes Metab, 2026]: Overlap of basal SC insulin before stopping IV infusion reduces rebound hyperglycemia.
Sources: Goldman-Cecil Medicine (International Ed.); Rosen's Emergency Medicine, 10e; Harrison's Principles of Internal Medicine, 22e (2025); Tintinalli's Emergency Medicine.
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