Incidence of Euglycemic Diabetic Ketoacidosis in Cataract Surgery
The incidence of euglycemic diabetic ketoacidosis (euDKA) in patients undergoing cataract surgery is extremely rare, with no specific data available for cataract surgery, but the overall perioperative risk of DKA in patients taking SGLT2 inhibitors is approximately 1.02 per 1000 patients compared to 0.69 per 1000 in non-users (OR 1.48,95% CI 1.02–2.15). 1
Risk Factors for euDKA in Surgical Patients
SGLT2 Inhibitor Use
- SGLT2 inhibitors are the primary medication associated with euDKA risk in surgical patients
- These medications promote glycosuria while maintaining normal or slightly elevated blood glucose levels, creating diagnostic challenges 2
- The mechanism involves altered insulin/glucagon ratio, predisposing patients to ketosis 1
Patient-Specific Risk Factors
- Type 1 diabetes (significantly higher risk than type 2)
- Previous episodes of DKA
- Insulin deficiency states
- Reduced beta cell function reserve
- Late-onset autoimmune diabetes (LADA) 2
Perioperative Triggers
- Prolonged fasting or reduced food intake
- Dehydration
- Substantial reduction in insulin dose (>20%)
- Acute illness
- Surgical stress 2
Perioperative Management to Prevent euDKA
Preoperative Assessment
- Check hemoglobin A1C if not obtained within 3 months of surgery 1
- Assess for risk factors of euDKA (type of diabetes, medication use, previous DKA)
SGLT2 Inhibitor Management
- SGLT2 inhibitors must be discontinued 3-4 days before surgery 1
- Discontinuing >2 days pre-operatively has been shown to prevent DKA 1
- For cataract surgery, which is typically brief and minimally invasive, the same precautions apply
Blood Glucose Targets
- Target perioperative blood glucose range: 100-180 mg/dL (5.6-10.0 mmol/L) 1
- Monitor blood glucose every 2-4 hours while NPO 1
Other Medication Management
- Hold metformin on the day of surgery 1
- Hold other oral glucose-lowering agents the morning of surgery 1
- Give half of NPH dose or 75-80% of long-acting insulin or pump basal insulin 1
Diagnosis of euDKA
Clinical Presentation
- Often masked by normal or near-normal blood glucose (<250 mg/dL)
- Symptoms include nausea, vomiting, abdominal pain, generalized weakness
- Metabolic acidosis with elevated anion gap
- Positive serum or urine ketones 2, 3
Diagnostic Challenges
- Normal blood glucose levels can delay diagnosis
- High clinical suspicion required, especially in patients with recent SGLT2 inhibitor use 4
- Consider checking ketones in patients with unexplained metabolic acidosis postoperatively 5
Treatment of euDKA
Immediate Management
- Discontinue SGLT2 inhibitor
- Intravenous insulin and dextrose infusions (dextrose is critical due to normal glucose levels)
- Aggressive fluid resuscitation
- Electrolyte monitoring and replacement
- Close monitoring of acid-base status 2
Special Considerations for Cataract Surgery
- Cataract surgery is typically brief and minimally invasive, but the risk of euDKA remains in patients taking SGLT2 inhibitors
- Most cataract surgeries use topical anesthesia, which carries minimal systemic risk 1
- Despite the low-risk nature of cataract surgery, SGLT2 inhibitors should still be discontinued 3-4 days before surgery 1
Clinical Pearls and Pitfalls
Common Pitfalls
- Failing to recognize euDKA due to normal glucose levels
- Inadequate preoperative discontinuation of SGLT2 inhibitors
- Not considering euDKA in patients with unexplained metabolic acidosis postoperatively
Best Practices
- Maintain high clinical suspicion for euDKA in patients with recent SGLT2 inhibitor use
- Check ketones in patients with unexplained acidosis, even with normal glucose levels
- Ensure adequate hydration perioperatively
- Resume SGLT2 inhibitors only after patient is clinically stable and has resumed normal diet 1
While cataract surgery is generally low-risk, the potential for euDKA in patients taking SGLT2 inhibitors requires appropriate medication management and vigilance for this rare but serious complication.