Management of a 33-Year-Old Without Known Diabetes Presenting with Ketonuria and Mild Leukocytosis
This patient requires immediate blood glucose measurement and assessment for diabetic ketoacidosis (DKA), as ketonuria in a previously undiagnosed individual with hyperglycemia suggests impending or established DKA—a medical emergency. 1
Immediate Diagnostic Workup
Measure blood glucose immediately to determine if hyperglycemia is present, as the combination of ketonuria and hyperglycemia strongly suggests DKA even without known diabetes. 1
Essential Laboratory Tests
- Blood glucose: DKA diagnostic threshold is >250 mg/dL 2
- Arterial blood gas or venous pH: DKA requires pH <7.3 2, 3
- Serum bicarbonate: DKA requires bicarbonate <15 mEq/L 2
- β-hydroxybutyrate (blood): Preferred over urine ketones for accurate assessment, as urine ketone dipsticks underestimate total ketone burden by missing β-hydroxybutyrate, the predominant ketone in DKA 1, 2
- Anion gap: Elevated anion gap metabolic acidosis confirms DKA 3
- Electrolytes, BUN, creatinine: Essential for management planning 2
Assess for Precipitating Infection
The WBC of 11,000 is only mildly elevated and leukocytosis alone is NOT a reliable indicator of bacterial infection in DKA, as DKA itself causes leukocytosis through stress hormone release. 4
To distinguish infection from DKA-related leukocytosis:
- C-reactive protein (CRP) is significantly more reliable than WBC count for identifying bacterial infection in DKA patients 4
- Elevated CRP in the setting of DKA suggests concomitant infection requiring antibiotics 4
- Search for common precipitating infections: urinary tract infection and pneumonia account for the majority of infection-related DKA 5, 6
- Obtain urinalysis, urine culture, chest X-ray, and blood cultures if infection is suspected 2, 5
Clinical Context Assessment
If Blood Glucose is Elevated (>250 mg/dL)
Immediately assess DKA severity and initiate treatment:
Fluid resuscitation: Begin isotonic saline (0.9% NaCl) at 15-20 mL/kg/hr to restore circulatory volume 2
Insulin therapy: Start continuous IV regular insulin at 0.1 units/kg/hr after fluid resuscitation begins 2
Electrolyte monitoring: Check potassium every 2-4 hours; begin replacement when <5.2 mEq/L with adequate urine output 2
Admit to hospital: DKA requires inpatient management with ICU-level monitoring 2
If Blood Glucose is Normal or Mildly Elevated (<200 mg/dL)
Consider euglycemic DKA, particularly important in this era of SGLT2 inhibitor use (though less likely in an undiagnosed patient). 1, 7
- Euglycemic DKA is challenging to diagnose due to absence of marked hyperglycemia 7
- Still requires full DKA workup with ketone measurement and blood gas analysis 7
- Management is identical to hyperglycemic DKA 7
Alternative Diagnoses for Ketonuria Without DKA
If DKA criteria are not met, consider:
- Starvation ketosis: Common with prolonged fasting or poor oral intake 1
- Alcoholic ketoacidosis: Presents with ketosis but typically without hyperglycemia 1
- Ketogenic diet: Intentional nutritional ketosis 1
Critical Pitfalls to Avoid
- Do not rely on urine ketones alone: Nitroprusside-based urine dipsticks miss β-hydroxybutyrate and underestimate ketone burden 1
- Do not assume leukocytosis equals infection: DKA itself causes leukocytosis; use CRP to guide antibiotic decisions 4
- Do not delay treatment: If DKA is confirmed, immediate fluid resuscitation and insulin therapy are paramount to prevent mortality 2, 3
- Do not stop insulin even if not eating: This is a common error that precipitates DKA 1
Disposition
If DKA is confirmed: Immediate hospital admission with ICU-level care for continuous monitoring, IV insulin infusion, and aggressive fluid/electrolyte management. 2
If DKA is ruled out: Investigate alternative causes of ketonuria and determine if new-onset diabetes requires outpatient endocrinology follow-up and diabetes education. 1