What are the next steps in managing a patient with glycosuria and ketonuria?

Management of a Patient with Glycosuria and Ketonuria

The presence of glycosuria (1+) and ketonuria (trace) on urinalysis requires immediate evaluation for diabetic ketoacidosis (DKA), even if mild, and initiation of appropriate treatment based on the patient's clinical status. 1

Initial Assessment

1. Obtain immediate laboratory tests:

   • Venous blood gases
   • Electrolytes with anion gap calculation
   • Blood glucose level
   • Serum ketones (β-hydroxybutyrate preferred over nitroprusside method)
   • Blood urea nitrogen and creatinine
   • Complete blood count with differential

2. Assess vital signs and mental status to determine severity:

   • Mild DKA: pH 7.25-7.30, bicarbonate 15-18 mEq/L, alert
   • Moderate DKA: pH 7.00-7.24, bicarbonate 10-15 mEq/L, drowsy
   • Severe DKA: pH <7.00, bicarbonate <10 mEq/L, stupor/coma

Differential Diagnosis

While glycosuria and ketonuria strongly suggest diabetes with ketosis, consider other causes:

• Starvation ketosis (usually blood glucose <250 mg/dL, bicarbonate >18 mEq/L)
• Alcoholic ketoacidosis
• Salicylate intoxication (can present with similar laboratory findings) 2
• SGLT2 inhibitor-associated ketosis (can occur with normal or only mildly elevated glucose) 3

Treatment Algorithm

If DKA is confirmed:

1. Fluid Replacement:

   • Start with isotonic saline (0.9% NaCl) at 15-20 mL/kg/hr for the first hour
   • Adjust subsequent fluid based on hydration status and electrolytes
   • Switch to 0.45% NaCl when corrected serum sodium is normal or elevated 1

2. Insulin Therapy:

   • For anything but mild DKA: IV insulin bolus (0.1 U/kg) followed by continuous infusion (0.1 U/kg/hr)
   • For mild DKA: Consider subcutaneous insulin regimen (0.4-0.6 U/kg initial dose, half as IV bolus and half as subcutaneous) 1
   • Monitor blood glucose hourly; adjust insulin to achieve decline of 50-75 mg/dL/hr
   • When glucose reaches 250 mg/dL, add dextrose to IV fluids and reduce insulin rate

3. Electrolyte Management:

   • Monitor potassium closely and begin replacement when K+ <5.3 mEq/L and adequate urine output is established
   • Use combination of KCl and KPO4 (2/3 KCl, 1/3 KPO4) at 20-30 mEq/L of IV fluid 1
   • Bicarbonate therapy generally not recommended unless pH <6.9 1

4. Monitoring:

   • Check blood glucose every 1-2 hours until stable
   • Monitor electrolytes, venous pH, and anion gap every 2-4 hours
   • Track fluid input/output
   • Assess mental status regularly

If Not DKA:

If laboratory results do not confirm DKA, consider other causes of glycosuria and ketonuria:

• Evaluate for pregnancy (gestational diabetes)
• Consider stress hyperglycemia with starvation ketosis
• Screen for other metabolic disorders

Resolution Criteria and Transition of Care

DKA resolution is defined as:

• Blood glucose <200 mg/dL
• Serum bicarbonate ≥18 mEq/L
• Venous pH ≥7.3 1

Once resolved:

1. If patient can eat, transition to subcutaneous insulin:

   • Start with combination of short/rapid-acting and intermediate/long-acting insulin
   • Continue IV insulin for 1-2 hours after first subcutaneous dose to ensure adequate coverage 1

2. If patient cannot eat:

   • Continue IV insulin and fluids
   • Add subcutaneous regular insulin as needed (5 units for every 50 mg/dL increase in blood glucose above 150 mg/dL) 1

Prevention of Recurrence

For patients with established diabetes:

• Identify and address the precipitating cause (infection, medication non-adherence, etc.)
• Provide education on sick-day management and ketone monitoring
• Ensure access to insulin and supplies
• Consider psychosocial assessment if recurrent DKA is suspected (often associated with insulin omission) 1

For newly diagnosed diabetes:

• Comprehensive diabetes education
• Establish follow-up within 24-48 hours after discharge
• Ensure patient has access to insulin, supplies, and knows how to reach healthcare team

Important Caveats

• Measurement of β-hydroxybutyrate in blood is preferred over urine ketones for monitoring DKA resolution 1, 4
• As DKA resolves, β-hydroxybutyrate converts to acetoacetate, which may make urine ketones appear to worsen even as the condition improves 1
• Never abruptly discontinue IV insulin when transitioning to subcutaneous insulin to avoid rebound hyperglycemia 1
• Consider SGLT2 inhibitor use as a potential cause of euglycemic DKA in patients on these medications 3