What is the diagnosis and management for a patient with urinalysis showing hyperglycemia, proteinuria, ketonuria, and possible diabetic ketoacidosis?

Diagnosis: Diabetic Ketoacidosis (DKA)

This patient has diabetic ketoacidosis, confirmed by the triad of severe hyperglycemia (glucose >1000 mg/dL), ketonuria (10 mg/dL), and proteinuria with glycosuria, requiring immediate emergency department evaluation for fluid resuscitation, insulin therapy, and electrolyte management. 1, 2

Diagnostic Confirmation

The urinalysis findings definitively establish DKA:

• Severe hyperglycemia: Urine glucose >1000 mg/dL indicates blood glucose likely >250 mg/dL (the DKA threshold) 1, 3
• Ketonuria: Positive ketones (10 mg/dL) on dipstick confirms ketone body accumulation 1
• High specific gravity (>1.030) indicates significant dehydration, a hallmark of DKA 1
• Proteinuria (70 mg/dL) suggests renal stress from hyperglycemia and dehydration 1

Critical Next Steps for Diagnosis

Immediately obtain these laboratory tests to confirm DKA severity and guide treatment: 1, 2

• Venous pH (must be <7.3 for DKA diagnosis) 2
• Serum bicarbonate (must be <18 mEq/L for DKA) 1, 2
• Serum electrolytes with calculated anion gap (should be >10 mEq/L) 1, 2
• Blood beta-hydroxybutyrate (preferred over urine ketones; threshold ≥3.8 mmol/L for adults) 1, 2
• Serum potassium BEFORE starting insulin (critical to prevent life-threatening hypokalemia) 2, 4
• BUN/creatinine (assess dehydration and renal function) 1
• Complete blood count with differential 1
• HbA1c (determines if this is new-onset or poorly controlled diabetes) 1

Important Diagnostic Caveat

Do not rely solely on urine ketones for monitoring DKA treatment. 1, 2 Standard urine dipsticks only measure acetoacetate and acetone, NOT beta-hydroxybutyrate, which is the predominant and strongest acid in DKA. 1, 2 This can severely underestimate total ketone body concentration and mislead treatment decisions. 1

Immediate Management Protocol

Step 1: Fluid Resuscitation (First Priority)

Begin aggressive fluid replacement immediately with isotonic saline (0.9% NaCl) at 15-20 mL/kg/hour (1-1.5 liters in average adult) for the first hour. 1 This expands intravascular volume and restores renal perfusion before insulin therapy. 1

After the first hour, adjust fluid choice based on corrected serum sodium: 1

• If corrected sodium is normal or elevated: Switch to 0.45% NaCl at 4-14 mL/kg/hour 1
• If corrected sodium is low: Continue 0.9% NaCl at 4-14 mL/kg/hour 1

Step 2: Insulin Therapy (After Confirming Potassium)

Do NOT start insulin if serum potassium is low, as insulin will precipitate life-threatening cardiac complications. 2, 4

Once potassium is confirmed adequate: 2

• Give IV bolus of regular insulin 0.15 units/kg body weight 2
• Follow with continuous infusion at 0.1 unit/kg/hour 2
• Expect plasma glucose to decrease 50-75 mg/dL per hour 2
• If glucose doesn't fall by 50 mg/dL in first hour, double insulin infusion hourly until steady decline achieved 2

Step 3: Electrolyte Replacement

Once renal function is assured, add 20-30 mEq/L potassium to IV fluids (2/3 KCl and 1/3 KPO4). 1 Insulin therapy drives potassium intracellularly, causing potentially fatal hypokalemia. 2, 4

Step 4: Identify Precipitating Factors

Obtain bacterial cultures (urine, blood, throat) and start appropriate antibiotics if infection is suspected. 1 Infection is the most common precipitating factor for DKA. 1

Other precipitating factors to investigate: 1

• New-onset type 1 diabetes or inadequate insulin in established diabetes
• Cerebrovascular accident
• Myocardial infarction
• Pancreatitis
• Medications (corticosteroids, thiazides, sympathomimetics, SGLT2 inhibitors)
• Alcohol abuse

Resolution Criteria

DKA is resolved when ALL three criteria are met: 2

• Glucose <200 mg/dL
• Serum bicarbonate ≥18 mEq/L
• Venous pH ≥7.3

Critical: Ketonemia takes longer to clear than hyperglycemia, requiring direct blood ketone measurement to monitor resolution. 2 Do not stop treatment based solely on glucose normalization.

Differential Diagnosis Considerations

While DKA is most likely, rule out: 1

• Starvation ketosis: Glucose rarely >250 mg/dL, bicarbonate usually not <18 mEq/L 1, 5
• Alcoholic ketoacidosis: Normal to low glucose, clinical history of alcohol abuse 1
• Other high anion gap acidoses: Lactic acidosis, salicylate/methanol/ethylene glycol ingestion 1

The severe hyperglycemia (>1000 mg/dL) essentially excludes starvation or alcoholic ketoacidosis. 1

Critical Pitfalls to Avoid

• Never start insulin before checking potassium - can cause fatal cardiac arrhythmias 2, 4
• Never use nitroprusside-based ketone tests to monitor treatment - they measure acetoacetate which rises as beta-hydroxybutyrate (the actual problem) improves 1, 2
• Never assume resolution based on glucose alone - ketoacidosis persists longer than hyperglycemia 2
• Never overlook infection workup - most common precipitating cause requiring specific treatment 1
• Watch for abdominal pain - can be either cause or result of DKA; requires further evaluation if it doesn't resolve with treatment 1

Special Consideration: Euglycemic DKA

If this patient is taking SGLT2 inhibitors (canagliflozin, empagliflozin, dapagliflozin), consider euglycemic DKA where glucose may be only mildly elevated despite severe ketoacidosis. 6, 7, 8, 9 This complicates diagnosis but requires identical aggressive treatment. 6, 7