In a patient with a serum glucose of 390 mg/dL, normal anion gap (12), normal bicarbonate (CO₂ 24 mm Hg), and intact mental status, does this represent diabetic ketoacidosis, hyperglycemic hyperosmolar state, or uncontrolled diabetes?

This is Uncontrolled Diabetes, Not DKA or HHS

Based on the laboratory values provided—glucose 390 mg/dL, normal anion gap (12), normal bicarbonate (CO₂ 24), and preserved mental status—this patient has uncontrolled diabetes without meeting criteria for either diabetic ketoacidosis (DKA) or hyperglycemic hyperosmolar state (HHS).

Why This is NOT DKA

The diagnostic criteria for DKA require ALL of the following 1:

• Plasma glucose >250 mg/dL ✓ (patient has 390)
• Serum bicarbonate <18 mEq/L ✗ (patient has 24—normal)
• pH <7.30 (not provided, but normal bicarbonate makes acidosis unlikely)
• Elevated anion gap (≥10-12) ✗ (patient has 12, which is at the upper limit of normal)
• Positive serum/urine ketones (not checked, but unlikely given normal bicarbonate and anion gap)

The patient's normal bicarbonate (24) and normal anion gap (12) effectively rule out DKA, as ketoacidosis produces metabolic acidosis with an elevated anion gap and low bicarbonate. While rare cases of normal anion gap DKA exist 2, these still demonstrate acidosis with low bicarbonate—which this patient does not have.

Why This is NOT HHS

HHS diagnostic criteria include 1:

• Plasma glucose ≥600 mg/dL ✗ (patient has 390)
• Effective serum osmolality ≥320 mOsm/kg (not calculated, but unlikely with glucose of 390)
• pH >7.30 (likely present)
• Bicarbonate >15 mEq/L ✓ (patient has 24)
• Altered mental status (stupor/coma) ✗ (patient is alert with good mental status)

The patient's glucose of 390 mg/dL falls well short of the ≥600 mg/dL threshold, and the preserved mental status is inconsistent with HHS, which typically presents with profound lethargy or coma 1.

What You Need to Do Next

Immediate actions:

1. Check serum/urine ketones to definitively exclude ketosis
2. Calculate effective serum osmolality: 2[Na] + glucose/18 to confirm it's <320 mOsm/kg
3. Assess hydration status clinically
4. Identify precipitating factors: infection, medication non-adherence, new stressors 1

Management approach:

• This patient requires intensification of diabetes management, not emergency DKA/HHS protocols
• If type 1 diabetes: adjust insulin regimen
• If type 2 diabetes: consider adding/intensifying therapy
• Ensure adequate hydration
• Address any precipitating factors (infection, steroids, non-adherence)

Critical Pitfall to Avoid

Do not confuse simple hyperglycemia with hyperglycemic crises. The presence of elevated glucose alone does not define DKA or HHS—the metabolic derangements (acidosis, severe hyperosmolality, altered mental status) are what make these conditions emergencies 3, 4. This patient lacks these features and should be managed as uncontrolled diabetes with appropriate outpatient or inpatient diabetes management depending on clinical context, not as a hyperglycemic crisis requiring ICU-level care.