This patient is in DKA (Diabetic Ketoacidosis)
Based on the laboratory values provided, this patient meets diagnostic criteria for DKA rather than pure HHS, though there are overlapping features suggesting a mixed presentation.
Diagnostic Analysis
Why This is DKA:
The patient fulfills the three key diagnostic criteria for DKA 1, 2:
- Hyperglycemia: Blood glucose 557 mg/dL (>250 mg/dL required for DKA) 1
- Ketosis: Serum ketones 0.9 mmol/L (positive ketones present) 1
- Metabolic acidosis with elevated anion gap: Anion gap 18 mEq/L (>10 mEq/L diagnostic for DKA) and bicarbonate 22 mEq/L 1, 2
Severity Classification:
This represents mild DKA based on the bicarbonate level of 22 mEq/L, which is above the typical DKA range but still consistent with mild disease 1, 2. The American Diabetes Association criteria specify:
- Mild DKA: bicarbonate 15-18 mEq/L, anion gap >10 mEq/L 1
- Moderate DKA: bicarbonate 10-15 mEq/L, anion gap >12 mEq/L 1
- Severe DKA: bicarbonate <10 mEq/L, anion gap >12 mEq/L 1
Why This is NOT Pure HHS:
HHS diagnostic criteria require 1:
- Blood glucose typically >600 mg/dL (this patient has 557 mg/dL - borderline)
- Effective serum osmolality >320 mOsm/kg (this patient has 311 mOsm/kg - does not meet criteria)
- Small or absent ketones (this patient has ketones 0.9 mmol/L - positive ketones present)
- Bicarbonate >15 mEq/L (this patient has 22 mEq/L - meets this criterion)
Mixed Presentation Considerations:
This patient likely has overlapping features of both DKA and HHS, which occurs in approximately one-third of hyperglycemic crisis cases 3. The elevated osmolality (311 mOsm/kg, though below the 320 threshold for HHS) combined with positive ketones and elevated anion gap suggests a mixed picture 3.
Key Clinical Implications:
- Renal impairment (creatinine 1.82, GFR 37) is present and common in both conditions, resulting from osmotic diuresis and dehydration 4
- The impaired renal function may be contributing to the metabolic acidosis and limiting ketone clearance 4
- Treatment should address both the ketoacidosis (with insulin) and the significant dehydration/hyperosmolality (with aggressive fluid resuscitation) 3
Treatment Approach:
For this mixed presentation, management should include 1, 3:
- Intravenous insulin infusion to suppress ketogenesis and correct hyperglycemia 1
- Aggressive fluid replacement with isotonic saline (0.9% NaCl) at 15-20 mL/kg/h initially, given the elevated osmolality and renal impairment 1
- Electrolyte monitoring and replacement, particularly potassium, as insulin therapy will drive potassium intracellularly 1, 5
- Frequent monitoring of glucose, electrolytes, anion gap, and venous pH every 2-4 hours 2
- No bicarbonate therapy needed as the pH is likely >7.0 (bicarbonate only indicated if pH <6.9) 2, 6
Important Pitfall:
Standard ketone measurements using nitroprusside method only detect acetoacetate and acetone, NOT β-hydroxybutyrate (the predominant ketone body in DKA) 6. The reported ketone level of 0.9 mmol/L may underestimate the true degree of ketosis 6. During treatment, as β-hydroxybutyrate converts to acetoacetate, standard ketone measurements may paradoxically increase despite clinical improvement 6.