What is the management approach for a patient with altered mental status, ketonuria, and no history of diabetes, who has not been drinking or eating for 2 days?

Management of Starvation Ketosis with Altered Mental Status

This patient has starvation ketosis causing altered mental status and requires immediate intravenous fluid resuscitation with isotonic saline or lactated Ringer's solution, followed by dextrose-containing fluids once adequate hydration is established. 1

Initial Assessment and Diagnosis

This clinical presentation represents starvation ketosis, not diabetic ketoacidosis (DKA), given the absence of diabetes history and the 2-day period of no oral intake. The key distinguishing features are:

• Ketonuria without hyperglycemia - In starvation ketosis, blood glucose is typically normal or low, whereas DKA requires glucose >250 mg/dL for diagnosis 2, 3
• Altered mental status from dehydration and ketonemia - The combination of volume depletion and metabolic derangement causes neurologic symptoms 1

Obtain immediate laboratory studies including:

• Complete metabolic panel with glucose, electrolytes (especially sodium and potassium), BUN, creatinine 2, 3
• Venous blood gas to assess pH and bicarbonate 2
• Serum osmolality 1
• Beta-hydroxybutyrate if available (preferred over urine ketones) 2, 3

Immediate Fluid Resuscitation

Begin aggressive IV fluid therapy immediately - this is the cornerstone of treatment:

• Start with isotonic saline (0.9% NaCl) or lactated Ringer's solution at 15-20 mL/kg/hour for initial volume expansion 1, 3
• In patients with ketonemia and altered mental status, IV hydration takes priority and is required to enable tolerance of oral rehydration 1
• Continue IV fluids until pulse, perfusion, and mental status normalize and the patient awakens with no aspiration risk 1

Critical Monitoring During Fluid Resuscitation

• Monitor serum sodium closely - Correct no faster than 8-10 mEq/L per 24 hours to avoid osmotic demyelination syndrome 4, 5
• The induced change in serum osmolality should not exceed 3 mOsm/kg H₂O per hour 1
• In patients with renal or cardiac compromise, frequent assessment of cardiac, renal, and mental status is essential to avoid fluid overload 1

Dextrose Administration

Once adequate hydration is established and the patient shows clinical improvement:

• Add 5% dextrose to IV fluids to provide glucose substrate and suppress ketogenesis 3
• This helps resolve ketonemia by providing an alternative energy source to fat metabolism
• Continue dextrose-containing fluids until the patient can tolerate oral intake 1

Electrolyte Management

Potassium replacement is critical even though initial levels may appear normal:

• Once renal function is confirmed and urine output is adequate, add 20-30 mEq/L potassium to IV fluids 2, 3
• Starvation and refeeding can cause significant intracellular potassium shifts 6
• Monitor potassium levels every 2-4 hours during initial resuscitation 2, 3

Transition to Oral Intake

When mental status normalizes and aspiration risk is absent:

• Resume oral rehydration solution (ORS) or clear liquids 1
• Progress to age-appropriate normal diet as tolerated 1
• Continue maintenance fluids to replace ongoing losses 1

Common Pitfalls to Avoid

• Do not assume this is DKA without confirming hyperglycemia - Starvation ketosis requires fundamentally different management (no insulin needed) 2, 3
• Avoid overly rapid sodium correction - Increases >10 mEq/L in 24 hours or >18 mEq/L in 48 hours risk osmotic demyelination syndrome 4, 6, 5
• Do not rely on urine ketones for monitoring - They measure acetoacetate, not beta-hydroxybutyrate, and can be misleading 2, 3
• Never give insulin - This patient does not have DKA and insulin would worsen hypoglycemia 2, 3
• Monitor for refeeding syndrome - Aggressive nutritional repletion after starvation can cause dangerous electrolyte shifts, particularly phosphate and potassium 6

Resolution Criteria

The patient is ready for discharge when:

• Mental status returns to baseline 1
• Tolerating adequate oral intake 1
• Electrolytes normalized 2, 3
• Ketonuria resolving (though may persist briefly after clinical improvement) 2