What is the best ER treatment for a 65-year-old patient with hyperketonemia (elevated serum ketones), uncontrolled anxiety, and bulimia who refuses inpatient psychiatric care?

Emergency Department Management of Starvation Ketosis in Bulimia

This patient requires aggressive IV fluid resuscitation, subcutaneous insulin if hyperglycemic, electrolyte monitoring and replacement (especially potassium), treatment of the underlying eating disorder with outpatient psychiatric follow-up, and addressing the acute anxiety—not inpatient psychiatric admission against their will.

Immediate Assessment and Stabilization

Determine the Type of Ketosis

• Assess blood glucose immediately to differentiate between diabetic ketoacidosis (DKA), hyperosmolar hyperglycemic state (HHS), and starvation ketosis 1
• In bulimia with purging behaviors, this is most likely starvation ketosis from caloric restriction and vomiting, not DKA, unless the patient has underlying diabetes 2
• Serum ketones of 3.4 mmol/L represent moderate ketonemia that requires treatment but is not immediately life-threatening if glucose is normal 1

Fluid Resuscitation

• Begin with isotonic saline (0.9% NaCl) at 15-20 mL/kg/hr for the first hour to restore circulatory volume and tissue perfusion 1, 3
• Continue fluid replacement at 4-14 mL/kg/hr based on hemodynamic status after the initial hour 1
• Adequate fluid replacement is the cornerstone of treatment and will help resolve ketosis even without insulin if glucose is normal 3

Electrolyte Management—Critical in Bulimia

• Check comprehensive metabolic panel immediately, including potassium, as hypokalemia is common in purging behaviors 3
• Hypokalemia occurs in bulimic patients who purge daily through vomiting and/or laxative abuse, and is virtually certain evidence of active purging 2
• Begin potassium replacement when serum levels fall below 5.2 mEq/L (assuming adequate urine output), typically 20-30 mEq per liter of IV fluid 1
• Monitor potassium every 2-4 hours as refeeding and any insulin therapy can precipitate dangerous hypokalemia 1, 3

Insulin Therapy (If Needed)

• If blood glucose is elevated (>250 mg/dL), start continuous IV regular insulin at 0.1 units/kg/hr after fluid resuscitation has begun 1
• If glucose is normal or only mildly elevated, insulin is generally not required—fluid resuscitation alone will resolve starvation ketosis 3
• For uncomplicated ketosis with normal glucose, subcutaneous rapid-acting insulin may be used if needed, which is safer and more cost-effective than IV insulin 3

Ongoing Monitoring in the ED

• Check blood glucose every 1-2 hours until stable 1
• Monitor electrolytes every 2-4 hours, particularly potassium, as this is the highest risk in purging bulimia 1, 2
• Assess vital signs including orthostatic blood pressure and pulse, as these patients are often volume depleted 3
• Obtain ECG to assess for QTc prolongation from electrolyte abnormalities, which is recommended in patients with severe purging behavior 3

Addressing the Acute Anxiety

• Treat anxiety symptomatically with benzodiazepines if needed (e.g., lorazepam 0.5-1 mg PO) while addressing the underlying metabolic derangements 3
• Recognize that anxiety may improve as ketosis resolves and metabolic stability is restored 4
• Do not force inpatient psychiatric admission if the patient has decision-making capacity and refuses, as this will damage therapeutic alliance and is not indicated for metabolic stabilization 3

Disposition and Outpatient Planning

Discharge Criteria

• Ketosis resolving (ketones trending down)
• Electrolytes normalized, particularly potassium
• Tolerating oral intake
• Hemodynamically stable without orthostatic changes
• Patient agrees to outpatient follow-up

Structured Discharge Plan

• Schedule outpatient psychiatric follow-up within 1 week for eating disorder-focused cognitive-behavioral therapy, which is the recommended treatment for bulimia nervosa 3
• Consider prescribing fluoxetine 60 mg daily either at discharge or if minimal response to psychotherapy alone by 6 weeks, as this is the recommended pharmacotherapy for bulimia 3
• Provide clear sick-day management instructions including when to seek emergency care for recurrent vomiting or inability to maintain oral intake 3
• Arrange outpatient medical follow-up within 3-5 days to monitor electrolytes and ensure metabolic stability 3
• Refer to outpatient registered dietitian for nutritional rehabilitation 3

Common Pitfalls to Avoid

• Do not assume this is DKA without checking glucose—starvation ketosis in bulimia is far more common and requires different management 2
• Do not overlook hypokalemia, which can be life-threatening and is the most dangerous complication in purging bulimia 2
• Do not aggressively treat with insulin if glucose is normal—this will cause hypoglycemia and worsen the clinical picture 3, 1
• Do not force psychiatric hospitalization for a patient with capacity who refuses—focus on medical stabilization and voluntary outpatient psychiatric engagement 3
• Do not discharge without ensuring outpatient follow-up is scheduled, as appointment-keeping behavior is enhanced when arranged prior to discharge 3