What is the best course of treatment for a 40-year-old female with relapsed anorexia nervosa, significant weight loss, orthostatic hypotension, and a history of Adderall (amphetamine and dextroamphetamine) abuse?

Immediate Hospitalization Required

This patient requires immediate hospitalization for medical stabilization given her severe orthostatic hypotension, significant weight loss, and BMI of 16.1 kg/m², which meets criteria for inpatient treatment of anorexia nervosa. 1, 2

Critical Medical Findings Requiring Hospitalization

Your patient demonstrates multiple high-risk features:

• BMI 16.1 kg/m²: This falls below the threshold of 16 kg/m² associated with higher premature mortality in anorexia nervosa 1
• Severe orthostatic hypotension: Drop from 103/67 to 81/54 mmHg with heart rate increase from 85 to 118 bpm indicates significant cardiovascular instability 2
• 19% weight loss over 3 months: This represents rapid, dangerous weight loss requiring immediate intervention 2
• Adderall abuse: This stimulant abuse compounds cardiovascular risk and must be discontinued immediately 1

Immediate Management Steps

First 24-48 Hours

• Discontinue Adderall immediately - stimulant use with this degree of cardiovascular instability poses risk of sudden cardiac death 2
• Continuous cardiac monitoring with serial ECGs to monitor for QTc prolongation and arrhythmias, as patients with restrictive eating disorders require ongoing cardiac surveillance 2
• Intravenous fluid resuscitation with careful monitoring for refeeding syndrome (monitor phosphorus, magnesium, potassium closely) 2, 3
• Bed rest with supervised bathroom privileges until orthostatic vital signs stabilize 4

Nutritional Rehabilitation

• Set individualized weekly weight gain goals targeting 0.5-1 kg per week initially, with a target BMI >18.5 kg/m² before considering discharge 1, 2
• Structured meal plan with gradual caloric increases to avoid refeeding syndrome 3, 5
• Multidisciplinary team involvement including medical physician, psychiatrist, psychologist, and registered dietitian 2, 6

Psychotherapy and Long-Term Treatment

Once medically stabilized:

• Individual eating disorder-focused psychotherapy is the cornerstone treatment for adults with anorexia nervosa, focusing on normalizing eating behaviors, restoring weight, and addressing fear of weight gain and body image disturbance 2
• No role for stimulant medications - lisdexamfetamine is FDA-approved only for binge eating disorder, not anorexia nervosa, and stimulants are contraindicated in your patient 7
• Consider olanzapine for severe anxiety, agitation, or obsessive thoughts about food/weight once cardiovascular status stabilizes, as atypical antipsychotics may help with weight restoration 8

Discharge Criteria

Do not discharge until ALL of the following are met:

• BMI >18.5 kg/m² achieved 1
• Orthostatic vital signs normalized 2
• Normal electrolytes maintained on oral intake 2
• Established outpatient multidisciplinary treatment plan 2, 4
• Patient demonstrates ability to maintain adequate oral intake independently 4

Critical Pitfall to Avoid

The most dangerous error would be attempting outpatient management given her BMI <16 kg/m² and severe orthostatic hypotension. While outpatient treatment can be appropriate for some patients with severe anorexia nervosa if they are medically stable 4, your patient is demonstrably medically unstable and requires inpatient care. Most medical complications of anorexia nervosa are reversible with optimal medical care 3, but only if treatment is initiated before irreversible damage occurs.