What is the best course of action for a 40-year-old adult patient with anorexia nervosa and leukopenia (white blood cell count of 1.7)?

Management of Anorexia Nervosa with Severe Leukopenia (WBC 1.7)

This patient requires immediate hospitalization for nutritional rehabilitation, as the leukopenia is almost certainly due to starvation-induced bone marrow suppression and will resolve with refeeding—not with G-CSF or other hematologic interventions. 1

Immediate Actions

Hospitalize for Medical Stabilization

• Admit this patient immediately for inpatient medical stabilization and nutritional rehabilitation. 2
• The WBC of 1.7 (1,700/μL) represents severe leukopenia with likely neutropenia (ANC likely <1.0 k/μL), which occurs in 29% of severely malnourished anorexia nervosa patients 1
• This degree of leukopenia indicates severe malnutrition requiring intensive medical monitoring during refeeding 1

Complete Initial Assessment

• Obtain vital signs, height, weight, and BMI immediately to quantify severity of malnutrition 2
• Order comprehensive laboratory workup: complete metabolic panel, electrolytes (especially phosphorus, magnesium, calcium), liver function tests, thyroid function (TSH, free T4), and ECG 2
• Perform complete blood count with differential to determine absolute neutrophil count and assess for thrombocytopenia (present in 25% of severe cases) 1
• The leukopenia in anorexia nervosa is caused by gelatinous transformation of bone marrow from starvation, not true bone marrow failure 1

Treatment Strategy

Nutritional Rehabilitation is the Primary Treatment

• Begin careful refeeding with close monitoring for refeeding syndrome—this is the definitive treatment for the leukopenia, not hematologic interventions. 1
• Establish individualized target weight and weekly weight gain goals (typically 0.5-1 kg/week in inpatients) 2
• Monitor phosphorus, magnesium, and potassium closely during refeeding, as hypophosphatemia is characteristic of refeeding syndrome and can be life-threatening 3
• The hematologic abnormalities will resolve spontaneously with nutritional rehabilitation in 89% of patients by discharge 1

Infection Monitoring (Not Prophylaxis)

• Do not routinely treat with G-CSF or prophylactic antibiotics despite the severe leukopenia. 4
• Patients with anorexia nervosa and leukopenia do not have increased infection propensity compared to controls, even with severe neutropenia 4
• The bone marrow shows relative myeloid hyperplasia with normal neutrophil reserves despite peripheral leukopenia 4
• Monitor for fever and signs of infection, but understand that serious infections are infrequent even with severe leukopenia 5

G-CSF: Reserved for Sepsis Only

• G-CSF should only be considered if the patient develops documented sepsis with positive blood cultures in the setting of severe neutropenia 5
• Even then, G-CSF is controversial and should be used only as adjunctive therapy alongside antibiotics and continued nutritional rehabilitation 5
• The combination of severe neutropenia (ANC <500) plus low BMI may contribute to bacterial infection risk 5

Multidisciplinary Treatment Plan

Psychiatric and Psychological Components

• Implement eating disorder-focused psychotherapy that normalizes eating behaviors and addresses the psychological aspects of the disorder 2
• Provide comprehensive psychiatric evaluation to identify co-occurring conditions (depression, anxiety, obsessive-compulsive features) 2
• Weekly weight monitoring during active weight restoration phase 2

Medical Monitoring During Hospitalization

• Daily electrolyte monitoring during initial refeeding (first 5-7 days) to detect refeeding syndrome 3
• Repeat CBC weekly to document improvement in leukopenia with nutritional rehabilitation 1
• Continuous cardiac monitoring if ECG shows QTc prolongation, as both malnutrition and electrolyte abnormalities affect cardiac function 2
• Monitor for other common abnormalities: anemia (present in 83%), thrombocytopenia (25%), elevated transaminases, and hypoglycemia 3, 1

Expected Course and Prognosis

Hematologic Recovery Timeline

• Leukopenia typically begins improving within days to weeks of adequate nutritional rehabilitation 1
• 89% of patients have resolved neutropenia by hospital discharge with proper refeeding alone 1
• All hematologic abnormalities are readily reversible after resolution of the underlying anorectic state 6

Common Pitfalls to Avoid

• Do not pursue extensive hematologic workup (bone marrow biopsy, hematology consultation) unless the leukopenia fails to improve with nutritional rehabilitation. 1
• Do not delay nutritional rehabilitation while investigating the leukopenia—refeeding is both diagnostic and therapeutic 1
• Avoid overly aggressive refeeding that precipitates refeeding syndrome; start conservatively and advance calories gradually 3
• Do not use restrictive "cardiac" or other therapeutic diets that may worsen nutritional status—provide adequate calories tailored to patient preferences 7