What is the best course of treatment for a patient with anemia, numbness, and itchiness?

Severe Anemia with Neurologic Symptoms: Immediate Workup and Treatment

This patient requires urgent evaluation for vitamin B12 deficiency given the combination of severe macrocytic anemia (Hgb 7.2 g/dL, MCV 92.9 fL) with numbness and itching for 1 month, and should receive immediate intramuscular vitamin B12 supplementation while awaiting confirmatory testing. 1, 2

Immediate Diagnostic Priorities

The laboratory values reveal severe anemia (Hgb 7.2 g/dL) with several critical findings that guide the workup 1:

• MCV 92.9 fL: Normocytic anemia, though the elevated RDW-CV (19.8) suggests a mixed picture or evolving macrocytosis 1, 3
• Low reticulocyte count (30,000/mm³): Indicates inadequate bone marrow response, pointing toward nutritional deficiency or bone marrow pathology 4, 1
• Neurologic symptoms: The 1-month history of numbness strongly suggests B12 deficiency, which can cause irreversible neurologic damage if untreated 2

Essential Laboratory Tests

Complete the anemia workup immediately with 4, 1:

• Vitamin B12 and folate levels (highest priority given neurologic symptoms)
• Iron studies: Serum ferritin and transferrin saturation (TSAT)
• Peripheral blood smear: Look for hypersegmented neutrophils (B12 deficiency) or other morphologic abnormalities
• Reticulocyte count confirmation: The reported value of 30,000/mm³ is inappropriately low for this degree of anemia
• Renal function: Creatinine and estimated GFR to assess for chronic kidney disease 4
• Parietal cell antibodies and intrinsic factor antibodies if B12 is low 2

Immediate Treatment Strategy

Start Treatment Before Results Return

Given the severity of anemia (Hgb 7.2 g/dL) and neurologic symptoms, begin intramuscular vitamin B12 1000 mcg daily immediately without waiting for laboratory confirmation 2. This approach is critical because:

• Neurologic damage from B12 deficiency can become permanent if treatment is delayed 2
• The patient has macrocytic indices with neurologic symptoms, making pernicious anemia highly likely 2
• Starting B12 therapy will not interfere with diagnostic testing if blood is drawn before the first injection 2

Transfusion Decision

This patient requires packed red blood cell (PRBC) transfusion based on 4, 1, 3:

• Hemoglobin <8.0 g/dL defines severe anemia 1, 3
• Symptomatic presentation (numbness, itching) indicates tissue hypoxia 4, 1
• One unit of PRBCs will increase Hgb by approximately 1 g/dL 4
• Transfuse 2 units initially and reassess symptoms 4

Critical caveat: Do not delay transfusion based solely on the Hgb threshold—the presence of symptoms mandates immediate correction 4, 1.

Definitive Management Based on Etiology

If B12 Deficiency Confirmed

• Continue intramuscular B12 1000 mcg daily for 1 week, then weekly for 4 weeks, then monthly for life 2
• Neurologic symptoms should begin improving within days to weeks 2
• Monitor CBC weekly initially to confirm reticulocyte response 1, 3

If Iron Deficiency Identified

When ferritin <30 ng/mL or TSAT <20% 4, 1:

• Intravenous iron is preferred over oral iron for severe anemia (Hgb <10 g/dL) 4, 1, 3
• Oral iron (ferrous sulfate 324 mg daily) is acceptable only for mild anemia without active inflammation 1, 3
• Continue iron therapy for 2-3 months after Hgb normalizes to replenish stores 1, 3

If Chronic Kidney Disease Present

Check renal function given the patient's age and severe anemia 4:

• If GFR <30 mL/min/1.73 m², monitor Hgb every 3 months 4
• Treat with erythropoiesis-stimulating agents (ESAs) if anemia persists despite iron repletion 4
• Target Hgb 10-12 g/dL with ESA therapy to avoid thrombotic complications 4

Addressing the Pruritus (Itching)

The 1-month history of itching requires specific evaluation 4:

• Check renal function: Uremic pruritus occurs with chronic kidney disease 4
• Assess for iron deficiency: Can cause pruritus independent of anemia severity 4
• Rule out polycythemia vera: Though unlikely with low Hgb, check JAK2 mutation if other causes excluded 4
• Symptomatic management: Emollients for xerosis, antihistamines (cetirizine 10 mg daily) if uremic pruritus confirmed 4

Critical Monitoring Plan

First 4 Weeks

• Repeat CBC weekly to confirm reticulocyte response and Hgb improvement 1, 3
• Reassess neurologic symptoms at each visit—lack of improvement suggests alternative diagnosis 2
• Monitor potassium if starting B12 therapy, as rapid cell production can cause hypokalemia 2

Long-term Follow-up

• Repeat Hgb after 4 weeks of treatment to ensure adequate response 1, 3
• Continue monitoring every 3 months once stable, especially if chronic kidney disease present 4
• Screen for recurrence: Over 50% of patients with inflammatory conditions develop recurrent anemia within 1 year 3

Common Pitfalls to Avoid

• Do not wait for B12 results before starting treatment when neurologic symptoms are present—permanent damage can occur 2
• Do not rely solely on ferritin to exclude iron deficiency, as it is falsely elevated in inflammatory states 1, 3
• Do not use oral iron for severe anemia (Hgb <10 g/dL) or active inflammation—intravenous iron is superior 4, 1, 3
• Do not overlook the elevated RDW-CV (19.8), which suggests mixed deficiency or evolving process requiring comprehensive workup 1
• Do not discharge without ensuring follow-up within 1 week to review laboratory results and assess treatment response 1, 3