What is the diagnosis and management for a patient with normal hemoglobin, elevated RDW, and thrombocytopenia?

Interpretation of CBC with Normal Hemoglobin, Elevated RDW, and Thrombocytopenia

This CBC pattern with normal hemoglobin (13.3 g/dL), elevated RDW (16.3%), and thrombocytopenia (62,000/μL) is most consistent with early essential thrombocythemia (ET) or another myeloproliferative neoplasm. 1, 2

Analysis of CBC Parameters

• Normal hemoglobin (13.3 g/dL) with normal hematocrit (39%) indicates absence of anemia 1
• Elevated RDW (16.3%) suggests heterogeneity in red cell size, indicating abnormal erythropoiesis 3, 2
• Severe thrombocytopenia (62,000/μL) with elevated MPV (12.8) suggests potential bone marrow disorder or peripheral destruction 1, 4
• Normal RBC count (4.1) with these other findings points toward a primary bone marrow disorder rather than a deficiency state 1, 3

Differential Diagnosis

Most Likely Diagnosis

• Essential thrombocythemia or early myeloproliferative neoplasm - the combination of thrombocytopenia with elevated MPV and RDW suggests abnormal megakaryocyte function and disordered hematopoiesis 1, 4

Other Considerations

• Early/developing iron deficiency - can present with elevated RDW before anemia develops, but would not typically cause significant thrombocytopenia 3, 2
• Thrombotic thrombocytopenic purpura (TTP) - presents with thrombocytopenia and elevated RDW (sensitivity 95% for RDW >18%), but typically includes anemia 4
• Bone marrow infiltration - metastatic disease or primary bone marrow disorder can present with thrombocytopenia and elevated RDW 5
• Fanconi anemia - characterized by increased RDW with correlation to thrombocytopenia and neutropenia 6

Recommended Diagnostic Workup

1. Complete blood count with differential - to assess white cell lineage and confirm thrombocytopenia 1, 3
2. Peripheral blood smear - to evaluate for abnormal cell morphology, schistocytes, or blasts 4, 5
3. Iron studies - serum ferritin, transferrin saturation to rule out iron deficiency 3, 2
4. JAK2 mutation testing - to evaluate for myeloproliferative neoplasm 1
5. Bone marrow aspiration and biopsy - essential for definitive diagnosis, particularly to evaluate megakaryocyte morphology and cellularity 1, 5
6. ADAMTS13 activity - if TTP is suspected based on clinical presentation 4

Management Approach

Initial Management

• Hematology consultation - immediate referral for specialized evaluation 1, 5
• Avoid antiplatelet medications - due to severe thrombocytopenia 1

Definitive Management (Based on Diagnosis)

• For myeloproliferative neoplasm: Treatment according to WHO criteria and risk stratification 1
• For TTP: Plasma exchange and immunosuppression if confirmed 4
• For iron deficiency: Iron supplementation if confirmed, with investigation for source of blood loss 3

Clinical Pearls and Pitfalls

• Pearl: Elevated RDW with normal MCV can mask early iron deficiency or combined deficiency states 3, 7
• Pitfall: Assuming iron deficiency based solely on elevated RDW without considering other causes of abnormal erythropoiesis 3, 7
• Pearl: The combination of thrombocytopenia and elevated RDW has high sensitivity (95%) for TTP when RDW >18% 4
• Pitfall: Failing to consider bone marrow examination in patients with unexplained cytopenias and elevated RDW, which can reveal non-hematologic malignancies 5

Follow-up Recommendations

• Close monitoring of complete blood counts to assess disease progression 3, 6
• Repeat bone marrow examination if diagnosis remains unclear or clinical status changes 1, 5
• Long-term surveillance based on final diagnosis 1