What is the next step in managing a 44-year-old female with erythrocytosis (high red blood cell count), normal hemoglobin, iron deficiency (low ferritin), vitamin B12 deficiency, and vitamin D deficiency, on amlodipine (calcium channel blocker) for hypertension?

Management of a 44-Year-Old Female with Hematologic Abnormalities

The next step in management should be iron supplementation to address the iron deficiency, followed by vitamin B12 and vitamin D supplementation, while investigating the underlying cause of the erythrocytosis and thrombocytosis. 1

Initial Assessment and Interpretation of Findings

• The patient presents with a constellation of hematologic abnormalities: high red blood cell count (erythrocytosis), high hematocrit, high platelets (thrombocytosis), normal hemoglobin, and deficiencies in ferritin, vitamin B12, and vitamin D 1
• This pattern suggests a complex picture with multiple nutritional deficiencies alongside a paradoxical increase in red blood cells and platelets 1
• The normal hemoglobin despite high RBC count indicates that the cells may be microcytic or hypochromic due to iron deficiency 1

Management Algorithm

Step 1: Address Iron Deficiency

• Begin oral iron supplementation with 45-60 mg of elemental iron daily 1
• Low ferritin (40) confirms iron deficiency, which requires immediate treatment 1
• Monitor response with reticulocyte count within 1-2 weeks of starting therapy 1
• Consider evaluation for sources of blood loss, particularly gastrointestinal, as iron deficiency in adults often indicates occult bleeding 1

Step 2: Correct Vitamin B12 Deficiency

• Initiate vitamin B12 supplementation with oral cyanocobalamin 1000 mcg daily 2, 3
• Although the patient's B12 level (307) is low-normal, supplementation is warranted given the hematologic abnormalities 2
• Monitor for improvement in blood counts and neurologic symptoms if present 2
• Avoid folic acid supplementation without concurrent B12 supplementation as it may mask B12 deficiency while allowing neurologic damage to progress 2

Step 3: Address Vitamin D Deficiency

• Start vitamin D supplementation with 1000-2000 IU daily 1
• Low vitamin D (53.7) should be corrected to optimize bone health and immune function 1

Step 4: Further Investigation

• Complete a comprehensive workup for the cause of erythrocytosis and thrombocytosis 1
• Order complete blood count with red cell indices, reticulocyte count, peripheral blood smear, and inflammatory markers (CRP) 1
• Consider bone marrow examination if blood counts do not improve with nutritional supplementation 1
• Evaluate renal function, as chronic kidney disease can contribute to hematologic abnormalities 1
• Screen for myeloproliferative disorders, particularly if counts remain elevated after correction of deficiencies 1

Monitoring and Follow-up

• Recheck complete blood count, ferritin, and transferrin saturation in 4-6 weeks 1
• Monitor reticulocyte count as a marker of response to therapy 1
• If anemia persists despite iron and B12 supplementation for 4 weeks, evaluate for other contributing factors 1
• Assess blood pressure regularly, as the patient is on amlodipine for hypertension, and anemia treatment may affect blood pressure control 1

Special Considerations

• The combination of iron deficiency with elevated RBC count and platelets is unusual and suggests a possible reactive process or underlying hematologic disorder 4, 5
• Persistent anemia after appropriate supplementation requires further evaluation for other causes such as chronic inflammation, malignancy, or rare nutritional deficiencies 1, 6
• Consider screening for celiac disease or other malabsorption disorders if nutritional deficiencies persist despite adequate supplementation 1
• The paradoxical finding of normal hemoglobin with high RBC count may represent a compensatory mechanism in the setting of chronic iron deficiency 7