From the Guidelines
These lab values suggest macrocytic anemia with thrombocytopenia, and the first step should be to investigate the underlying cause, with a focus on vitamin B12 and folate deficiency, as well as potential myelodysplastic syndrome (MDS) given the high MCV (106.5) and low platelet count (107). The high RDW SD (53.5) also indicates a significant variation in red blood cell size, which can be seen in MDS or other conditions such as iron deficiency anemia. According to the guidelines for diagnosis, treatment, and follow-up of myelodysplastic syndromes 1, it is essential to consider MDS in the differential diagnosis, especially given the presence of thrombocytopenia.
- Key considerations in the initial evaluation include:
- Vitamin B12 and folate level tests to assess for deficiency, which can cause macrocytic anemia
- Iron studies to evaluate for iron deficiency or overload
- Thyroid function tests, as thyroid disorders can affect hematopoiesis
- Liver function tests, given the potential for liver disease to cause macrocytic anemia
- Reticulocyte count to assess bone marrow response
- Assessment of alcohol consumption, as it can contribute to macrocytic anemia and thrombocytopenia
- Given the thrombocytopenia, monitoring and possibly consulting with a hematologist is recommended, especially if the platelet count drops further or if there are signs of bleeding. The use of thrombopoietin receptor agonists (TPO-RAs) like romiplostim or eltrombopag may be considered in specific cases of thrombocytopenia in lower-risk MDS, but these are not approved for MDS in Europe and should be used with caution and only in patients without an excess of marrow blasts 1.
- Investigating for myelodysplastic syndrome (MDS) is crucial, given the combination of macrocytic anemia, thrombocytopenia, and elevated RDW SD. If MDS is diagnosed, treatment options may include erythropoiesis-stimulating agents (ESAs) for anemia, and in cases of lower-risk MDS with thrombocytopenia, high-dose androgens or TPO-RAs might be considered, although the latter are not approved for this indication in Europe 1.
From the FDA Drug Label
The FDA drug label does not answer the question.
From the Research
Laboratory Results
The patient's laboratory results show:
- RBC: 3.85
- MCV: 106.5
- MCH: 35.6
- RDW SD: 53.5
- PLT: 107
Diagnosis and Treatment
Based on the laboratory results, the patient has macrocytic anemia, which is defined as a mean corpuscular volume (MCV) >100 fL 2, 3, 4. The causes of macrocytic anemia can be classified into megaloblastic and nonmegaloblastic anemia. Megaloblastic anemia is caused by deficiency or impaired utilization of vitamin B12 and/or folate, whereas nonmegaloblastic macrocytic anemia is caused by various diseases such as myelodysplastic syndrome (MDS), liver dysfunction, alcoholism, hypothyroidism, certain drugs, and inherited disorders of DNA synthesis 2, 3.
Differential Diagnosis
The differential diagnosis of macrocytic anemia includes:
- Megaloblastic anemia
- Nonmegaloblastic macrocytic anemia
- Myelodysplastic syndrome (MDS)
- Liver dysfunction
- Alcoholism
- Hypothyroidism
- Certain drugs
- Inherited disorders of DNA synthesis
Treatment Approach
The treatment approach for macrocytic anemia depends on the underlying cause. For megaloblastic anemia, treatment with vitamin B12 and/or folate supplementation is recommended 5. For nonmegaloblastic macrocytic anemia, treatment is focused on addressing the underlying cause, such as discontinuing certain drugs or treating liver dysfunction or hypothyroidism 2, 3. In some cases, a hematology consultation may be necessary to determine the underlying cause and develop an appropriate treatment plan 2.
Further Evaluation
Further evaluation, including a blood smear, vitamin B12 and red blood cell folate levels, reticulocyte count, and thyroid and liver function tests, may be necessary to determine the underlying cause of the macrocytic anemia 3, 4. A bone marrow biopsy may also be considered in some cases, particularly if cytopenias are present 6.