Macrocytosis
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Macrocytosis
 | |
|---|---|
| Other names | Macrocytes |
| Specialty | Hematology |
| Symptoms | Shortness of breath, weakness, heart murmur, tachycardia |
| Causes | Vitamin B12 deficiency, Folic acid deficiency, Malabsorption, Alcoholism |
| Risk factors | Bone marrow failure, hematologic malignancy |
| Diagnostic method | Symptoms, Complete blood count, Peripheral blood smear, Vitamin B12 level, Red cell folate level |
Macrocytosis is a condition where red blood cells are larger than normal.[1] These enlarged cells, also known as macrocytes, are defined by a mean corpuscular volume (MCV) that exceeds the upper reference range established by the laboratory and hematology analyzer (usually >110 fL).[2] Upon examination of a peripheral blood smear under microscope, these macrocytes appear larger than standard erythrocytes. Macrocytosis is a common morphological feature in neonatal peripheral blood.[3] The presence of macrocytosis can indicate a range of conditions, from benign, treatable illnesses to more serious underlying disorders.
Types
[edit]Macrocytes may be oval or round. Oval macrocytes (also called megalocytes)[4] are seen in conditions associated with dyserythropoiesis including megalobalstic anemia, myelodysplstic syndromes, Fanconi anemia and CDA type I & III. Round macrocytes are associated with other causes of macrocytosis.
Causes
[edit]In humans, the most prevalent causes of macrocytosis are often linked to alcoholism and deficiencies in vitamin B12 or folate (vitamin B9), or a combination of these factors.[5] These conditions can affect the production and development of red blood cells, leading to their enlargement. Another cause of macrocytosis is benign familial macrocytosis, which is a hereditary condition that does not present symptoms.[6] Despite the larger size of the red blood cells, individuals with this condition typically have normal red blood cell function. Causes of macrocytosis may include:
- Megaloblastic anemia due to deficiency or abnormal metabolism of vitamin B12 or folate
- Poor dietary intake, including due to strict veganism
- Increased requirements
- Pernicious anemia
- Malabsorption syndromes
- Alcoholism
- Smoking
- Reticulocytosis due to hemolysis, blood loss and hematinics
- Hypothyroidism
- Myelodysplastic syndromes (MDS)
- Congenital dyserythropoietic anemia
- Aplastic anemia and bone marrow failure syndromes
- Inherited disorders of DNA synthesis
- Homocystinuria
- Lesch–Nyhan syndrome
- Deficient enzymes for folate metabolism
- Liver disease
- Chronic obstructive pulmonary disorder (COPD)
- Certain drugs, including folate antagonists, purine antagonists, tyrosine kinase inhibitors, anti-HIV drugs etc.
Complications
[edit]Macrocytosis does not itself lead to complications. Prognosis depends on its cause.
See also
[edit]References
[edit]- ^ Kaferle, Joyce; Strzoda, Cheryl E. (2009-02-01). "Evaluation of macrocytosis". American Family Physician. 79 (3): 203–208. ISSN 0002-838X. PMID 19202968.
- ^ Woodruff, James N.; Blanchard, Anita K. (2016-06-11). Primary Care of Adult Women, An Issue of Obstetrics and Gynecology Clinics of North America. Elsevier Health Sciences. ISBN 978-0-323-44623-5.
- ^ Bain, Barbara J. (2015-01-20). Blood Cells: A Practical Guide. John Wiley & Sons. ISBN 978-1-118-81733-9.
- ^ Anderson, Shauna Christine; Poulsen, Keila (2003). Atlas of Hematology. Lippincott Williams & Wilkins. ISBN 978-0-7817-2662-7.
- ^ Pacholok, Sally; Stuart, Jeffrey J. (2011-01-01). Could It Be B12?: An Epidemic of Misdiagnoses. Linden Publishing. ISBN 978-1-61035-065-5.
- ^ "Macrocytosis: Practice Essentials, Pathophysiology, Etiology". 2022-10-07.
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