This article needs additional citations for verification. (May 2021)
|Other names||Macrocytes, megalocytes|
Macrocytosis is the enlargement of red blood cells with near-constant hemoglobin concentration, and is defined by a mean corpuscular volume (MCV) of greater than 100 femtolitres (the precise criterion varies between laboratories). The enlarged erythrocytes are called macrocytes or megalocytes (both words have roots meaning "big cell"). As a symptom its cause may be relatively benign and need no treatment or it may indicate a serious underlying illness.
Poor absorption of vitamin B12 in the digestive tract can also cause macrocytosis.
Gastrointestinal diseases that may cause macrocytosis include celiac disease (severe sensitivity to gluten from wheat and other grains that causes intestinal damage) and Crohn's disease (inflammatory bowel disease that can affect any part of the gastrointestinal tract).
Other causes may include:
- megaloblastosis (vitamin B12 or folate deficiency) because slowly dividing erythrocytes accumulate cytoplasmic components, resulting in larger-than-normal cells.
- chronic obstructive pulmonary disease (COPD)
- aplastic anemia
- reticulocytosis (commonly from hemolysis or a recent history of blood loss).
- liver disease because of an increase in circulating phospholipids and cholesterol, which bind on erythrocytes and induce membrane expansion
- myeloproliferative disease
- myelodysplastic syndrome which most commonly presents with macrocytic anemia
- chronic exposure to benzene
- pregnancy (most common, and requires no treatment as the person affected will return to normal post-partum)
- Certain anti-inflammatory drugs, e.g. salazopyrin, azathioprine.
No complications arise from macrocytosis itself and a prognosis will be determined from its cause.
- Yadav, Manish K.; Manoli, Nandini M.; Madhunapantula, SubbaRao V. (25 October 2016). "Comparative Assessment of Vitamin-B12, Folic Acid and Homocysteine Levels in Relation to p53 Expression in Megaloblastic Anemia". PLOS ONE. 11 (10): e0164559. Bibcode:2016PLoSO..1164559Y. doi:10.1371/journal.pone.0164559. PMC 5079580. PMID 27780269.
- Fessler, Michael B.; Rose, Kathryn; Zhang, Yanmei; Jaramillo, Renee; Zeldin, Darryl C. (November 2013). "Relationship between serum cholesterol and indices of erythrocytes and platelets in the US population". Journal of Lipid Research. 54 (11): 3177–3188. doi:10.1194/jlr.P037614. PMC 3793622. PMID 23999863.
- Greenberg, Peter L.; Attar, Eyal; Bennett, John M.; Bloomfield, Clara D.; Borate, Uma; De Castro, Carlos M.; Deeg, H. Joachim; Frankfurt, Olga; Gaensler, Karin; Garcia-Manero, Guillermo; Gore, Steven D.; Head, David; Komrokji, Rami; Maness, Lori J.; Millenson, Michael; O’Donnell, Margaret R.; Shami, Paul J.; Stein, Brady L.; Stone, Richard M.; Thompson, James E.; Westervelt, Peter; Wheeler, Benton; Shead, Dorothy A.; Naganuma, Maoko (July 2013). "Myelodysplastic Syndromes". Journal of the National Comprehensive Cancer Network. 11 (7): 838–874. doi:10.6004/jnccn.2013.0104. PMC 4000017. PMID 23847220.