Macrocytosis is the enlargement of red blood cell

Red blood cell

Red blood cells are the most common type of blood cell and the vertebrate organism's principal means of delivering oxygen to the body tissues via the blood flow through the circulatory system...

s with near-constant hemoglobin

Hemoglobin

Hemoglobin is the iron-containing oxygen-transport metalloprotein in the red blood cells of all vertebrates, with the exception of the fish family Channichthyidae, as well as the tissues of some invertebrates...

 concentration, and is defined by a mean corpuscular volume

Mean corpuscular volume

The mean corpuscular volume, or "mean cell volume" , is a measure of the average red blood cell size that is reported as part of a standard complete blood count....

 (MCV) of greater than 100 femtolitres (the precise criterion varies between laboratories).

Causes

Most commonly (especially when the increase in size is mild, and just above normal range) the etiology is bone marrow

Bone marrow

Bone marrow is the flexible tissue found in the interior of bones. In humans, bone marrow in large bones produces new blood cells. On average, bone marrow constitutes 4% of the total body mass of humans; in adults weighing 65 kg , bone marrow accounts for approximately 2.6 kg...

 dysplasia

Dysplasia

Dysplasia , is a term used in pathology to refer to an abnormality of development. This generally consists of an expansion of immature cells, with a corresponding decrease in the number and location of mature cells. Dysplasia is often indicative of an early neoplastic process...

 secondary to alcohol abuse

Alcohol abuse

Alcohol abuse, as described in the DSM-IV, is a psychiatric diagnosis describing the recurring use of alcoholic beverages despite negative consequences. Alcohol abuse eventually progresses to alcoholism, a condition in which an individual becomes dependent on alcoholic beverages in order to avoid...

 and Chronic alcoholism. Other causes may include:

• Megaloblastosis (Vitamin B12
  Vitamin B12
  Vitamin B12, vitamin B12 or vitamin B-12, also called cobalamin, is a water-soluble vitamin with a key role in the normal functioning of the brain and nervous system, and for the formation of blood. It is one of the eight B vitamins...
  
   or folate deficiency; or DNA synthesis-inhibiting drugs)
• hypothyroidism
  Hypothyroidism
  Hypothyroidism is a condition in which the thyroid gland does not make enough thyroid hormone.Iodine deficiency is the most common cause of hypothyroidism worldwide but it can be caused by other causes such as several conditions of the thyroid gland or, less commonly, the pituitary gland or...
  
  
• reticulocytosis
  Reticulocytosis
  Reticulocytosis is a condition where there is an increase in reticulocytes, immature red blood cell.It is commonly seen in Anemia. They are seen on blood films when the bone marrow is highly active in an attempt to replace red blood cell loss such as in haemolytic anaemia, haemorrhage.-External...
  
   (commonly from hemolysis
  Hemolysis
  Hemolysis —from the Greek meaning "blood" and meaning a "loosing", "setting free" or "releasing"—is the rupturing of erythrocytes and the release of their contents into surrounding fluid...
  
   or a recent history of blood loss).
• liver disease
  Liver disease
  Liver disease is a broad term describing any single number of diseases affecting the liver.-Diseases:* Hepatitis, inflammation of the liver, caused mainly by various viruses but also by some poisons , autoimmunity or hereditary conditions...
  
  
• myeloproliferative disease
  Myeloproliferative disease
  The myeloproliferative diseases are a group of diseases of the bone marrow in which excess cells are produced. They are related to, and may evolve into, myelodysplastic syndrome and acute myeloid leukemia, although the myeloproliferative diseases on the whole have a much better prognosis than...
  
  
• Pregnancy- is the most common and requires no treatment as female will return back to normal post-partum

Complications

No complications arise from macrocytosis itself and a prognosis

Prognosis

Prognosis is a medical term to describe the likely outcome of an illness.When applied to large statistical populations, prognostic estimates can be very accurate: for example the statement "45% of patients with severe septic shock will die within 28 days" can be made with some confidence, because...

 will be determined from its etiology

Etiology

Etiology is the study of causation, or origination. The word is derived from the Greek , aitiologia, "giving a reason for" ....

.

See also

• Macrocytic anemia