Microcytosis or microcythemia
is a condition in which
red blood cells
Red blood cells (RBCs), referred to as erythrocytes (, with -''cyte'' translated as 'cell' in modern usage) in academia and medical publishing, also known as red cells, erythroid cells, and rarely haematids, are the most common type of blood cel ...
are unusually small as measured by their
mean corpuscular volume
The mean corpuscular volume, or mean cell volume (MCV), is a measure of the average volume of a red blood corpuscle (or red blood cell). The measure is obtained by multiplying a volume of blood by the proportion of blood that is cellular (the hem ...
.
When associated with
anemia
Anemia (also spelt anaemia in British English) is a blood disorder in which the blood has a reduced ability to carry oxygen. This can be due to a lower than normal number of red blood cells, a reduction in the amount of hemoglobin availabl ...
, it is known as
microcytic anemia
Microcytic anaemia is any of several types of anemia characterized by smaller than normal red blood cells (called microcytes). The normal mean corpuscular volume of a red blood cell is approximately 80–100 fL. When the MCV is <80 fL, the red c ...
.
Causes
Microcytic anemia is not caused by reduced DNA synthesis.
Thalassemia
Thalassemias are a group of Genetic disorder, inherited blood disorders that manifest as the production of reduced hemoglobin. Symptoms depend on the type of thalassemia and can vary from none to severe, including death. Often there is mild to ...
can cause microcytosis. Depending upon how the terms are being defined, thalassemia can be considered a cause of microcytic anemia, or it can be considered a cause of microcytosis but not a cause of microcytic anemia.
There are many causes of microcytosis, which is essentially only a descriptor. Cells can be small because of mutations in the formation of blood cells (hereditary microcytosis) or because they are not filled with enough hemoglobin, as in iron-deficiency-associated microcytosis.
Red blood cells can be characterised by their haemoglobin content as well as by their size. The haemoglobin content is referred to as the cell's colour. Therefore, there are both "normochromic microcytotic red cells" and "hypochromic, microcytotic red cells". The normochromic cells have a normal concentration of haemoglobin, and are therefore 'red enough' while the hypochromic cells do not; thus the value of the
mean corpuscular hemoglobin concentration
The mean corpuscular hemoglobin concentration (MCHC) is a measure of the concentration of hemoglobin in a given volume of packed red blood cell.
It is calculated by dividing the hemoglobin by the hematocrit. Reference ranges for blood tests are ...
.The most common cause of microcytosis is iron deficiency anemia. Every time Hb synthesis being impaired in bone marrow microcytosis can occurs such as iron deficiency and Hb pathy may occur in fact when Hb production was impaired: size of each RBCs is decreased in early stage to save mean corpuscular Hb concentration : i.e. MCHC: so MCV is decreased as compensating mechanism.
See also
*
Macrocytosis
Macrocytosis is a condition where red blood cells are larger than normal. 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 he ...
References
External links
{{Portal bar, Biology, Medicine
Red blood cell disorders
Clinical pathology
Abnormal clinical and laboratory findings for RBCs
de:Mikrozytose