Now we cover aplastic anemia.
Aplastic anemia is where the stem
cells in the bone marrow are suppressed.
The bone marrow normally makes the blood cells including
the platelets, the red blood cells and the white blood cells
but here in the setting of aplastic anemia, this process
is disrupted and the bone marrow goes into failure.
Here you can see that if the bone marrow is in failure,
it's not gonna be contributing in a meaningful way
to creating these new blood cells including the red
blood cells, the white blood cells and the platelets.
The patient will develop a pancytopenia which
means it's a decrease in all of the cell types.
Remember pan- means "all", -cyto- means "cell"
and -penia means "low", so "all cells are low".
Tthe patient will have a normocytic
normochromic anemia which means
the cells are the right size and they have the right
amount of hemoglobin there just aren't enough in total.
The bone marrow's gonna slow the
development of these new blood cells
and it's gonna become aplastic or empty
or hypoplastic where it just has a few cells.
There are multiple causes of aplastic anemia.
This can be a sudden
onset or slow development
It can be mild or severe and it can lead to serious
medical conditions and it can even be life-threatening.
First let's do an overview of the
causes and then will delve deeper.
There are primary and secondary
causes of aplastic anemia.
These are the primary causes.
To start, most causes are idiopathic
which means the cause is unknown
and there is no history of exposure to
other substances or causative agents.
The other primary cause of aplastic
anemia is called Fanconi anemia
and this disorder usually becomes symptomatic around
age 5 as the bone marrow becomes more hypoplastic
These are also the secondary causes of bone
marrow failure that can cause aplastic anemia.
Medications - examples are those to treat
rheumatoid arthritis and some antibiotics.
Viruses have been linked to the development
of aplastic anemia and these include
Hepatitis,the Epstein-Barr virus,
Cytomegalovirus, Parvovirus B19 and HIV.
Aplastic anemia can occur in pregnancy and
this can be related to an autoimmune problem.
Your immune system can attack
your bone marrow during pregnancy.
Toxins such as chemotherapy,
radiation and chemicals.
Hematopeitic cells are especially
susceptible to ionizing radiation
and with the sublethal doses, the
bone marrow can eventually recover.
During treatments for cancer, the bone marrow's
healthy stem cells are also gonna be damaged
along with the targeted cancer cells
Aplastic anemia can be a temporary
side effect of these treatments.
In addition, exposure to toxic chemicals
such as those used in pesticides and insecticides.
These can cause aplastic anemia.
Exposure to benzene and ingredient
gasoline has also been linked.
This type of anemia will resolve spontaneously if
you avoid the repeated exposure to these chemicals.
Here we see possible triggers for aplastic anemia and
these will result in disorders of the pluripotent stem cell
and cause a decreased production in the
red blood cells, white blood cells and platelets.
So idiopathic, this is the most common cause.
Aplastic anemia can be acquired or
inherited although most cases are acquired.
Inherited forms usually present
during the first decade of life.
Idiopathic causes of aplastic anemia remain a mystery
but it's believed to be an immune mediated attack
directed at these hematopoeitic stem cells.
Then the T-cells, a type of white blood cell is gonna target
the hematopoeitic stem cells and will kill these cells.
Finally. the lymphocytes are gonna suppress the
blood cell production and division in the marrow.