What is aplastic anemia? Be careful with medications!

Aplastic anemia is also called aplastic anemia. There are two main types of aplastic anemia: acute and chronic. Many people don’t know what aplastic anemia is. This disease is related to many factors, including drug factors and disease factors.

1. Drug factors (40%):

It is dose-related and is a drug toxicity effect. When a certain dose is reached, it will cause bone marrow suppression, which is generally reversible. For example, various anti-tumor drugs and cell cycle-specific drugs such as cytarabine and methotrexate mainly act on more mature pluripotent stem cells that are easy to divide. Therefore, when pancytopenia occurs, the bone marrow still retains a certain amount of pluripotent stem cells, and aplastic anemia can be recovered after drug discontinuation.

2. Environmental factors (20%):

In industrial production and daily life, people have extensive opportunities to come into contact with benzene (C6H6) and its derivatives. Benzene is volatile and easily inhaled into the human body. Hematological abnormalities are common among people exposed to benzene, including: anemia (48%), macrocytosis (47%), thrombocytopenia (33%), leukocytopenia (15%), and pancytopenia (2.7%) among shoemaking workers in poor working environments. Severe benzene poisoning can lead to aplastic anemia.

3. Viral hepatitis (10%):

In 1955, Lorenz reported the first case of viral hepatitis-associated aplastic anemia (HAAA). It is generally believed that the incidence of HAAA in patients with viral hepatitis is 0.05% to 0.9%, and the constituent ratio in patients with aplastic anemia is 3.2% to 23.9%. 80% of HAAA is caused by hepatitis C virus, and a few are caused by hepatitis B virus (HBV). Hagler divided HAAA into two types. The occurrence of HAAA is related to the direct inhibitory effect of hepatitis virus on hematopoietic stem cells. Virus-mediated autoimmune abnormalities or the production of anti-stem cell antibodies, virus damage to the bone marrow microenvironment, and decreased liver detoxification function also play a certain role in the pathogenesis of HAAA.

4. Occupational factors (10%):

Radiation-induced bone marrow failure is non-random, dose-dependent, and related to tissue-specific sensitivity. Hematopoietic tissue is more sensitive to radiation. Lethal or sublethal doses (4.5-10Gy) of whole-body irradiation can cause fatal acute aplastic anemia, but rarely cause chronic aplastic anemia. Only a few cases of delayed aplastic anemia developed among the survivors of the atomic bomb explosion in Japan. High-dose local irradiation can also cause serious damage to the bone marrow microenvironment. This irradiation dose far exceeds the lethal dose of progenitor cells. Long-term exposure to low-dose external irradiation, such as radiologists or patients with indwelling radium or thorium, can develop chronic aplastic anemia.