Aplastic anemia (referred to as reanemia) is a pluripotent stem cell disease. It often presents clinically with more severe anemia, infection and bleeding. Patients are predominantly young adults, with more males than females. Etiology About half of the cases are referred to as primary remittent disease because no obvious cause can be found. Some cases are apparently caused by toxic effects of chemical, physical or biological factors on the bone marrow and are referred to as secondary reoccurrence. The most common cause is poisoning or allergy from exposure to chemicals in the medicinal industry or in life, followed by various forms of ionizing radiation and, less commonly, viral infections and immune reactions. Symptoms The main clinical manifestations are progressive anemia, bleeding and infection, the severity of which is related to the degree of hematocrit and the speed of progression. Symptoms of anemia include fatigue, weakness, pale skin and mucous membranes, petechiae and petechiae on the skin and mucous membranes, bleeding from the gums, epistaxis, excessive menstruation in female patients, as well as symptoms of infection in the mouth, around the anus, skin and upper respiration. There is usually no enlargement of lymph nodes and spleen, but repeated infections and long-term blood transfusions may cause mild enlargement of the spleen. Acute type: Most of the cases have a rapid onset, with mild symptoms, and the early prominent symptoms are infection and bleeding. High fever, chills, sweating, oral or pharyngeal ulcers, skin infections, pneumonia are common, and in severe cases, death may occur due to sepsis. This type of case is sinister and has a short course. Chronic type: Most of them have a slow onset, and the main manifestations are often tiredness and weakness, shortness of breath after exertion, palpitations, dizziness, and pallor. Bleeding, if any, is also mild, and visceral bleeding is rare. Infection and fever are generally mild, appear late, and are easily controlled after treatment. The liver and spleen lymph nodes are not enlarged, but the spleen is occasionally mildly enlarged in advanced cases. The course of the disease is long and patients can survive for many years with gradual improvement or even near cure. Some patients transform into the acute form. Blood picture: Complete blood count is the most important feature, but the degree of reduction of red blood cells, granulocytes and platelets varies. Bone marrow picture: In acute cases, there are few bone marrow granules in the bone marrow aspirates, and fat droplets are apparently increased. Microscopically, the bone marrow is hypoproliferative or severely hypoplasmic, with a significant decrease in nucleated cells, mainly granulocytes and red lineage cells, and a decrease or disappearance of megakaryocytes. There is an increase in the proportion of lymphocytes and an increase in non-hematopoietic cells such as plasma cells, histiocytes and histophile cells. Bone marrow biopsy: The hematopoietic tissue is significantly reduced on the pathological section of bone marrow biopsy, replaced by fatty tissue with lymphocytes, plasma cells and histiocytes distributed in the loose interstitium. Treatment I. Prevent the abuse of drugs that are harmful to the hematopoietic system, especially chloramphenicol, pautazone and other drugs, and when they must be used, strengthen the observation of blood picture and take appropriate measures in time. Second, long-term exposure to chemical and physical factors that can cause the disease should strictly implement protective measures, strictly comply with the operating procedures, and prevent harmful chemical and radioactive substances from contaminating the surrounding environment.