Low platelets are defined as a blood platelet count <100 x 10.
Low platelets are seen in a variety of hematologic diseases, rheumatic immune diseases, radiotherapy injury and drug-related thrombocytopenia. Depending on the degree of thrombocytopenia, different clinical manifestations may occur: in mild cases, there may be bleeding spots and bruises on the skin, blood oozing from the gums and epistaxis, and in severe cases, there may be bleeding from organs: such as vomiting blood, black stools, hematuria and brain hemorrhage.
The function of platelets is to promote hemostasis and accelerate clotting, and platelets also have the function of maintaining the integrity of capillary walls.
In the process of hemostasis and coagulation, platelets have the functions of forming blood clots, blocking wounds and releasing various factors related to coagulation. At the rupture of small blood vessels, platelets aggregate to form platelet plugs that block the rupture and release epinephrine, 5-hydroxytryptamine and other substances with vasoconstrictive effects, which are among the important factors that promote blood clotting.
Platelets also have a role in nourishing and supporting capillary endothelial cells, making capillaries less brittle. It is usually caused by antibodies (biochemical substances that have a protective effect) formed by the body that attack its own platelets. Some acute infections are the root cause of this condition, too many blood transfusions in a short period of time (such as during major surgery), or abnormal bleeding and clotting can cause thrombocytopenia.
1.Decreased platelet production
(1) Hereditary: such as Fanconi anemia, congenital anomalous thrombocytopenia and May-Hegglin anomaly, etc.
(2) Acquired: aplastic anemia, bone marrow infiltration (malignant tumor bone marrow metastasis, leukemia, myelofibrosis, tuberculosis), chemotherapy drugs, radiation, megakaryocyte aplasia, viral infections (measles, mumps), drugs affecting platelet production (such as alcohol), vitamin B12, folic acid deficiency.
2.Increased platelet destruction caused by non-immune factors
Thrombotic thrombocytopenic purpura, pregnancy, infection, hemangioma-thrombocytopenia syndrome, snake bite, acute respiratory distress syndrome, severe burns, etc.
3.Increased platelet destruction caused by immune factors
Immune thrombocytopenic purpura, HIV infection, periodic thrombocytopenia, drug-induced thrombocytopenia (heparin, quinine, quinidine, antipyretic analgesics, penicillin, cephalosporin antibiotics, rifampin, furosemide, carbamazepine, sodium valproate, sulfonylurea hypoglycemic agents and phenytoin sodium, etc.), thrombocytopenia after blood transfusion
4.Abnormal platelet distribution
Hypersplenism, hypothermia.
5.Loss of platelets
Bleeding, extracorporeal perfusion, hemodialysis.
6.Other
Pseudo-thrombocytopenia.
Clinical manifestations.
1, Skin bleeding: bleeding spots, purpura, bruises.
2, gingival bleeding: gingival bleeding is common in normal individuals and in dental disease; therefore, repeated gingival bleeding or difficulty in stopping bleeding after bleeding often suggests bleeding disorders such as thrombocytopenia.
Epistaxis: Epistaxis can also occur occasionally in normal people, but epistaxis combined with other bleeding symptoms often indicates bleeding disorders.
4. Joint bleeding, muscle and deep tissue hematoma: Bleeding from joints and muscles caused by thrombocytopenia alone is rare.
5. Gastrointestinal bleeding: It can be manifested as vomiting blood, blood in stool, black stool, etc.