Pediatric Thrombocytopenia
Introduction
Introduction to pediatric thrombocytopenia Thrombosthenia, also known as glanomnn's disease, is the most common type of hemorrhagic disease caused by hereditary platelet function defects. It is known that this disease is a platelet membrane glycoprotein (gp) IIb/IIIa deficiency, and is divided into three types: type I (gpIIb/IIIa is less than 5% of normal), type II (gpIIb/IIIa is less than normal 5) % to 25%), and variant (gpIIb/IIIa is 40% to 100% normal, but structurally abnormal). A variety of gpIIIa gene defects or gpIIa gene defects have been detected by molecular biology techniques. 10% to 50% of patients have a blood relationship with parents, showing autosomal recessive inheritance. Heterozygous has no obvious symptoms of blood. basic knowledge The proportion of illness: 0.001% Susceptible people: children Mode of infection: non-infectious Complications: hematuria
Cause
Causes of childhood thrombocytopenia
Causes:
The disease is autosomal recessive, GT has a high incidence in specific populations and is often associated with the marriage of close relatives. Arabs, Iraqi Jews, French Gypsies and Southern Indians have more carriers. It is due to the abnormality of the quality or quantity of IIb (GPIIb, CD41) and/or 3 (GPIII, CD61), which is required when platelets are aggregated under the action of physiological inducers, and when platelet particles are taken up with fibrinogen. The involvement of GPIIb/IIIa receptors, therefore, abnormalities in GPIIb and/or GPIIIa lead to abnormalities in platelet adhesion and aggregation in this disease, and various molecular defects have been found at the molecular level including in the aIIb-sheet domain, 3 MIDAS The domain and three types of mutations affecting receptor activation involve multiple mutations such as point mutations, deletions, and inversions.
Pathogenesis:
The biochemical defect of GT is the reduction of the amount of platelet membrane glycoprotein GPIIb/IIIa complex, deletion or qualitative abnormality. GPIIb/IIIa can be used as receptor and fiber when its surrounding microenvironment changes or its configuration changes due to platelet activation. Proteinogen, vWF fibronectin, laminin and other adhesion molecules bind to mediate platelet aggregation. When the quantity or quality is abnormal, aggregation defects occur. This platelet can adhere to the damaged subendothelial tissue normally, but not Further normal extension and platelet aggregation can be clinically divided into three subtypes: type I: GPIIb/IIIa complex is less than 5% normal, type II: equivalent to normal 5% to 25%, III Type: equivalent to normal 40% to 100%, the amount is not significantly reduced and the structure is abnormal, is a variant, the current study found that GPIIb and GPIIIa are encoded by different genes, all located on chromosome 17 (17q21-22) GT is due to The gene has been deleted, caused by a point mutation or insertion.
Prevention
Prevention of thrombocytopenia in children
With the prevention of genetic diseases, especially close relatives should be avoided. Prevention should be carried out from pre-pregnancy to prenatal: pre-marital physical examination plays an active role in preventing birth defects. The size of the effect depends on the examination items and contents, including serological examination (such as hepatitis B). Virus, Treponema pallidum, HIV), reproductive system tests (such as screening for cervical inflammation), general physical examination (such as blood pressure, electrocardiogram), and asking about family history of the disease, personal medical history, etc., doing genetic disease counseling work, during pregnancy Pre-health care requires systematic screening of birth defects, including regular ultrasound examinations, serological screening, etc., if necessary, for chromosomal examinations. Pregnant women should avoid hazards as much as possible, including away from smoke, alcohol, drugs, radiation. , pesticides, noise, volatile harmful gases, toxic and harmful heavy metals, etc., in the event of abnormal results, it is necessary to determine whether to terminate the pregnancy. What are the prognosis after birth, etc., and take practical measures for diagnosis and treatment.
Complication
Pediatric thrombocytopenia complications Complications
Homozygous can be complicated by visceral hemorrhage, such as hematuria, gastrointestinal bleeding or even intracranial hemorrhage.
Symptom
Symptoms of thrombocytopenia in children Common symptoms Nasal bleeding Bleeding Hemorrhoids Skin Defects Intracranial hemorrhage Freckles visceral hemorrhage Hematuria gastrointestinal bleeding
The disease is autosomal recessive, so many people in the same family often have onset, heterozygous hemorrhagic is not obvious, homozygous can express skin, mucous membrane self-bleeding or even visceral bleeding, such as skin defects, ecchymosis, nosebleeds , bleeding gums, menorrhagia, hematuria, gastrointestinal bleeding, etc., rare intracranial hemorrhage.
Examine
Examination of pediatric thrombocytopenia
The number and shape of platelets are normal, but they do not accumulate on the blood slices, the bleeding time is prolonged, the blood clots are poorly contracted or not contracted, and the aggregation reaction of platelets to ADP, collagen, adrenaline and thrombin is absent or reduced, but to the Swiss The induced aggregation reaction of vulcan and vWF is normal. If the amount of platelet GPIIb/IIIa complex is reduced or the quality abnormality can be further determined, B-ultrasound is routinely performed, and other choices are made according to clinical needs.
Diagnosis
Diagnosis and diagnosis of thrombocytopenia in children
diagnosis
The revised diagnostic criteria in China in 1986 are as follows.
Clinical manifestation
(1) Autosomal recessive inheritance.
(2) There are bleeding symptoms from childhood, showing moderate or severe skin, mucosal bleeding, there may be more menstruation, bleeding after trauma surgery.
2. Laboratory examination
(1) The platelet count is normal, and the platelets on the blood smear are scattered and do not aggregate into a heap.
(2) The bleeding time is prolonged.
(3) The blood clot is poorly contracted and can also be normal.
(4) platelet aggregation test: adding ADP, adrenaline, collagen, thrombin, arachidonic acid did not cause aggregation; a small amount of collagen, arachidonic acid, thrombin aggregation reaction, ristocetin, aggregation Normal or lower.
(5) The platelet bead retention test was reduced.
(6) Platelet membrane glycoprotein (GP) IIb/IIIa (CD41/CD61) reduced or qualitative abnormalities.
Differential diagnosis
The disease should be differentiated from other platelet counts and normal platelet function-deficient diseases. Some patients with gray platelet syndrome have defects in clot retraction, but platelet aggregation is only mildly abnormal, and platelet alpha-granule secreted protein is absent. Patients with dense particle deficiency Platelet biphasic aggregation was abnormal, but blood clot retraction was normal, hereditary pattern was autosomal dominant, and bleeding time was prolonged in patients with congenital fibrinogenemia, but the coagulation test was abnormal.
