giant platelet disease
Introduction
Introduction to giant platelet disease Giant platelet disease is a hereditary disease characterized by thrombocytopenia, giant platelets, prolonged bleeding, and poor prothrombin consumption. The treatment of this disease is basically the same as that of thrombocytopenia. There is no other effective treatment except symptomatic treatment and transfusion of platelets when necessary. As long as supportive treatment and timely infusion of platelets are supported, the prognosis of this disease is still good. basic knowledge The proportion of illness: 0.005% Susceptible people: infants and young children Mode of transmission: mother-to-child transmission Complications: thrombocytopenia
Cause
Cause of giant thrombocytosis
(1) Causes of the disease
The basic defect of this disease is the defect of the platelet membrane glycoprotein GPIb-V-IX complex. The bleeding symptoms caused by this disease may be related to the following factors: thrombocytopenia, abnormal interaction between platelets and vWF, abnormal interaction between platelets and thrombin, platelets Abnormal clotting activity.
The cause of thrombocytopenia is unknown, but the severity of bleeding in this disease is not parallel with the degree of thrombocytopenia, suggesting that abnormal platelet mass is an important factor causing bleeding.
(two) pathogenesis
GPIb-V-IX is present on the surface of platelets and is the main adhesion receptor of platelets. The receptor binds to vWF and adheres to the subendothelial tissues. Due to the lack of adhesion receptors, platelets cannot adhere to the subendothelial tissues, leading to hemostasis, giant platelets. In patients with syndrome, platelet response to thrombin activation is low, especially at low thrombin concentrations. Thrombin is one of the main physiological activators of platelet activation and can bind to GPIb. Studies have shown that GPIb amino acids 239-299 contain The binding sites of thrombin, GPIX and GPV are reduced in the platelets of patients with this disease, and parallel with the decline of GPIb and GPIb. These four proteins are considered to be present in the same complex, and transfection experiments have shown that the cell surface is intact. The expression of the complex must be preceded by the presence of GPIb, GPIb, and GPIX cDNAs, and any abnormality of any of the genes may cause abnormalities in the complex, leading to giant platelet syndrome.
Prevention
Giant platelet disease prevention
There is no effective preventive measure for this disease. Early detection and early diagnosis are the key to the prevention and treatment of this disease.
Complication
Huge platelet disease complications Complications, thrombocytopenia
Giant platelet disease may cause thrombocytopenia.
Symptom
Symptoms of giant platelet disease Common symptoms Thrombocytopena visceral bleeding nosebleeds skin purpura
Heterozygous has no clinical symptoms, only mild biological abnormalities, such as platelet GPIb-IX complex content is half of normal people, homozygous moderate to severe bleeding, the baby can develop within a few days after birth, such as skin purpura, ecchymosis And nosebleeds, severe visceral hemorrhage, joint bleeding, women may have menorrhagia, excessive bleeding after surgery and tooth extraction, the clinical manifestations of this disease can gradually reduce with age, different patients with the same family bleeding The difference in symptoms is also greater.
Examine
Inspection of giant platelet disease
1. Platelet count: moderate to severe reduction, a small number of patients are normal.
2. The platelets are huge, up to the size of lymphocytes, and giant platelets can account for 80%.
3. The adhesion rate of platelets to collagen, glass beads, etc. decreases.
4. The bleeding time that is not parallel to the decrease in platelets is prolonged.
5. Platelet aggregation was normal for ADP, adrenaline, thrombin and collagen, but not for ristocetin and vWF.
6. The blood clot retracts normally and the prothrombin is poorly consumed.
7. Platelet membranes GPIb-IX and GPIb-V are deficient or reduced.
According to the condition, clinical manifestations, symptoms, signs, choose to do ECG, B-ultrasound, X-ray, biochemical examination.
Diagnosis
Diagnosis and diagnosis of giant platelet disease
Diagnostic criteria
The diagnosis of this disease is based on the following:
Clinical manifestation
1 autosomal recessive inheritance, both men and women can be sick;
2 mild to moderate skin, mucosal bleeding, women with menorrhagia;
3 liver spleen is not swollen.
2. Laboratory examination
1 thrombocytopenia with giant platelets;
2 bleeding time is extended;
3 In the platelet aggregation experiment, ristocetin did not aggregate, and other aggregation agents were basically normal;
4 platelet bead retention test can be reduced;
5 blood clot contraction is normal;
6vWF is normal;
7 Platelet membrane lacks glycoprotein Ib.
3. Exclusion of secondary giant platelet syndrome.
4. Need to be differentiated from other diseases with giant platelets, such as May-hegglin abnormalities.
5. The diagnostic criteria for the revision of the National Conference on Thrombosis and Hemostasis of the First Chinese Society of Hematology are as follows:
(1) Clinical manifestations:
1 mild to moderate skin and mucous membrane bleeding.
2 autosomal recessive inheritance.
3 liver spleen is not swollen.
(2) Laboratory inspection:
1 thrombocytopenia with large platelets.
2 bleeding time is prolonged.
3 platelet aggregation test: ristocetin does not aggregate, plus other attracting agents, the aggregation is basically normal.
4 platelet bead retention test can be reduced.
5 blood clots contracted normally.
6vWF is normal.
7 Platelet membrane lacks GPIb.
8 exclude secondary giant platelet syndrome.
Differential diagnosis
The disease needs to be differentiated from other congenital thrombocytopenia and diseases associated with giant platelets, such as: May-Hegglin abnormality, Epstein syndrome, Fechtner syndrome, Montreal platelet syndrome, gray platelet syndrome, etc. Identification of platelet weakness.
