Pediatric Giant Platelet Syndrome

Introduction to giant platelet syndrome in children Giant platelet syndrome, also known as Bernard-Soulier syndrome (Bernard-Souliersyndrome, BSS), is characterized by mild to moderate thrombocytopenia, increased platelet volume, prolonged bleeding time, and poor prothrombin consumption. Chromosomal recessive platelet adhesion function deficient bleeding disease. basic knowledge The proportion of illness: 0.001% - 0.0025% Susceptible people: children Mode of infection: non-infectious Complications: intracranial hemorrhage anemia

The cause of giant platelet syndrome in children

(1) Causes of the disease

BSS is a chromosomal abnormal disease, the patient platelet membrane glycoprotein GPIb/IX is deficient, GPIb/IX complex is a platelet adhesion essential substance, GPIb is a platelet surface vWF receptor, which is the main receptor for platelet adhesion, and platelets are combined with vWF through GPIb. Adhesion to subcutaneous tissue, due to the lack of GPIb/IX in this disease, leading to abnormal platelet adhesion, accompanied by thrombocytopenia, in addition, the patient's platelet volume increased, diameter > 4m, large like lymphocytes, platelet membrane system was found under electron microscope Abnormalities, intracellular vacuoles, surface attachment systems, dense tube systems, microtubule systems and membrane complexes increase, and large platelet proteins and dense particles also increase.

(two) pathogenesis

The fundamental problem of BSS lies in the defects of platelet membrane glycoprotein GPIb-IX and GPV. Polyacrylamide electrophoresis indicates that this is actually a deficiency. So far, the number of GPIb-IX is abnormal and dysfunctional, and the first part of platelet hemostasis is found. The step is to adhere to the damaged vessel wall. GPIb-IX, which is present in the form of heterodimer on the platelet membrane, is the main adhesion receptor of platelets. Further studies have found that GPIb has two polypeptide chains of and ; The -chain contains a specific receptor for von Willebrand Factor (vWF). In the case of blood flow, GPIb-deficient platelets cannot bind to vWF in the subendothelial matrix, and thus its adhesion function cannot be achieved. The relationship between GPV and GPIb-IX is unclear, may be related to the stability of the membrane, and it is also a protein sensitive to prothrombin on the platelet membrane, which may be the cause of poor prothrombin consumption, and the volume of platelets becomes larger. It is speculated that due to the lack of GPIb-IX complex, the platelet membrane is lost in contact with the cytoskeleton and deformed, so the bleeding performance of BSS is due to GPIb-IX complex. Lack, reduce platelet count, platelet increase easily transported interaction result to the damaged vessel wall, it was also found that the genetic BSS due GPIb and point mutations GP caused.

Pediatric giant platelet syndrome prevention

The giant platelet syndrome in children is an autosomal recessive platelet adhesion-deficient bleeding disorder. Therefore, the pollution impact caused by environmental pollution is serious and far-reaching. Therefore, do a good job of "three wastes", avoid overdose exposure to ionizing radiation, mutagens and teratogens, and promote smoking cessation (already that alcohol and nicotine have damage to germ cells), for a variety of new chemical products Strict mutagenicity testing is carried out before leaving the factory and the necessary restrictions are imposed on its use. This comprehensive environmental protection measure is very important to prevent possible genetic damage.

Pediatric giant platelet syndrome complications Complications intracranial hemorrhage anemia

Severe cases can also be complicated by hematuria or even intracranial hemorrhage, or anemia.

Hematuria refers to 3 red blood cells per high-powered field of view in centrifuged urine, or more than 100,000 urinary red blood cell counts in non-centrifugal urine for more than 1 or 1 hour, or more than 500,000 urine sediment counts in 12 hours, all showing red blood cells in urine Abnormal increase is a common urinary system symptom.

After finding red urine, it is first necessary to distinguish whether it is true hematuria or pseudo hematuria. Some drugs can cause red urine, such as aminopyrine, phenytoin, rifampicin, phenol red, etc.; need to be distinguished from true hematuria. In recent years, there is no obvious accompanying symptom of hematuria, and most of them are glomerular hematuria, which has been widely regarded and studied.

Symptoms of giant platelet syndrome in children Common symptoms Skin defects, thrombocytopenia, skin mucosal bleeding, spot, nosebleed, gastrointestinal bleeding, bleeding gums

Heterozygous may have biological abnormalities such as increased platelet volume, but no hemorrhagic symptoms. There are moderate to severe hemorrhage in homozygotes, and spontaneous hemorrhage of skin mucosa, such as sputum, ecchymosis, epistaxis, bleeding gums, Gastrointestinal bleeding, menorrhagia and so on.

Examination of children with giant platelet syndrome

Decreased platelet count with large platelets, prolonged bleeding time, poor prothrombin consumption, decreased platelet adhesion, varstomycin and human or bovine vWF can not induce platelet aggregation, low concentration of thrombin induces platelet aggregation decreased, such as Membrane glycoprotein determination, can be found in platelet membrane GPIb, IX and V decreased or lack, according to clinical needs, routine B-ultrasound.

Diagnostic identification of huge platelet syndrome in children

diagnosis

The diagnostic criteria for giant platelet syndrome, which was enacted in 1981 in China and revised in 1986, are as follows:

Clinical manifestation

(1) Autosomal recessive inheritance, both men and women can be sick.

(2) mild to moderate skin, mucosal bleeding, and menorrhagia.

(3) The liver and spleen are not swollen.

2. Laboratory examination

(1) thrombocytopenia with large platelets.

(2) The bleeding time is prolonged.

(3) Platelet aggregation test plus ristocetin, no aggregation, plus other attracting agents, the aggregation is basically normal.

(4) The platelet bead retention test can be reduced.

(5) The blood clot shrinks normally.

(6) vWF is normal.

(7) Platelet membrane lacks glycoprotein Ib (GpIb).

(8) Exclusion of secondary giant platelet disease.

Differential diagnosis

1. Platelet weakness syndrome autosomal recessive disease, platelet has functional defects, platelet count and morphology are normal, platelets have no aggregation of ADP, platelet adhesion function is normal, platelet GPIIb/IIIa is lacking,

2. Platelet storage pool disease platelet count and morphology are normal, while platelet dense or reduced, the first phase of aggregation test caused by ADP, etc. is normal, the second phase is lack of aggregation, the disease still needs to be related to other hereditary platelet function Identification of defective diseases and disease-deficient platelet-deficient diseases.

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