Idiopathic thrombocytopenic purpura in pregnancy

Introduction to pregnancy with idiopathic thrombocytopenic purpura Idiopathic thrombocytopenic purpura (ITP) is a clinical syndrome that increases platelet destruction due to immune mechanisms. It is also known as immune thrombocytopenic purpura. It is the most common thrombocytopenic purpura, characterized by shortened platelet life. Bone marrow megakaryocytes increase and platelet turnover rate accelerates. Clinically, it is divided into acute type and chronic type. Acute type is more common in children, and chronic type is more common in young women. This disease does not affect fertility, so it is not uncommon to have a pregnancy, which is one of the serious complications of obstetrics. basic knowledge Sickness ratio: 1% - 2% Susceptible people: common in young women Mode of infection: non-infectious Complications: intracranial hemorrhage

Pregnancy with idiopathic thrombocytopenic purpura

(1) Causes of the disease

Acute type occurs mostly in the recovery period of viral infection or upper respiratory tract infection. Patients have higher antiviral antibodies in serum and platelet surface related antibodies (PAIgG) are significantly increased.

Chronic type of pre-infection has no obvious history of pre-infection. It is believed that the onset is caused by autoantibodies caused by changes in platelet structure antigens. 80% to 90% of cases have platelet surface-related antibodies (PAIgG, PAIgM, PA-C3, chronic type). In women of childbearing age during pregnancy, and easy to relapse, indicating that estrogen increased phagocytosis and destruction of platelets.

(two) pathogenesis

The pathogenesis of acute ITP has not been elucidated. It may be due to the adsorption of viral antigens on the surface of platelets, which changes the antigenicity of platelet components and binds to the corresponding antibodies produced, resulting in platelet destruction, shortened platelet life, and severe platelet life. In a few hours, platelet surface-associated immunoglobulin (PAIg) is often increased in patients with acute ITP. This increase is mostly transient. When the platelet count starts to rise, PAIg drops rapidly. In addition, the virus can directly damage platelets and destroy platelets. increase.

Studies of histocompatibility antigens in patients with ITP have shown that ITP is particularly prevalent in patients with DR antigens, and HLADR4 (LB4) is closely related to treatment response. These patients have poor efficacy on adrenal cortical hormones, but have a better effect on spleen resection. Good efficacy, some scholars believe that ITP is a manifestation of some immune dysfunction, thrombocytopenia in systemic lupus erythematosus (SLE) is quite common, 7% to 26% of patients with ITP, in contrast, <2% of ITP patients The development will eventually evolve into SLE, and these patients are often positive for ACL (anti-cardiolipin antibodies).

The pathogenesis of chronic ITP has not yet been fully elucidated. Over the past 40 years, studies on ITP platelet-associated antibodies have confirmed that this disease is a group of immune-related diseases.

In 1975, Dixon first detected the immunoglobulin on the surface of platelets by quantitative methods, called platelet-associated antibody (PAIg). It has been confirmed that 80% to 90% of patients with ITP have significantly higher PAIg values than normal controls and non-immune platelets. In patients with reduced purpura, the increase of PAIg is negatively correlated with platelet count and platelet life. PAIg has three types: PAIgG, PAIgM, and PAIgA. In ITP patients, PAIgG is more common, up to 10 to 20 times higher than normal. PAIg The reason for the increase is unclear and may be a non-specific phenomenon. Some diseases related to elevated serum PAIg, such as cirrhosis, have been found, and thus PAIg is not a specific antibody related to ITP.

Complements 3 and 4 (C3, C4, in ITP patients have also been shown to bind to IgG on the platelet surface, increasing platelet-associated C3 and C4 (PAC3, PAC4).

Anti-platelet antibody production is mainly in the spleen. The amount of IgG in the spleen tissue of ITP patients is 5 to 55 times higher than that of normal controls. Platelet-specific IgG can also be detected in bone marrow, and other lymphoid tissues can also produce small amounts of IgG. Recent studies have confirmed In ITP patients, the number of NK cells is normal, but its activity is defective. This defect, together with the abnormality of T cell immunoregulatory function in ITP patients, causes B cells to secrete antibodies, which cause platelet destruction.

At present, it is believed that the main organs that destroy ITP platelets are in the spleen, liver and bone marrow. The role of the spleen in destroying platelets is most important. The platelet-associated antigen antibody specifically binds, and the platelets are retained in the spleen to accelerate the destruction. After the spleen is removed, the bone marrow becomes the main body. In areas where platelets are destroyed, ITP platelets are rarely destroyed in the liver when the antibody titer in the blood is low. If the antibody titer is high and C3b fragments are attached to the platelet surface, platelets can be destroyed in the liver, and platelet-associated antibodies in ITP patients. After binding of the Fab fragment to the relevant antigen, the Fc fragment of the antibody IgG molecule is exposed to bind to the Fc receptor of the macrophage, and the complement is activated during the binding of the antibody to the antigen, resulting in the attachment of C3 lysate C3b to the platelet surface, with C3b platelets bind to the C3b receptor of macrophages in the liver, causing IgG-affected platelets to be phagocytosed and destroyed, and severe platelets can be significantly reduced in a short period of time.

Because chronic ITP is more common in women, and after puberty, menopause is easy to occur, sometimes recurrence during pregnancy, suggesting that estrogen may play a role in the occurrence of this disease, studies in mice found that estrogen can significantly stimulate mononuclear macrophages The phagocytic capacity of the cellular system.

In summary, the occurrence of this disease is mainly due to the presence of immune antibodies in the serum of patients, shortening the survival of platelets, increasing platelet destruction, and reducing thrombocytopenia. In a small number of patients, megakaryocytes may also be affected by antibodies. A qualitative change.

Pregnancy with idiopathic thrombocytopenic purpura prevention

Prevention: Prevent colds, closely observe changes in purple spots, such as density, color, size, etc., pay attention to body temperature, consciousness and bleeding, help to understand the prognosis and outcome of the disease, and then deal with it in a timely manner. Avoid trauma, severe bleeding must be absolutely bed rest. Chronic patients, according to the actual situation, appropriate exercise, avoid seven emotions, maintain a good mood, diet should be soft, if there is gastrointestinal bleeding, should be semi-liquid or fluid, do not eat spicy and spicy food. Spotted itch, can be rubbed with calamine lotion or Jiuhua powder lotion, pay attention to skin hygiene, avoid scratching the skin bow with infection.

Pregnancy complicated with idiopathic thrombocytopenic purpura Complications intracranial hemorrhage

Acute ITP patients with intracranial hemorrhage are 3% to 4%, and those who die from intracranial hemorrhage account for 1%.

Pregnancy with idiopathic thrombocytopenic purpura symptoms Common symptoms Skin purpura skin acne chills thrombocytopenia blood blister intracranial hemorrhage

1. Acute type: It is common in children, accounting for 90% of cases of immune thrombocytopenia. The incidence rate of male and female is similar. 84% of cases 1 to 3 weeks before onset have a history of respiratory infection or other viral infections, so the incidence is the most in autumn and winter. Acute onset, may have fever, chills, sudden and widespread skin and mucous membrane purpura, and even large areas of ecchymosis or hematoma, skin defects are mostly systemic, lower limbs, even distribution, mucosal bleeding is more common in the nose, Gum, oral cavity may have blood blisters, gastrointestinal and urinary tract bleeding is rare, intracranial hemorrhage is rare, but life-threatening, spleen often does not enlarge, platelets are significantly reduced, the course of disease is mostly self-limiting, more than 80% of patients Can be self-relieved, the average duration of disease is 4 to 6 weeks, a few can be delayed for half a year or more, and the acute type accounts for less than 10% of adult ITP.

2. Chronic type: common in young women, women are 3 to 4 times more likely to be male, slow onset or insidious, mild symptoms, frequent recurrent bleeding, each bleeding lasts for several days to several months, bleeding degree and platelets Counting, platelet count> 50 × 109 / L, often after injury, platelet count (10 ~ 50) × 109 / L may have different degrees of spontaneous bleeding, platelet count <10 × 109 / L often have severe bleeding Skin purpura is more common in the distal extremities of the lower extremities. It may have nasal, gingival and oral mucosal hemorrhage. Female menstruation is sometimes the only symptom, and there are also deaths caused by intracranial hemorrhage. This type of spontaneous relief is less, and the patient has a general condition except for bleeding symptoms. Good, a small number of recurrent episodes can cause anemia or mild spleen enlargement, if there is obvious splenomegaly, the possibility of secondary thrombocytopenia should be excluded.

Examination of pregnancy with idiopathic thrombocytopenic purpura

1. The acute type of platelet count is often <20×109/L, and the chronic type is mostly (3080)×109/L. Due to the decrease of thrombocytopenia, the bleeding time is prolonged, the blood clot is poorly contracted, and the beam arm test is positive, except for a large amount of bleeding. , generally no significant anemia and leukopenia.

2. Platelet morphology and function Peripheral platelet morphology may be changed, such as increased volume, special morphology, reduced particles, and too deep staining. The large platelets in the surrounding blood are some naive platelets, which reflects the accelerated platelet turnover.

3. Bone marrow examination The number of megakaryocytes in bone marrow is normal or increased. The number of megakaryocytes in acute type is increased, but the megakaryocytes producing platelets are significantly reduced. The megakaryocytes in chronic type are significantly increased, but the cytoplasm is reduced in granules. Strong, platelet-producing megakaryocytes are significantly reduced or absent, vacuolar degeneration occurs in the cytoplasm, and megakaryocytes in the bone marrow can be reduced in a few patients with refractory ITP who have a long course of disease.

4. Platelet antibody acute type platelet surface-associated antibody (PAIgG) is higher than chronic type, and its elevation is transient. PAIgG has rapidly decreased or even returned to normal before platelet rise. Patients in remission period continue to have high levels of PAIgG. Platelet compensatory destruction, the patient is prone to recurrence, PAIgG decreased to normal after spleen removal, if still elevated, it means that the antibody is produced in the liver, or there is a spleen. In general, the level of PAIgG is related to platelet count, but there is a false Positive or false negative.

According to the condition, clinical manifestations, symptoms, signs, B-ultrasound, X-ray, CT, MRI, liver and kidney function tests.

Diagnosis and differentiation of pregnancy complicated with idiopathic thrombocytopenic purpura

Diagnostic criteria

Clinically, according to the bleeding symptoms of this disease, thrombocytopenia, prolonged bleeding time, physical examination of spleen is not swollen, bone marrow megakaryocytes increase, maturity disorder, anti-small plate antibody increased, exclude secondary thrombocytopenia, the main diagnostic criteria for this disease In 1986, the Chinese Society of Hematology National Conference on Thrombosis and Hemostasis diagnosed the disease as:

1. Multiple tests to check for thrombocytopenia.

2. The spleen does not increase or slightly increase.

3. Bone marrow examination of megakaryocytes increased or normal, there are maturity disorders.

4. Have any of the following 5 items

(1) Prednisone treatment is effective.

(2) The treatment of spleen is effective.

(3) Increased platelet-associated IgG.

(4) Increased platelet-associated C3.

(5) The platelet life measurement was shortened.

Differential diagnosis

Because of the many causes of thrombocytopenia, chronic ITP must be differentiated from chronic thrombocytopenia caused by other causes, such as tumors, systemic lupus erythematosus, rheumatoid arthritis, ulcerative colitis, Evans syndrome, etc. Onset or obvious pathogenic factors, and have corresponding clinical and test characteristics:

1. Systemic lupus erythematosus thrombocytopenic systemic lupus erythematosus is often associated with red blood cell and leukopenia, 14% to 26% of cases with platelet and megakaryocyte reduction, mostly caused by immune abnormalities, idiopathic thrombocytopenia Purpura can be used as a precursor symptom of SLE. After a certain stage, it shows typical SLE performance. The platelet labeled with 51Cr is used to determine its life span. It is definitely excessive destruction. The cause of platelet destruction is related to the presence of anti-platelet antibody in serum. SLE combined with thrombocytopenia Treatment with chronic primary thrombocytopenic purpura, it is believed that spleen can promote the occurrence of potential SLE, but most scholars do not agree.

2. No megakaryocyte thrombocytopenic purpura aplastic anemia, vitamin B12, macrophage anemia caused by folate deficiency, paroxysmal nocturnal hemoglobinuria, intramedullary infiltration of malignant tumors, thrombocytopenia in these patients, The number of megakaryocytes is reduced, although a few can be increased, but platelet life is normal.

3. Microvascular disease accelerates platelet destruction, leading to thrombocytopenia caused by various causes of small vasculitis, cavernous hemangioma, and prosthetic heart valve syndrome, severe infection, etc. In these diseases, thrombocytopenia often accompanied by red blood cell destruction Anemia caused, in addition, there are still the primary disease or the cause of the disease.

4. Spleen function hyperthyroidism makes platelets retain and destroy in the spleen, causing thrombocytopenia. In addition to splenomegaly and thrombocytopenia, there are still leukopenia and anemia, and there are primary diseases such as liver that cause hypersplenism. Hardening, malaria, etc.

5. Evans syndrome This is a syndrome of ITP with immune hemolytic anemia, which can be primary or secondary. In addition to the bleeding symptoms caused by thrombocytopenia, there are signs of jaundice and anemia. Coomb's test is often (+).

6. Thrombotic thrombocytopenic purpura is rare in clinical practice and its characteristics are:

(1) Microangiopathic hemolytic anemia.

(2) thrombocytopenic purpura.

(3) Neurological symptoms.

Any age can occur, often onset, fever, bleeding symptoms, neurological symptoms after onset, manifested as disturbance of consciousness, confusion, numbness, aphasia, convulsions, etc., renal lesions expressed as proteinuria, mirror Lower hematuria, jaundice can occur, there are varying degrees of anemia, laboratory tests: platelet count decreased, hemoglobin decreased to varying degrees, a large number of broken and deformed red blood cells appeared in the blood picture; bone marrow examination showed erythroid hyperplasia, megakaryocyte number was normal or increased; A typical laboratory examination of disseminated intravascular coagulation changes.

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