Primary thrombocytosis

disease

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Primary Thrombocytosis Is a group of relatively chronic Myeloproliferative disease It is also called "hemorrhagic", "true" or "idiopathic" thrombocytosis. Similar to other myeloproliferative diseases, this disease is Pluripotent hematopoietic stem cell Clone disease. Characterized by bone marrow Megakaryocyte Dysplasia ， platelet count Significantly higher. main clinical manifestation For bleeding and Thrombosis Tendency.

Di Guglielmo (1920), Epstein and Goedel (1934) first reported this disease. The incidence of this disease is still unclear. Silverstein estimates that there are 10 cases per million people every year, about Polycythemia vera 1/4 of. This disease is mostly seen in adults over middle age, and occasionally in children. Because of blood Automatic analyzer The use of, asymptomatic cases can also be diagnosed, young cases are also increasing. This disease No gender Distribution difference.

TCM disease name: Primary thrombocytosis
Foreign name: primary thrombocytosis
Alias: Hemorrhagic thrombocytosis 、 True thrombocytosis 、 Idiopathic thrombocytosis

Visiting department: blood specialty
Common causes: Clonal proliferation of single abnormal pluripotent stem cell
common symptom: Spontaneous bleeding tendency and/or thrombosis

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pathogeny

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Primary thrombocytosis is caused by a single abnormality Pluripotent stem cell Clonality Diseases caused by proliferation. The nature of cloning is established because in a female case of this disease Red blood cell line Found in Glucose-6-phosphate dehydrogenase One of (G-6-PD) isozyme , showing G-6-PD two types of "A" and "B" Heterozygote 。 Erythrocyte and granulocyte of another patient Progenitor cell The same exception was found in. Main disease Phenotypic expression stay Meganucleus -The cause of platelet lineage is unknown, which may be related to the abnormal cloning of megakaryocyte platelet lineage Regulatory factor existence Preponderant response Related, possibly Mutagenesis The differentiation of pluripotent stem cells mainly tends to megakaryocyte platelet line. Histology Inspection and Megakaryocyte In vitro culture showed abnormal expansion of megakaryocyte progenitor cells in bone marrow. In vitro culture of megakaryocyte colony forming units in patients' bone marrow and blood（ CFU -MEG) is significantly more than that of normal persons or secondary thrombocytosis controls, and may be accompanied by abnormal CFU-MEG clone size and nuclear Intranuclear replication , at none Exogenous growth factor CFU-MEG often grows when it is added. A few cases are also accompanied by granules- monocyte Colony forming unit And the number of RBC colony forming units.

The number of megakaryocytes and the average megakaryocyte volume were increased in this disease. Thrombopoiesis It can reach 15 times of normal speed. Platelet life Usually normal, the shortening in a few cases may be caused by the destruction of platelets by the spleen. The mechanism of massive thrombocytosis leading to hemorrhage and thrombosis is uncertain. It is generally believed that abnormal platelet function is the main cause of bleeding. Some patients Coagulation factor Reduction may be one of the reasons. A significant increase in the number of platelets leads to a high Aggregation Thrombosis. platelet Intrinsic defect It is shown in platelet 5-hydroxytryptamine Decreased platelet adhesion function Adenosine diphosphate (ADP) and adrenaline Induced platelet aggregation Reduced function, etc. The megakaryocyte proliferation of this disease is not only in bone marrow, but also in extramedullary tissues. Hyperplasia foci dominated by megakaryocyte lines can appear in liver, spleen and other tissues. Due to the low degree of malignancy, Growth rate The liver and spleen are often moderately enlarged. so far Not found External pathogenic factors related to this disease.

clinical manifestation

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The course of primary thrombocytosis is slow, and many patients have no symptoms for a long time Blood cell test The use of instruments increases the chances of diagnosing asymptomatic cases. Main causes of the disease clinical manifestation Hemorrhage and thrombosis. Unlike other myeloproliferative diseases, fever hyperhidrosis Weight loss is very rare. About 40% patients only found splenomegaly on physical examination, which was generally mild or moderate enlargement. Spleen atrophy and Splenic infarction 。 Lymph node enlargement Rare.

Bleeding can be spontaneous, or it can be caused by trauma or surgery. Spontaneous bleeding is more common in nasal, oral and gastrointestinal mucosa. Urinary tract 、 respiratory tract There may also be bleeding in other parts. cerebral hemorrhage Occasionally, it may cause death. The bleeding symptoms of this disease are generally not serious, but severe trauma or postoperative bleeding may endanger life. Aspirin or other anti-inflammatory drugs can cause or aggravate bleeding.

Thrombosis occurs in Elderly patients It is easy to see in young patients. Arteries and veins can occur, but arterial thrombosis is more common. Cerebrovascular, splenic vascular mesentery Blood vessels and blood vessels of fingers and toes are the predilection sites. Thrombosis usually occurs in small blood vessels, but it can also occur in Large blood vessel 。 Blockage of blood vessels in fingers or toes may occur Local pain , burning sensation Redness and swelling And heating, which can develop into Cyan violet Or necrosis. Cerebral vascular thrombosis often causes nervous system Symptoms, Temporary cerebral ischemia 、 Visual impairment 、 Sensory disturbance 、 headache 、 dizzy , insomnia, etc, Cerebrovascular accident It also happens. Pulmonary thrombosis and miocardial infarction All occur. Habitual abortion and Abnormal erection of penis There are also reports. skin Itch Authenticity Polycythemia Rare.

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Platelet count exceeds 600 × 10 nine /50. Most patients exceed 1000 × 10 nine /50. There have been 14000 × 10 cases nine /L。 Platelets often have abnormal morphology: giant platelets, platelets with strange morphology, platelets with light blue staining, and platelets with reduced particles can be seen. The mean platelet volume increased. Megakaryocyte fragments may also appear in blood smears. Red blood cells are usually normal, and cases of chronic blood loss may present as small cell hypochromic anemia. existence Splenic atrophy Can appear Hao Zhou Corpuscle Target red blood cell And deformed red blood cells. Available Mild anemia Hemoglobin is rarely lower than 100g/L. In some patients, the hemoglobin can be increased, but the red blood cell volume is normal. The white blood cell count is often increased, usually 15~40 × 10 nine /L。 Occasionally visible Neutrophil and Late granulocyte 。 Neutrophil alkaline phosphatase The integral is generally normal and occasionally decreases or increases.

The proliferation of bone marrow is active or obviously active, the number of megakaryocytes is significantly increased, and the number of primitive and immature megakaryocytes is increased, the latter is preferred. Megakaryocytes can appear in clusters, and platelets often gather in piles. Most patients do not cytogenetics Some cases have abnormal chromosomes. If Ph chromosome or Bcr/Abl fusion gene appears, it is chronic myeloid leukemia. Although these reported cases do not have chronic myeloid leukemia white blood cell Significant increase and other characteristics, but the development of the course of disease is more inclined to chronic myeloid leukemia, most cases die of accelerated or acute change.

The life span of platelets in this disease is generally normal, sometimes slightly shortened. Platelet function may decrease, especially the platelet aggregation induced by adrenaline. It can also occur due to enhanced platelet aggregation function spontaneity gather. The bleeding time can be normal or slightly prolonged. Coagulation test is usually normal. Plasma von Willebrand factor in some cases（ Von Willebrand factor ）Lower level or Subunit Structural anomaly 。 Other platelet defects include Compact body Number reduction and its Contents ADP、 Adenosine triphosphate （ ATP ）And 5-hydroxytryptamine（ Acquirability Storage pool disease), α- Adrenergic receptor Decreased, damaged membrane coagulation activity, Cyclooxygenase Reduced activity, membrane glycoprotein Exceptions Fc receptor Enhancement, prostaglandin D two The decrease of receptor was reported. But these defects have not been proved to stop bleeding complication The connection between.

Blood uric acid And vitamin B twelve Always increase. Some patients have false Hyperkalemia It is related to the destruction of a large number of platelets and the release of potassium.

diagnosis

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Causeless platelet This disease should be considered in case of significant increase, and others should be excluded Myeloproliferative disease and Secondary thrombocytosis Then it can be diagnosed. Murphy et al diagnostic criteria For reference: ① platelet count Above 600 × 10/L; ② hemoglobin ≥ 130g/L or red blood cell Normal capacity (male<36ml/kg, female<32ml/kg); ③ bone marrow Iron staining Normal or Ferrocene The trial treatment was ineffective (hemoglobin increased less than 10g/L after one month of iron treatment); ④ No Ph chromosome; ⑤ bone marrow Pathological examination nothing Collagen fiber , or none Splenomegaly , childish Granulocyte And red blood cells Reaction time Collagen fiber is less than 1/3 of biopsy area; ⑥ Nonreactivity Thrombocytosis 。

differential diagnosis

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Differentiation between this disease and other myeloproliferative diseases: authenticity Erythrocytosis The syndrome is easy to differentiate when erythrocytosis and erythrocyte volume increase, and when iron deficiency occurs Blood volume When the increase is not obvious but the platelet is significantly increased, iron can be used to treat the typical characteristics of polycythemia vera. It is sometimes difficult to differentiate chronic myeloid leukemia with marked thrombocytosis, but the examination of Ph chromosome or Bcr/Abl fusion gene is enough to distinguish it. Primary myelofibrosis Splenomegaly Significant and typical Extramedullary hematopoiesis ， Blood smear There were immature granulocytes and erythrocytes, and extensive collagen fibers were found in bone marrow pathological examination. There are characteristic differences in myeloproliferative diseases, which are not difficult to differentiate. Occasionally, some cases show "overlapping" syndrome that is difficult to differentiate.

Secondary thrombocytosis should be excluded from this disease. See Table 1 for key points of differentiation.

Table 1 Primary Differential diagnosis of thrombocytosis and secondary thrombocytosis

Secondary thrombocytosis Primary thrombocytosis

Cause of disease secondary to certain pathology or Physiological factors Unknown

The disease period is usually temporary and persistent

Bleeding and thrombosis are rare and common

Splenomegaly often occurs

Platelet count<1000 × 10/L can>1000 × 10/L

Platelet morphology and function are normal or abnormal

White blood cell count Normal 90% patients increase

Bleeding time Normally extendable

The number of megakaryocytes increased slightly and significantly

Decreased and increased mean megakaryocyte volume

treatment

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It is still controversial whether the treatment of asymptomatic primary thrombocytosis is to reduce platelet count. In general, there is little evidence that long-term antiplatelet therapy can improve the prognosis 。 There is consensus that reducing platelets can improve symptoms in patients with bleeding or thrombosis. The patient has fingers and toes capillary ischemia or Cerebrovascular In case of ischemic symptoms, antiplatelet therapy should be actively carried out. The goal is to reduce megakaryocyte proliferation and platelet production.

Available for patients with acute and dangerous bleeding or thrombosis Blood cell separator Apheresis platelets 。 This method reduces platelets for a short time, and then rebound occurs, which needs to be connected with bone marrow inhibitor Collaborative use. 32P and alkylating agent such as Mar flange Marilan 、 Thiotepa 、 Phenylpropionic acid Nitrogen mustard In the past, it was used more often, but now it tends to give up, because it may cause leukemia.

Hydroxyurea Non alkylating agent Myelosuppression It has a good effect on this disease. The starting dose is 10-30mg/kg per day. Since it can cause rapid myelosuppression, it should be checked within 7 days Blood cell count And monitor later. Maintenance dose Individualization is required, and the dosage is adjusted according to the blood cell count. About 80% of patients can reduce the number of platelets to below 500 × 10/L within 8 weeks, and can control the number of platelets for a long time.

The inhibition of hydroxyurea on bone marrow is mild, and severe bone marrow suppression can be avoided by adjusting the dosage. Some patients have mild Gastrointestinal reactions , some patients may appear Oral mucosa Ulcer. Similar to other chemotherapy drugs that can increase the incidence of leukemia, hydroxyurea also has side effects that can increase the incidence of leukemia. In patients with primary thrombocytosis treated with hydroxyurea Acute myeloid leukemia and Myelodysplastic syndrome A large proportion of them are characterized by chromosome 17p deletion and other 17p syndromes.

Anagrelide (imiquidone) is very effective in reducing platelet count and is now one of the first-line drugs. It can reduce platelets by inhibiting the maturation of bone marrow megakaryocytes. The dosage required for platelet control is generally about 2.0~3.0mg/d, about 11 Tianke Reduce platelet count by half. This medicine does not affect the white blood cell count, and a small number of patients may have a slight decrease in blood volume. Platelet count of patients can be well controlled during medication, but most patients' platelet count rises rapidly after drug withdrawal. Side effects include neurological and gastrointestinal symptoms palpitation and Fluid retention 。

recombination Alpha interferon It is an effective drug for treating this disease, which can inhibit the differentiation of abnormal megakaryocyte clones, reduce the size and multiplication of megakaryocytes. Most patients use Interferon therapy After one month, the platelet count can be reduced to normal or close to normal. Start dose subcutaneous injection interferon 3 million units per day. After the platelets are close to normal Therapeutic response and Tolerance Adjust the dose, and then use a smaller dose of subcutaneous injection three times a week for many years. Platelets may increase and recur after discontinuation of use. Mainly influenza Such side effects can be fever , joint Muscle soreness Etc., reduce dosage or relieve fever anodyne It can be alleviated or alleviated. Interferon treatment may be accompanied by a decrease in leukocyte count.

aspirin Is valid Adjuvant therapy Drugs are especially effective for finger and toe ischemia and cerebrovascular ischemia. The disadvantage is that some patients can cause serious bleeding, which significantly prolongs the bleeding time, so it needs to be used carefully.

prognosis

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main Cause of death Serious bleeding and Thrombosis 。 Some cases can be transformed into chronic granulocytes leukemia 、 Myelofibrosis Or polycythemia vera, which can be converted to acute leukemia 。 32P or Alkylating agent etc. Chemotherapy drugs Treatment may increase the transformation to leukemia. The survival curve of patients with primary thrombocytosis is similar to that of normal people of the same age Good prognosis 。

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