Hypersplenism
Introduction
Introduction to hypersplenism Hypersplenism (referred to as splenic spleen) is a syndrome of splenomegaly and cytopenia caused by different diseases. The clinical manifestations are splenomegaly, one or more kinds of blood cells are reduced, and bone marrow hematopoietic cells are correspondingly hyperplasia, which can be removed by splenectomy. However, after the treatment of the disease, the clinical symptoms of some cases can be alleviated. It is generally believed that hypersplenism is accompanied by different degrees of spleen enlargement. This enlarged spleen has a retention effect on blood cells and hyperplasia of the spleen sinus. Enhance the phagocytosis and destruction of blood cells, which is an important reason for the clinical manifestations of hypersplenism. After the spleen is removed, the clinical symptoms can be corrected. Mainly due to splenomegaly and cytopenia and corresponding symptoms, the nature and size of the spleen vary according to the primary disease, to the late spleen can be significantly enlarged, blood cell reduction can lead to anemia, infection and bleeding, and some patients although white blood cells or The number of platelets is very low, but the signs and symptoms of infection or bleeding are not necessarily obvious or very mild. basic knowledge The proportion of illness: 0.025% Susceptible people: no special people Mode of infection: non-infectious Complications: anemia
Cause
Cause of hypersplenism
Primary splenomegaly (30%):
Primary person refers to a series of manifestations of basic diseases that have not been determined, but clinically have hypersplenism. There are so-called primary spleen hyperplasia, non-tropical idiopathic splenomegaly, and primary splenic granulocytes. Primary spleen whole blood cell reduction, spleen anemia or splenic thrombocytopenia, due to unknown etiology, it is difficult to determine whether the disease is a different disease caused by the same cause or an independent disease that is not related to each other.
Secondary splenomegaly (30%):
Secondary to the spleen, which affects the spleen due to diseases other than the spleen, leading to hypersplenism, most of the primary diseases have been diagnosed clearly, and more clinically seen secondary hypersplenism, including the following The cause is more clear:
1, acute infection with splenomegaly: such as viral hepatitis or infectious mononucleosis.
2, chronic infections: such as tuberculosis, brucellosis, malaria and so on.
3, congestive splenomegaly portal hypertension: intrahepatic obstructive such as portal cirrhosis, necrotizing cirrhosis, biliary cirrhosis, hemosiderosis, sarcoidosis, and extrahepatic obstructive There is external pressure or thrombosis of the portal vein or splenic vein, and so on.
4, inflammatory granuloma such as systemic lupus erythematosus, rheumatoid arthritis, Felty syndrome and sarcoidosis.
5, malignant tumors such as lymphoma, leukemia and cancer metastasis.
6, chronic hemolytic diseases such as hereditary spherocytosis, autoimmune hemolytic anemia and marine anemia.
7, lipidoidosis such as Gaucher disease and Niemann-Pick disease.
8, myeloproliferative disorders such as polycythemia vera, chronic myeloid leukemia and myelofibrosis.
9, other: such as splenic aneurysm and cavernous hemangioma.
Occult spleen (20%):
Regardless of primary or secondary splenomegaly, because the bone marrow compensatory hyperplasia is good, the peripheral blood picture does not show blood cell reduction, but once infected or drugs and other factors inhibit hematopoietic function, it can lead to single or whole blood cell cytoreduction.
Pathogenesis
Although the pathogenesis of hypersplenism still needs further investigation, according to the physiological functions of the spleen, there are several theories:
1. Excessive retention: The blood vessels in the spleen are rich and the structure is special. The blood cells are in the sinusoids and the spleen and cords are retained for a long time. The sinus cells and the macrophages in the red pulp are rich in the blood cells filtered by them. , the performance of retention, under normal circumstances, most of the blood cells that are blocked are aging, congenital morphological abnormalities, abnormal hemoglobin structure, cells damaged by oxidized substances or encapsulated by antibodies, these blood cells are usually in the spleen The internal resistance is retained and destroyed. There is no red blood cell or white blood cell storage in the normal spleen, but about 1/3 of the platelets and some lymphocytes are blocked in the spleen. When the spleen has pathologically significant swelling, not only more Platelets 50% to 90%, and lymphocytes are retained in the spleen, and more than 30% of red blood cells are retained in the spleen, resulting in a decrease in platelets and red blood cells in the surrounding blood.
2, excessive screening and phagocytosis: spleen spleen mononuclear-macrophage system is overactive, while spleen cord abnormal red blood cells such as spherical cells and antibodies, oxidants or other chemical poisons, physical factors damaged red blood cells, etc. Increased, and cleared by macrophages, resulting in a significant reduction in red blood cells in the surrounding blood, some erythrocyte membranes appear hydantoplasts, or there are gluten-like bodies in the pulp, and even the trophozoites of the malaria parasite. When the spleen enters the sinus, the common red blood cells are dilemma due to the inclusion of the hydantoplast or the giant-gel body in the small hole of the sinus base membrane, and finally the sinus wall macrophage is excavated, and the erythrocyte membrane is damaged. After repeated damage, the red blood cells become spherical cells, and eventually cannot be swallowed through the small pores of the basement membrane.
3, body fluid factors: Some scholars have suggested that the spleen can produce certain secretin to inhibit the formation and maturation of bone marrow blood cells, and also inhibit the release of mature blood cells in the bone marrow. Once the inhibitory factor is removed, the abnormal performance of bone marrow cells quickly returns to normal. It has been proved that: 1 spleen leachate can be injected into animals to reduce blood cells. 2 patients with spleen after the increased tolerance to radiation therapy and chemotherapy, may be the result of removal of body fluid factors.
4. Immune factors: It is considered that hypersplenism is a type of autoimmune disease. The spleen can produce antibodies, destroying its own blood cells, and reducing peripheral blood cells. The bone marrow has compensatory hyperplasia, such as immune thrombocytopenic purpura. And autoimmune hemolytic anemia, the spleen is the main place to produce antibodies, but also the place to destroy blood cells, when the spleen is removed, the blood and bone marrow often tend to improve.
5. Dilution: When the spleen is enlarged, the total plasma volume is also significantly increased, which can dilute the blood and cause blood cells to decrease. The anemia is the result of the double action of pseudo-anemia caused by the retention and dilution of the spleen on blood cells. The enlarged spleen can correct the dilute anemia and restore normal plasma volume.
Prevention
Prevention of hypersplenism
Actively prevent cirrhosis caused by various causes (especially schistosomiasis cirrhosis), chronic infections such as malaria, tuberculosis, malignant tumors such as lymphoma, chronic lymphocytic leukemia, myelofibrosis and chronic hemolytic anemia and rare nets Endothelial cell disease.
Complication
Hypersplenism complications Complications anemia
1, spleen embolism, inflammation around the spleen, visible left upper abdomen or left lower chest pain, and with the increase in breathing, local tenderness and friction, can be heard and rubbing sound.
2, combined with various infections, the main reason is the reduction of white blood cells.
Symptom
Symptoms of hypersplenism Symptoms Hepatosplenomegaly, spleen and kidney yang deficiency bleeding, nose yellow or brown granulocytes, reduction of whole blood cells, thrombocytopenia, dizziness, palpitations
The clinically seen hypersplenism is mostly secondary, so its outstanding performance has two aspects:
1, the performance of the primary disease
Depending on the disease, the performance is also different. Commonly, portal hypertension caused by cirrhosis - congestive splenomegaly, with or without splenomegaly, may or may not be associated with liver dysfunction.
2, the performance of hypersplenism
Mainly due to splenomegaly and cytopenia and corresponding symptoms, the nature and size of the spleen vary according to the primary disease, to the late spleen can be significantly enlarged, blood cell reduction can lead to anemia, infection and bleeding, and some patients although white blood cells or The number of platelets is very low, but the signs and symptoms of infection or bleeding are not necessarily obvious or very mild, but if accompanied by liver dysfunction or coagulopathy, more severe bleeding symptoms may occur, and spleen hyperfunction usually has spleen Swollen, but not all splenomegaly have spleen hyperfunction, the more obvious spleen tissue enlargement, the more severe the degree of spleen hyperactivity, so the spleen enlargement has a certain relationship with the degree of hypersplenism, but it is not absolute Parallel relationship.
Examine
Examination of hypersplenism
1, peripheral blood: red blood cells, granulocytes and thrombocytopenia, can also be a reduction in a single series of cells.
2, bone marrow: hematopoietic cells have compensatory hyperplasia, and some have cell maturation disorders.
3. After spleen resection: blood and bone marrow can be restored or close to normal, and the spleen should be confirmed by cytopathological examination.
Further diagnosis of the primary disease of the spleen function is more important, and the following tests should be performed according to the conditions and needs.
1, ultrasound imaging
At the time of physical examination, if the spleen is not accessible under the rib arch, ultrasound imaging should be further performed. Ultrasound imaging can accurately detect the size, thickness and nature of the spleen, and assist in the diagnosis of the relationship between the lesions in the spleen and adjacent organs. The value of the current ultrasound imaging level and its clinical application have played an important role in the diagnosis of splenomegaly itself and the diagnosis of primary disease. Some diseases are not completely dependent on further nuclides. Therefore, some scholars believe that In most cases, ultrasound imaging of the viscera can partially replace CT and radionuclide examinations.
2. Computerized tomography (CT)
CT can measure the size of the spleen, and can also find deep and superficial lesions of the spleen, such as lymphoma. CT often shows a circular or irregular uneven macroscopic shape in the spleen, low density and blurred boundary. The spleen angiosarcoma appears to be round and has an uneven shape of the oval. Spleen infarction manifests as single or multiple triangular or wedge-shaped low-density areas. Simultaneous CT examination of spleen and liver can further reveal the relationship between liver size and nature and spleen.
3. Nuclear resonance imaging (MRI)
This is a biomagnetic nuclear spin imaging technique that displays similar changes in CT imaging. It primarily measures the distribution of fluids in the body, the chemical structure and the velocity of blood flow to show its internal structure and its changes. Such as edema, bleeding and tumors, especially in the detection of portal vein or splenic vein changes have a certain significance.
4. Application of radionuclide in hypersplenism
(1) Measurement of spleen volume: Injecting red blood cells into the blood circulation with 51Cr, then measuring the clearance rate of red blood cells in the blood circulation, and measuring the red blood cell retention index in the spleen. Different splenomegaly patients have different erythrocyte retention ability. The normal value is 0, 15O, 30ml/g. Some people think that the spleen caused by cirrhosis, the volume of spleen is obviously increased, the ability to retain red blood cells is also enhanced, and the ability of spleen to retain red blood cells can be used as one of the indicators of hypersplenism. Some scholars applied a plane scintillation map to measure the spleen volume, and designed a formula for calculating the spleen volume:
V=F3/2
Where: Vthe spleen volume to be sought; Fthe body surface area of the spleen; the constant obtained by practice 0, 30, with an error of about 10%.
(2) Determination of red blood cell life: commonly used tracer is 51Cr, intravenous injection of 51Cr red blood cell suspension, the fluorescence activity of the precordial area, spleen area and liver area were measured by scintillation probe, and then the same position in 24 h and the next day. The measurement is performed until the radioactivity of the precordial region is reduced by half or the outer half of the red blood cells. The normal spleen/liver ratio is 1:1, the spleen/heart ratio is 1, 5:1, and the liver/heart ratio is less than 1:1. When the spleen is enlarged, the spleen/liver is increased to 2:1. When the spleen hyperfunction causes hemolytic anemia, it is 3:1 to 4:1. It is generally considered that the spleen/liver ratio is 2:1, which is already hypersplenism and normal. The human red blood cell half-preservation period (T1/2) is 26 to 40 days, and the survival time is 110 to 120 days. When the spleen function is hyperthyroidism, the red blood cell T1/2 is significantly shortened. Wuhan Union Medical College Hospital has 51Cr for 34 patients with advanced schistosomiasis. The half-life of red blood cells was determined to be 10, 5 to 19 days, with an average of 19 and 89 days, which was lower than the half-life of normal red blood cells.
(3) Spleen imaging: 99mTC heat-denatured red blood cells, 113In-heat-denatured red blood cells or 51Cr-heat-denatured red blood cells are often used. The purpose of spleen imaging examination is to determine the location, size, spleen mass and pathological properties of the spleen and the presence or absence of spleen. Such as diagnosis, 111In-platelet or 111In-leukocyte can also be used for the examination of spleen imaging, but because of the expensive price of 111In, it is still not widely used in China. Simultaneous labeling with 51Cr and 59Fe can detect the location and quantity of cell destruction and cell production. .
Diagnosis
Diagnosis and differentiation of spleen hyperfunction
diagnosis
Diagnosis of hypersplenism depends on the following indicators, which can generally be diagnosed.
(1) Spleen enlargement In most cases, the spleen is swollen. For those who have not touched the spleen under the ribs, further examination should be carried out to confirm whether the swelling is large. Apply spleen area after injection of 99m , 198 gold or 113m indium colloid. Scanning helps to estimate the size and shape of the spleen. Computerized tomography can also measure spleen size and spleen lesions, but the degree of splenomegaly is not necessarily proportional to the degree of hypersplenism.
(B) blood cells reduce red blood cells, white blood cells or platelets can be reduced alone or simultaneously, in general early cases, only white blood cells or thrombocytopenia, complete cases of complete blood cell reduction.
(3) Bone marrow is a hematopoietic cell hyperplasia. In some cases, maturity disorders may also occur at the same time. It may also be due to the destruction of a large number of peripheral blood cells, and the release of mature cells is excessive, resulting in a similar maturity disorder.
(D) changes in splenectomy after splenectomy can make the number of blood cells close to or return to normal, unless the bone marrow hematopoietic function has been impaired.
(5) Radionuclide scanning 51Cr-labeled platelets or red blood cells were injected into the body and scanned on the body surface. It was found that the amount of 51Cr in the spleen area was 2 to 3 times higher than that in the liver, suggesting that platelets or red blood cells were destroyed excessively in the spleen.
Differential diagnosis
It mainly involves the differential diagnosis of splenomegaly and the differential diagnosis of cytopenia. The former is mainly the identification of various secondary spleen and spleen. The latter needs to be distinguished from other various blood cells in addition to the identification of various secondary splenomegaly. Reduced identification, including aplastic anemia, non-leukemia leukemia, myelodysplastic syndrome, paroxysmal nocturnal hemoglobinuria, multiple myeloma, megaloblastic anemia, chronic renal failure, etc., and chronic renal failure Identification, detection of serum creatinine, urea nitrogen, can be clearly distinguished.
