Splenic aneurysm
Introduction
Introduction to splenic aneurysms Splenic aneurysms are the most common aneurysms in visceral arteries, accounting for more than 50% of abdominal visceral aneurysms. Although it is not a tumor in nature, it is still clinically advocated to classify it as a benign tumor of the spleen. The incidence of splenic aneurysms is low and difficult to diagnose, so most of them are not noticed. They are only discovered during surgery or pathological anatomy. . Although splenic aneurysms are rare, the actual incidence is higher than currently known. basic knowledge The proportion of illness: 0.03% Susceptible people: no special people Mode of infection: non-infectious Complications: rupture of abdominal aortic aneurysm
Cause
Cause of splenic aneurysm
Congenital arterial tissue defects (10%):
According to pathological examination in 1947, Casgrove believed that the atrophy and defect of the middle layer of the splenic artery and the elastic fiber layer are the important causes of the formation of splenic aneurysms. In addition, the splenic aneurysm can exist simultaneously with other aneurysms in the body, such as the common main. Aneurysms and intracranial aneurysms, but this multiple aneurysm accounts for only about 10% of all cases of splenic aneurysms. Therefore, congenital arterial structural defects cannot fully explain the cause of the disease. Some authors have proposed so-called central fibers. Dysplasia (medial fibrodysplasia) is one of the causes of splenic aneurysm formation.
Portal hypertension (10%):
A group of 229 cases of splenic aneurysms, 20% with cirrhosis, portal hypertension, Owens group of 159 cases, also have the same proportion of portal hypertension patients, a group of 220 cases of portal hypertension in China, 73 cases Surgical treatment, 2 cases of splenic aneurysms were found, indicating that portal hypertension has a certain relationship with the occurrence of splenic aneurysms.
Arteriosclerosis (8%):
Of the 159 splenic aneurysms collected by Owens, 96 (60%) had atherosclerotic lesions in the splenic artery, and the arterial intima was hyaline degeneration or calcification. The splenic artery was twisted and twisted, mostly in elderly patients.
Trauma (5%):
Especially the upper abdominal penetrating injury or gunshot wounds, such as the injury to the splenic artery, can cause the disease.
Pregnancy (3%):
Pregnancy has an important relationship with the occurrence of splenic aneurysms. According to statistics, splenic aneurysms occur mostly in women, and the incidence rate can be 2 to 4 times higher than that of men. Especially in women with multiple pregnancies, about 20% of patients with splenic aneurysms are pregnant. Women, this is enough to explain the relationship between the two, but the exact cause is still unclear, whether due to changes in secretion during pregnancy and hemodynamic changes caused by arterial disease, is not completely certain.
Heart valve disease and splenic artery embolization (5%):
About 23% of patients with splenic aneurysms underwent pathological examination and found emboli formation in the splenic artery, and most of these patients had heart valve disease.
Splenic arteritis (3%):
Systemic arteritis or simple splenic arteritis causes hyaled degeneration of the arterial wall, and even fibrinous necrosis, the wall of the tube is fragile, prone to local arterial wall dilatation, and gradually develop into a splenic aneurysm.
Syphilis (2%):
It is a component of systemic syphilis infection.
Fungal infection (5%):
It is characterized by local splenic artery disease.
Inflammatory process involving splenic artery wall (5%):
Such as acute pancreatitis, occasionally can induce splenic aneurysms.
In summary, the formation of splenic aneurysms is likely to be the result of a combination of factors, but women, especially women with multiple pregnancies, are high-risk groups of this disease.
Pathogenesis
The mechanism of spleen aneurysm is still inconclusive. According to the study of hemodynamics and artificial blood circulation pattern, the first is that the normal arterial repair factor and the injury factor are out of balance, the latter has an advantage, and secondly, the splenic artery is partially narrow, although There is no damage to the arterial wall, but it can also lead to aneurysm. In portal hypertension, the pressure of the spleen vein is obviously increased, the wall of the wall is dilated, and it is characterized by buckling and nodular expansion, and even the tumor itself can have sinus. Expansion and fibrous tissue hyperplasia, this will inevitably lead to increased splenic artery pressure, thickening of the tube, hardening of the wall, fibrosis, uneven thickness of the arterial wall, narrowing of the tube diameter in the thickened area, cystic dilatation in the weak area, formation of aneurysm .
Generally seen in splenic aneurysms, cystic dilatation or spherical dilatation of different degrees of splenic arteries, diameter 0.6-3.0 cm, average 2.0 cm, microscopic examination of arteriosclerosis, vascular fibrosis or necrosis, inner layer Elastic fibers are calcified, overlapping, ruptured, and even disappearing.
According to the location of the tumor, it can be divided into 3 types:
1 away from the spleen type: the tumor is located in the trunk of the splenic artery, more than 5cm from the spleen;
2 near spleen type: the tumor is located on the splenic artery branch of the spleen, even extending into the spleen parenchyma;
3 intermediate type: between the above two, the tumor is located between the trunk and branches of the splenic artery, this type is more common.
The majority of splenic aneurysms are single-shot, and the multiple tumors are small. The diameter of the tumor is more than 2.0cm. There is a risk of rupture. The incidence of rupture of the spleen aneurysm is about 3%. Once the rupture occurs, the mortality rate is higher. Before the rupture, the arterial wall has a fissure first, followed by a local hematoma. If the process is slow, the hematoma is not large, and the adhesion may form with the surrounding area for a long time. If there is an increase in abdominal pressure, trauma, blood pressure, etc., it can be induced. The tumor is ruptured.
Prevention
Splenic aneurysm prevention
Visceral aneurysms are relatively rare vascular diseases, which are often missed in clinical practice. About 22% of patients have visceral aneurysms when the aneurysm ruptures. The mortality rate of aneurysm rupture is about 8.5%, so clinicians Knowledge of visceral aneurysms can help diagnose and treat this disease as early as possible, which is the key to lifting the disease's life threat to patients.
Complication
Splenic aneurysm complications Complications abdominal aortic aneurysm rupture
The most dangerous complication of splenic aneurysms is massive hemorrhage caused by acute tumor rupture. A group reports that spleen aneurysm rupture during pregnancy, fetal mortality is greater than 95%, maternal mortality is greater than 70%, and other conditions (non-pregnant) occur The spleen aneurysm rupture mortality rate is greater than 25%.
Symptom
Symptoms of splenic aneurysm Common symptoms Upper abdominal pain, nausea, splenomegaly, right side of the right side of the right waist... Cat asthmatic ascites
Symptoms of splenic aneurysms can be upper abdominal pain, paroxysmal colic, nausea, vomiting, splenomegaly, and even intestinal obstruction; about 10% of cases can reach the mass, 6% have pulsation and cat asthma, but there are Cases may not have obvious symptoms until the aneurysm ruptures into the stomach, intestines or abdominal cavity, and the diagnosis is made by surgical exploration. Less than 10% of the cases are diagnosed correctly before rupture, and the symptoms after rupture have severe pain in the upper abdomen. Left shoulder radiation pain (Kehr sign) and abdominal wall pain under the left costal margin, accompanied by nausea, vomiting and other bleeding manifestations, splenic aneurysm can also form internal hemorrhoids with the portal system, causing ascites, hepatosplenomegaly Such as portal hypertension.
Examine
Examination of splenic aneurysms
1. Abdominal plain film and angiography
The onset of the disease is concealed, so the vast majority of patients are occasionally found to have this disease in a non-targeted abdominal examination. The typical sign is a curve of the left upper abdomen or a circular calcification. At present, angiography is still a diagnosis. The "gold standard" of visceral aneurysms, which can reveal the exact location of an aneurysm and help to determine whether there are other aneurysms. When the aneurysm is located in the trunk of the large vessel, the contrast pressure and flow rate should be reduced accordingly to prevent the aneurysm from rupturing. .
2. Ultrasound and color Doppler inspection
Ultrasound examination can reveal typical aneurysm manifestations, blood flow in the cystic dark area, color Doppler can further clarify the intravascular blood flow velocity and whether there is embolism.
3.CT and MRA Advanced spiral CT can perform three-dimensional reconstruction of images, help identify the relationship between tumor and adjacent organs, and provide great convenience for surgery. Magnetic resonance angiography is a new non-invasive angiography diagnostic technology. Factors have limited the application of MRA in the diagnosis of abdominal arterial diseases. Recently, MRA has made a new breakthrough. It is called three-dimensional contrast-enhanced magnetic resonance angiography, which is a vascular contrast enhancer. The technology has a T-1 shortening effect and removes the blood flow signal, thereby overcoming the confused blood flow saturation phenomenon and the interference of the turbulent signal. The abdominal large-capacity image signal can be quickly obtained, and various three-dimensional reconstruction can be performed along the blood vessel axis. The obtained images are similar to angiographic and spiral CT images. Because of the lack of ionic contrast agents, the side effects and possible allergic reactions of contrast agents are avoided, and patients with renal insufficiency have higher safety. Promising angiography method.
Diagnosis
Diagnosis and diagnosis of splenic aneurysm
diagnosis
General clinical examination is not easy to find splenic aneurysms. The diagnosis of this disease is mainly determined by imaging examination.
Differential diagnosis
Abdominal pain, nausea, vomiting and other symptoms need to be differentiated from pancreatitis and dyspepsia. Once there is an acute abdomen with shock, the disease should be considered and differentiated from other visceral aneurysms. CTA and angiography are helpful in differential diagnosis. Mainly should be differentiated from lymphoma. Most of the former have a history of cancer, while the latter has persistent high fever, systemic lymphadenopathy, bone marrow and blood abnormalities. For cystic metastases in the spleen, it is necessary to distinguish from benign cysts of the spleen.
