Splenic abscess

　　Causes of the disease: blunt or penetrating injury to the spleen, mild infarction of the spleen, or other diseases; infection from adjacent sites, such as the spread of subdiaphragmatic abscesses to the spleen, the most common pathogens being staphylococci, streptococci, anaerobes, and Gram-negative aerobic bacilli, including Salmonella; Candida species can often infect hosts with impaired immunity.

　　Splenic purulent infections are generally secondary, but the primary lesions are often not obvious because the symptoms of splenic abscesses themselves may appear several weeks to several months after the primary infection has disappeared, so patients often do not remember the past predisposing infections. Common primary causes of splenic abscesses include:

　　① The most common cause is the hematogenous spread of infection from other sites to the spleen, accounting for 75% to 90% of cases. Staphylococcal, streptococcal, or pneumococcal sepsis or septicemia, endocarditis, and puerperal fever are the most common predisposing diseases for splenic abscesses, but in fact, almost all purulent infections can act as predisposing factors for splenic abscesses. The spread of foci generally occurs via arteries, but infections within the abdominal cavity can also enter the spleen via the portal vein;

　　② Injuries or infarctions to the spleen account for 10% to 25% of splenic abscesses. Even minor trauma can lead to splenic hematoma, and secondary infection can cause splenic abscesses and infarction. Pathological hemoglobinemia (abnormal hemoglobinemia or sickle cell disease) can occur due to splenic artery ligation and embolism, and splenic infarction can also occur. The infarcted spleen is an ideal focus for bacterial sedimentation or proliferation;

　　③ Infection of adjacent organs can also directly invade the spleen to cause abscesses, but this is relatively rare in clinical practice, accounting for less than 10% of the causes of splenic abscesses. Renal perinephric abscesses, subdiaphragmatic abscesses, acute pancreatitis, tumors in the stomach and colon, etc., can all directly invade the spleen to cause splenic abscesses;

　　④ Immunosuppression or defects, such as long-term use of immunosuppressive drugs in critically ill patients. AIDS patients may develop splenic infection, and in addition to abscesses, splenic cysts can also become infected and transform into splenic abscesses.

　　Patients with splenic abscesses complicated by abscesses in other organs such as the liver, lung, and kidney account for more than 25% of cases, and the condition is often severe. The splenic abscess can rupture and lead to diffuse peritonitis, which is a severe surgical disease commonly caused by bacterial infection, chemical irritation, or injury. Most cases are secondary peritonitis, originating from organ infections in the abdominal cavity, necrotic perforation, trauma, etc. The main clinical manifestations include abdominal pain, abdominal muscle tension, as well as nausea, vomiting, fever. In severe cases, it can lead to a decrease in blood pressure and systemic toxic reactions. If not treated promptly, death can occur due to toxic shock. Some patients may also develop pelvic abscesses, interintestinal abscesses, subdiaphragmatic abscesses, iliac fossa abscesses, and adhesive intestinal obstruction, etc.

　　There are also perforations into the stomach, colon, and small intestine. The rupture of an abscess secondary to splenic trauma and hematoma with secondary infection often results in massive hemorrhage, which can easily lead to acute hemorrhagic shock, even death.

　　Complications of untreated abscesses include: hemorrhage within the abscess cavity, rupture of the abscess, invasion of the abdominal cavity by the intestines and trachea, or pleural splenic abscess, which can become an uncommon cause of persistent bacteremia leading to endocarditis. Appropriate chemotherapy is still ineffective.

　　1. Subacute onset:The main symptoms are fever, pain in the left pleura, upper abdomen, or lower chest, radiating to the left shoulder, with tenderness in the upper left abdomen. Splenic enlargement can be palpated during physical examination, and in a very few cases, splenic rubbing sound can be heard.

　　2. Splenic enlargement:Splenic enlargement is an important pathological sign. Normally, the spleen cannot be felt. If the spleen edge can be felt in supine or lateral position, it should be considered as splenic enlargement. In people with a low diaphragm position or thin physique, especially women, the spleen edge can also be felt occasionally, but it is quite soft without tenderness, different from pathological splenic enlargement. The enlargement of the spleen volume is the main manifestation of splenic disease.

　　3. Fever:Fever (fever, pyrexia) refers to pathological elevation of body temperature, which is caused by the action of pyrogens on the thermoregulatory center, leading to an upward shift of the set point. It is the most common symptom in clinical practice and an important clinical manifestation in the process of disease progression. It can be seen in various infectious and non-infectious diseases. It has typical fever patterns, course, and specific clinical characteristics, which are generally easy to diagnose; however, some patients with fever have a long course, lack specific signs, and have no diagnostic information, often referred to as fever of undetermined origin or fever of unknown origin (FUO). Most of these patients have potential foci, which have not been clarified in the short term. After clinical observation and special examinations, most of them can be diagnosed definitively, and about 10% of the patients, despite various examinations, still cannot be diagnosed definitively, with the course dragging on for several months, indicating that the diagnosis of long-term fever of unknown origin is indeed an important clinical issue.

　　Splenic abscess seriously affects the patient's daily life, so it should be prevented actively. During prevention, attention should be paid to the following two aspects:

    1. Aggressive treatment of infectious diseases, strengthening anti-bacterial therapy;

　　2. For abdominal trauma, especially blunt or penetrating injury to the spleen, debridement and anti-infection should be performed as soon as possible.

　　(1) Ultrasound:It shows an enlarged spleen with single or multiple circular, oval, or irregular hypoechoic areas within the spleen, with irregular edges and relatively thick walls. The edges of the hypoechoic areas have stronger, blurred echoes, with scattered small punctate echoes within, visible fluid levels, and occasionally, echo of gas; the echoes behind the hypoechoic areas are enhanced. About 60% of the lesions are located at the upper pole of the spleen, and may be accompanied by reactive pleural effusion in the left chest.

　　(2) Chest and abdominal X-ray examination: The diaphragm is elevated with restricted movement, the spleen shadow is expanded, there is pleural effusion in the left chest, and atelectasis. Barium meal造影 shows displacement of the stomach and transverse colon to the right anteriorly, with compression and deformation of the greater curvature of the stomach.

　　(3) CT examination:The spleen appears to be outwardly bulging with a circular or oval-shaped hypodense area within the spleen, uneven in density, and with irregular edges. Fluid levels or gas may be visible within the abscess, and the abscess wall is equal in thickness to the spleen parenchyma. During contrast-enhanced scanning, the abscess wall may enhance, but the contents of the abscess do not. Scattered calcification spots may be seen within the spleen.

　　(4) Angiography:Enlarged spleen, during the arterial phase, there is an avascular, expansive mass within the spleen, with rough edges, causing displacement, straightening, and separation of vessels. In the capillary phase, the abscess appears as irregular and blurred filling defects, with no staining and increased vessels around the abscess, no surrounding vessels or vascular lakes, and normal splenic vein.

　　(5) Radioisotope spleen scan: Large solitary abscesses manifest as large areas of radioactive defects, multiple small abscesses, and radioactive nuclide uptake images that are not uniform.

　　For the diet of patients with splenic abscess, a liquid and easily digestible diet is needed. Avoid greasy foods and overeating. It is advisable to eat light and easily digestible foods as the main diet, not to eat greasy, spicy, and刺激性 foods. The main treatment is to have a good antibacterial effect. Pay attention to eating nutritious foods, and currently, eat light and easily digestible foods. Pay attention to appropriately increasing nutrition.

　　1. General Treatment

　　It mainly includes the use of broad-spectrum, high-efficiency, and sensitive antibiotics as well as systemic supportive treatment. Generally, a combination of third-generation cephalosporins and metronidazole is chosen, and attention should be paid to fungal infection issues. If there is a bacteriological culture result, the medication should be adjusted in a timely manner.

　　2. Surgical Treatment

　　If conditions permit, splenectomy can be performed. If it is difficult to remove due to dense adhesions around the spleen, it can also be considered to incise and drain the abscess.

　　3. Local Treatment

　　The principle of local treatment for splenic abscess is that if the spleen can be removed, it should be removed. If it is difficult to remove due to dense adhesions around the spleen, it can also be considered to incise and drain the abscess. Usually, such cases are first explored through a left upper abdominal transrectus sheath incision, which will find that there are varying degrees of adhesions around the spleen, and a transverse incision in the upper abdomen can also be made to reduce the risk of postoperative wound dehiscence. Adhesions that can be separated should be separated, and then the entire spleen should be removed. If the adhesions are too dense to separate, the spleen removal is difficult, or the patient's overall condition is poor and cannot tolerate surgery, then puncture can be performed at the most dense adhesions (usually the most superficial part of the abscess). Once pus is aspirated, it can be incised and drained at that location, and the drain can be directly led out through another abdominal wall stab incision. The original incision can be sutured in one stage. It should be emphasized again: Splenic abscess treatment should prioritize splenectomy, and incision and drainage should only be occasionally used when unavoidable.