Diagnosis and treatment of bacterial liver abscess
Zhengzhou Central Hospital Li Xuemin
(1) 【Cause of disease】
Bacterial liver abscess is a purulent infection of the liver caused by purulent bacteria, also known as purulent liver abscess. Common pathogenic bacteria in adults are Escherichia coli, Proteus, Pseudomonas aeruginosa, Streptococcus, Staphylococcus and anaerobic bacteria. In children, Staphylococcus aureus and Streptococcus, and Friedländer pneumoniae bacillus are the second place.
Pathogens can enter the liver through the following ways:
1. Biliary system: It is currently the most important route of infection for Chinese patients. Such as common bile duct stones, biliary ascaris or clonorchiasis, and other patients with acute suppurative cholangitis, bacteria can move up the biliary tract and infect the liver to form liver abscess.
2. Abdominal infections of the portal vein system (such as gangrenous appendicitis, suppurative pelvic inflammatory disease, etc.), intestinal infections (such as ulcerative enteritis, bacillary dysentery, etc.), hemorrhoid infections, etc. can cause thrombophlebitis of the portal vein branch, and its sepsis After the embolus falls off, it can enter the liver along the portal vein system and cause liver abscess. Due to the widespread use of antibiotics, infections by this route are rare.
3. Lymphatic system If there are purulent lesions adjacent to the liver, such as cholecystitis, subdiaphragmatic abscess, and perforation of the stomach and duodenum, bacteria can invade the liver through the lymphatic system.
4. Blood infections Purulent infections in any part of the body, such as upper respiratory tract infections, acute osteomyelitis, subacute endocarditis, furuncle and carbuncle and other complicated bacteremia, pathogenic bacteria can enter the liver through the hepatic artery.
5. Direct invasion When the liver has open damage, bacteria can invade directly through the wound. Sometimes, after the closed injury of the liver forms a subcapsular hematoma of the liver, the original bacteria in the liver can turn the hematoma into an abscess.
6. Other unexplained ways: Many liver abscesses have no obvious cause, such as occult liver abscesses. There may be some infectious disease in the body. When the body's resistance is weakened, accidental bacteremia causes inflammation and abscesses in the liver. It has been reported that 25% of occult liver abscesses are accompanied by diabetes. Sometimes the bacterial culture result of liver abscess is negative, which is not ruled out due to improper anaerobic culture technique.
two. 【Clinical manifestations】
Bacterial liver abscess usually has no typical clinical manifestations, and the acute inflammation period is often masked by the primary disease. This disease usually has a rapid onset. Due to the rich blood supply of the liver, once a purulent infection occurs, a large amount of toxins enter the blood circulation, causing systemic septic reaction. Clinically, it is often followed by a certain precursor disease (such as biliary ascariasis) after sudden chills, high fever, and liver pain. The main clinical manifestations are as follows:
1. Chills and high fever: most of the earliest symptoms, but also the most common symptoms. The patient had a sudden chill at the beginning of the onset, followed by a high fever. The fever was mostly flaccid, with a body temperature of 38-40°C, up to 41°C. The hot and cold exchanges were accompanied by a lot of sweating, and the pulse rate increased. Several times a day, repeated attacks.
2. Liver area pain: inflammation causes liver enlargement, leading to acute swelling of the liver capsule, and persistent dull pain in the liver area; the time can occur before or after other symptoms appear, or it can occur at the same time as other symptoms, and the pain is severe It often indicates a single abscess; the early abscess is continuous dull pain, and the later period is often sharp and severe pain. As breathing worsens, it often indicates an abscess on the top of the liver diaphragm; sometimes the pain can radiate to the right shoulder, and the left liver abscess can also radiate to the left shoulder.
3. Fatigue, loss of appetite, nausea and vomiting: due to systemic toxicity and continuous consumption, gastrointestinal symptoms such as fatigue, poor appetite, nausea and vomiting are more common. A small number of patients show more serious illnesses such as listlessness in a short period of time, and a small number of patients have symptoms such as diarrhea, bloating, or more intractable hiccups.
4. Signs: Tenderness and hepatomegaly are the most common in the liver area; percussive pain in the right lower chest and liver area; sometimes reactive pleurisy or pleural effusion on the right side; if the abscess is located on the liver surface, the intercostal skin of the corresponding part is present Redness, fullness, tenderness, and pitting edema; if the abscess is located in the lower right, it is common to have fullness of the right quarter rib or upper right abdomen, and even localized swelling, often can touch the enlarged liver or fluctuating mass, and there is obvious Tenderness and abdominal muscle tension, etc.; when the left liver abscess, the above signs are limited to the xiphoid process. Ascites may occur in advanced patients, which may be due to portal phlebitis and the compression of peripheral abscesses affecting the portal vein circulation and liver function damage, long-term consumption caused by malnutrition and low protein. Patients secondary to biliary obstruction are all accompanied by jaundice. For other causes of purulent liver abscess, once jaundice appears, it means that the condition is serious and the prognosis is poor. The above are typical manifestations of liver abscess. It is worth pointing out that due to the advancement of current diagnosis and treatment technology and the early application of antibiotics, the above-mentioned typical manifestations are rare, and abdominal pain, fatigue and night sweats are often the main symptoms.
Diagnosis is generally not difficult. For those with purulent disease, sudden chills and high fever, pain in the liver area with tenderness, hepatomegaly, and increased white blood cells suggesting bacterial infection, bacterial liver abscess should be considered. The following tests are helpful in the diagnosis of liver abscess.
1. X-ray examination: X-ray examination can find that the shadow of the liver is enlarged. If the abscess is located in the right liver lobe, it can be observed that the diaphragm is elevated, restricted movement, blurred costophrenic angle or small amount of pleural effusion, right lower pneumonia or lung Not waiting. Sometimes a gas-liquid level may appear at the abscess site, which often indicates that the abscess is caused by a gas-producing bacterial infection. Abscesses in the left lobe of the liver can cause compression of the gastric cardia and lesser curvature of the stomach. When the movement of the diaphragm is restricted, the costophrenic angle disappears, and a small amount of pleural effusion is present, the presence or absence of a subdiaphragmatic abscess should also be considered.
2. Ultrasonic examination: The abscess has a typical dark area of liquid echo or the liquid level in the abscess. At the same time, understand the location, size and depth of the abscess cavity from the body surface in order to determine the best puncture point and needle direction and depth of the abscess, or to provide an approach for surgical drainage. However, it is often difficult to find multiple liver abscesses smaller than 1 cm by ultrasound, and attention should be paid to clinical diagnosis. From the perspective of ultrasound, it needs to be differentiated from other cystic lesions. Under normal circumstances, the cyst wall of a liver cyst is neat and clear, and the density within the cyst is uniform. The cavity wall of liver abscess is irregular, the boundary is not clear, and the cavity often contains multiple echo regions.
3. CT examination: CT examination can find the size and shape of the abscess, show the exact location of the abscess in the liver, and provide clear and intuitive image data for clinicians to perform abscess puncture and surgical drainage. The main manifestation is the appearance of low-density areas in the liver, the CT value is slightly higher than that of liver cysts, most of the boundaries are not clear, and sometimes blocky shadows may appear in the low-density area. After the contrast agent is injected, the peripheral enhancement is obvious and the boundary is clearer. The typical manifestation of enhanced scan is the circular enhancement of the abscess wall (target sign). The appearance of the "target" sign strongly indicates that the abscess has formed.
4. MRI examination: early liver abscess is due to edema, so it has the characteristics of long T1 and T2 relaxation time during MRI examination. On the T1 weighted image, it appears as a low signal strength area with unclear boundaries, while on the T2 weighted image, the signal strength increases. When the abscess is formed, the abscess is a low-intensity signal area on the T1 weighted image; the abscess wall is inflamed granulation connective tissue, and its signal intensity is also lower, but slightly higher than the abscess; the inflammatory edema around the abscess wall forms a little Ring signal intensity below the abscess wall. On the T2 weighted image, the tissue signal intensity of abscess and edema is significantly increased, and there is a ring-shaped abscess wall with slightly lower signal intensity in between.
four. 【Common Complications】
A common complication is the rupture of the abscess, which penetrates the adjacent organs. Penetration into the thoracic cavity produces empyema and pleural bronchial fistula, or penetrates into the abdominal cavity and pericardial cavity; sometimes it can also penetrate the stomach, duodenum, colon, kidney, and pancreas; in a few cases, it can penetrate the vena cava, hepatic vein, and thoracic duct Or abdominal wall, etc., embolism, thrombosis, and abscess formation in other parts may also occur. It is rare to cause rupture of blood vessels in the liver to discharge from the biliary tract, that is, biliary bleeding.
1. Drug treatment: ① Anti-infection uses high-dose effective antibiotics while treating the primary lesions to control inflammation; currently, it is often advocated to apply antibiotics in a planned way, such as first selecting those that are effective against both aerobes and anaerobes For drugs, select sensitive antibiotics after bacterial culture and drug sensitivity results. ②Maintain the balance of water and electrolyte should be actively supplemented to correct water and electrolyte disorders; ③hepatic protection treatment; ④Improve the body's immunity: give vitamin B, C, K, if necessary, repeatedly inject small doses of fresh blood and plasma to correct Hypoproteinemia, improve liver function and infusion of immunoglobulin. ⑤ TCM treatment: Generally, in addition to the above treatment, TCM treatment is added.
2. B-guided percutaneous pus aspiration or catheter drainage: suitable for a single large abscess, puncture the abscess cavity with a thick needle under the guidance of B-ultrasonography, and repeatedly inject metronidazole solution for flushing after draining the pus Suction until the injected liquid is clear, and then pull out the puncture needle (Figure 1). After repeated washing and suction of pus, a catheter can also be inserted to prepare for regular drainage and drainage after the operation. When the abscess cavity is less than 1.5cm, it is removed. This method is simple, less traumatic, and satisfactory in curative effect. It is especially suitable for elderly, frail and critically ill patients. Puncture and drainage or catheter drainage cannot completely replace surgical drainage. The reasons are: ① If the pus in the abscess cavity is thick, it will Causes poor drainage. ② Thick drainage tube can easily cause tissue or abscess wall bleeding. ③Incomplete drainage of multiple septic cavities. ④The primary lesions such as bile duct stones cannot be treated at the same time. ⑤ After a thick-walled abscess is drained or drained, the abscess wall is not easy to collapse.
3. Surgical treatments mainly include abscess incision and drainage and hepatectomy. The former is suitable for large abscesses or systemic poisoning symptoms are still serious or complications after the above treatments, such as abscesses penetrating thoracic cavity and abdominal cavity causing peritonitis Or when it penetrates into the biliary tract; the latter is suitable for chronic liver abscesses that are difficult to treat with non-surgical treatment due to their thickness and are limited to one liver lobe.
(1) Abscess incision and drainage: The commonly used surgical methods are as follows: ① Trans-abdominal incision and drainage: Use an oblique incision under the right costal margin, enter the abdominal cavity, identify the site of the abscess, and protect the surgical field with a wet saline pad. The pus contaminates the abdominal cavity; first try to get the pus from the puncture, insert it into the abscess cavity along the needle direction with a straight vascular forceps, and after the aspirator sucks up the pus, extend the finger into the abscess cavity, gently separate the septal tissue in the cavity, and use The abscess cavity is washed repeatedly with hydrogen peroxide and normal saline. After suction, a double cannula is placed in the abscess cavity for suction; the abscess cavity and around the drainage tube are stuffed or covered with omentum; the drainage tube is drawn out from the abdominal wall by another poke. The pus is sent for bacterial culture. It is currently the most commonly used method. ②Extraperitoneal abscess incision and drainage (Figure 2): The liver abscesses located in the right anterior lobe and the left outer lobe of the liver have been closely adhered to the anterior peritoneum. The anterior extraperitoneal approach can be used to drain the pus. Because it cannot display the peritoneal cavity, it is not commonly used. ③ Posterior abscess incision and drainage (Figure 3): It is suitable for abscesses on the top or posterior side of the right liver diaphragm. The patient is lying on the left side with a sand bag on the left waist; an incision is made along the twelfth rib on the right side slightly to the outside to remove a section of ribs, and a transverse incision is made in the rib bed at the level of the spinous process of the first lumbar vertebra to expose the diaphragm, sometimes The diaphragm needs to be incised to reach the area of the posterior renal fat sac; use the fingers to separate the posterior renal fat sac upwards, revealing the upper pole of the kidney and the retroperitoneal space under the liver to the abscess; puncture the puncture needle into the abscess cavity along the direction of the finger, and draw pus After liquid, use long curved hemostatic forceps to insert the abscess cavity along the puncture direction to drain the pus. Others are the same as above and are not commonly used anymore.
(2) Hepatectomy: Suitable for: ①Long course of chronic thick-walled abscess, it is difficult to collapse the abscess cavity by incision and drainage of the abscess, long-term ineffective cavity remains, and the wound does not heal for a long time; ②Hepatic abscess incision After drainage, the sinus tract remains unhealed for a long time, pus is continuous, and cannot heal itself; ③With a certain hepatic bile duct stone, the liver loses normal physiological function due to repeated infection, tissue destruction, and atrophy; ④In the left outer lobe of the liver Multiple abscesses causing severe damage to liver tissue. In the treatment of liver abscess by liver lobectomy, care should be taken not to spread inflammatory infection to the surgical field or abdominal cavity during the operation. In particular, the treatment of the liver section should be meticulous and proper, and the drainage of the surgical field should be unobstructed. Once local infection, it will cause the gallbladder of the liver section. Complications such as fistula and bleeding. Emergency lobectomy of liver abscess may cause the inflammation to spread, and the surgical indications should be strictly controlled.
The prognosis of patients with bacterial liver abscess is closely related to their age, physique, primary disease, number of abscesses, the time when treatment starts, the thoroughness of treatment, and the presence or absence of complications. The prognosis of young and elderly patients is worse than that of young adults, and the mortality rate is also higher. The fatality rate of multiple liver abscesses is significantly higher than that of single liver abscesses. According to statistics, 106 deaths (75.7%) of 140 cases of multiple liver abscesses, while only 28 deaths (23.9%) of 117 cases of single liver abscesses. The type and toxicity of the bacteria are also closely related to the prognosis of liver abscess. The mortality rate of liver abscess caused by bacteria such as Escherichia coli, Staphylococcus, Streptococcus, Pseudomonas aeruginosa, etc. is higher, and the prognosis of those infected with bacteria that are not sensitive to multiple drugs is also poor. Those with poor general conditions, malnutrition and significant liver damage, such as hypoproteinemia and hyperbilirubinemia, have a higher mortality rate. Complications of liver abscess, such as subdiaphragmatic abscess, abscess rupture into the abdominal cavity leading to diffuse peritonitis, biliary bleeding, or combined with empyema or lung abscess, the mortality rate increases. In contrast, patients with a single abscess with mild symptoms without complications have a good prognosis. Therefore, the requirements for the treatment of bacterial liver abscess are early diagnosis, early treatment, timely use of effective antibiotics, effective drainage, thorough treatment of the primary lesion and strengthening of systemic supportive treatment, which can greatly reduce the mortality rate. In recent years, due to the rapid development of medical science and technology, the level of diagnosis and treatment has been continuously improved, and the incidence and mortality of bacterial liver abscess have decreased significantly.