Saturday, October 2, 2010

Liver Abscess: Complications and Causes

l
Liver abscess can result from the dissemination of a bacterial or fungal infections of the digestive tract through the portal vein, the biliary infection or by direct extension from adjacent infection.

The three major forms of liver abscesses, are classified by etiology: Piogene-abscesses, mostly polymicrobial, have more than 80% of liver abscesses Abscesses due to Entamoeba histolytica-ameobice, counts 10% of liver abscesses -Fungal abscesses, most commonly due to Candida species counts below 10% of cases.

Appendicitis was considered the most important cause of liver abscess formation. As the diagnosis and its treatment has improved, it remains the only cause in 10% of abscesses. Biliary tract disease is now the most common source piogene liver abscess. Obstruction allows bacterial proliferation. Gallstones, obstructive tumors affecting biliary tree and rare congenital diseases are conditions for the development of abscesses.

The clinical presentation most commonly for liver abscess include fever, chills, right upper quadrant pain, anorexia and malaise. Complications that may evolve through untreated abscess are sepsis, empyema continue dissemination of abscess or graft rupture, rupture of abscess with peritonitis and endophthalmitis, when an abscess is associated with bacteremia with Klebsiella pneumonia.

Single antibiotic therapy is not routinely indicated, although successful in some cases. It may be the only alternative for patients too ill to withstand an invasive intervention, or in cases with multiple abscesses, percutaneous drainage can not be. In these situations, patients will receive antibiotics for a period of several months, with careful monitoring of the development and deployment of any complications.
Surgical drainage was the standard for curative treatment, until the introduction of percutaneous drainage in 1970. Today, guided by imaging techniques, percutaneous drainage is the most widely used method for treating liver abscesses.

Left untreated an abscess in the liver is invariably fatal complications include sepsis, empyema, or peritonitis, by breaking into the pleural space or peritoneal abscess and retroperitoneal extension.

Pathogenesis of liver abscess
Piogenic abscess.
Piogene Bacteria can reach the liver by direct extension by contiguity to neighboring organs or the portal vein or hepatic artery. Clearance of bacteria through the port seems to be a normal phenomenon in healthy individuals, however, the proliferation of microorganisms, tissue invasion and abscess formation may occur in obstruction, poor perfusion or microembolizare.

In the biliary tree diseases.
Biliary diseases include 21-30% of reported cases of abscesses. Extrahepatic biliary obstruction leading to cholangitis and abscess formation is the most common cause and is usually associated with coledocolitiaza, malignant or benign tumors, or postsurgical strictures.

Bilio-enteric anastomoses (coledocoduodenostomia and coledocojejunostomia) were also associated with an increased incidence of abscess formation. Biliary complications (strictuirle) after liver transplantation are also causes of abscesses piogenis.

Port system infections.
Infectious processes originate from the abdomen to reach the liver through seeding or venous embolization. The restrictive use of antibiotics for intra-abdominal infections, piemia portal is now an uncommon cause liver abscesses, but still contains 20% of cases.

Appendicitis and pileflebitis are the predominant causes. Although any source of intra-abdominal abscess, such as acute diverticulitis, inflammatory bowel disease and intestinal perforation may lead to liver abscess and portal piemitis.

By disseminating marrow-via hepatic artery.
Infectious processes resulting in bacterial seeding of the liver in systemic cases of bacteremia, bacterial endocarditis, urinary sepsis after intravenous injection of drugs.
Penetrating wounds and hepatic necrosis by vascular damage inevitable laparoscopic procedures are recognized causes of liver abscesses. In addition, transarterial embolization and liver crioablations piogenis abscesses are new etiologies.

Cryptogenic etiology unknown.
In almost half of cases due to an abscess is found. Incidence is increased in patients with metastatic cancer. Patients with recurrent cryptogenic liver abscesses require careful investigation, and biliary and gastrointestinal.

Amoebic abscess.
Liver involvement results after the invasion of mesenteric venules with Entamoeba histolytica. Ameobis then enter the circulation and migrate up to the liver where it forms large abscesses typical. Protein Gal / GalNAc lectin is one that supports bacterial invasion. Abscess contains acellular proteinaceous debris that are considered to be a consequence of induced apoptosis and is surrounded by a ring trofozoizis that invade tissue.
Right hepatic lobe is most commonly affected because of the right lobe blood flow is supplemented predominantly superior mesenteric vein, while the left lobe is drained by the splenic vein.

No comments:

Post a Comment