Liver Abscess

Liver abscess is a relatively uncommon but life­threatening disorder that occurs when bacteria or protozoa destroy hepatic tissue. The damage produces a cavity, which fills with infectious organisms, liquefied hepatic cells, and leukocytes. Necrotic tissue then walls off the cavity from the rest of the liver.

Liver abscess carries a mortality of 30% to 50% , which soars to more than 80% with multiple abscesses and to more than 90% with complications. Liver abscess affects both sexes and all age-groups, although it's slightly more prevalent in hospitalized children (because of a high rate of immunosuppression) and in women (most commonly those between ages 40 and 60).

Causes

There are many potential causes of liver abscesses. They can be caused by an abdominal infection such as appendicitis, diverticulitis, or a perforated bowel. Other causes may be an infection in the blood, an infection of the biliary (liver secretion) tract, or trauma that damages the liver.

The most common bacteria that cause liver abscesses are Escherichia coli, klebsiella, enterococcus, staph and strep, and bacteroides.

Signs and Symptoms

The clinical manifestations of a liver abscess depend on the degree of involvement. Some patients are acutely ill; in others, the abscess is recognized only at autopsy, after death from another illness. Onset of symptoms of a pyogenic abscess is usually sudden; in an amoebic abscess, onset is more insidious.

The patient may report right abdominal and shoulder pain, chills, fever, diaphoresis, nausea, vomiting, and weight loss. If the abscess extends through the diaphragm, he may complain of dyspnea and chest pain (symptoms of pleural effusion); if he has developed anemia, he may report fatigue.

Inspection may disclose jaundice, a sign of liver damage. On palpation, the liver may feel enlarged, indicating hepatic disease.

Diagnostic tests

Liver scan showing filling defects at the abscess area more than ¾" (2 cm), together with characteristic clinical features, confirms the diagnosis.

Hepatic ultrasonography may indicate defects caused by the abscess but is less definitive than a liver scan. Computed tomography (CT) scanning verifies the diagnosis after a liver scan or hepatic ultrasonography.

Chest X-ray shows the diaphragm on the right side as raised and fixed.

Blood tests demonstrate elevated levels of serum aspartate aminotransferase, serum alanine aminotransferase, alkaline phosphatase, and bilirubin. Serum albumin level is decreased. White blood cell count is elevated (usually more so in pyogenic than in amoebic abscess).

Blood cultures and percutaneous liver aspiration may help identify the causative organism in pyogenic abscess.

Stool cultures and serologic and hemagglutination tests can isolate Entamoeba histolytica in amoebic abscess.

Treatment

If the organism causing the liver abscess is unknown, long-term antibiotic therapy begins immediately with aminoglycosides, cephalosporins, clindamycin, or chloramphenicol. If cultures demonstrate that the infectious organism is E. coli, treatment includes ampicillin. If the infectious organism is E. histolytica, treatment includes emetine, chloroquine hydrochloride, chloroquine phosphate, or metronidazole. The therapy continues for 2 to 4 months. Surgery is usually avoided, but it may be required for a single pyogenic abscess or for an amoebic abscess that fails to respond to antibiotics. Placement of drains (using CT scanning or ultrasonography), particularly in large abscesses, reduces the need for abdominal surgery.

Prevention

When traveling in tropical countries where poor sanitation exists, drink purified water and do not eat uncooked vegetables or unpeeled fruit. Public health measures include improved water purification and waste treatment for underdeveloped countries.