An abscess is a local accumulation
of pus in an organ. As this accumulation of pus in the beginning is contained
in a cyst-like structure, it can be difficult to diagnose. However, as time goes
on the pathogens in this abscess cavity are exerting pressure and are eating their
way more and more into the healthy surrounding liver tissue.
Here is an
of a CT scan of a liver abscess. The end result can be that an overwhelming
infection suddenly can gain entrance into the blood stream at which point the
patient gets extremely sick with septicemia.
A liver abscess can originate
from a variety of conditions as follows.
•Bile ducts can
get infected when a gallstone is present and the infection can travel against
the bile flow into the liver tissue (=ascending cholangitis).
can reach the liver through the systemic circulation in the case of septicemia
(blood poisoning with bacteria).
•Another mode of transmission is via
the portal vein system in the case of appendicitis or diverticulitis, where the
pus from an appendicitis or from a case of diverticulitis of the colon reaches
the liver through the portal vein system.
•Finally, sharp or blunt trauma
can cause an abscess. In the case of a stab wound or a gun shot wound the bacteria
are directly introduced into the liver tissue.
the case of blunt trauma from a blow to the upper abdomen a hematoma forms on
the surface or inside the liver. A hematoma is a localized blood collection, which
tends to attract bacteria that happen to travel through the blood. Normally they
are immediately removed by white blood cells. However, in a hematoma, there is
no circulation of white blood cells, but blood serves as an ideal growth medium
for the bacteria, which by chance have found their way into the liver. After they
have multiplied enough, the digestive enzymes eat a cavity into the liver tissue,
where pus forms and a membrane demarcates it from the healthy tissue. This forms
the wall of the abscess.
The pathogens that cause liver abscesses are quite
varied. Common bacteria are streptococci or staphylococci, which usually originated
systemically through the blood stream. Abscesses due to the infected biliary tract
grow E.coli and Klebsiella bacteria. E. coli and anaerobic bacteria are usually
isolated from an intraabdominal infection that was transmitted via the portal
vein system. An amebic abscess from Entamoeba histolytica( which is a parasite)
has a better prognosis than the bacterial abscesses and responds well to appropriate
are several abscesses in the liver, the symptoms are acute with acute right upper
abdominal pain, vomiting, nausea, weight loss, a fever and weakness. The patient
might also experience right chest pain( due to pleuritic irritation)and might
be jaundiced, particularly with biliary tract disease. In other cases with a single
liver abscess it might take several weeks to see symptoms develop. There might
be only a fever, malaise, weight loss and nausea. Then gradually the other symptoms
develop as more and more pus is produced in the abscess cavity.
Before treatment can be instituted, the surgeon will want to be
absolutely sure where the abscess is. A CT scan or MRI scan are the most sensitive
tests, but an ultrasound
of the liver can detect abscesses of more than 2 cm (=0.8 inch) in
The imaging studies are in addition to the normal basic history
and physical examination. Blood tests would also be useful with high white blood
cell readings and elvated liver enzymes.
Treatment depends on the pathogen, which has caused the abscess.
For instance, an amebic abscess will respond well to chemotherapy with metronidazole,
emetine or chloroquine. Other (bacterial) abscesses will be treated with the appropriate
antibiotic first and often with percutaneous needle aspiration pus can also be
sucked out. Surgery is reserved only for those patients, where these other measures
did not resolve the abscess. Usually for prevention of recurrence patients are
put on antibiotics for several weeks.
abscess can rupture or spread locally. This can cause such things as a subphrenic
abscess( an abscess between the liver and the right diaphragm), a rupture into
the right pleural cavity, into the right lung, bleeding into the abscess, rupture
of the abscess into the peritoneal cavity with development of generalized peritonitis
and septicemia. Despite the best therapy the mortality rate of a liver abscess
is still between 10% and 30%.