Liver Abscess

Notes

Disease

General Surgery | Infectious Disease and Microbiology

Author

Areej Zeeshan Ahmed
Dr. Armando Faigl (editor)

Overview

Collection of pus forming a mass in the liver as a result of infection. Mainly divided into two types

Pyogenic
Amoebic

Route of infection

Biliary tract (most common)
- Gallstones
- Cholangitis
- Congenital anomaly causing to bile stasis
Portal Vein
- Peritonitis
Hepatic artery
Trauma
- Penetrating
- Non-penetrating can cause bile leakage or haemorrhage and necrosis

Think

Since the liver receives its blood circulation from the systemic and portal circulations, it is more susceptible to getting infections and abscesses from the blood.

Pyogenic Liver Abscess

Can be solitary or multiple pus filled masses caused by bacteria and are generally polymicrobial involving gut-derived Gram-negative, gram positive and anaerobic organisms.

E.coli
Klebsiella
Streptococcus
Staphylococcus

Hemochromatosis is associated with Y. enterocolitica liver abscess. Reason being the bacteria thrives in iron rich environment.

Liver abscess can be one manifestation of the highly virulent klebsiella pneumoniae. Serotypes K1 and K2 is also associated with endopthlamitis.

Risk factors

Biliary tract disease
Diabetes mellitus
Liver surgery
Immunosuppression
age over 50
Malignancy
Being male
Proton pump inhibitors

Pathophysiology

Biliary tract
- Obstruction of bile flow allows proliferation of bacteria thus increased susceptibility to infection.
Portal Vein
- Peritonitis allows the bacteria to travel up the liver via the portal vein
Trauma
- Directly introduces bacteria into the liver parenchyma when penetrating,when non penetrating necrosis or bile leakage create a suitable environment for bacterial growth

Remember

In patients who present with cholangitis , but who remain septic despite relief of biliary obstruction, it is vital to exclude liver abscess.

Clinical Manifestation

Patients complain of a classic triad of fever (with chills), right upper quadrant pain, malaise

Similar triad to ascending cholangitis – fever, RUQ pain and leukocytosis

Some may present more indolently (> 1 month) with fever of unknown origin (FUO) with non specific symptoms as nausea, vomiting and unexplained weight loss.On GPE jaundice with hepatomegaly and large mass are observed.

Examination may reveal tender hepatomegaly, and occasionally jaundice.

Differential diagnosis

Amoebic liver abscess
Benign liver tumor
Ascending cholangitis
Liver cyst
Viral hepatitis

Investigations

FBC – neutrophilia and leukocytosis
LFT
↑ESR/CRP.
Blood cultures – positive in >50% of patients with pyogenic liver abscesses

Side note

Elevated serum Alk phosphatase are the most common finding.

Remember

Serological test for amebiases should be done in all patients.

Secondly abdominal imaging studies are performed

Liver ultrasound showing echoic lesion
CT scan (most sensitive)
- hypodense lesion with “rim enhancement” with contrast
- liver lesions where gas within is highly suggestive of pyogenic abscess

Remember

The characteristic presentation is solitary or multiple lesions in the right liver lobe with a edematous surrounding parenchyma.

Abscess aspiration (if blood cultures negative and failure to respond to initial treatment).

Consider colonoscopy to exclude colon cancer in Streptococcus milleri abscess.

Treatment

Percutaneous CT or Ultrasound guided drainage for lesions more than 3-5 cm.

Prolonged Antibiotics (IV and oral) 4-6 weeks

Antibiotics empirical pending results bacterial vs amoebic – Metronidazole + ceftriaxone or Tazocin
Once organism identified tailor antibiotics

Surgical drainage

Large (>5cm), multiple, loculated, or viscous abscesses
Failure to respond to percutaneous drainage within 7 days
Underlying disease requiring surgical management

Complications and Prognosis

Complications include:

Abscess rupture
- Peritonitis if into abdomen
- Empyema if chest
- Retroperitoneal
Metastatic complications (more common in Klebsiella pneumoniae)
Sepsis
Pneumonia
Pleuropulmonary fistula

Prognosis for treated PLA is good but 100 percent of untreated PLAs succumb to death.

Increased morbidity is associated with increasing age, pyogenic abscess with sepsis, immunosuppression, bacteraemia, multiple comorbidities and abscesses.

Side note

Recurrence of a liver abscess is more common in patients with an underlying biliary tract abnormality than in those without biliary disease.

Amoebic Liver Abscess

Infection is caused by anaerobes ,the most common being Entamoeba histolytica, which is transmitted feco-orally.

Patients usually present with fever (no chills), right upper quadrant pain, chest pain and sometimes diarrhoea. However Amebiasis presents with a variety of clinical states

Asymptomatic cyst passer – do not invade or cause issues
Diarrhoea or dysentery – moderate disease
Invasive intestinal amebiasis – dysentery, colitis, toxic megacolon and amebomas
Invasive extraintestinal amebiasis – liver abscess, peritonitis pleuropulmonary abscess, cutaneous and genital amebic lesions.

The main route of infection for this protozoan is the portal vein.

Side note

E histolytica is endemic in Central and South America, Africa, and Asia thus is suspected in individuals who travel there.

Diagnosis

Stool culture can not differential pathogenic to non pathogenic Entamoeba bacteria
To identify E. histolytica cysts – stool antigen or Stool PCR
Abscess drainage – fluid culture, antigen and PCR

Remember

The abscess is filled with a reddish brown paste like fluid and is a solitary mass in the right lobe of the liver.

Treatment

Metronidazole
Following treatment the use of a luminal agent (e.g. paromomycin) is required to eliminate intraluminal cysts.
Similar guidelines for drainage as of pyogenic abscess.