Liver cysts and abscesses

Cysts

• Hepatic cysts/abscesses encompass a spectrum of findings which can be incidental/of little relevance to those requiring urgent treatment
• Lesions include:
  • Simple cysts- extremely common (~5%) and usually of no concern
    • Believed to be congenital; lined with biliary-type epithelium (thought to maybe be remnants of the biliary tree which did not end up connecting to the outflow
    • Filled with plasma-like fluid secreted by the epithelium.
    • Usually patients are asymptomatic and do not require any treatment (almost all will recur)
      • Rarely, they can cause right upper quadrant discomfort.  If symptoms do occur, the cyst can be treated by ‘de-roofing’ to allow drainage into the peritoneal cavity
  • Multiple cysts- may or may not be due to polycystic liver disease
    • Adult PLD is an autosomal dominant inherited condition associated with polycystic kidney disease (gene mutations in PKD1 and PKD2)
    • Kidney disease is usually present earlier and is more severe than liver disease.  Occasionally causes hepatomegaly and abdominal pain, rarely causes fibrosis and liver failure.
  • Neoplastic (tumour) cysts (rare)
  • Hydatid (echinococcal) cysts
    • Caused by infection of Echinococcus granulosus (a kind of worm which is carried by dogs and can infect humans, cows and sheep- most commonly seen in those who work with animals).
    • Usually asymptomatic, and infection can go unnoticed for years.  Can present with hepatomegaly and abdominal pain
    • Have a characteristic appearance on imaging of ‘daughter’ cysts within the main cyst.  Eosinophilia and antibody tests may also support the diagnosis
    • Treatment is with anti-parasitic medication e.g. Mebendazole

Abscesses

Background/Epidemiology

• Uncommon and carry significant mortality/morbidity but are potentially curable
  • Mortality of between 20-40%; failure to make the diagnosis often contributes to the mortality
  • Annual incidence of ~2.3/100,000 people/year in the UK

Aetiology

• Pyogenic
  • Most are secondary to problems elsewhere in the abdomen e.g.
    • Biliary obstruction (stones/stricture/malignancy) and cholangitis
    • Haematogenous via the portal vein (e.g. in mesenteric infections) or via the herpatic artery (as in systemic bacteraemia e.g. in endocarditis)
    • Iatrogenic e.g. liver biopsy or stent; or trauma
  • Other risk factors include
    • Diabetes, chronic liver disease (cirrhosis), immunosuppresion
  • Most common organisms include
    • Klebsiella pneumoniae and Escheria Coli. Bacteroides, enterococci and anaerobic streptococci may also be found
    • Fungal infections may be found in immunocompromised patients and Staph aureus/Haemolytic Strep may be found in patients where infective endocarditis may be the reason for septicaemia.
    • Often polymicrobial
  • More commonly affects the right hepatic lobe than the left.
• Amoebic
  • Caused by Entamoeba histolytica. More common in developing countries but can rarely present without a travel history in the UK
  • Transmission is via the faecal-oral route.

Presentation

• Generally unwell- fever, rigors, malaise, night sweats, anorexia,weight loss
  • Quite often, pyrexia of unknown origin is all that can be present
  • Fever may or may not be swinging
• Abdominal pain (RUQ)
  • More common in amoebic abscesses than pyogenic
  • Occasionally radiates to the right shoulder and can be pleuritic
    • Occasionally, coughs or hiccups can be a problem caused by diaphragmatic irritation
  • Tender hepatomegaly
• Mild jaundice can be present (more common in severe disease/multiple abscesses)

Investigations

• Blood tests
  • FBC- anaemia (chronic disease); neutrophilic leucocytosis (NB eosinophilia is not often seen with amoebic disease)
  • LFTs- raised alkaline phosphatase, low albumin, raised ALT/AST, raised bilirubin
  • Blood cultures (will be positive in around 50%)
• Imaging
  • Liver USS is often first line.  Further imaging (CT) is usually useful for further investigation e.g. aspiration
• Needle aspiration (for microscopy and culture/sensitivity/serology for amoebiasis)
• Other investigations which may be ordered as part of the workup include
  • CXR- may show a raised right hemidiaphragm
  • Stool culture can be investigated for signs of amoebiasis

Management

• Antibiotics- Co-amoxiclav and Metronidazole
• Drainage (percutaneous, CT/USS guided)

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