Amoebic Liver Abscess

• It is common in tropical countries.
• It is caused by Entamoeba histolytica.
• It exist in vegetative form outside the body and is spread by the faeco-oral route.

Pathology

• Initially from infected recto-sigmoid or ileocaecal region, amoebic trophozoites reaches the liver through portal veins causing amoebic hepatitis, may be in the form of micro-abscesses all over the liver. This might resolve on its own or with antiamoebic drugs, but often leads to a localized amoebic liver abscess.
• It may be single large abscess or multiple, and may involve both lobes.
• Amoebic liver abscess is more common in right posterior-superior region because the portal vein is in direct continuation with the right tributary. It can be multiloculated.
• Pus is chocolate coloured, classically called as anchovy-sauce, contains dead liver cells, RBCs, WBCs, necrotic material. Pus may be green due to bile admixture.
• Often secondary infection by E. coli, staph, strepto may occur and thus may present with features of pyogenic liver abscess. Because of perihepatitis, liver is fixed to diaphragm or abdominal wall. There may also be pleural effusion on right side.
• Amoebic abscess commonly presents as an acute entity, but it can also present as chronic type where it is covered by a capsule, that remains dormant for a long peroid.
• Sometimes it can get calcified as well.

'Anchovy sauce' pus drained from and amoebic liver abscess.

Course and sequelae of Amoebic Liver Abscess

• It can rupture into lungs leading to expectoration of chocolate-coloured sputum resulting in natural regression of abscess.
• It can rupture into the peritoneum causing peritonitis which requires emergency laparotomy.
• It can rupture into pleural cavity leading to empyema.
• Rupture into bare area of liver causing retro-peritoneal abscess.
• Rupture into the intestines, or to the skin (Amoebiasis cutis)
• Rupture into pericardial cavity (cardiac temponade)-most dangerous complication.
• Septicaemia and liver failure

Clinical Features

• It is common in males, may be after an attack of amoebic dysentery or many months after the attack or h/o dysentery may not be there at all.
• Pts. Present with fever, weight loss, chills and rigors.
• Pain in the right hypochondrium.
• Soft, tender, smooth liver with increased liver span.
• Intercostal tenderness
• Right sided pleural effusion may be present.
• Mild jaundice may be present esp. in cirrhotic and multiple abscesses.
• Tenderness, rigidity and skin oedema in right hypochondrium may be present acute cases.
• In chronic amoebic liver abscess, smooth, firm/hard, nontender liver may be palpated.

Investigations

• Isolation of the parasite from the liver lesion or the stool and confirming its nature by microscopy.
• Total count may be increased.
• LFT may show altered bilirubin and albumin level.
• PT may be increased
• Altered serum alk. Phosphatase, SGPT, SGOT levels.
• USG abdomen:
•  shows altered echogenicity, size, location, number of abscess, nature of the liver.
• Chest X-ray findings:
• Raised fixed diaphragm
• Pleural effusion
• Soft tissue shadow
• Positive indirect haemagglutination test
• CT scan

Treatment

• Tab. Metronidazole 800mg X TID or inj. Metronidazole 500mg i.v X TID for 10 days.
• I.V or oral antibiotics are essential to control secondary infection.
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• In case of large abscess and infected abscess aspiration with a wide bore needle is done under USG guidance after correcting the PT and sent for c/s, cytology and for study of trophozoites.
• Surgery is done if above measure fail:
• Through transperitoneal approach, abscess area is opened, pus is evacuated and malecot’s catheter is kept in situ until draining stops completely, which is confirmed by repeat USG. 

Malecot’s catheter