Introduction► Amoebiasis is caused by Entamoeba histolytica► The majority of infected individuals are remain asymptomatic carriers.► The mode is via faeco – oral route.► Disease occurs as a result of substandard hygiene and sanitation.► Amoebic liver abscess is the commonest extraintestinal manifestation, occurs in less than 10%. In endemic areas it is much more common than pyogenic abscess.► Pts who are immunocompromised or alcoholic are more susceptible to infection.
Pathogenesis► The organisms enter the gut through food and water contaminated with cyst.► In small bowl hatching of cyst result into large number of trophozytes which reached to colon where “Flask Shaped Ulcer” form in the submucosa.► The trophozytes multiply, ultimately forming cyst which enter the portal circulation reach to liver, where they multiply in portal triad causing focal infarction of hepatocytes and liquificative necrosis (liver abscess), and also passed in the faces as an infective form that infect other humane being as result of unsanitary conditions.
Amoebic Liver Abscess► The right lobe is involved in 80% of the cases, the left in 10% and rest are multiple.► The abscess are most common high in diaphragmatic surface of right lobe, this may cause pulmonary symptoms and chest complication.► The abscess cavity contain chocolate colored, odorless, anchovy sauce – like fluid that is mixture of the necrotic liver tissue and blood.► Untreated abscess are likely to be rupture. While pus in abscess is sterile unless secondarily infected
Chronic Amoebic Infection Of Large Bowl► ChronicInfection of large bowl may result into granulomatous lesion along the large bowl, most commonly seen in caecum called as “Amoeboma”
Clinical Features► Typical pts with amoebic liver disease is young adult male with history of “Pain and fever” with insidious onset of non – specific symptoms - Anorexia - Night Sweats - Malaise - Cough► Then gradually more specific symptoms such as 1- Pain in right upper abdomen, shoulder tip pain 2- Hicoughs 3- Non – productive cough► There may also be past history of bloody diarrhea or travel to endemic areas raise the suspicious index.
Clinical Examination► Examination reveals pt who is toxic and anemic► Pt will have upper abdominal rigidity► Hepatomegaly► Tender & bulging intercostal space► Overlying skin edema► Pleural Effusion► Basal pneumonitis (usually late manifestation)► There may be jaundice or ascites also present► Rarely there may be rupture of abscess cavity into peritoneum, pleural space or pericardial cavity and pts present as an emergency.
How To Differentiate Amoeboma From Right Sided Colon Cancer?► An amoeboma should be suspected when a patient from endemic area with generalized ill health and pyrexia have a mass in right iliac fossae, with history of blood stained mucoid diarrhea.► Such type of pts is highly unlikely to have carcinoma as “altered bowl habit” is not feature of right sided colon cancer.
Investigation► Haematological Tests► Biochemical Tests► Serological Tests (more specific to detect antibodies) are 1- Test for compliment fixation 2- Indirect haemagglutination assay (IHA) 3- Indirect Immunoflourescence 4- Enzyme – like Immunosorbent assay (ELISA)► IHA has very high sensitivity rate in acute amoebic liver abscess in non – endemic region and remain elevated for some time.► An outpatient rigid sigmoidoscopy using disposable instrument is very useful particularly if pts complain bloody mucoid diarrhea.
Haemetological & Biochemical Tests► These investigation reflects the presence of chronic infective process with 1- Anemia 2- Leucocytosis 3- Elevated ESR 4- Elevated C – reactive protein 5- Hypoalbunaemia 6- Deranged Liver Function Test 7- Elevated alkaline phosphate
Sigmoidoscopy► Sigmoidoscopy show shallow skip lesion and flask shaped or “collar – stud” undermine ulcer may be seen and can be biopsied or scraping can be taken along with mucus for microscopic examination.► Presence of trophozoites distinguish the condition from ulcerative collitis.
Imaging Technique► Ultrasound and CT – scan are the imaging method of the choice.► Ultrasound investigation is very accurate and is used for aspiration, both diagnostic and therapeutic purpose.► Doubtful cases CT – scan confirm the diagnosis.
Amoebic Treatment► Medical treatment is very effective should be first choice.► Metronidazole and tinidazole are effective drugs► Diloxanide furoate, not effective against hepatic infestation is used for 10 days to destroy intestinal amoeba► In large abscess repeated aspiration is combined with drug treatment, threshold for aspiring abscess in left lobe is lower because its predilection for rupturing into pericardium.► Surgical treatment reserve for the complication such as rupture into pleural, peritoneal or pericardial cavity.► Resuscitation, Drainage and appropriate lavage with vigorous medical treatment are key principles.► Acute toxic megacolon and hemorrhage are intestinal complication that are treated with intensive supportive therapy followed by resection and exteriorisation.► When an amoeboma is suspected in a colonic mass cancer should be excluded by appropriate imaging.