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Definition
Amoebiasis is an infection with intestinal protozoa Entamoeba Histolytica.
90% of infection – asymptomatic.
10% of infection – Clinical syndrome.Ranging from Dysentery to Abscess of the
liver or other organs.
PHYLUM SARCOMASTIGOPHORA
SUBPHYLUM SARCODINA
SUPER CLASS RHIZOPODA
CLASS LOBOSEA
SUB CLASS GYMNAMOEBIA
ORDER AMOEBIDA
SUBORDER TUBULINA
“ ENTAMOEBA HISTOLYTICA ”
HISTORY
1875 LOSCH – RUSSIAN.Differentiated the amoebic dysentery from
bacillary dysentery by describing amoeba in the stool.
1887 KARTULIS – EGYPT.Found amoeba in the pus from a liver abscess.
1881 COUNCILMAN AND COFFLEUR.Described true bowel lesions and used the term Amoebic Dysentery.
1903 SCHAUDINN.Differentiated pathogenic and non pathogenic
types of amoeba.
Third most common cause of death from the parasitic disease. (after schistosomiasis , Malaria)
480 Million people (world)
12% of world’s population
High risk groups
Travellers, immigrants, immunocompromised individual, pregnant women, sexually active male. Mental institutes, prisons, Children in day care centres.
Cyst carriers
Sexual transmission also occurs.
EPIDEMIOLOGY
the intestinal lesion Gut
Minute crypt lesion
Extends through the muscularis mucosa and submucosa.
“Flask shaped” ulcer
Thrombosis of blood vessels
“Toxic megacolon”
Irreversible coagulation necrosis of bowel wall.
PATHOLOGY
Tumor like lesion
Several cms in length
M C in caecum
Multiple
Histologically tissue edema patchy round cell infiltration
Types intussusceptions stricture like
AMOEBOMAS
Asymptomatic infection
Mild to moderate colitis (non dysenteric colitis)
Severe colitis (dysenteric colitis)
Localised ulcerative lesions of the colon
Localised granulomatous lesion of the colon (amoeboma)
CLINICAL FINDINGS
INTESTINAL AMOEBIASIS
Infective colitis
Ulcerative colitis
Colorrectal carcinoma
Intestinal schistosomiasis
Trichuris infection
Balantidiasis
Crohn’s disease
Diverticulosis
Ileoceacal TB
LABORATORY DIAGNOSIS
Microscopy And Culture1. Wet Mount Preparation
(i) mounts in saline solution (ii) mounts in saline + lodine (iii) mounts in saline + methylene blue
2. Sample Fixative Examination Stain
1. Stool
2. Sigmoid colon
3. Aspirate
Direct
Fixed
4. Biopsy
-PVA 10 % formalin
-sodium acetate acetic
acid formalin
-PVA, schauddins
fixative
None
PVA, Schauddin’s
Fixative
Formalin
Permanently stained slide
Permanently
Stained slide
Wet mount with
enzyme digest
Permanently stained
slide
Routine histology
Gomori,trichrome,
Iron haematoxylin
Gomori,trichrome Iron haematoxylin
PAF Gomori Haematoxylin and eosin
Enzyme Immunoassay
Indirect Immunoflorescence
Latex Agglutination
Gel diffusion
Sensitivity60 % invasive Bowel disease 100 % with
Amoeboma
Immunological Test
Indirect Haemagglutination
Clinical presentation
Drugs of Choice Adult Dosage
Asymptomahic
Intestinal carrier
Intestinal infection
1st Choice
Diloxanide Furoate
2nd Choice
Paramomycin (or)
Iodoquinol
1st Choice
Metronidazole followed by diloxanide furoate
( or )
Tinidazole followed by diloxanide furoate
2nd Choice
Paramomycin
500 mg t.i.d × 10 days
25 – 30 mg kg-1 day-1 in 3 doses × 7-10 days.
650 mg t.i.d × 20 days
750 – 800 mg.t.i.d × 10 days
500 mg.t.i.d × 10 days
2 g/day 2 -3 days
500 mg .t.i.d × 10 days
25 – 30 mg kg-1 day-1 in 3
doses × 7 – 10 days
PREVENTION
Health Education
Improved water supply
Chlorination – not effective
Amoebic cysts Destroyed by 200 parts / 106 of Iodine 5 – 10 acetic acid.Heating > 680C
Removed by sand filtration Boling for 10 minutes kill the cysts
This is the most common extra intestinal form of invasive amoebiasis.
Adults > children ( 10 : 1 )
Male > female
20 % with past history of dysentery
PATHOGENESIS
Journey of E. Histolytica to the Liver
1. Direct Extension from the Gut to the Liver
2. Via the Lymphatics
3. Along the portal stream
Infarction – Enzymatic Dissolution
CLINICAL FEATURES Symptoms
PainDiarrhoea and / or DysenteryWeight LossCoughDyspnoea
Physical findingsLocalized tendernessEnlarged LiverFeverRales,rhonchiLocalized intercostal tendernessEpigatric TendernessJaundice
COMPLICATONS
Right chest
Peritoneum
Pericardium
Amoebic brain abscess - rare
Hemobilia – Rupture in to major bileduct
Portal hypertension
LABORATORY FINDINGS
Normocytic Normochromic anaemia
Leucocytosis -> more than 10× * 10 9 / L
ESR
Stool Cyst or Vegetative form of E . Histolytica
LFT Bilirubin
Transaminases more than 50 %
Alkaline phosphatase more than 75 %
RADIOLOGY 1. CXR – Elevated Right Hemi diaphragm
2. Isotope liver scan
3. USG Abdomen – B mode , Hypoechoic
4. CTScan
DD1. Subphrenic Abscess
2. Cholecystitis
3. Liver Hydatid cyst
4. Primary and Secondary carcinoma of liver
5. Lesions of the right lung and right pleura
Anterior view of 133/Rose Bengal dot liver scan showing a small
cold area on the inferior surface of the left lobe.
99m Tc sulphur colloid photo liver scan (anterior view) showing a
cold area in the superior surface of the left lobe
X-ray chest demonstrating the more lateral and vertical spread of an empyema following a liver
abscess
1st Choice
2nd choice
Metronidazole followed
by
diloxanide furoate
or
tinidazole followed by
diloxanide furoate
dehyderoemetine followed by
diloxanide furoate
750-800 mg.t.i.d × 10 days
500 mg t.i.d. ×10 Days
2g/day × 3-5 days
500 mg t.i.d × 10
Days
1-1.5 mg kg-1 day -1 ( max.90 mg/day ) i.v
× 5 days
500 mg t.i.d × 10 days.
TREATMENT
Formal Indications
To rule out a pyogenic abscess (, particularly with multiple lesions )
As adjunct to medical therapy ( No response after 72 hours )
If rupture is believed to be imminent
Abscess in the left lobe where the risk of rupture is increased.
Possible Indications
To reduce the period of disability
INDICATIONS FOR ASPIRATION OF AMOEBIC
LIVER ABSCESS
Color – Anchovy sauce, Chocolate color or pinkish brown, varying color’s
Odour – OdourlessConsistency – thick , Viscosity – thick lubricating Oil , Quantity – Accroding to the size of the abscess Microscopy – Dead and deformed Hepatocytes
RBC’S Few Polymorphs Trphozoites of E.Histolytica present in 10
to 25 % cases Microbiology – Sterile
PUS IN AMOEBIC LIVER ABSCESS
Hepatoma, livercyst, Hemangimoa
DD
1. ALA with Secondary infection
2. Left lobe Abscess
3. Bowel perforation
4. Rupture into pericordium
SURGERY
1. Haematogenous pulmonary amoebiasis without liver involvement.
2. Haematogenous pulmonary amoebiasis with independent liver abscess.
3. Pulmonary amoebiasis extending from a liver abscess.
4. Broncho hepatie fistula with pulmonary involvement.
5. Empyema entering from a liver abscess
PULMONARY AMOEBIASIS
• PERITONEAL AMOEBIASIS
• PERICARDIAL AMOEBIASIS
• CEREBRAL AMOEBIASIS
• GENITO URINARY AMOEBIASIS
• CUTANEOUS AMOEBIASIS
PRIMARY AMOEBIC MENINGO ENCEPHALITIS
1. Negleria fowleri
2. Swimming -> 2 – 14 days
3. Cribriform plate -> olfactory -> sub arachnoid space
4. Like meningitis picture
5. 200 cases since 1965 , young adults and children
6. Amphotericin B 1 mg / kg per day
Acanthamoeba – 5 species MC by A.Castellani, A.PolyphagaLocal propamide and neomycinCorneal grafting Contact lense users – Avoid raw tap waterMost appropriate – Chlorhexidine and hydrogen
peroxide
AMOEBIC KERATITIS
Balamuthia mandriallaris60 cases since 1990Albendazole and itraconazole
AMOEBIC MENINGO ENCEPHALITIS