Dr.S.Palanivelrajan,M.D (Final Year P.G)

Stanley Medical College

Chennai

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

Clear 'halo' around an amoeba

Destruction of liver tissue

Congestion of the sinusoids

Bulge due to superficial abscess

Shaggy appearance of the walls of the abscesses

Abscess surrounded by a distinct area of severe

congestion

Abscess showing a thick fibrous wall

CLINICAL FEATURES Symptoms

PainDiarrhoea and / or DysenteryWeight LossCoughDyspnoea

Physical findingsLocalized tendernessEnlarged LiverFeverRales,rhonchiLocalized intercostal tendernessEpigatric TendernessJaundice

huge abscess of the inferior surface of the left lobe.

Clinical enlargement of the left lobe of the liver.

Compression Sign

Point tenderness

Intercostal tenderness

Multiple large amoebic abscess seen at autopsy.

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 showing obliterated costophrenic angle and an elevated right dome of the

diaphragm

X-ray chest showing an elevated left dome of the diaphragm

X-ray chest showing a fluid level in a lung abscess in pulmonary

amoebiasis.

X-ray chest showing left sided pyopneumothorax

X-ray chest demonstrating the more lateral and vertical spread of an empyema following a liver

abscess

CAT SCAN

Peritoneoscopic view of amoebic 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

Aspiration of flank 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

A bottle of anchovy sauce and amoebic pus.

Bile aspirated from liver abscess

Different coloured pus obtained during a single session by

changing the direction of the needle.

Chocolate coloured pus.

Dirty yellowish pus

Ivory or creamy white pus.

Brown coloured pus compared to anchovy sauce.

Pus resembling color of tea. Tea and anchovy sauce placed on either side for comparision.

Specks of necrotic tissue floating in the pus

Thin yellow pus from a 'chronic' abscess

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