AMOEBIASIS 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.
Sexual transmission also occurs .
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
Histologically tissue edema
patchy round cell infiltration
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
DD- Amoebic Colitis
Microscopy And Culture
Wet Mount Preparation (i) mounts in saline solution (ii) mounts in saline + lodine (iii) mounts in saline + methylene blue
Gomori,trichrome, Iron haematoxylin Gomori,trichrome Iron haematoxylin PAF Gomori Haematoxylin and eosin Permanently stained slide Permanently Stained slide Wet mount with enzyme digest Permanently stained slide Routine histology
Sensitivity 60 % invasive Bowel disease 100 % with Amoeboma
Immunological Test Indirect Haemagglutination
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 1 st Choice Diloxanide Furoate 2 nd Choice Paramomycin (or) Iodoquinol 1 st Choice Metronidazole followed by diloxanide furoate ( or ) Tinidazole followed by diloxanide furoate 2 nd Choice Paramomycin
Adult Dosage Drugs of Choice Clinical presentation
PREVENTION Health Education Improved water supply Chlorination – not effective Amoebic cysts Destroyed by 200 parts / 10 6 of Iodine 5 – 10 acetic acid. Heating > 68 0 C Removed by sand filtration Boling for 10 minutes kill the cysts
Amoebic Liver Abscess
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 Pain Diarrhoea and / or Dysentery Weight Loss Cough Dyspnoea Physical findings Localized tenderness Enlarged Liver Fever Rales,rhonchi Localized intercostal tenderness Epigatric Tenderness Jaundice
huge abscess of the inferior surface of the left lobe.
Clinical enlargement of the left lobe of the liver .
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 %
CXR – Elevated Right Hemi diaphragm
Isotope liver scan
USG Abdomen – B mode , Hypoechoic
Liver Hydatid cyst
Primary and Secondary carcinoma of liver
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
Peritoneoscopic view of amoebic liver abscess .
TREATMENT 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. Metronidazole followed by diloxanide furoate or tinidazole followed by diloxanide furoate dehyderoemetine followed by diloxanide furoate 1st Choice 2nd choice
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 – Odourless Consistency – 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
ALA with Secondary infection
Left lobe Abscess
Rupture into pericordium
Haematogenous pulmonary amoebiasis without liver involvement.
Haematogenous pulmonary amoebiasis with independent liver abscess.
Pulmonary amoebiasis extending from a liver abscess.
Broncho hepatie fistula with pulmonary involvement.
Empyema entering from a liver abscess
GENITO URINARY AMOEBIASIS
FREE LIVING AMOEBAE
PRIMARY AMOEBIC MENINGO ENCEPHALITIS
Swimming -> 2 – 14 days
Cribriform plate -> olfactory -> sub arachnoid space
Like meningitis picture
200 cases since 1965 , young adults and children
Amphotericin B 1 mg / kg per day
Acanthamoeba – 5 species
MC by A.Castellani, A.Polyphaga
Local propamide and neomycin
Contact lense users – Avoid raw tap water
Most appropriate – Chlorhexidine and hydrogen peroxide