Entamoeba

Question 1

Clinical types of amoebiasis

Answer 1

Intestinal amoebiasis
- acute amoebic dysentery
- chronic intestinal amoebiasis
- asymptomatic intestinal amoebiasis

Extra intestinal amoebiasis
- Hepatic —amoebic hepatitis , amoebic liver abscess
- amoebic lung abscess
- amoebic Brain abscess
- amoebic vaginitis( May’s disease)
- amoebic cutis

Question 2

Trophozoites of Entamoeba

Answer 2

Growing or feeding stage

Shape: Not fixed (constantly changing position)
Colour: glassy green
Movement:- by pseudopodium - jerky movement
- active, progressive & unidirectional

Cytoplasm:- a clear translucent ectoplasm
- a granular endoplasm
Nucleus:- Karyosome, Nuclear membrane
Spoke like radiations between karyosome and nuclear membrane

Question 3

Cysts of entamoeba

Answer 3

Shape: rounded, surrounded by cyst wall
Nucleus: uninucleate,binucleate or (mature)quadrinucleate
Cytoplasm: - clear & hyaline
- in early stages, contain:-
(a) chromatoid bodies( do not stain with iodine)
(b) glycogen mass( stain with iodine)

Question 4

Morphology of entamoeba

Answer 4

Trophozoites ( feeding or growing stage)
Precystic stage
Cystic stage

Question 5

Saline preparation of entamoeba

Answer 5

Identify motility and RBC
Nucleus not visible

Question 6

Iodine preparation of entamoeba

Answer 6

Identify cysts
by staining internal structures of the cyst such as nuclei and glycogen mass

Body - yellow to light brown
Nucleus- central karyosome
Cytoplasm- smooth and hyaline appearance
Chromatoid bodies - not stain
Glycogen mass- stains brown

Question 7

Pathogenecity

Answer 7

Cytolytic effect
By amoebapores
Cytolysins haemolysins enzymes which cause necrosis of tissue cells and lysis

Question 8

Pathogenesis

Answer 8

+ Infective form: mature quadrinucleate cyst

+ Source of infection:
- cyst-passing chronic patient
- asymtomatic carrier

Portal of entry - alimentary tract

MOT - fecal oral route
-ingestion of contaminated food and drinks
-ingestion of uncooked vegetables and fruits fertilized with infected human faeces
- house flies may transmit the cysts while passing from faeces to unprotected food stuff
-cysts of E. histolytica have found in the droppings of cockroaches which also serve as a source of infection

Question 9

Amoebic dysentery

Answer 9

Infection is confined to intestinal tract and characterized by mucus and blood in the stool

Question 10

Intestinal amoebiasis distribution

Answer 10

LI

Generalized -whole length of the large intestine (the internal anal sphincter is involved.
Localized-
a.Ileo-caecal region - the caecum, ascending colon,
b.ileo-caecal valve and appendix are involved.
Sigmoido - rectal region, sigmoid colon and rectum

Question 11

CF of acute amoebic dysentery

Answer 11

1. Dysentory
   frequent motions (6 ~ 8 times)
   amount - large
   blood and mucus in stool
   faecal matter present
2. Gripping abdominal pain
3. Tenesmus

Question 12

RE of Stool

Answer 12

Macroscopic Examination
Colour, form and Consistency - Dark red, semi-formed
Blood and Mucus present with fecal matter
Odour- very offensive
Reaction- acid

Microscopic Examination
Cellular exudate scanty
Pus cells ++
Macrophages+
RBCS++
Pyknotic bodies (Nuclear masses)
Charcot-Leyden crystals
Bacterial flora
Protozoa_Trophozoite of Ent histolytica
Structure that may be mistaken for trophozoite of Entamoeba histolytica
1. Trophozoite of Entamoeba coli
2. Macrophage with ingested RBCS.

Microscopic examination of stained smears is rarely done.