Post on 22-Mar-2018
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Pathology(for international students)
Zhou Ren M.D., Ph.D
Institute of Pathology & Forensic Medicine
Department of Pathology & PathoPatho--physiologyphysiology
Centre of Centre of Forensic Science & Technology ServicesTechnology Services
Zhejiang Univeristy
It is caused by Entamoeba histolytica excystation
cysts──→(small) trophozoites──→ cysts
↓
(large) trophozoites
Pathogenicity(1)Contact lysis of (large) trophozoites(2)Mechanical damage and phagecytosis(3)enterotoxin(4) The effect of enterobacteria(5)The susceptiblity of adult male and female(6) Decreased host defense function
(1)In acute stage
– Scattered foci of flask shaped ulceration(a narrow neck and a broad base) surrounded by edematous mucosa.
– Normal-looking mucosa between the ulcers
Grossly:
– undermining ulceration (flask-shaped)– Relative absence of inflammatory
infiltration– Ameboid trophozoites(that often have
phagocytized red cells) in the margins of ulcers
Microscopically:
Clinicopathologic Association
mild cramps, which increases gradually in severity, diarrhea, and, occasionally, melena or sauce-like feces
(2) In chronic stage
Proliferation of mucosal epithelium and formation of polypsProliferation of fibrous connective tissue and scar formation made the lumen narrowed.amoeboma : focal masses formed by excessive proliferation of granulation tissue in chronic amoebiasis
Extraintestinal amoebiasis1. amoebic abscess of liverA complication of amebic dysentery , brought about by amebic entering colonic venules and passing by the portal vein to the liver.liquefaction necrosis, not a true abscess.
MacroscopicallyUsually a single ‘abscess’,most often in the upper part of the right lobe.The lesion has a compressed fibrous capsule, with an irregular shaggy necrotic inner wall and the cavity contains thick paste-like material rather than pus, often chocolate-colored or showing admixture of blood.
Microscopically
The contents include necrotic liver cell debris and a varying number of red cells.Trophozoites may be numerous or scanty in the wall of the cavity Only a few neutrophils are present
Three species:a. Schistosoma hematobium b. Schistosom mansonic. Schistosom japonicum
Oncomelania snailEgg ─→ miracidium ─────→ cercaria ─→
schistosomulum ─→adult schistosome
Etiology and transmission route
Basic lesions and pathogenesis
1.Penetration of the skin by cercariae caused a transient local inflammatory reaction: Cercarial dermatitis
3. Lesions caused by eggs: the main lesion of Schistosomiasis
(1) Acute egg nodule (eosinophilic abscess) : In schistosomiosis, eggs surrounded by many
eosinophils and like abscesses. Hoeppli phenomenonCharcot-Leyden crystal
(2) Chronic egg nodule (pseudotubercle):
In schistosomiosis, eggs surrounded by epithelioid cell, multinuclear giant cell; eggs are often necrotic or calcified. This structure is like that of a tubercle. It is a granuloma.
In schistosomiosis, eggs surrounded by many eosinophils and like abscesses.
Hoeppli phenomenonCharcot-Leyden crystal
In schistosomiosis, eggs surrounded by epithelioid cell, multinuclear giant cell; eggs are often necrotic or calcified. This structure is like that of a tubercle. It is a granuloma.
In schistosomiosis, eggs surrounded by epithelioid cell, multinuclear giant cell; eggs are often necrotic or calcified. This structure is like that of a tubercle. It is a granuloma.
Infectious DiseasesEPIDEMIC CEREBROSPINAL MENIGITIS/MENI-
GOCOCCAL MENIGITISType B Epidemic EncephalitisBacillary dysenteryTyphoid Fever
Sexually Transmitted Diseases Acquired Immunodificiency Syndrome (AIDS)Condyloma acuminatumSyphilisGonorrhea
Parasitic DiseasesAMOEBIASISSchistosomiasis
inflammations
Briefly summary: