4 Prevalent in the third world country Outbreaks are rare,but in some areas such as in Indonesia and New Guinea,it ranks among the 5 most common causes of death Bacterial infection of the intestinal tract and occasionally the bloodstream The ileum is most affected
5 Mononuclear Phagocytic System(MPS): Monocytes and its derivations mononuclear cells (blood) macrophages (connective tissue) kupffer cells (liver) ……….. Typhoid fever is characterized by macrophages Proliferation of MPS, which are particularly predominant in ileum.
6 The germ that causes typhoid is a unique human strain of salmonella called Salmonella typhi Gram negative bacillus. O-Ag, H-Ag, vi-Ag (Widal reaction) Pathogenesis
7 Infection source ： typhoid fever patient and carrier route of transmission ： fecal-oral route susceptible population:children and young people Food, fly, finger, water
8 Salmonella typhi Contaminanted food Proliferate in ileum tissue bacteremia First contactWhole body Gall bladder second contact Lymph tissue in ileum Septicaemia Hyperplasia stage (1w) Toxemia Excretion Necrosis and ulceration (2w) Healing (1w) Incubation period(10 d)
10 Pathological changes Hallmark histologic finding:the infiltration of tissue by typhoid cells typhoid cells:large macrophages contain Phagocytized erythrocytes, lymphocytes, bacteria and necrotic cellular debris Typhoid nodule (typhoid granuloma) : the aggregates of typhoid cells
11 Typhoid nodule can present in the lymph tissue of small intestine, mesenteric lymph node, the liver, spleen and marrow, its typical changes often occur in the lower part of ileum, especially in the Peyer‘s patches and Isolated lymphonodulus.
17 Intestinal pathological changes The principal lesions are those of lymphoid tissue of terminal small intestine. (1) Hyperplasia Stage ( Peyer’s patches) (2) Necrosis Stage; (3) Ulceration Stage; (4) Healing Stage.
18 Hyperplasia stage ： the 1st w after onset lymphoid tissue swelling protrude out the mucosa, looks like lymphoid tissue swelling protrude out the mucosa, looks like cerebral convolution
19 Showing the hyperplasia of Peyer’s patches of ileum, which is button-like elevation Hyperplasia stage
20 Hyperplasia stage looks like cerebral convolution
21 Hyperplasia stage looks like cerebral convolution
25 the 2nd w after onset multi-focal necrosis in lymphoid tissueNecrosis stage ： the 2nd w after onset multi-focal necrosis in lymphoid tissue
26 Ulceration stage ： the 3rd w after onset ， necrosis tissue fall off and ulcer formation, longitudinal ulceris parallel with the axis of longitudinal ulcer is parallel with the axis of intestinal canal, deep to the muscularis layer and involve the artery,which will result in bleeding
27 Key features ： Round or oval Elevated margins Uneven bottom Parallel to the axis of intestine ulceration stage
28 ulceration stage Key features ： Round or oval Elevated margins Uneven bottom Parallel to the axis of intestine
38 Bacillary Dysentery Chengcheng You Dept. of pathology China Three Gorges University
39 Bacillary dysentery is an acute bacterial infection caused by the genus Shigella resulting in colitis affecting predominantly the rectosigmoid colon. The disease is characterized by diarrhea, dysentery, fever, abdominal pain, and tenesmus. It is usually limited to a few days. Mainly occur in infants and young children Mainly occur in infants and young children
40 Pathogen Shigellae are nonmotile gram-negative bacilli belonging to the family Enterobacteriaceae Four species: S. dysenteriae (group A), S. flexneri (group B), S. boydii (group C), S. sonnei (group D).
41 Incidence most cases of shigellosis occur in children of developing countries S. flexneri is the predominant species Children between 1 and 4 years old
42 Infection source ： patient and carrier route of transmission ： fecal-oral route Susceptible population:children and young people seasonal patterns: autumn and summer
43 PATHOGENESIS organisms traverse the small bowel, penetrate colonic epithelial cells and multiply intracellularly acute inflammatory response pseudomembranous type of colitis Epithelial cells containing bacteria are lysed, resulting in superficial ulcerations and shedding of shigella organisms into stools Diarrhea results because of impaired absorption of water and electrolytes by the inflamed colon
44 Feature Location: predominantly the rectosigmoid colon Clinical type : l Acute bacillary dysentery l Chronic bacillary dysentery l Toxic bacillary dysentery
55 Clinic Feature Symptoms begin with sudden onset of high grade fever, abdominal cramps and watery diarrhoea. Subsequently diarrhea become mucoid, of small volume and mixed with blood. This is accompanied by abdominal pain and tenesmus. Physical signs are those of dehydration beside fever, lower abdominal tenderness and normal or increased bowel sounds.
56 Chronic bacillary dysentery lasting more than 2 months, infected by S.flexneri( 福氏菌 ). Clinical features ： Mild symptom of abdominal pain,diarrhea Infectious source pathological changes ： ① chronic ulcers; ② forming polypi ; ③ intestinal wall are fibrosis.
57 Toxic bacillary dysentery Children at the age of 2-7 years old are sensible most are result from S.sonnei and S.flexneri. clinical features ： ① toxic symptom all over the body: Toxic shock 、 respiratory or circulation failure. ② intestinal symptom: mild
58 Questions for the class bacillary dysentery 1.What kind of inflammation is involved in bacillary dysentery? typhoid granuloma 2.The definition of typhoid granuloma