W5: intestine Flashcards
infectinous coligits(acute self limited): pathogens causing it
campylobacter jejuni
salmonella, shigella species,ecoli, yersinia enterocolitica
CONTAMINATED FOOD:e: Travellers Diarrhea, ETEC, EPEC, EHEC, EIEC etc. NORO
pathophysiological mechanism of infectious colitis
microorganism incae mucosa/produce enterotoxins..>epi injury and acute infla reaction–>eneterotocin–>alter transport of electrolytes and water
The ability of microorganisms to infiltrate the intestinal mucosa or produce enterotoxins
infectious colitis: clinically
abdomainal pain, diarrhea-bloody, fever
pseudomembranous colitis: pathogene
C.difficele
-antibiotic adminiastaion
-destruction of normal flora
TOXIC MEGACOLON
Indlammatory bowel disease include
crohn disease + ulcerative colitis
crohn disease
affect
key feature
micro
complicaiton
affect:TERMINAL ILEUM
-distal small and procimal large intesitne
key feature
-transmural
-discontinous
mciro:
-presence of non casefying infla granulomas
- affected part is thick. rigid liek a hose
- spreding ulcers in mucosa, mucosa btw them is swollen like cubes
-ulcer–>deeper linear(fissure)
-mesenteric LN enlathed
complication
-fistula and strictures
-fibrostenosisng
Also risk for adenocarcinoma but less than ulcerative
extrintestinal manifestation of chrons
athropathy, arthralhaos
mucocutaneos lesions: pyoderma, gangresoum, erythema nodosum
episclerative and uveits
cholelithiasis
ulcerative colitis
charcateristic clinical
key fetaure
micro
charcteristic:
-bloody diarrhea
key:
-limited to mucosa
-continous: RECTUM and extending proximally
mcir:
-normal thickness
-mucosa flattened, bloody
- diffuse lymphoplasmocytic infiltarte in lamina propina
-paneth cell metaplasia in left colon
-EROSINONS AND ULCERS:Intact mucosa between ulcers has the shape of “inflammatory pseudopolyps” !!!!!!!!!!!!!
Ulcerative colitis
-complications
- clinical
extrintestinal manifiestetion
complictions:
-toxic megacolon
-perfroation with peritonits
-adenomcarcinoma,
-pseudopolyos
-hemorrhage
clinically:
-procotos
-extensive colitis diarrhea, rectal bleeding abd pain, fever, weight loss
-fulminant colitis
etraintesinal ,amnif
-athropathy
-pri scelorising cholangitis -PSC
- episcleritis and uveitis
-mucocutanous lesion: erythrema nodosum, pyoderma
polyp defintiaiotn
localised projection above the surrounding colonic mucosa
Hamartomatous polyps
juvenile
polyposis syndrome, Peutz-Jeghers, PTEN hamartoma tumour syndrome)
peutx jeghers syndorme
AD
charcterized by mucocutanous pigmentaiton, hamartomatir poplups
most common polyp in colon
hyeperplastic:
-non dysplastic epi prolif
-asympt
-left colon and rectum
sessile serrated lesions/adenoma
Epithelial neoplasms with distinctive serrated epithelial architecture and associated risk for colorectal cancer
(serrated pathway of carcinogenesis)
o Precursor lesions for the carcinomas
traditional serrated adenomas
Serrated neoplastic precursor lesion for aggressive BRAF mutated microsatellite stable (MSS) subtype of colorectal
carcinoma
-ectopic prominent eosinophilic cytoplasm,ectopic crypts
conventional adenoma of colon
potential
classidication
where
clinically
the potential for transformation to invasive
carcinoma
* Types of conventional adenoma:
o Classified by architecture into
▪ Tubular
* Numerous tubular structures lined by dysplastic epithelium
▪ Villous
* Usually without stalk. Sessile. Micro: villous structures lined by dysplastic epithelium
▪ Tubulovillous
their epithelium is by definition dysplastic
- More common in the left hemicolon, but can involve any part of the large intestine
clinical: asymptomatoc, overt/occult rectal bleeding
msot of colonic cancers are
adenocarcinoma
most are in sigmoid colon and rectum
lynch sundrome
-AD
- younger age
-DNA MMR gene
- proximal colon
-incresed endometriu, ovary, stomach ,SI, UTM oancreas, hepatobiliary tract, skin, CNS
most commoon cause of inherited colorectal caner
familai adenomatous polyps-FAP
less than 1% of colorectal
-rectal bleeding, colicky abd pain diarrhea
-<5mm polyps
appencdicitis most common cause
obstruction in 50-80% du to FECALITH
also gallstone, tumor, enterobius vermicularis(worm), diffue lymphoid hyperplasia
children+elderlt over 60
pathophysio of acute appendicitis
pbstruction causes ^ontraluminal pressure, collapse of draining veins, ischemia, mucosal injury and ulceration
acute appendicitiso: clinicall and complicaiton
clinical:
- periumbilical to right lower quadrant pain
-nausea, vomiting
-abd tenderness
-mild fever
complicaiton
-wall abcess and perforation–>PERITONINTS
-phylephlebitis-inflammed thombosis of portal venous drainage
granulomatous appendicitis cause
-idiopathic
peritonitis
Peritonitis = inflammation of the peritoneum
* 2 form: bacterial and non-bacterial peritonitits
bacterial peritonits: causes
Causes:
- Perforation of an abdominal organ e.g.,
▪ Appendix
▪ diverticula
▪ severe ischaemia may lead to perforation
▪ tumours with ulcerative growth pattern which can perforate to the serosa surface - Peritoneal dialysis
▪ due to contamination of instruments or dialysate
!!!!!enteric organisms move from gut to the mesenteric lymph node and seed the ascitic fluid!!!!!!!!!!!!!
bacterial peritonitis: clinically
- Clinically:
o Acute abdomen, distention, severe abdominal pain and tenderness, nausea, vomiting, high fever
o Generalized peritonitis -> paralytic ILEUS and SEPTIC SHOCK
* Fibrinopurulent exudate covers the surface of the intestine -> fibrous adhesions between loops of bowel -> obstruction
of lumen (ileus)
* Such adhesions may lead to volvulus and intestinal obstruction
Non bacetrial/chemcial peritonitis cause
perforated GALLBLADDER,
perforated pepti ulcer
acute pancreatitis
foreign material in surgery
leakage of urine-pelivc trauma
blodo-endometriosis, abd trauma
A serious complication of acute peritonitis is
Generalized peritonitis and septic shock
A complication of overcome (suffered) peritonitis is:
Intestinal adhesion and ileus
Transverse (??) bacterial peritonitis may be:
Cirrhous complication by portal hypertension and ascites
ileus
disruption of the normal peristalsis of the GIT (failure of peristalsis) (=no movement in the GIT)
* Divided into mechanical obstruction and dynamic ileus
obturation ileus
-Due to intraluminal obstruction (e.g., by gallstone, foreign body, tumour)
-external compression of
lumen (e.g., by adhesions, tumour), or inside the wall (M. Crohn, strictures, tumour (esp. signet ring
cell carcinoma))
strangulation ileus
Intraluminal occlusion + compression of mesenteric (volvulus, intussusception, hernia
incarceration)
spastic ileus
Spasm of muscle (e.g., due to porphyria, poisoning, …)
paralytic ileus
Muscular and neurological disorders (e.g., by myasthenia, cerebrovascular accidents, ALS)
upper gi bleeding
Oesophageal varices
* Associated with liver cirrhosis and portal hypertension
▪ Mallory-Weiss tear
* Occurs after extensive coughing or vomiting
▪ Haemorrhagic gastritis
▪ Gastric ulcer
* Mainly peptic ulcers but also caused by tumours
* Mostly caused by Helicobacter pylori infection and NSAIDs
▪ Duodenal ulcer
SI bleeding
Ischaemic bowel disease
* May be due to obstruction of the main artery
▪ Intussusception
▪ Meckel diverticulum
lower intestinal bleeding
Anal fissure & Haemorrhoids
* Most common cause of LI bleeding
▪ Inflammatory bowel disease
* Ulcerative colitis
▪ Diverticulosis
▪ Colonic carcinoma
▪ Rectosigmoid carcinoma
▪ Angiodysplasia
hernia consist of
Neck, sac and contents
The protrusion of peritoneum with an organ or tissue through a defect in its surrounding abdominal walls
complication of abd hernia
-Irreducibility or incarceration, in which it cannot be reduced, or pushed back into place
- Obstruction of any lumen, such as bowel obstruction in intestinal hernias
-Strangulation -> ceased blood supply of the contents due to compression at the hernial orifice
diverticulim
blind puch leading off alimenatry tract lined by mucod that communicates with gut lumen
-congenital: 3 layers
-aquired: mucosa and submucsa
intestinal ischemia: causes
50%: arterial occlusion by thrombosis or embolizaiton
30%: nonocclusive intestinla ischemia: shcok, spesis, HF, MI, dehydraiton, hypotension, hypovolemia
10%: thrombosis of mesenteric veins
