Transcript Document

GIT 2
New
Dr. Basu
Topic
• Malabsorption
• Diarrhea and Dysentery
• IBD
– Ulcerative colitis
– Crohns disease
Malabsorption : Classification
•
Diagnosis: Steatorrhea, fat soluble vitamin
Deficiency, protein and other deficiency.
1. Celiac sprue
2. Whipple disease
3. Disaccharide deficiency
Celiac sprue
Celiac sprue
(chronic
sprue)
Morphology
Clinical
Antigen involved: gluten. GeneticHLA-DQ2 or HLA-DQ8.
Atrophy of Villi, increased number
of intraepithelial lymphocytes (
CD4 and CD8 cells).
Diarrhea, flatulence, weight loss,
and fatigue, dermatitis
Respond to gluten free diet.
Normal
Atrophy of Villi
Complication of celiac sprue: Dermatitis
Herpitiformis and NHL.
Tropical sprue
• Definition : malabsorption due to unknown
( ? Infection) etiology.
• Location: Caribbean and South America
• Treatment: antibiotics and B12
supplements.
WHIPPLE DISEASE
WHIPPLE
DISEASE
Morphology
Other organ
involvement
Etiology: Bacterium Tropheryma
whippelii
Macrophages contain PASpositive, diastase-resistant
granules and rod-shaped bacilli
on electron microscopy
GIT, CNS, Joint and lymph nodes
Clinical Features
Age: 40-50 yr.
Malabsorption, Arthropathy, psychiatric
complaints and Lymphadenopathy.
Light microscope (H&E)
Foamy macrophage in villi.
Electron microscopy
LACTASE DEFICIENCY
Etiology : Atrophy of the apical villous cells>
deficiency of lactase.
Clinical :
The infants develop explosive, watery,
frothy stools and abdominal distention.
Osmotic diarrhea with milk product.
Termination of which result in recovery.
Vitamin deficiency
Vitamin A
Vitamin K
Vitamin D
Vitamin E
Vitamin B12
Night blindness, xerophthalmia,
blindness, Squamous metaplasia,
infection.
Bleeding diathesis- not corrected by k
injection.
Rickets in children, Osteomalacia in
adults.
Spinocerebellar degeneration
Megaloblastic pernicious anemia and
myelin loss of spinal cord tracts.
DIARRHEA AND DYSENTERY
DIARRHEA AND DYSENTERY
• DIARRHEA Def; An increase in stool
mass, stool frequency, and/or stool fluidity
are perceived as diarrhea.
• DYSENTERY: Dysentery is a severe
diarrhea illness often associated with
blood in the feces.
Diseases
Viral enterocolitis
Rota virus (dsRNA): child and
self limiting.
Adenovirus (dsDNA): adult
/child
E. coli - Shiga-like Hemorrhagic colitis and
toxin
Hemolytic-Uremic syndrome
(Undercooked
(HUS): Hemolysis, Acute
beef products:
Renal failure and DIC.
hamburger)
Others
• Staphylococcus aureas :
– Source is milk product and fatty food → Acute
explosive Exudative diarrhea.
– Within a few hours (1-6 hr)
• Vibrio cholera:
– Source is Water → Watery diarrhea, cholera,
pandemic spread.
– Morphology of GI: normal mucosa
Cholera: pathogenesis of diarrhea
Cholera toxin A1
↓
A1+ ADP-ribosylation factors (ARF)
↓
catalyzes G protein
↓
stimulates adenylate cyclase
↓
high levels of intracellular cAMP
↓
stimulates secretion of chloride and bicarbonate, with
associated sodium and water secretion.
Others
Salmonella enteritidis→
Milk, beef, eggs, poultry
Self limiting diarrhea /
dysentery pain,
bacteremia.
Incubation: 12 to 72 hr
Shigella: Person-to-person.
Milk, poultry
S. flexneri infection produce
Reiter syndrome (chronic
arthritis , red eye- conjunctivitis).
Fever, pain, mucosal
ulcer.
Exudative diarrhea
,dysentery, epidemic
spread
Clostridium difficile
Clostridium difficile →
Following antibiotic
use, nosocomial
acquisition: Cytotoxin,
local invasion
Fever, pain, bloody
diarrhea, pseudo
membrane formation
over mucosa.
Neural reflex pathways increases epithelial fluid secretion
In addition to
production intracellular cAMP
Pseudomembranous colitis from C. difficile
infection morphology
Study unknown picture
Campylobacter Enterocolitis
Source: dog, ingestion of improperly cooked
chicken.
Clinical: Diarrhea, dysentery.
Complications:
Reactive arthritis in HLA-B27 carriers
Guillain-Barré syndrome- myelin loss (PNS).
C. jejuni: immunoproliferative small intestinal
disease.
Amebiasis
Agent
Entamoeba histolytica (ameba)
Route
Fecal oral
Morphology
Produce flask shaped ulcer in
submucoca.
Abdominal pain, bloody exudative
diarrhea, or weight loss and
amebic liver abscess- right
upper Q pain.
Clinical
features
Rest a while
Other intestinal disorders
• Necrotizing Enterocolitis
• Idiopathic Inflammatory Bowel Disease
Necrotizing Enterocolitis
Definition
An acute, necrotizing inflammation of
the small and large intestines
Age
Neonate : premature or of low birth
weight, when infants are started on
oral foods
Necrotizing Enterocolitis
Pathogenesis: factor
• Intestinal ischemia
Clinical course : Bloody stools,
abdominal distention, and
development of circulatory
collapse.
Site: involves the terminal
ileum, cecum, and right
colon.
Morphology of the gut: gross and micro
• Distended, friable, and congested, or it
can be frankly gangrenous.
• Accompanying peritonitis may be seen.
• Morphology: sub mucosal gas bubbles
formation.
Distended
intestine
Submucosal
gas bubbles
Prognosis
• High mortality
• Post-NEC stricture is COMMON.
Idiopathic Inflammatory Bowel
Disease
• Type
• Pathogenesis
• Comparative morphology of these two
diseases
• Complications and clinical features
• Diagnosis
IBD
•
Types:
– Crohns disease
– Ulcerative colitis
•
Pathogenesis:
A. Exaggerated local CD4 T-Cell immune
response- damage to mucosa
B. Inflammation
Crohn disease
• Features:
– Occur any part of GIT
– Transmural inflammation .
– Noncaseating granulomas.
– Fissuring with formation of fistulae.
– Smoking is a risk factor.
– Recurrent diarrhea, pain, fever common.
– Blood in stool 50%.
Ulcerative colitis
• Features:
– Disease limited to the colon and
affecting only the mucosa and sub
mucosa.
– Smoking is a risk factor.
– Bloody mucoid diarrhea more
common.
Gross
Crohn disease ( gross)
Any part of bowel :
common in ileocecal
junction (regional ileitis)
Produce “skip” lesions.
Transmural inflammation.
Cobblestone effect
Ulcerative colitis ( gross)
Large intestine: Pan
colitis.
Rectum→ colon: back
wash ileitis
No skip lesion, entire
length of bowel is
involved.
Mucosal involvement
Pseudo polyps
Gross
Crohn disease ( gross)
Diseased wall is
rubbery and thick
Linear ulceration
Mesenteric fat wraps
around the bowel
surface (creeping fat).
Ulcerative colitis (
gross)
Mural thickening does
not occur in UC
Broad-based ulceration
No such features
Crohn disease : Diseased wall is rubbery and
thick and lumen is narrow that give rise to
String sing on X-ray
Study unknown picture
Gross of Ulcerative colitis :Pseudopolyps
Microscopy of IBD
Crohn disease
Ulcerative colitis
Non Caseating
granuloma
Crypt abscess
Pseudopolyps
Dysplasia +
Ulcerative colitis; crypt abscess and glandular
architectural distortion and dysplasia.
Study unknown picture
IBD: complication
Ulcerative colitis
Complication:
Toxic megacolon
Adenocarcinoma.
Crohn's
Complication:
Fistula and fissure,
obstruction
Fistula with other organ like
U. Bladder, vagina and,
skin (Enteroculaneous
fistula)
Toxic mega colon in UC
No motility, lead
pipe
Crohn disease: Fissure
Extra intestinal manifestation of IBD
Crohn disease
Ulcerative colitis
Migratory poly arthritis
++.
Aphthous ulcer.
Migratory poly arthritis ++++
Uveitis++++++++
Hepatic primary sclerosing
Cholangitis +++++++
Erythema nodosum
(painful skin lesionshow similar granuloma)
Diagnosis/ treatment of IBD
Crohn disease
Ulcerative colitis
Surgery not helpful
Surgery helpful with
steroid
pANCA : +
pANCA: ++++++++,
HLA B27
Irritable Bowel Syndrome
• Intrinsic motility disorder ( ? Due to foods,
stress- serotonin).
• Clinical: altered bowel habits, frequently
suffering from constipation, diarrhea, or both.
• The episodes may subside with a bowel
movement
Thank you