Transcript colon path 1a oct 2.. - University of Illinois at Chicago

Pathology of the Gastrointestinal Tract
Part 1
Small and Large Intestines
Grace Guzman, M.D.
[email protected]
The Department of Pathology
University of Illinois at Chicago
Atresia and stenosis
 Congenital intestinal
obstruction
-Complete: Atresia
-Incomplete: Stenosis
 Duodenal: most common
-Jejunum and ileum: equal
-Rectum: rare
 Developmental failure
 intrauterine vascular
accidents, or
intussuception
 Imperforate anus
Meckel
Diverticulum
 Persistence of
omphalomesenteric duct
(vitelline duct)
 Disease of 2’s
-2% of population (mostly
asymptomatic)
-M:F 2:1
-2” in length
-2 ft of ileocecal valve
-2 types of ectopic tissue in
1/2 of cases (gastric and
pancreatic)
-2 major complications (pain
with inflammation;
hemorrhage with ulcer)
Congenital Aganglionic
Megacolon
“Hirschsprung Disease”
 Absence of ganglia
-submucosal (Meissner)
-myenteric (Auerbach)
Intestinal neuronal plexus
develop from neural crest cells
migrate to the bowel during development
Sporadic
Familial
 Alternating obstruction and
diarrhea
 Presents in neonatal
 Aganglionic segment causes
period (failure to pass
functional obstruction with
meconium; abdominal
distention proximal to
distention)
aganglionic segment
 Risk of perforation, sepsis,
 M:F 4:1 Down syndrome
enterocolitis, fluid
(10%)and (5%) serious
disturbances
neurologic abnormalities
Gentic defects:  Acquired (Chagas disease)
Endothelin 3
 1 in 5000 to 8000
GCDGF
Receptor tyrosine kinase
Enterocolitis
 Infectious
 Necrotizing
 Pseudomembranous
Infectious
-Viral (Rotavirus,
Norwalk)
-Bacterial
E. coli; Shigella; V.
Cholerae; C. difficile
-Parasites and protozoa
(nematodes; flatworms;
protozoa -Giardia
lambdia; E. histolytica)
Necrotizing
enterocolitis
 Acute, necrotizing
inflammation of small and/or
large intestines
 Most common acquired GI
emergency in premature or
low birth weight neonate
 Mild GI symptoms or
fulminant illness
 Multifactorial - immaturity of
the gut’s immune system
 Release of cytokines and
endotoxins damages mucosa
and blood supply
 Terminal ileum or ascending
colon
 Edema to necrosis to
gangrenous bowel
Pseudomembranous colitis
(antibiotic associated)
Dx: C. difficile cytotoxin in stool
Response to tx is usually prompt
Relapse occurs in up to 25% of px
 Yellow green false membrane
(mixture of mucous and
neutrophils)
 Toxin produced by Clostridium
difficile (acquired nasocomially
in 20% of pxs in long term
hospitalization)
 Antibiotics allow overgrowth
of C. difficile
 Sudden onset of fever and
diarrhea in a patient who is
seriously ill or post operative
who is receiving antibiotics
 diarrhea, dehydration, shock
Exotoxin A and B
death
binds to enteric receptors
inactivates RhO cytoplasmic proteins
causing injury to actin filaments and
cell retraction
Malabsorption
 Defect in the assimilation of food (digestion and absorption)
 Intraluminal stage
a. Secretory Phase (Chronic pancreatitis/insufficiency)
b. Biliary Phase (Biliary obstruction due to calculus of or
tumor)
 Intestinal Stage (terminal digestion)
a. Surface Phase (Celiac disease; bowel resection)
b. Cellular Phase (Disaccharidase deficiency)
 Removal Stage (transepithelial transport)
a. Delivery Phase (Whipple diease)
Celiac sprue
 Gluten, gliadin protein in
wheat, oat, barley, and rye
 hypersensitivity
(immunologic) reaction to
gluten
 90-95% - HLA DQ
heterodimer in Ch 6
 Whites - rare in native
Africans, Japanese, Chinese
 Gluten - malabsorption gluten free - improvement
 Long term risk of malignancy
-lymphoma (2X normal)
 Distinct from Tropical sprue
Celiac disease: loss of villi
increased crypts, inflammation,
intraepithelial lymphocytes,
loss of brush border,  goblet cells
Whipple disease
 Rare
 Gram positive rod
shaped actinomycete:
Tropheryma whippleli
 Engulfed by
macrophages (PAS
positive diastase
resistant)
 Electron microscopy
 M:F 10:1
Inflammation
 1. Miscellaneous
-graft vs. host
-drug induced
-radiation enterocolitis
-neutropenic colitis
-diversion colitis
 2. Acute appendicitis
-etiology: bacteria
-fecalith impairing circulation,
causing ischemia, necrosis
and bacterial contamination
-acute abdomen -RLQ painMcBurney’s point
-fever and leukocytosis
Inflammation
3. Collagenous and lymphocytic colitis
 Etiology: unknown
 possibly auto-immune
 chronic watery diarrhea in
middle aged and older
women
 spectrum of disease ranging
from increased
intraepithelial lymphocytes
to the presence of collagen
band under the surface
epithelium
Idiopathic Inflammatory
Bowel disease
Inflammatory
bowel disease
(IBD) - single term
to collectively refer
to either Crohn
disease or
ulcerative colitis
Etiology unknown
a. Genetic
predisposition:HLA
Class II locus on
Ch 6
b. Abnormal host
immunoreactivity
Crohn disease:
Regional enteritis
1. Chronic inflammation
involving all layers
(transmural) of the SI
 may occur at any point
along the GI tract
 primarily involving SI
and LI
2. Mucosa shows linear
ulceration and fistula
3. Segmental
involvement/sparing
 Serosal creeping fat
Crohn disease:
Regional enteritis
 Inflammation spread
through the bowel wall to
adjacent mesenteric fat
 -characteristic noncaseating granulomas
 tends to occur in young
adults
 increased incidence of
cancer of SI and colon
 diarrhea, crampy
abdominal pain, fever
 complications: fistula,
obstruction, occult blood
loss, Fe++ def anemia
 malabsorption,
malnutrition, weight loss
Ulcerative
colitis
1. Inflammation primarily
involving the mucosa of
the colon
2. Diffuse, continuous
inflammation that begins
in the rectum and
progresses proximally
3. Pseudopolyp formation
4. Bloody diarrhea, from
ruptured vessels in
inflamed mucosa
 Toxic megacolon - rare
complication - prominent
dilatation and septic shock
Ulcerative
colitis
 Early phase: neutrophils
accumulate within the
depths of the crypts of
Leiberkuhn forming crypt
abscesses
 Later phase: mucosa
ulcerates and pseudopolyps form
 Late phase: after many
years, mucosa becomes
dysplastic, increasing risk
of colon carcinoma
Between Crohn and UC, this finding is more
commonly seen in:







Transmural inflammation
pseudopolyp
granuloma
diffuse
skip lesions
toxic megacolon
creeping fat
 Primary Sclerosing Cholangitis




fissures and fistulas
Cancer
at any point in GI tract
Rectum












Crohn
UC
Crohn
UC
Crohn
UC
Crohn
both but more in UC
Crohn
both but more in UC
Crohn
UC
Vascular diseases:
a. Ischemic bowel disease
b. Angiodysplasia
c. Hemorrhoids
 Ischemic bowel disease
 -blood clot in mesenteric
artery causing ischemia,
transmural infarction,
necrosis of bowel,
peritonitis
a.embolus: superior
mesenteric artery
-source: embolus of heart
(mural thrombus, valvular
vegetation)
b. thrombus (arterial;
venous: ATIII def,
cirrhosis, OC)
c. hypoperfusion (nonocclusive): shock, CHF
50-75% death rate
older px with cardiac, vasc disease
D/Dx: IBD
Vascular diseases:
a. Ischemic bowel disease
b. Angiodysplasia
c. Hemorrhoids
 Angiodysplasia
 -ectasia of veins
 -prone to rupture 20% of significant LGI bleed
 -GI bleeding
 -Osler-Weber-Rendu
syndrome (hereditary
hemorrhagic telangiectasia)
Prevalence:<1%
5% of population
 Hemorrhoids
elevated venous pressure
constipation
 -dilated veins of
straining venous stasis of pregnancy
channels in portal HTN
hemorrhoidal plexus collateral
rare under 30 except in pregnant women
 -Internal
 -External
 -(BRBPR or streaks on
stool), thrombosis, pain
Non-neoplastic bowel diseases
a. Diverticular disease
b. Hernias
c. Adhesions
d. Intussusception
e. Volvulus
 Diverticular disease:
Acquired
under 30
 Diverticulosis and rare
western pop over 60
prevalence: 50%
Diverticulitis
 Acquired herniation
 Most common in left colon;
particularly sigmoid colon
 Acute or chronic
inflammation may occur
 Perforation, peritonitis,
fistula
Non-neoplastic bowel diseases
a. Diverticular disease
b. Hernias
c. Adhesions
d. Intussuception
e. Volvulus
 Hernias
-Serosal lined out-pouching
of peritoneum
-Loop of intestines becomes
trapped (incarcerated)
within the hernia sac
-Bowel compressed, twisted
at the mouth of hernia,
compromising blood supply
- infarction (strangulation)
Non-neoplastic bowel diseases
a. Diverticular disease
b. Hernias
c. Adhesions
d. Intussuception
e. Volvulus
 Adhesions
 -string-like or band-like portions of scar tissue that form
during healing after surgery or peritonitis
 -may result in obstruction (kinking, compression)
Non-neoplastic bowel diseases
a. Diverticular disease
b. Hernias
c. Adhesions
d. Intussusception
e. Volvulus
 Intussusception
 -caused by an in-folding or telescoping of one segment of
bowel into the adjacent distal segment
 Infants and children: spontaneous and reversible
 Adults: tumor is usually a lead point
Non-neoplastic bowel diseases
a. Diverticular disease
b. Hernias
c. Adhesions
d. Intussuception
e. Volvulus
 Volvulus
 -obstruction due to
rotation or twisting of a
loop of bowel around its
mesenteric base of
attachment
 Sigmoid - most common
site (cecum next)