Transcript The Gastrointestinal Tract

The Gastrointestinal Tract
GI – Congenital Anomalies
Atresias, fistulae, duplications, stenosis
Esophageal atresia usually associated
with TE fistula
Imperforate anus – most common
form of congenital intestinal
atresia, failure of the cloacal
diaphragm to involute
GI – Congenital Anomalies
Diaphragmatic hernia – incomplete
formation of the diaphragm
allowing the abdominal viscera to
herniate into the chest,
associated with pulmonary
hypoplasia
Omphalocele – abdominal musculature
incomplete, abdominal viscera
into a ventral membranous
sac
is
herniate
Gastroschisis – defect in all the layers of the
abdominal wall from peritoneum to the skin
GI
Ectopia (developmental arrests) – common in the
GI tract, e.g. inlet patch (gastric
mucosa in
upper 1/3 of the esophagus)
Meckel diverticulum – blind outpouching
of
the alimentary tract that is lined by
mucosa, communicates with the lumen,
includes all three layers of the bowel
wall,
“rule of 2’s” – 2% of the
population, within 2
feet of the ileocecal valve, twice as common in
males than
females, most often symptomatic
by age
two
GI – Congenital Anomalies
Pyloric stenosis
Males > females
Associated with Turner, Trisomy 18
2nd -3rd week of life
New-onset regurgitation
Persistent projectile vomiting
Hyperperistalis, firm ovoid mass “olive”
Hirschsprung Disease
Congenital aganglionic megacolon
Failure of the normal migration of neural crest cells from cecum to
or ganglion cells undergo premature death
Functional obstruction
Megacolon
Failure to pass meconium in immediate post-natal period
RET mutation
rectum
GI - Esophagus
Obstruction
Nutcracker esophagus
Diffuse esophageal spasm
Zenker diverticulum
Traction diverticulum
Epiphrenic Diverticulum
Stenosis – most often due to
inflammation and scarring
Esophageal webs – Plummer-Vinson
syndrome (Paterson-Brown-Kelly)
Esopahgeal (Schatzki) rings
Achalasia – incomplete LES relaxation, increased
LES tone, and aperistalsis of the esophagus
GI-Esophagus
Esophagitis
Lacerations – Mallory-Weiss syndrome
linear lacerations associated with
prolonged vomiting
Chemical and Infectious – pillinduced, chemotherapy,
radiation therapy, GVH, HSV,
fungal, bullous pemphigoid,
bullosa, Crohn
disease
Reflux – GERD –most frequent cause of
esophagitis, most common cause of
diagnosis in US, hiatal hernia
Eosinophilic – atopic individuals
CMV,
epidermolysis
GI
GI - Esophagus
Barrett esophagus – intestinal metaplasia
within the esophageal squamous
mucosa, increased risk of esophageal
adenocarcinoma, red,velvety
mucosa,
goblet cells, may progress to
dysplasia
GI - Esophagus
Esophageal varices
Portal hypertension, collateral
circulation, cirrhosis –most commonly due
to alcoholic liver disease,
schistosomiasis, massive hematemesis
GI- Esophagus
Esophageal tumors
Adenocarcinoma – GERD, Barrett
esophagus, increasing incidence.
difficulty swallowing, progressive
weight loss, hematemesis, chest
pain, vomiting, distal third
Squamous cell carcinoma – alcohol,
smoking, prior radiation therapy,,
HPV, high-risk areas: Iran, China,
Hong Kong, Brazil, South Africa,
middle third, insidious onset
GI - Stomach
Acute gastritis
Transient mucosal inflammatory
process
Histologically – continuum from
moderate edema and
congestion of the lamina propria
with an intact epithelium to
acute erosive hemorrhagic
gastritis
GI - Stomach
Acute gastric ulceration
Stress ulcer
Curling ulcer
Cushing ulcer
Complications
Bleeding – most frequent
Perforation – accounts for 2/3 ulcer
deaths
Obstruction - pyloric
GI-Stomach
Chronic gastritis
Symptoms less severe, more persistent
Most common cause is infection with
H.pylori –spiral shaped or curved
bacilli – present in gastric biopsy
specimens of all most everyone
with
duodenal ulcers and the
majority with
gastric ulcers and
chronic gastritis
GI – Stomach
H.Pylori- flagella, urease, adhesins, toxins
Predominantly antral gastritis with high acid production
despite hypogastrinemia
May progress to involve the entire stomach
with multifocal mucosal atrophy, reduced
acid
secretion, intestinal metaplasia, increased risk of gastric
adenocarcinoma
Intraepithelial neutrophils, subepithelial
plasma cells, pit abscesses, mucosal – associated
lymphoid tissue (MALT)
GI-Stomach
Autoimmune gastritis
Hypergastrinemia
Antibodies to parietal
cells and
intrinsic factor
Antral endocrine cell
hyperplasia
Reduced serum
pepsinogen I
concentration
Vitamin B12
deficiency
Defective gastric
acid secretion
(achlorhydria)
Damage to the oxyntic (acidproducing cells)
Clinical- atrophic glossitis,
epithelial megaoblastosis,
malabsortive diarrhea, anemia,
peripheral neuropathy, spinal
cord lesions, cerebral dysfunction
GI- Stomach
Reactive gastropathy
Eosinophilic gastritis
Lymphocytic gastritis
Granulomatous gastritis
GI - Stomach
Complications of chronic gastritis
Peptic ulcer disease:
Imbalances of mucosal defenses and damaging forces that
cause chronic gastritis are also responsible for PUD
H.pylori -85%-100% duodenal ulcers
65% gastric ulcers
NSAID use
Sharply punched-out defect, round to oval, four times more
common in the duodenum (usually anterior wall near pyloric
valve) than in the stomach (along the lesser curvature)
Clinical – epigastric burning or aching pain, 1-3 hours after
eating, worse at night, relieved by alkali or food
GI-Stomach
Complications of chronic gastritis
Mucosal atrophy and intestinal
metaplasia:
Increased risk of gastric
adenocarcinoma
Dysplasia
Gastric Cystica:
Exuberant reactive epithelial proliferation
with entrapment of
epithelial-lined cells
GI - Stomach
Hypertrophic Gastropathies
Menetrier disease- excessive
production of TGF-alpha,
hyperplasia of folveolar mucous
cells,
hypoproteinemia
Zollinger-Ellison syndrome –gastrinsecreting tumor (usually small
intestine or pancreas), increase in
number of parietal cells,
duodenal ulcers, diarrhea,60-90%
are
slow-growing malignant, 255
associated with
MEN-I
GI- Stomach
Gastric polyps and tumors
Inflammatory and hyperplastic polyp- most common,
frequently multiple
Fundic gland polyp – associated with PPI use
Gastric adenoma
Gastric adenocarcinoma-loss of E-cadherin
function seems to be key step in
development, signet-ring cells, linitis plastica,
Virchow’s node, Sister Mary joseph node
Lymphoma – MALToma,
Carcinoid tumor- well-differentiated
neuroendocrine tumor, location is most important
prognostic factor, flushing, diarrhea, sweating,
bronchospasm, colic, right-sided cardiac vavular
fibrosis
GIST (GI stromal tumor)- tyrosine kinase c-KIT gene mutation,
NF type 1
Small Intestine and Colon
Obstruction
Hernias, adhesions, volvulus,
intussusception
Ischemic bowel disease
Mucosal and mural infarctions
Chronic ischemia
CMV infection
Radiation enterocolitis
NEC
Angiodysplasia
Malformed submucosal and mucosal blood
intestinal bleeding, most often cecum or right colon
vessels, lower
Small Intestine and Colon
Malabsorption
Defective absorption of fats, vitamins, proteins,
carbohydrates, electrolytes, minerals, and water
Steatorrhea – excessive fecal fat
Most common disorders in US –
disease, Crohn disease
pancreatic insufficiency,
Disturbance in at least one phase of digestion:
intraluminal transport
terminal digestion
tranepithelial transport
lymphatic transport
Clinical – diarrhea, flatus, abdominal pain, weight loss
celiac
Small Intestine and Colon
Diarrhea
Increase in stool mass, frequency, or
fluidity ,> 200g per day
Dysentery – painful, bloody, smallvolume
Categories
Secretory
Osmotic
Malabsortive
Exudative
Small Intestine and Colon
Celiac disease
Celiac sprue or gluten-sensitive
enteropathy
Immune-mediated
HLA-DQ2 or HLA-DQ8
Intraepithelial lymphocytosis (CD8+ T cells), crypt
hyperplasia, villous atrophy
Dermatitis herpetiformis
Lymphocytic gastritis or colitis
Enteropathy-associated T cell lymphoma
Small intestinal adenocarcinoma
Small Intestine and Colon
Tropical sprue
Autoimmune enteropathy
Lactase deficiency – congenital or
Abetalipoproteinemia
acquired
Small Intestine and Colon
Infectious enterocolitis
Cholera – Vibrio cholerae,
contaminated drinking water,
shellfish,
non-invasive, enterotoxin
causes secretory
diarrhea via
increase in cAMP, “rice water”
stools
Campylobacter – Most common
bacterial enteric pathogen in
developed
countries, traveler’s diarrhea, improperly cooked
chicken, dysentery,
enteric fever, reactive arthritis,
erythema nodosum, Guillain-Barre, invasive
Small Intestine and Colon
Shigellosis – Bloody diarrhea, Reiter syndrome, Shiga toxin – HUS, in endemic areas is
responsible for 75% of diarrheal deaths
Salmonellosis – nontyphoid infection, meat (poultry), milk, eggs, antibiotics can
prolong carrier state,
Typhoid fever – enteric fever, gallbladder colonization, hyperplasia of lymphoid
tissues, oval ulcers that may perforate in ileum, typhoid nodules, bacteremia, rose
spots, extraintestinal complications, sickle cell disease-osteomyelitis
Yersinia – pork, raw milk, contaminated water,lymph node and Peyer’s patch
hyperplasia, pharyngitis,arthralgia, erythema nodosum, reactive arthritis, Reiter
syndrome, myocarditis, GN,thyroiditis
Small Intestine and Colon
Escherichia coli – (most E.coli are
nonpathogenic)
ETEC – principal cause of traveler’s
diarrhea, secretory diarrhea
EHEC – HUS, 0157:H7, ground beef
EIEC – invade epithelial cells
EAEC – adherence fimbriae
Small Intestine and Colon
Pseudomembranous colitis-Clostridium. Difficile,
antibiotic-associated, overgrowth of organism,
toxins, eruption of damaged crypts leads to
pseudomembrane formation
Whipple disease – Tropheryma whippelii
(gram-positive actinomycete), organism-laden
macrophages accumulate causing lymphatic
obstruction  malabsorption, arthritis, fever,
lymphadenopathy, neurologic, cardiac, pulmonary
disease
Small Intestine and Colon
Viral gastroenteritisNorovirus –cruise ships,schools,
nursing homes
hospitals,
Rotovirus – the most common cause
of
severe childhood diarrhea and diarrhea
mortality worldwide, vaccine
Adenovirus –second most common
cause of pediatric diarrhea
Small Intestine and Colon
Parasitic enterocolitis –
Ascaris lumbricoides-hepatic abscess,
pneumonitis, intestinal obstrution
Strongyloides - autoinfection
Necator duodenale and Ancylostoma duodenale
– hook worms, iron deficiency anemia
Enterobius vermicularis - pinworms
Trichuris trichura – whipworms, rectal prolapse
Schistomiasis – granulomatous reaction
Intestinal cystodes - tapeworms
Entamoeba histolytica – dysentery, hepatic abscesses
Giardia lamblia – most common pathogenic parasitic
infection in humans
Cryptosporidium – chronic diarrhea in AIDS
Small Intestine and Colon
Irritable Bowel syndrome – diagnosis of
exclusion
Inflammatory Bowel Disease – idiopathic,
combination of defects in host interactions with
intestinal microbiota,
intestinal epithelial
dysfunction, and aberrant mucosal immune responses,
hygiene hypothesis
Crohn disease
Ulcerative colitis
Small Intestine and Colon
Crohn disease
Any area of GI tract
Most common terminal ileum, iliocecal
valve, cecum
Skip lesions, aphthous ulcers, creeping fat,
transmural inflammation,
noncaseating granulomas, ,
fistulas and strictures,
malabsorption
Clinical – intermittent attacks of fever,
diarrhea, and abdominal pain
Extra-intestinal – uveitis, migratory polyarthritis,
sacroillitis,, skin lesions, primary sclerosing
cholangitis
Small Intestine and Colon
Ulcerative colitis
Pancolitis to proctitis
Backwash ileitis
Broad-based ulcers, pseudopolyps,
inflammation diffuse and limited
the mucosa
Toxic megacolon
Extra-intestinal – same as Crohn
Increased inidence of neoplasia
to
Small Intestine and Colon
Indeterminate colitis
Diversion colitis
Microscopic colitis
Sigmoid diverticulitis
Small Intestine and Colon
Polyps
Sessile vs Pedunculated
Inflammatory-solitary rectal ulcer
syndrome
Hamartomatous – Juvenile, PeutzJeghers ,Cowden, BannayanRuvalcaba , Cronkhite-Canada,
Tuberous Sclerosis
Hyperplastic
Neoplastic – premalignant adenomas
Small Intestine and Colon
Familial syndromes
Familial adenomatous polyposis
Hereditary non-polyposis colorectal
Lynch syndrome
Adenocarcinoma
Adenoma-carcinoma sequence
Microsatellite instability
Mismatch repair deficiency
Clinical – right-sided – fatigue and
weakness due to iron-deficiency
anemia, left-sided – occult bleeding,
changes in bowel habits, cramping
cancer –
Small Intestine and COlon
Anal canal tumors – basaloid, squamous
cell
– HPV
Hemorrhoids
Acute appendicitis
Appendix tumors – carcinoid,mucinous
cystadenoma or cystadenocarcinoma –
pseudomyxoma peritoneii
Peritoneal Cavity
Inflammatory - peritonitis
Sterile peritonitis- leakage of bile or
enzymes
Perforation of rupture of biliary system
Acute hemorrhagic pancreatitis
Foreign material
Endometriosis
Ruptured dermoid cyst
Perforation of abdomen viscera
Bacterial
Spontaneous bacterial – nephrotic syndrome,
ascites
pancreatic
Peritoneal Cavity
Sclerosing retroperitonitis or fibrosis –
Ormond disease
Cysts and pseudocysts
Tumors
Primary –mesothelioma, desmoplastic
small round cell tumor related to
Wilms and Ewing sarcoma)
Secondary – most common ovarian,
pancreatic, appendiceal