The foregut is the...
pharynx to the duodenum.
The midgut is the...
duodenum to the proximal 2/3 of the transverse colon.
The hindgut is the...
distal 1/3 of the transverse colon to the anal canal above the pectinate line.
Failure of rostral fold closure causes...
Failure of lateral fold closure causes...
ompholocele and gastroschisis.
Failure of caudal fold closure causes...
Duodenal atresia is due to...
failure to recanalize. (associated with trisomy 21)
Jejunal, ileal, and colonic atresia is due to...
vascular accident. (apple peel atresia)
During the 6th wk, the midgut will...
herniate through the umbilical ring.
During the 10th wk, the midgut will...
return to the abdominal cavity and rotate around the SMA.
extrusion of abdominal contents through abdominal folds; not covered by peritoneum
persistence of herniation of abdominal contents into umbilical cord; sealed by peritoneum
The most common tracheoesophageal anomaly is...
esophageal atresia with distal tracheoesophageal fistula. (EA w/ TEF)
EA w/ TEF results in...
drooling, choking and vomiting with the first feed.
air to enter the stomach (visible on CXR).
Cyanosis is seen in EA w/ TEF secondary to...
laryngospasm (to avoid reflux-related aspiration).
Clinical test for EA w/ TEF
failure to pas NG tube into stomach
In H-type tracheoesophageal anomaly, it is...
a fistual alone (no atresia).
In pure atresia (no TEF), the CXR shows...
Congenital pyloric stenosis is when...
hypertrophy of the pylorus causes obstruction.
Features of congenital pyloric stenosis
-palpable "olive" mass in epigastric region -nonbilious projectile vomiting at 2-6 wks old (common in firstborn males)
Treatment for congenital pyloric stenosis
The pancreas is derived from the...
Ventral pancreatic buds contribute to...
the pancreatic head and main pancreatic duct.
The uncinate process is formed by..
the ventral bud alone.
The dorsal pancreatic duct becomes...
everything else (body, tail, isthmus and accesory duct).
ventral pancreatic bud abnormally encircles the 2nd part of the duodenum and forms a ring of pancreatic tissue that may cause duodenal narrowing
ventral and dorsal parts fail to fuse at 8 wks
The spleen arises in...
the mesentery of the stomach (hence, mesodermal) but is supplied by the foregut (celiac artery).
Retroperitoneal structures include GI structures that...
lack a mesentery and non-GI structures.
Injuries to retroperitoneal structures can cause...
blood or gas accumulation in the retroperitoneal space.
Retroperitoneal structures (10)
SAD PUCKER 1. Suprarenal (adrenal) glands 2. Aorta and IVC 3. Duodenum (2nd through 4th parts) 4. Pancreas (except tail) 5. Ureters 6. Colon (descending and ascending) 7. Kidneys 8. Esophagus (lower 2/3) 9. Rectum
Falciform ligement connects...
liver to anterior abdominal wall.
Falciform ligament contains...
the ligamentum teres hepatis (fetal umbilical vein).
Falciform ligament is a derivative of...
The hepatoduodenal ligament connects the...
liver to the duodenum.
Structures in the hepatoduodenal ligament
Portal triad: Hepatic artery, portal vein and common bile duct
the hepatoduodenal ligament may be compressed between the thumb and index finger placed in the omental foramen to control bleeding.
The hepatoduodenal ligament borders the...
omental foramen which connects the greater and lesser sacs.
-connects liver to lesser curvature -contains gastric arteries -separates greater and lesser sacs on the right -may be cut during surgery to access the lesser sac
-connects greater curvature to transvere colon -contains gastroepiploic arteries -part of greater omentum
-connects greater curvature and spleen -contains short gastrics and left gastroepiploics -separates greater and lesser sacs on the left
-connects spleen to posterior abdominal wall -conatins splenic artery, splenic vein and tail of pancreas
Layers of the gut wall (inside to outside)
1. Mucosa 2. Submucosa 3. Muscularis externa 4. Serosa (adventitia)
The mucosa contains...
epithelium (for absorption) lamina propria (for support) muscularis mucosa (for motility)
The submucosa contains...
the submucosal nerve plexus (Meissner).
The muscularis externa contains...
myenteric nerve plexus (Auerbach).
The outer layer of the gut wall is called the...
serosa when intraperitoneal and adventitia when retroperitoneal.
Ulcers extend into...
the submucosa, inner or outer muscular layer.
Erosions only are in..
Frequencies of basal electric rhythm
Stomach - 3 waves/min Duodenum - 12 waves/min Ileum - 9 waves/min
Histology of the Esophagus
nonkeratinized stratified squamous epithelium
Histology of the Stomach
Histology of the Duodenum
-villin and microvilli -Brunner glands (submucosa) -cryps of lieberkuhn
Histology of the Jejunum
-plicae circulares -crypts of lieberkuhn
Histology of the Ileum
-Peyer patches (lamina propria, submucosa) -plicae circulares -crypts of Lieberkuhn
The ileum has the largest number of...
goblet cells in the small intestine.
Histology of the colon
-crypts of lieberkuhn -NO villi -numerous goblet cells
Arteries supplying GI structures branch from the aorta...
anteriorly while those supplying non-GI structures branch laterally.
Superior Mesenteric Artery (SMA) Syndrome occurs when...
the transverse portion (3rd segment) of the duodenum is entrapped between the SMA and aorta causing intestinal obstruction.
Artery supply, PNS innervation and vertebral level of the foregut
-Celiac artery -vagus nerve -T12/L1
Artery supply, PNS innervation and vertebral level of the midgut
-SMA -vagus nerve -L1
Artery supply, PNS innervation and vertebral level of the hindgut
-IMA -pelvic nerve -L3
Organs included in foregut supplies
-liver -gallbladder -pancreas -spleen
In the hindgut, the splenic flexure is...
a watershed region.
Branches of the celiac trunk
-common hepatic -splenic -left gastric (these consitute the main blood supply of the stomach)
If the splenic artery is blocked, the short gastrics have...
In the gastric circulation, strong anostomses exist between...
-left and right gastroepiploics -left and right gastrics
If branches off the abdominal aorta are blocked, these arterial anastomoses compensate (4):
1. superior epigastric w/ inferior epigastric 2. superior pancreaticoduodenal w/ inferior pancreaticoduodenal 3. middle colic w/ left colic 4. superior rectal w/ middle/inferior rectal
3 Portosystemic anastomosis sites
1. Esophagus 2. Umbilicus 3. Rectum (show varices and seen w/ portal HTN)
Clinical sign of anastomosis at the esophagus is...
esophageal varices. Anastomosis between left gatric and esophageal.
Clinical sign of anastomosis at the umbilicus is...
caput medusae. Anastomosis is between paraumbilical and small epigastric veins of wall
Clinical signs of anastomosis at the recutm is...
anorectal varices. Anastomosis is between superior rectal and middle/inferior rectal.
Treatment for Portosystemic anastomoses/varices is...
transjugular intrahepatic portosystemic shunt (TIPS) between the portal vein and hepatic vein which can relieve portal HTN by shunting blood to the systemic circulation.
The pectinate line is formed where...
the endoderm (hindgut) meets the ectoderm.
Pathology that occurs above the pectinate line includes...
internal hemorrhoids and adenocarcinoma.
Arterial supply above the pectinate line is from...
the superior rectal artery (a branch of the IMA). Venous drainage is to the superior rectal vein (to the IMV to the portal system). (Lymphatic drainage to deep nodes)
Internal hemorrhoids receive....
visceral innervation and are therefore not painful.
Pathology below the pectinante line includes...
external hemorrhoids, anal fissures and SCC.
Arterial supply below the pectinate line is from..
the inferior rectal artery (branch of the pudendal artery). Venous drainage is to the inferior rectal vein (to internal pudendal vein to internal iliac to IVC). (lymphatic drainage to superficial inguinal nodes)
External hemorrhoids recieve...
somatic innervation (inferior rectal branch of pudendal nerve) and are therefore painful.
Anal fissue is a...
tear in the anal mucosa below the pectinate line. Features include pain while pooping and blood on toilet patper. Occur posteriorly bc this area is poorly perfused.
The apical surface of hepatocytes faces...
The basolateral surface of hepatocytes faces...
Zone I of the hepatocyte
Periportal zone -affected 1st by viral hepatitis (and ingested toxins)
Zone II of the hepatocyte
Zone III of the hepatocyte
Pericentral vein Zone -affected 1st by ischemia -contains CYP450s -most sensitive to metabolic toxins -site of alcoholic hepatitis (acetaminophen toxicity)
Gallstones that reach the ampulla of vater can...
block both the bile and pancreatic ducts.
Tumors that arise in the head of the pancreas can...
cause obstruction of the common bile duct.
Organization of the Femoral Region
Lateral to Medial: Nerve, Artery, Vein, Lymphatics
The femoral triangle contains....
the femoral vein, artery and nerve.
The femoral sheath is a...
fascial tube 3-4 cm below the inguinal ligament. It contains the femoral vein, artery and canal (deep inguinal LNs) but NOT the nerve.
A hernia is a...
protrusion of peritoneum through an opening.
abdominal structures enter the thorax; may occur in infants as a result of defective development of pleuroperitoneal membrane
A diaphragmatic hernia is most commonly a...
hiatal hernia in which the stomach herniates upward through the esophageal hiatus of the diaphragm.
A sliding hiatal hernia is the..
most commono type. The GE junction is displaced upward. **hourglass stomach
A paraesophageal hernia is when...
the fundus protrudes into the thorax; GE junction is normal.
An indirect inguinal hernia goes through...
the internal inguinal ring, external inguinal ring and into the scrotum. Enters the internal inguinal ring lateral to the inferior epigastric artery.
An indiriect inguinal hernia occrus in...
infants owing to failure of the processus vaginalis to close and is much more common in males.
An indirect inguinal hernia follows...
the path of testicular descent and is covered by all 3 layers of spermatic fascia.
A direct inguinal hernia protrudes through the...
inguinal (Hesselbach) triangle. It bulges directly through the abdominal wall medial to the inferior epigastric artery and only goes throut the external inguinal ring.
Direct inguinal hernias are covered by...
external spermatic fascia and are usually seen in older men.
Femoral hernias protrude...
below the inguinal ligament through the femoral canal below and lateral to the pubic tubercle. More common in females.
Femoral hernia is the leading cause of...
Hesselbach triangle is formed by...
the borders of the inferior epigastric vessels, the lateral border of the rectus abdominis and the inguinal ligament.
I cells in the duodenum and jejunum
CCK actions (4)
1. increase pancreatic secretion 2. increase gallbladder contraction 3. decrease gastric emptying 4. increase sphincter of Oddi relaxation
increased by fatty acids and amino acids
To cause pancreatic secretion, CCK acts on..
neural muscarinic pathways.
G cells in the antrum of the stomach
Gastrin actions (3)
1. increase gastric H+ secretion 2. increase growth of gastric mucosa 3. increase gastric motility
Regulation of Gastrin
increased by stomach distention, alkalinization, amion acids, peptides, vagal stimulation decreased by stomach pH <1.5
Gastin is increased by...
chronic PPI use, phenylalanine and tryptophan.
Gastrin is greatly increased in...
Glucose-dependent insulinotropic peptide (GIP) source
K cells in the duodenum and jejunum
Exocrine: decrease gastric H+ secretion Endocrine: increase insulin release
increased by fatty acids, amino acids, and oral glucose
An oral glucose load is used more rapidly that the equivalent given by IV due to...
produces migrating motor complexes
increased in fasting state
Motilin receptor agonists are used to...
stimulate intestinal peristalsis (ex. erythromycin).
S cells int he duodenum
Secretin actions (3)
1. increased pancreatic HCO3- secretion 2. decreased gastric acid secretion 3. increased bile secreton
increased by acid, fatty acids in lumen of duodenum
Increased HCO3- in the duodenum, stimulated in response to secretin, acts to...
neutralize gastric acid allowing pancreatic enzymes to function.
D cells in pancreatic islets and GI mucosa
Somatostatin actions (4)
1. decrease gastric acid and pepsinogen secretion 2. decrease pancreatic and small intestine fluid secretion 3. decrease gallbladder contraction 4. decrease insulin and glucagon release
increased by acid decreased by vagal stimulation
Somatostatin is an inhibitory hormone that...
has antigrowth hormone effects (inhibits digestion and absorption of substances needed for growth).
Nitric oxide action
increases smooth muscle relaxation, includeing lower esophageal sphincter
Loss of NO secretion is implicated in...
increased LES tone of achalasia.
Vasoactive Intestinal Polypeptide (VIP) source
parasympathetic ganglia in sphincters, gallbladder and small intestine
increase intestinal water and electrolyte secretion increase relaxation of intestinal smooth muscle and sphincters
increased by distention and vagal stimulation decreased by adrenergic input
VIPoma is a...
non-alpha, non-beta islet cell pancreatic tumor that secretes VIP See copious watery diarrhea, hypokalemia and achlorhydria
Intrinsic factor source
Intrinsic factor action
vitamin B12-binding protein (IF is required fro uptake of B12 in the terminal ileum)
Autoimmune destruction of parietal cell leads to...
chronic gastritis and pernicious anemia.
Gastric acid source
Gastric acid action
decrease stomach pH
Gastric acid regulation
increased by histamine, ACh and gastrin decreased by somatostatin, GIP, prostaglandin and secretin
gastin-secreting tumor that causes high levels of acid secretion and ulcers refractory to medical therapy
increased by vagal stimulation and local acid
Inactive pepsinogen is converted to...
pepsin by H+.
mucosal cells (stomach, duodenum, salivary glands, pancreas) Brunner glands (duodenum)
increased by pancreatic and biliary secretion with secretin
Gastin increases acid secretion primarily through its action on...
enterochromaffin-like (ECL) cells, which leads to histamine release, rather than through its direct effects on parietal cells.
Atropine blocks vagal stimulation of...
parietal cells but NOT G cells because a different transmitter is used at G cells (GRP, not ACh).
Brunner glands secrete...
Hypertrophy of Brunner glands is seen in...
peptic ulcer disease.
isotonic fluid low flow = high chloride high flow = high HCO3-
starch digestion (secreted in active form)
lipase, phospholipase A, colipase role
trypsin, chymotrypsin, elastase and carboxypeptidase. These are secreted as proenzymes (zymogens).
Tyrpsinogen is converted to...
active trypsin which acts to activate other proenzymes and cleaving additional trypsinogen to make more trypsin (positive feedback).
Trypsinogen is converted to trypsin by...
enterokinase/enteropeptidase (a brush border enzyme on duodenal/jejunal mucosa).
Enterocytes absorb only...
monosaccharides (glucose, galactose and fructose).
Glucose and galactose are taken up by...
SGLT1 (Na+ dependent).
Fructose is taken up by...
facilitated diffusion by GLUT-5.
All monosaccharides are transported to blood by...
D-xylose absorption test distinguishes...
GI mucosal damage from other causes of malabsorption.
Iron is absorbed as....
Fe2+ in the duodenum.
Folate is absorbed in..
the jejunum (and ileum).
B12 is absorbed in...
the terminal ileum along with bile acids (requires intrinsic factor).
Peyer patches are...
unencapsulated lymphoid tissue found in the lamina propria and submucosa of the ileum.
Peyer patches contain...
specialized M cells that sample and present antigens to immune cells.
In the germinal centers of Peyer Patches, there is stimulation of...
B cells that differentiate into IgA-secreting plasma cells which ultimately reside in the lamina propria.
IgA from Peyer Patches receives...
a protective secretory component and is then transported across the epithelium ot the gut to deal with intraluminal antigen.
Bile is composed of...
bile salts (bile acids conjugated to glycine or taurine, making them water soluble), phospholipids, cholesterol, bilirubin, water and ions.
The rate limiting step of bile synthesis is catalyzed by...
Functions of bile (3):
1. digestion and absorption of lipids and fat soluble vitamins 2. cholesterol excretion 3. antimicrobial activity
Bilirubin is a product of...
Bilirubin is removed from the blood by...
the liver, conjugated with glucuronate and excreted in bile.
-conjugated with glucuronic acid -water soluble
-unconjugated -water insoluble
Salivary gland tumors are generally...
benign and occur in the parotid glands.
3 types of salivary gland tumors
1. Pleomorphic adenoma 2. Warthin tumor 3. Mucoepidermoid carcinoma
Pleomorphic adenoma is composed of...
chondromyoid stroma and epithelium.
Pleomorphic adenoma presents as a..
painless, mobile mass. It will recur if incompletely excised or ruptured intraoperatively.
Warthin tumor is a...
benign cystic tumor with germinal centers.
Mucoepidermoid carcinoma is the most common..
malignant salivary gland tumor and has mucinous and squamous components.
Mucoepidermoid carcinoma presents as...
a painless, slow-growing mass.
Achalasia is due to..
failure of relaxation of LES due to loss of myenteric plexus.
High LES opening pressure and uncoordinated peristalsis leads to...
progressive dysphagia to solids and liquids.
A barium swallow of achalasia shows...
a dilated esophagus with an area of distal stenosis. **bird's beak
Achalasia is associated with increased risk of...
esophageal squamous cell carcinoma.
Secondary achalasia may arise from...
transmural, distal esophageal rupture due to violent retching; surgical emergency
infiltration of eosinophils in the esophagus in atopic pts -food allergens lead to dysphagia, heartburn and strictures -unresponsive to GERD therapy
Esophageal strictures are associated with...
lye ingestion and acid reflux.
painless bleeding of dilated submucosal veins in lower 1/3 of esophagus secondary to portal HTN
Esophagitis is associated with..
reflux, infxn in immunocompromised, or chemical ingestion.
Immunocompromised infxn characteristics in esophagitis
Candida: white pseudomembrane HSV-1: punched out ulcers CMV: linear ulcers
GERD commonly presents as...
heartburn and regurgitation upon lying down. May also present with nocturnal cough and dyspnea, and adult-onset asthma.
GERD is due to..
a decrease in LES tone.
Mucosal lacerations at the GE junction due to severe vomiting; leads to hematemesis; seen in alcoholics and bulimics
Triad of: -dysphagia (due to esophageal webs) -Iron deficiency anemia -glossitis
Sclerodermal esophageal dysmotility
esophageal smooth mucsel atrophy leads to decreased LES pressure and dysmotility leads to acid reflux and dysphagia leads to stricture, Barrett esophagus, and aspiration
Barrett esophagus is...
glandular metaplasia (replacement of nonkeratinized stratified squamous epithelium with intestinal nonciliated columnar epithelium with goblet cells) in the distal esophagus
Barrett esophagus is due to..
chronic acid reflux (GERD).
Barrett esophagus is associated with....
esophagitis, esophageal ulcers and increased risk of esophageal adenocarcinoma.
Esophageal cancer typically presents with...
progressive dysphagia and weight loss; has poor prognosis.
In the US, the type of esophageal cancer more common is...
adenocarcinoma. Worldwide, it is squamous cell.
Squamous cell carcinoma affects...
the upper 2/3 of the esophagus.
the lower 1/3 of the esophagus.
Risk factors of Esophageal Cancer:
AABCDEFFGH -Achalasia -Alcohol (squamous) -Barrett's (adeno) -Cigarettes (both) -Diverticula (Zenker's; squamous) -Esophageal web (squamous) -Familial -Fat (adeno) -GERD (adeno) -Hot liquids (squamous)
Acute gastritis is...
disruption of the mucosal barrier leading to inflammation.
Acute gastritis can be caused by...
-stress -NSAIDs (decreased PGE2 leading to decreased mucosal protection) -alcohol -uremia -burns (Curling ulcer) -brain injury (Chushing ulcer)
A curling ulcer causes...
decreased plasma volume leading to sloughing of the gastric mucosa.
A cushing ulcer causes...
increased vagal stimulation leading to increased ACh and increased H+ production.
Acute gastritis is especially common amoung...
alcoholics and persons taking daily NSAIDs.
Type A chronic gastritis is...
an autoimmune disorder characterized by autoantibodies to parietal cells, pernicious anemia and achlorhydria. (occurs in fundus/body)
Type B chronic gastritis is more common and caused by...
H.pylori infxn. Increased risk of MALT lymphoma and gastric adenocarcinoma.
Menetrier disease is...
gastric hypertrophy with protein loss, parietal cell atrophy and increased mucous cells. Precancerous.
In Menetrier disease, the rugae of the stomach are...
so hypertrophied that they look like brain gyri.
Stomach cancer is almost always...
Stomach cancer often presents with...
Intestinal stomach cancer is associated with...
H. pylori infection, dietary nitrosamines, tobacco smoking, achlorhydria, and chronic gastritis.
Intestinal stomach cancer is commonly on...
the lesser curvature of the stomach and looks like an ulcer with raised margins.
Diffuse stomach cancer
-not associated with H. pylori -signet ring cells -stomach wall grossly thickened and leathery (linitis plastica)
involvement of the left supraclavicular node by metastasis from the stomach
bilateral mestatases to the ovary from gastric cancer; abundant mucous and signet ring cells
Sister Mary Joseph nodule
subcutaneous periumbilical metastasis
Gastric Ulcer features
-pain greater with meals (weight loss) -70% H.pylori infection -decreased mucosal protection against gastric acid -also due to NSAIDs -increased risk of carcinoma -occurs in older pts
Duodenal ulcer features
-pain decreases with meals (gain weight) -100% H. pylori infxn -decreased mucosal protection or increased gastric acid secretion -ZE syndrome -generally benign -see hypertrophy of Brunner glands
-hemorrhage (usually posterior) -perforation (usually anterior)
A ruptured gastric ulcer on the lesser curvature of the stomach leads to..
bleeding from the left gastric artery.
An ulcer on the posterior wall of the duodenum leads to...
bleeding from the gastroduodenal artery.
Duodenal perforation from an ulcer may lead to..
free air under the diaphragm with referred pain to shoulder.
Malabsorption syndromes can cause...
diarrhea, steatorrhea, weight loss, weakness and vitamin and mineral deficiencies.
Tropical sprue has similar findings to...
celiac sprue (affects small bowel) but it responds to antibiotics.
Whipple disease is due to an...
infection with Tropheryma whipplei.
Whipple disease features
-PAS + foamy macrophages in the intestinal lamina propriia and mesenteric nodes -Cardiac symptoms, arthralgias, neuro symptoms -seen in older men
Celiac sprue is an...
autoimmune-mediated intolerance of gliadin leading to malabsorption and steatorrhea. Decreased mucosal abosrption affecting the distal duodenum and proximal jejunem.
Celiac sprue is associated with...
HLA-DQ2 and HLA-DQ8 and dermatitis herpetiformis.
Findings of Celiac sprue
-anti-endomysial Abs -anti-tissue transglutaminase Abs -anti-gliadin Abs -blunting of villi -lymphocytes in lamina propria
Celiac sprue has a moderately increased risk of...
malignancy (T-cell lymphoma).
The most common disaccharidase deficiency is...
lactase deficiency. -normal appearing villi -osmotic diarrhea
Since lactase is located at the tips of the intestinal villi, following injury...
self-limited lactase deficiency can occur.
Lactose tolerance test is positive for lactase deficiency if....
administration of lactose produces symptoms and glucose rises <20 mg/dL.
decreased synthesis of apolipoprotein B leads to the inability to generate chylomicrons which leads to decreased secretion of cholesterol and VLDL goes into the bloodstream leading to fat accumulation in enterocytes
Abetalipoproteinemia presents in early childhood with...
FTT, steatorrhea, acanthocytosis, ataxia and night blindness.
Pancreatic insufficiency is due to...
cystic fibrosis, obstructing cancer and chronic pancreatitis.
Pancreatic insufficiency causes...
malabsorption of fat and fat-soluble vitamins. (increased neutral fat in stool)
D-xylose absorption test
normal urinary excretion in pancreatic insufficiency decreased excretion with intestinal mucosa defects or bacterial overgrowth
disordered response to intestinal bacteria
any portion of the GI tract, usually the terminal ileum and colon; contains skip lesions and has rectal sparing
Crohn's gross morphology
transmural inflammation leading to fistulas -cobblestone mucosa -creeping fat -bowel wall thickening (string sign) -linear ulcers -fissures
noncaseating granulomas and lymphoid aggregates (Th1 mediated)
-strictures -fistulas -perianal disease -malabsorption -nutritional depletion -colorectal cancer -gallstones
Crohn's intestinal manifestation
diarrhea that may or may not be bloody
Crohn's extraintestinal manifestations
-migratory polyarthritis -erythema nodosum -anklyosing spondylitis -pyoderma gangrenosum -aphthous ulcers -uveitis -kidney stones
Treatment for Crohn's
-corticosteroids -azathioprine -methotrexate -infliximab -adalimumab
colitis = colon inflammation; continuous colonic lesions, always with rectal involvement
UC gross morphology
-mucosal and submucosal inflammation only -friable mucosal pseudopolyps with freely hanging mesentery -loss of haustra (lead pipe appearance)
-crypt abscesses and ulcers -bleeding -no granulomas -Th2 mediated
-malnutrition -sclerosing cholangitis -toxic megacolon -colorectal carcinoma
UC intestinal manifestation
UC extraintestinal manifestation
-pyoderma gangrenosum -erythema nodosum -primary sclerosing cholangitis -ankylosing spondylitis -apthous ulcers -uveitis
-ASA preparations (sulfasalazine) -6-MP -infliximab -colectomy
Irritable Bowel Syndrome is...
recurrent abdominal pain with 2 or more of the following: -pain improves w/ defecation -change in stool frequency -change in appearance of stool
Other features of IBS
-no structural abnormalities -middle-aged women -chronic symptoms -may present with diarrhea, constipation or alternating symptoms
acute inflammation of the appendix due to obstruction by fecalith (in adults) or lymphoid hyperplasia (children).
Appendicitis presents with...
initial diffuse periumbilical pain that migrates to McBurney point. Also nausea and fever.
In appendicitis, the appendix may...
perforate leading to peritonitis.
Positive signs in Appendicitis
Psoas, Obturator and Rovsing signs
DDx of Appendicitis
-diverticulitis (elderly) -ectopic pregnancy (check beta-HCG)
Diverticulum is a...
blind pouch protruding from the alimentary tract that communicates with the lumen of the gut.
Most diverticula are...
acquired and are termed "false" in that they lack or have an attenuated muscularis extern.
Most diverticula are located in the...
all 3 gut wall layers outpouch (ex. Meckel's)
only mucosa and submucosa outpouch; occur especially where the vasa recta perforates the muscularis extern
many false diverticula of the colon, commonly sigmoid.
Diverticulosis is caused by...
increased intraluminal pressure and focal weakness in the colon wall.
Diverticulosis is associated with...
low-fiber diets. Complications include diverticulitis and fistulas.
Diverticulosis is a common cause of...
inflammation of diverticula classically causing LLQ pain, fever, leukocytosis.
Diverticulitis may perforate causing...
peritonitis, abscess formation or bowel stenosis.
Treatment for diverticulitis
Findings of Diverticulitis
-stool occult blood +/- hematochezia -colovesical fistula leading to pneumaturia
pharyngoesophageal false diverticulum; herniation of mucosal tissue at the Killian triangle between the thyropharyngeal and cricopharyngeal parts of the inferior pharyngeal constrictor
Presenting symptoms of Zenker Diverticulum
-dysphagia -obstruction -foul breath from trapped food (most common in elderly males)
-true diverticulum -persistence of the vitellin duct -most common congenital anomaly of GI tract
Meckel diverticulum may contain...
ectopic acid-secreting gastric mucosa and/or pancreatic tissue.
Meckel diverticulum can cause...
melena, RLQ pain, intussusception, volvulus or obstruction near the terminal ileum.
An omphalomesenteric cyst is...
a cystic dilation of the vitelline duct (this is NOT meckel's diverticulum).
Diagnose Meckel Diverticulum with...
pertechnetate study for uptake by the ectopic gastric mucosa.
The 5 2's of Meckel Diverticulum
1. 2 inches long 2. 2 ft from ileocecal valve 3. 2% of population 4. present in first 2 years of life 5. may have 2 types of epithelia
"telesoping" of one bowel segment into a distal segment, commonly at hte ileocecal junction.
compromised blood flow leading to intermittent abdominal pain often with "currant jelly" stools.
Intussusception is uncommon in adults and when seen is associated with...
intraluminal mass or tumor. Majority occur in children and may be seen folowing enteric/respiratory viral infxn.
twisting of bowel around it's mesentery leading to obstruction and infarction.
Common locations of volvulus
-midgut in infants/children -sigmoid in elderly
Hirschsprung Disease is...
congenital megacolon characterized by lack of ganglion cells/enteric nerve plexuses (both Auerbach and Meissner).
Hirschsprung Disease is due to...
failure of neural crest cell migration.
Hirschsprung is associated with...
mutations in the RET gene.
Hirschsprung presents with...
bilious emesis, abdominal distention and failure to pass meconium in first 48 hrs. It ultimately manifests as chronic constipation.
In Hirschsprung disease, there is a "transition zone" of...
dilated colon proximal to the aganglionic segment.
Risk of Hirschsprung increases with...
Hirschsprung is diagnosed by...
rectal suction biopsy and treated with resection.
fibrous band of scar tissue; commonly forms after surgery; most common cause of small bowel obstruction; can have well-demarcated necrotic zones
tortuous dilation of vessels leading to hematochezia
Angiodysplasia is most often found in the...
cecum, terminal ileum and ascending colon. Seen in older pts.
Angiodysplasia is confirmed by...
Duodenal atresia causes...
early bilious vomiting with proximal stomach distention (double bubble) because of failure of small bowel recanalization
Duodenal atresia is associated with...
intestinal hypomotility without obstruction leading to constipation and decreased flatus
Findings of ileus
distended/tympanic abdomen with decreased bowel sounds
Ileus is associated with...
abdominal surgeries, opiates, hypokalemia and sepsis
Ischemic colitis is a...
reduction in intestinal blood flow causing ischemia.
Ischemic colitis presents with...
pain after eating (leading to weight loss). It occurs at splenic flexure and distal colon and affects the elderly.
In CF, meconium plug obstructs the intestine, preventing stool passage at birth.
necrosis of intestinal mucosa and possible perforation; colon is usually involved; more common in preemies due to decreased immunity
Colonic polyps are...
masses protruding into the gut lumen leading to a sawtooth appearance. Often rectosigmoid; can be tubular or villous.
Adenomatous polyps are...
precancerous and malignant risk is associated with increased size, villous histology (more villous, more malignant potential), and increased epithelial dysplasia. Precurorsor to colorectal cancer.
Adenomatous polyps symptoms
-often asymptomatic -lower GI bleed -partial obstruction -secretory diarrhea
-most common non-neoplastic colonic polyp -majority in rectosigmoid colon
-sporadic lesions in children under 5 -80% in rectum -if single, no malignant potential
Juvenile polyposis syndrome
multiple juvenile polyps in GI tract increased risk of adenocarcinoma
autosomal dominant syndrome featuring multiple, nonmalignant hamartomatous polyps throughout the GI tract along with hyperpigmented mouth, lips, hands, genitalia
Peutz-Jeghers syndrome is associated with
increased risk of colorectal cancer.
Familial Adenomatous Polyposis (FAP) is due to...
an autosomal dominant mutation of APC gene on chromosome 5q; 2-hit hypothesis.
FAP has 100% progress to...
colorectal cancer unless the colon is resected.
FAP presents with...
thousands of polyps that arise at a young age; pancolonic; always involves rectum
FAP + osseous and soft tissue tumors + congenital hypertrophy of retinal pigment epithelium
FAP + malignant CNS tumor
Herediatry nonpolyposis colorectal cancer (HNPCC/Lynch Syndrome)
-autosomal dominant mutation of DNA mismatch repair genes -usually progresses to colorectal cancer -proximal colon always involved
Risk factors for colorectal cancer
-IBD -tobacco use -large villous adenomas -juvenile polyposis syndrome -Peutz-Jeghers syndrome
Presentation of Colorectal Cancer
Rectosigmoid > ascending > descending Right side bleeds; left side obstructs Rarely presents as S. bovis bacteremia
Presentation of Ascending Colon cancer
exophytic mass iron deficiency anemia weight loss (bleeds)
Presentation of Descending Colon cancer
infiltrating mass partial obstruction colicky pain hematochezia
Diagnosis of Colorectal Cancer
-"apple core" lesion seen on barium enema -CEA tumor marker can monitor for recurrence (NOT for screening)
Be suspicious of colorectal cancer in...
males over 50 and postmenopausal females with iron deficiency anemia.
There are 2 molecular pathways that lead to colorectal cancer:
1. Microsatellite instability pathway 2. APC/Beta-catenin pathway
Microsatellite instability pathway is due to..
DNA mismatch repair gene mutations leading to sporadic CRC and HNPCC syndrome. Mutations accumulate.
The APC/Beta-catenin pathway is due to...
chromosomal instability that leads to sporadic cancer.
Order of events in pathogenesis of CRC
-loss of APC gene -K-RAS mutation -loss of tumor suppressor genes
diffuse fibrosis and nodular regeneration that destroys the normal architechture of the liver.
Cirrhosis increases the risk for...
Etiologies of cirrhosis
-alcohol** -viral hepatitis -biliary disease -hemochromatosis
Effects of portal HTN (6)
1. Esophageal varices (hematemesis) 2. Melena 3. Splenomegaly 4. Caput medusae (ascites) 5. Gastropathy 6. Anorectal varices
Effects of Liver Cell Failure (11)
1. Hepatic encephalopathy 2. scleral icterus 3. fetor hepaticus 4. spider nevi 5. gynecomastia 6. jaundice 7. testicular atrophy 8. asterixis 9. bleeding 10. anemia 11. ankle edema
Diagnostic Use of Alkaline phosphatase (ALP)
-obstructive hepatobiliary disease** -HCC -bone disease
Diagnostic use of AST and ALT
Viral hepatitis (ALT > AST) Alcoholic hepatitis (AST > ALT)
Diagnostic use of amylase
acute pancreatitis mumps
Diagnostic use of ceruloplasmin
decreased in Wilson disease
Diagnostic Use of gamma-glutamyl transpeptidase (GGT)
increased in liver and biliary disease (like ALP) but NOT in bone disease; associated with alcohol use
Diagnostic Use of Lipase
acute pancreatitis (most specific**)
Reye Syndrome is rare but often causes...
fatal childhood hepatoencephalotpathy.
Findings of Reye Syndrome
-mitochondrial abnormalities -fatty liver (microvesicular) -hypoglycemia -vomiting -hepatomegaly -coma
Reye syndrome is associated with...
viral infection (esp. VZV and influenza B) that has been treated with aspirin.
Mechanism of Reye Syndrome
aspirin metabolites decrease beta-oxidation by reversible inhibition of the mitochondrial enzyme
Due to Reye Syndrome risk, Aspirin should be avoided in all children except...
those with Kawasaki disease.
reversible change seen with moderate alcohol intake; macrovesicular fatty change
requries sustained, long-term consumption; swollena nd necrotic hepatocytes with neutrophilic infiltration; mallory bodies present
Mallory bodies are...
intracytoplasmic eosinophilic inclusions seen in alcoholic hepatitis.
final and irreversible form of alcoholic liver disease; micronodular, irregularly shrunken lvier with "hobnail" appearance; sclerosis around central vein
Alcoholic cirrhosis has manifestations of..
chronic liver disease (jaundice, hypoalbuminemia).
Non-alcoholic fatty liver disease
Metabolic syndrome (insulin resistance) leads to fatty infiltration of hepatocytes leads to cellular "ballooning" and eventual necrosis
Non-alcoholic fatty liver disease may cause...
cirrhosis and HCC
Hepatic encephalopathy is due to...
cirrhosis leading to portosystemic shunts leading to decreased NH3 metabolism leading to neuropsychiatric dysfunction.
Triggers of hepatic encephalopathy
-increased NH3 production (dietary protein, GI bleed, constipation, infxn) -decreased NH3 removal (renal failure, diuretics, post-TIPS)
Treatment for hepatic encephalopathy
-lactulose (increases NH4+) -low protein diet -rifaximin (kills intestinal bacteria)
The most common primary malignant tumor of the liver in adults is..
heaptocellular carcinoma. It is associated with hep B and C, Wilson disease, hemochromatosis, alpha1-antitrypsin deficiency, alcoholic cirrhosis and carcinogens (aflatoxin from Aspergillus).
Hepatocellular carcinoma may lead to..
Findings of Hepatocellular Carcinoma
-jaundie -tender hepatomegaly -ascites -anorexia -spreads hematogenously
Diagnosis of HCC is with...
increased alpha-fetoprotein, ultrasound or contrast CT.
-common, benign liver tumor -30-50 yrs -biopsy contraindicated bc of risk of hemorrhage
-rare, benign liver tumor -often related to oral contraceptive or anabolic steroid use -may regress or rupture (pain and shock)
-malignant tumor of endothelial origin -associated with exposure to arsenic, vinyl chloride
Nutmeg liver is due to...
backup of blood into the liver commonly caused by right-sided heart failure and Budd-Chiari syndrome.
If nutmeg liver persists, then...
centrilobular congestion and necrosis can result in cardiac cirrhosis.
Budd-Chiari syndrome is...
occlusion of IVC or hepatic veins with centrilobular congestion and necrosis leading to congestive liver disease (hepatomegaly, ascites, abdominal pain, liver failure).
Budd-Chiari pts may develop...
varices and have visible abdominal and back veins. Absence of JVD.
Budd-Chiari is associated with...
hypercoaguable states, polycythemia vera, pregnancy and HCC.
misfolded gene product protein aggregates in hepatocellular ER leading to cirrhosis with PAS + globules (codominant trait)
Decreased Alpha1-antitrypsin in the lungs leads to..
uninhibited elastase in alveoli leading to decreased elastic tissue and panacinar emphysema.
abnormal yellowing of the skin/sclera due to bilirubin deposition. It occurs at high levels of blood bilirubin (> 2.5) secondary to increased production or defective metabolism.
Diseases with Unconjugated hyperbilirubinemia
-hemolytic -physiologic (newborns) -Crigler-Najjar -Gilbert syndrome (increased urine urobilinogen)
Diseases with Conjugated hyperbilirubinemia
-biliary tract obstruction (gallstones, pancreastic liver cancer, liver fluke) -biliary tract disease (primary sclerosing cholangitis, primary biliary cirrhosis) -excretion defect (Dubin-Johnson syndrome, Rotor syndrome) (decreased urine urobilinogen)
Mixed hyperbilirubinemia diseases
Physiologic neonatal jaundice
At birth, immature UDP-glucuronosyltransferase leads to unconjucgated hyperbilirubinemia causing jaundice/kernicterus.
Treatment for physiologic neonatal jaundice
phototherapy which converts unconjugated bilirubin to the water-soluble form
Gilbert Syndrome is due to...
Mildly decreased UDP-glucuronosyltransferase that leads to decreased bilirubin uptake by hepatocytes.
Findings of Gilbert Syndrome
-asymptomatic or mild jaundice -elevated unconjugated bilirubin without overt hemolysis -bilirubin increases with fasting and stress
Crigler-Najjar syndrome (type I) is due to..
absent UDP-glucuronosyltransferase that presents early in life and pts die within a few years.
-jaundice -kernicterus (bilirubin deposition in the brain) -increased unconjugated bilirubin
Treatment for Type I Crigler-Najjar
plasmapheresis and phototherapy
Type II Crigler-Najjar is...
less severe and responds to phenobarbital which increases liver enzyme synthesis.
Dubin Johnson syndrome is...
conjugated hyperbilirubinemia due to defective liver excretion; grossly black liver.
Rotor syndrome is similar to...
dubin johnson but milder and does not cause black liver.
Wilson disease is due to..
inadequate hepatic copper excretion and failure of copper to enter the circulation as ceruloplasmin. This leads to copper accumulation (esp in liver, brain, cornea, kidneys and joints). (autosomal recessive - chr 13)
Wilson disease is characterized by...
-decreased ceruloplasmin -cirrhosis -corenal deposits (kayser-fleischer rings) -copper accumulation -carcinoma -hemolytic anemia -basal ganglia degeneration -asterixis -dementia -dyskinesia -dysarthria
Copper is normally excreted...
into bile by hepatocyte copper transporting ATPase (ATP7B gene).
Treat Wilson Disease with...
penicillamine or trientine.
Hemochromatosis is due to...
deposition of hemosiderin (iron). Classic triad of micronodular cirrhosis, diabetes, and skin pigmentation (bronze diabetes).
Hemochromatosis results in...
CHF, testicular atrophy and increased risk of HCC.
Hemochromatosis may be either primary due to...
autosomal recessive inheritance or secondary to chronic transfusion therapy.
Findings of hemochromatosis
-increased ferritin -increased iron -decreased TIBC (leading to increased transferrin saturation)
Primary Hemochromatosis is due to...
C282Y or H63D mutation on HFE gene. Associated with HLA-A3.
Treatment of Hereditary Hemochromatosis
-repeated phelbotomy -deferasirox -deferoxamine
Pathology of Seondary biliary cirrhosis
extrahepatic biliary obstruction (gallstone, biliary stricture, chronic pancreatitis, pancreatic head carcinoma) leads to incresae pressure in intrahepatic ducts leading to injury, fibrosis and bile stasis
Pathology of Primary Biliary Cirrhosis
autoimmune rxn leading to lymphocytic infiltrate and granulomas resulting in destruction of the intralobular bile ducts
Pathology of Primary Sclerosing Cholangitis
concentric "onion skin" bile duct fibrosis leading to alternating strictures and dilation with "beading" of intra and extra hepatic bile ducts on ERCP.
Presentation of Biliary Tract Disease (Primary/Secondary Biliary Cirrhosis, Primary sclerosing cholangitis)
-pruritis -jaundice -dark urine -light stools -hepatosplenomegaly
Labs of Biliary Tract Disease (Primary/Secondary Biliary Cirrhosis, Primary sclerosing cholangitis)
-increased conjugated bilirubin -increased cholesterol -increased ALP
Secondary biliary cirrhosis is complicated by...
Primary Biliary cirrhosis has...
increased serum mitochondrial antibodies, including IgM.
Primary Sclerosing Cholangitis displays...
hypergammaglobulinemia (IgM) and is associated with UC.
Primary Sclerosing cholangitis can lead to...
secondary biliary cirrhosis and cholangiocarcinoma.
Causes of Gallstones
increased cholesterol or bilirubin decreased bile salts
2 types of gallstones
1. Cholesterol stones 2. Pigment stones
Cholesterol stones features (2)
-radiolucent; some are opaque due to calcifications -majority of stones
Cholesterol stones are associated with...
-obesity -Crohn disease -CF -advanced age -clofibrate -estrogen therapy -multiparity -rapid weight loss -Native American origin
Pigment stone features
black = radiopaque, hemolysis brown = radiolucent, infxn
Pigment stones are seen in...
pts with chronic hemolysis, alcoholic cirrhosis, adavanced age and biliary infxn.
Gallstones most often cause...
cholecystitis (also ascending cholangitis, acute pancreatitis, and bile stasis).
Gallstones can also lead to biliary colic which is when...
neurohormonal activation (CCK by fat) triggers contraction of the gallbladder forcing a stone into the cystic duct.
Gallstones can also cause a fistula between...
the gallbladder and small intestine leading to air in the biliary tree.
A gallstone can cause gallstone ileus by...
obstructing the ileocecal valve.
Diagnose gallstones with...
U/S and treat with cholecystectomy if symptomatic.
Risk Factors for Gallstones
4 F's 1. Female 2. Fat 3. Forty 4. Fertile (pregnant)
Charcot triad of cholangitis
1. Jaundice 2. Fever 3. RUQ pain
inflammation of the gallbladder usually from cholelithiasis most commonly blocking the cystic duct and causing secondary infection.
-positive Murphy sign (inspiratory arrest on RUQ palpation due to pain) -increased ALP if bile duct becomes involved
Cholecystitis is diagnosed with...
ultrasound or HIDA.
Porcelain gallbladder is a...
calcified gallbladder due to chronic cholecystitis usually found incidentally.
Treatment of porcelain gallbladder
prophylactic cholecystectomy due to high rates of gallbladder carcinoma
Acute pancreatitis is...
autodigestion of the pancreas by pancreatic enzymes.
Causes of Acute Pancreatitis
GET SMASHED -gallstones -ethanol -trauma -steroids -mumps -autoimmune disease -scorpion sting -hypercalcemia/hypertriglyceridemia -ERCP -Drugs (sulfa)
Clinical presentation of acute pancreatitis
epigastric pain radiating to the back anorexia nausea
Labs of acute pancreatitis
-increased amylase and lipase
Acute pancreatitis can lead to...
DIC ARDS diffuse fat necrosis hypocalcemia pseudocyst formation hemorrhage infection multiorgan failure
Complications of acute pancreatitis
pancreatic pseudocyst (lined by granulation tissue that can rupture and hemorrhage)
Chronic pancreatitis is...
chronic inflammation, atrophy and calcification of the pancreas.
Major causes of chronic pancreatitis are...
alcohol abuse and idiopathic.
Chronic pancreatitis can lead to....
pancreatic insufficiency causing steatorrhea, fat-soluble vitamin deficiency, diabetes and increased risk of pancreatic adenocarcinoma.
In chronic pancreatitis, amylase and lipase....
may or may not be elevated.
Pancreatic adenocarcinoma is a very aggressive...
tumor arising from the pancreatic ducts (disorganized glandular structure with cellular infiltration); usually already metastasized at presentation.
Pancreatic adenocarcinoma tumors are usually found in the...
pancreatic head leading to obstructive jaundice.
Tumor marker for pancreatic adenocarcinoma
Risk factors for pancreatic adenocarcinoma
-tobacco use -chronic pancreatitis -diabetes -age > 50 -jewish and AA males
Pancreatic adenocarcinoma often presents with...
-abdominal pain radiating to back -weight loss -migratory thrombophlebitis -obstructive jaundice with palpable, nontender gallbladder (Courvoisier sign)
Migratory thrombophlebitis is...
redness and tenderness on palpation of the extremities (Trousseau syndrome) seen in adenocarcinoma
Treatment of Pancreatic adenocarcinoma
-Whipple procedure -chemo -radiation
Inhaled anesthetics (6)
1. Halothane 2. Enflurane 3. Isoflurane 4. Sevoflurane 5. Methoxyflurane 6. Nitrous oxide
Effects of inhaled anesthetics
-myocardial depression -respiratory depression -nausea/emesis -increased cerebral blood flow
Toxicity of inhaled anesthetics
-hepatotoxicity (halothane) -nepharotoxicity (methoxyflurane) -proconvulsant (enflurane) -expansion of trapped gas (NO) -malignant hyperthermia
Malignant hyperthermia is a rare...
life-threatening hereditary condition in which inhaled anesthetics (except NO) and succinyllcholine induce fever and severe muscle contractions. Treatment: Dantrolene
-Barbituates -Benzodiapepine -Ketamine -Opioids -Propofol
The barbituate used for anesthesia is...
thiopental which has high potency and high lipid solubility and rapid entry into the brain.
Thiopental is used for..
induction of anesthesia and short surgical procedures.
Thiopental effect is terminated by...
rapid redistribution into tissue and fat.
Benzodiazepine used for anesthesia is...
Midazolam for endoscopy w/ gas anesthetics and narcotics.
Midazolam may cause...
severe postoperative respiratory depression, decreased blood bp and anterograde amnesia. Treat OD with Flumazenil.
Ketamine (arylcyclohexylamine) is a...
PCP analog that acts as dissociative anesthetics by blocking NMDA receptors.
cardiovascular stimulation, disorientation, hallucination and bad dreams. Increases cerebral bf.
Opioiods used for anesthesia include...
morphine and fentanyl.
Propofol is used for...
sedation in ICU, rapid induction and short procedures. It potentiates GABAa and has less nausea than thiopental.
1. Esters (procaine, cocaine, tetracaine) 2. Amides (lidocaine, mepivacaine, bupivacaine)
Local anesthetics MOA
block Na+ channels by binding to specific receptors on inner portion of channel
Local anesthetics can be given with vasoconstrictors (epinephrine) to...
enhance local action (decrease bleeding, increase anesthesia).
Order of nerve blockade from local anesthetics
small myelinated fibers > small unmyelinated > large myelinated > large myelinated
Order of loss from local anesthetics
1. pain 2. temp 3. touch 4. pressure
Clinical use of local anesthetics
-minor surgical procedures -spinal anesthesia
Toxicity of local anesthetics
-CNS excitation -severe CV toxicity (bupivacaine) -HTN -hypotension -arrhythmias (cocaine)