G.I. Flashcards
Tracheoesophageal anomalies can present with?
polyhydramnios in utero (due to the inability of the fetus to swallow amniotic fluid).
Cyanosis is 2° to laryngospasm (to avoid reflux-related aspiration).
Hypertrophic pyloric stenosis
Results in hypokalemic hypochloremic metabolic alkalosis (2° to vomiting of gastric acid and subsequent volume contraction).
Pancreas embryology - Ventral pancreatic
Ventral pancreatic bud contributes to the uncinate process and main pancreatic duct.
Both the ventral and dorsal buds contribute to the pancreatic head.
Pancreas embryology - The dorsal pancreatic bud
The dorsal pancreatic bud alone becomes the body, tail, isthmus, and accessory pancreatic duct.
Both the ventral and dorsal buds contribute to the pancreatic head.
Retroperitoneal structures
SAD PUCKER
Suprarenal (adrenal) glands [not shown] Aorta and IVC Duodenum (2nd through 4th parts) Pancreas (except the tail) Ureters Colon (descend ing and ascending) Kidneys Esophagus (thoracic portion) Rectum (partially)
Greater omentum consists of:
Gastrocolic ligament
Gastrosplenic ligament
Lesser omentum consists of:
Hepatoduodenal ligament
Gastrohepatic ligament
Separates the sacs:
Gastrohepatic ligament
Gastrosplenic ligament
Hepatoduodenal ligament Borders the _______, which connects the_________.
Borders the omental foramen, which connects the greater and lesser sacs
Digestive tract histology - Duodenum
Villi and microvilli
Brunner glands
crypts of Lieberkuhn
plicae circulares - present in the distal duodenum
Digestive tract histology - Jejunum
Villi
crypts of Lieberkiihn
plicae circulares
Digestive tract histology - Ileum
Peyer patches - lymphoid aggregates in lamina propria, submucosa
plicae circulares - proximal ileum
crypts of Lieberkiihn.
The largest number of goblet cells in the small intestine.
Digestive tract histology - Colon
Crypts of Lieberkiihn
abundant goblet cells
No viIii
crypts of Lieberkuhn contain
stem cells - replace enterocytes/goblet cells
Paneth cells - that secrete defensins, lysozyme, and TNF
Superior mesenteric artery syndrome
when SMA and aorta compress transverse (third) portion of duodenum.
Nutcracker syndrome
compression of left renal vein between superior mesenteric artery and aorta.
Two areas of the colon have dual blood supply from distal arterial branches (“watershed regions”) - susceptible in colonic ischemia:
- Splenic flexure - SMA and IMA
* Rectosigmoid junction-the last sigmoid arterial branch from the IMA and superior rectal artery
Foregut ARTERY/PARASYMPATHETIC INNERVATION/VERTEBRAL LEVEL
Celiac
Vagus
T12/L1
Midgut ARTERY/PARASYMPATHETIC INNERVATION/VERTEBRAL LEVEL
SMA
Vagus
L1
Hindgut ARTERY/PARASYMPATHETIC INNERVATION/VERTEBRAL LEVELCeliac
IMA
Pelvic
L3
Zone 1- periportal zone:
- Affected 1st by viral hepatitis
- Best oxygenated, most resistant to circulatory compromise
- Ingested toxins (eg, cocaine)
Zone II - intermediate zone:
• Yellow fever
Zone III - pericentral vein (centri lobular) zone:
- Affected 1st by ischemia (least oxygenated)
- High concentration of cytochrome P-450
- Most sensitive to metabolic toxins (eg, ethanol, CCl4, halothane, rifampin)
- Site of alcoholic hepatitis
Femoral region - ORGANIZATION Lateral to medial:
Lateral to medial: Nerve-Artery-Vein-Lymphatics.
Femoral region - Femoral triangle contains
femoral nerve, artery, vein.
“שילוש הקדוש”
Femoral region Femoral sheath contains
Fascial tube 3-4 cm below the inguinal ligament.
It contains femoral vein, artery, and canal (deep inguinal lymph nodes) but not femoral nerve.
Spermatic cord
I - lntemal spermatic -> T - transversalis fascia
C- Cremasteric muscle and fascia -> I - internal oblique fascia
E - External speonatic fascia -> E - external oblique
ICE TIE
Indirect inguinal hernia
INdirect INternal (deep) inguinal ring (goes through it. INto the scrotum INferior epigastric vessels (lateral) INfants
Direct inguinal hernia
Protrudes through the inguinal (Hesselbach) triangle - “going thought a wall is a hassle”
Bulges directly through parietal peritoneum (“directly”)
medial to the inferior epigastric vessels but lateral to the rectus abdominals.
external (superficial) inguinal ring only
Inguinal (Hesselbach) triangle:
- Inferior epigastric vessels
- Lateral border of rectus abdominis
- Inguinal ligament
D cells located…
pancreatic islets, GI mucosa
secret Somatostatin
G cells located…
Antrum and duodenum
Cells in deudenum:
G - gastrin
I - cholecystokinin
K - GIP
S - secretin
Cells in Jejunum:
K - GIP
I - cholecystokinin
Ghrelin source
stomach
Motilin source
small intestine
Gastrin
ACTION:
REGULATION:
ACTION: motility, growth (mucosa), acid (H+)
REGULATION:
Increase -Think drinking milk: AA and peptides, alkalinization, distention. GRP (VAGAL)
Decrease - pH of less than 1.5
Secretin
ACTION:
REGULATION:
ACTION:
Secretion - pancreatic HC03- (inc)
Secretion - bile secretion (inc)
Secretion - gastric acid secretion (DEC!)
REGULATION: acid and FA in the duodenum.
Cholecystokinin
ACTION:
REGULATION:
ACTION:
pancreatic secretion and gall bladder contraction, sphincter of Oddi relaxation
dec. gastric emptying.
REGULATION: FA and AA
Somatostatin
ACTION:
REGULATION:
ACTION:
Decreases: Decreases CASH
C - contraction (gallbladder)
A - acid (gastric) and pepsinogen
S - secretions of pancreas and small intestine
H - Hormones (insulin and glucagon)
REGULATION:
Inc by the presence of acid (to dec it)
Dec by vagal (to inc acid)
GIP
ACTION:
REGULATION:
ACTION: “stops breaking this down and puts them in”
Exocrine - dec gastric H+ secretion
Endocrine - inc insulin release
REGULATION: FA, AA, oral glucose (“everything”)
Motilin
ACTION:
REGULATION:
ACTION: migrating motor complexes
REGULATION: inc in fasting
Nitric oxide
ACTION:
ACTION: relaxation of smooth muscles and sphincters (LES)
VIP
LOCATION:
ACTION:
REGULATION:
LOCATION: Parasympathetic ganglia (gallbladder, sphincters, small intestine)
ACTION:
secretion of intestinal water and electrolytes.
relaxation of smooth muscles and sphincters
REGULATION:
inc by distension and vagal stimulation
dec by adrenergic input
Parietal cells (stomach)
REGULATION
INC. by - HAG
H - histamine
A - ACh (vagal stimulation)
G - gastrin
DEC. by - GoSSiP G - GIP o S - secretin S - somatostatin i P - prostaglandin
Bicarbonate is Trapped in_________
mucus that covers the gastric epithelium.
Chief cells (stomach)
REGULATION
INC. by “AA”
Acid
ACh (vagal stimulation)
Pancreatic secretions -
_______ fluid;
low flow -> ______
high flow -> ______
Pancreatic secretions -
Isotonic fluid;
low flow -> high Cl-
high flow -> highHC03-
always high in something
Bile composed of
bile salts
bilirubin
“plasma membrane”
phospholipids
cholesterol
water and ions
like “plasma membrane”: phospholipids, cholesterol, water, and ions.
bile salts are made from
bile acids conjugated to glycine or taurine, making them water-soluble
the rate-limiting step of bile acid synthesis
Cholesterol 7 alfa -hydroxylase
Dec. absorption of enteric bile salts at distal ileum (as in short bowel syndrome, Crohn disease) ->
prevents normaI fat absorption.
Calcium, which normally binds oxalate, binds fat instead, so free oxalate is absorbed by gut - inc frequency of calcium oxalate kidney stones.
Bile functions:
- Digestion and absorption of lipids and fat-soluble vitamins
- Cholesterol excretion (body’s 1° means of eliminating cholesterol)
- Antimicrobial activity (via membrane disruption)
Sialolithiasis - Single stone more common
Single stone more common in the submandibular gland (Wharton duct).
sub - mono - dibular, Whart- one
Pleomorphic adenoma (benign mixed tumor) Composed of
chondromyxoid stroma and epithelium and recurs if incompletely excised or ruptured intraoperatively
The most common salivary gland tumor - May undergo malignant transformation.
Mucoepidermoid carcinoma- has ___ , ___ components.
mucinous and squamous
most common malignant tumor
Warthin tumor (papillary cystadenoma lymphomatosum)
benign cystic tumor with germinal centers
Typically found in smokers
bilateral/multifocal - 10%
Achalasia loss of _______neurons (which contain_______).
postganglionic inhibitory
NO and VIP (“NO VIP access”)
LES tone
Inc in…
Same in…
Dec…
LES tone
Inc in achalasia
Same in spasm
Dec in CREST, GERD (transient)
Esophagitis causes in general:
eosinophilic PIC
eosinophilic
P- pills
I - infection
C - caustic
Esophagitis infections:
Candida: white pseudomembrane
HSV-1: punched-out ulcers
CMV: linear ulcers
Esophagitis - pills
T -tetracycline
B - bisphosphonates
I - iron
N - NSAIDs
K - K+ chloride
Esophagitis - eosinophilic
Esophageal rings and linear furrows are often seen on endoscopy. Typically unresponsive to GERD therapy.
Esophageal cancer causes and locations
Adenocarcinoma - lower BOG lower 1/3 B - Barrett O - obesity G - GERD (chronic)
Squamous cell carcinoma - Upper SAL upper 2/3 S - strictures A - alcohol L - liquids (hot)
BOTH - smoking and achalasia
gastric adenocarcinoma types and associations.
Associated with blood type A -> gastric adenocarcinoma -> Intestinal/Diffusse
Intestinal gastric adenocarcinoma- associated with:
Intestinal - associated with SNATCH
S - smoking N - Nitrosamines (smoked foods) A - Achlorhydria T - Tobacco C - Chronic gastritis H - H. Pylori
Commonly on lesser curvature; it looks like an ulcer with raised margins.
Diffuse gastirc adenocarcinoma-not associated with_______, and propertiese:
not associated with H pylori;
signet ring cells (mucin-filled cells with peripheral nuclei)
stomach wall grossly thickened and leathery (linitis plastica).
Blumer shelf
palpable mass on digital rectal exam suggesting metastasis to pouch of Douglas.
Menetrier disease Presents
(WAVEE).
Weight loss Anorexia Vomiting Epigastric pain Edema (due to protein loss)
Menetrier disease pathology
Hyperplasia of gastric mucosa -> hypertrophied rugae
Celiac disease - presentation
malabsorption and steatorrhea (primarily affec ts distal duodenum and/or proximal jejunum)
northern European descent
dermatitis herpetiformis,
dec. bone density.
Celiac disease - pathology
Findings:
Ig’s - IgA anti-tissue transglutaminase (IgA tTG), anti-endomysial, anti-deamidated gliadin peptide antibodies;
villous atrophy, crypt hyperplasia, and intraepithelial lymphocytosis.
Moderate risk of malignancy (eg, T-cell lymphoma).
Tropical sprue vs celiac
Similar findings as celiac sprue (affects small bowel), but responds to antibiotics and can involve ileum with time.
Associated with megaloblastic anemia due to folate deficiency and, later, B12 deficiency.
Whipple disease
PAS the foamy Whipped cream in a CAN.
PAS (+)
foamy macrophages in intestinal lamina propria, mesenteric nodes
C - Cardiac symptoms,
A - Arthralgias
N - Neurologic symptoms
Th1 VS Th2 in Crohn disease and UC
Th1 - Crohn (CrONE)
Th2 - UC - (UleceraTWOve Colitis)
IBD general EXTRAINTESTINAL MANIFESTATIONS
IBD has EARS
E - Eye inflammation (episcleritis, uveitis)
R - Rash (pyoderma gangrenosum, erythema nodosum)
A - Aphthous stomatitis
S - Spondylitis (or peripheral arthritis)
Crohn EXTRAINTESTINAL MANIFESTATIONS
Kidney stones (usually calcium oxalate), gallstones.
May be (+) for anti-Saccharomyces cerevisiae antibodies (ASCA).
Sac of mice in the cervix
UC EXTRAINTESTINAL MANIFESTATIONS
Primary sclerosing cholangitis.
Associated with p-ANCA.
Crohn TREATMENT
Immune depressants: Corticosteroids, azathioprine,
Antibiotics: (eg, ciprofloxacin, metronidazole),
Biologics: infliximab, adalimumab.
UC TREATMENT
5-aminosalicylic preparations (eg, mesalamine), 6-mercaptopurine
infliximab,
colectomy.
Zenker diverticulum
Elder MIKE has bad breath:
Elderly
M - Males
I - Inferior pharyngeal constrictor
K - Killian triangle (thyropharyngeal and cricopharyngeal parts)
E - Esophageal dysmotility
Halitosis
Meckel diverticulum The rule of 2’s:
The rule of 2’s:
2 times as likely in males.
2 inches long.
2 feet from the ileocecal valve.
2% of the population.
Commonly presents in the first 2 years of life.
May have 2 types of epithelia (gastric/ pancreatic).
Angiodysplasia
Tortuous dilation of vessels ->hematochezia -> Confirmed by angiography.
Most often found in the right-sided colon in older patients
Associated with aortic stenosis and von Willebrand disease.
lieus
Intestinal hypomotility without obstruction
Associated with: SOcKS
S - surgeries (abdominal) O - opiates c K - K+ (decreased) S - sepsis
Treatment: bowel rest, electrolyte correction, cholinergic drugs (stimulate intestinal motility).
Serrated polyps sequence of events
CpG island methylator phenotype (CIMP) ->
CpG island methylation (cytosine base followed by guanine,linked by a phosphodiester bond) ->
silence MMR gene expression (DNA mismatch repair) ->
microsatellite instability and mutations in BRAF.
“Sawtooth” pattern of crypts on biopsy.
Up to 20% of cases of sporadic CRC.
Submucosal polyps
May include lipomas, leiomyomas, fibromas, and other lesions.
“fat, muscle, collagen, other shit, are all in the submucosa”
Colorectal Cancer Screen
2 C’s 3 F’s
Screen low-risk patients starting at age 50 with colonoscopy;
alternatives include:
Flexible sigmoidoscopy
Fecal occult blood testing (FOBT)
Fecal immunochemical testing (FIT)
CT colonography.
Patients with a first-degree relative who has colon cancer should be screened via colonoscopy at age 40, or starting 1O years prior to their relative’s presentation. Patients with IBD have a distinct screening protocol.
Aspartate aminotransferase and alanine aminotransferase
in most liver disease: ALT> AST (AlmoST all disease)
in alcoholic liver disease: AST> ALT (when you toAST) - AST usually will not exceed 500 U/L in alcoholic hepatitis.
AST> ALT in nonalcoholic liver disease suggests progression to advanced fibrosis or cirrhosis (>1000 U/L) - differential includes: DIVe
D - drug-induced liver injury (eg, acetaminophen toxicity)
I - ischemic hepatitis
V - viral hepatitis (acute)
e
FUNCTIONAL LIVER MARKERS
- measuring the liver’s biosynthetic function
Prothrombin time
FUNCTIONAL LIVER MARKERS - in advanced liver disease:
in advanced liver disease:
Dec - Platelets (also in Portal HTN), Albumin
Inc - PT, Bilirubin (also hemolysis)
Hepatocellular carcinoma/hepatoma
(causes of):
H - HBV/HCV
A - Alcoholic
N - Nonalcoholic
A - Autoimmune
C - Carcinogens (aflatoxin)
H - hemochromatosis
A - alfa1-antitrypsin deficiency
W - Wilson disease
Budd-Chiari syndrome
Pathology
Associations
Absence of ______.
centrilobular congestion and necrosis - congestive liver disease.
Absence of JVD.
Associated with: “PP-CC” :
Coagulable states, Polycythemia vera, Postpartum state, Carcinoma (HCC)
alfa1-antitrypsin deficiency
Misfolded gene product protein aggregates in hepatocellular ER -> cirrhosis with PAS (+) globules
Crigler-Najjar Type II is…
less severe and responds to phenobarbital, which inc liver enzyme synthesis.
Type 2 (B) like Barbies
Risk factors for cholelithiasis regardless of the type of stones?
“SAC with low bile salts and high cholesterol/bilirubin”
S - stasis
A - Age
C - Crohn disease
Cholelithiasis - Cholesterol stones risk factors
(4 F’s):
I. Female
- Fat
- Fertile (multiparity)
- Forty
- native American
Cholelithiasis - Pigment stones
C - Crohn H - hemolysis I - infections (chlonorcis sinesis) N - Nutrition (parenteral) A - Alcohol
Cholelithiasis - stone type radiolucency and frequency
Cholesterol stones - radiolucent with I0- 20% opaque due to calcifications)
80% of stones.
Pigment stones - black= radiopaque, Ca2+ bilirubinate, hemolysis; brown = radiolucent, infection).
20% of stones
Acalculous cholecystitis-due to
S - stasis of gallbladder
H - hypoperfusion
I - infection (CMV)
C - critically ill patients
Acute pancreatitis complications
P - pseudocyst (lined by granulation tissue, not epithelium) I - infection N - necrosis C - Ca2+ (hypocalcemia) H - hemorrhage
F - failure of an organ (ALI/ARDS, shock, renal failure)
A - abscess
Acute pancreatitis causes:
I - Idiopathic
G - Gallstones
E - Ethanol
T - Trauma
S - Steroids
M - Mumps,
A - Autoimmune disease
S - Scorpion sting
H - hypercalcemia/hypertriglyceridemia (> 1000 mg/dL)
E - ERCP
D - Drugs (eg, sulfa drugs, NRTis, protease inhibitors).
Pancreatic adenocarcinoma risk factors:
C - Chronic pancreatitis (especially> 20 years)
A - Age> 50 years
D - Diabetes
E - Ethnicity (Jewish and African-American males)
T - Tobacco use
Both cimetidine and ranitidine…
Dec. renal excretion of creatinine.
Histamine-2 blockers can cross the…
the blood-brain barrier (confusion, dizziness, headaches) and placenta.
PPI ADVERSE EFFECTS
risk of C difficile infection
pneumonia
acute interstitial nephritis
Dec. serum Mg2+ with long-term use
Aluminum hydroxide ADVERSE EFFECTS
C - Constipation H - Hypophosphatemia O - Osteodystrophy P - Proximal muscle weakness S - Seizures
Magnesium hydroxide
Diarrhea, hyporeflexia, hypotension, cardiac arrest
Sulfasalazine mechanism
A combination of sulfapyridine (antibacterial) and 5-aminosalicylic acid (anti-inflammatory).
Activated by colonic bacteria.
Sulfasalazine ADVERSE EFFECTS
sulfonamide toxicity, reversible oligospermia.
