GI Flashcards
hydrochloric acid
- secreted by parietal cells
- dissolves food
- activates pepsin (for protein digestion)
- stimulates duodenal release of other digestive enzymes
- kills bacteria
pepsin
digests proteins into small absorbable peptides
-prehormone pepsinogen secreted by CHIEF CELLS (to prevent autodigest) –> converted to pepsin by HCl in gastric lumen
parietal cells (make HCl) stim by 3 hormones
GASTRIN - stim stomach acid secretion and motility
-secreted by G cells –> enterochromaffin-like cells (ECL) secrete histamine –> parietal cells secrete HCl
HISTAMINE - produced by ECL cells in response to gastrin
- stim parietal cells to secrete HCL
- H2 blockers reduce acid secretion
ACETYLCHOLINE - directly stim parietal cells to secrete HCl
-parasympathetic (via vagus) inc GI activity “rest + digest”
somatostatin
produced by pancreatic delta (D-cells) acts as negative feedback –> INHIBITS SECRETION OF GASTRIN, insulin, glucagon, pancreatic enzymes and inhibits gallbladder contraction
mucus layer protection x2
mucus production
bicarbonate production
fx of large intestine (3)
- absorb remaining water from undigested food
- transport undigested food for removal via feces
- absorb certain vitamins produced by bacteria (K, biotin)
doudenum
responsible for most small int absorption, analyzes chyme and releases approp hormones:
SECRETIN - released by duodenum, inhibits parietal cell gastric acid production + causes pancreas to release bicarbonate (to buffer)
CHOLECYSTOKININ (CCK) - aids in breakdown of fats/proteins by stimulating pancreatic release of digestive enzymes
- increases bicarb release (pancreatic enzymes work maximally in basic environment)
- stimulates GB contraction + bile release (emulsify fats into smaller micelles)
pancreas (exocrine)
ACINAR CELLS - produce substances that drain into duodenum:
BICARBONATE: neutralizes gastric acid and activates the other enzymes below
PROTEASES (trypsinogen, chymotrypsinogen) - precursors to enzymes that breakdown protein
AMYLASE: breaks down starches into simple sugars
LIPASE: breaks down fats into fatty acids (w/ help of bile salts that inc surface area)
pancreas (endocrine)
ISLETS OF LANGERHANS:
- INSULIN - produced by beta cells
- GLUCAGON - produced by alpha cells
- SOMATOSTATIN - produced by delta cells
- suppresses release of GI hormones (CCK, gastrin, secretin, insulin, glucagon, panc enzymes)
- in CNS, inhibits growth hormone production
esophagitis**
GERD MC cause, INFECTION IN IMMUNOCOMPROMISED (CANDIDA, CMV, HSV)
- RF: pregnancy, smoking, obesity, ETOH use, chocolate, spicy foods, caustic
- med causes: NSAIDs, BB, CCB, BISPHOSPHONATES, vitamins
-sx- ODYNOPHAGIA (painful swallow), DYSPHAGIA (difficult swallow), retrosternal chest pain
- dx- upper endoscopy
- candida - linear lesions (fluconazole)
- CMV - large, shallow ulcers (gancyclovir)
- HSV - small deep ulcers (acylcovir)
infectious esophagitis*
MC in immunocompromised pt
-CANDIDA, CMV, HSV
- sx- ODYNOPHAGIA (PAINFUL SWALLOW), dysphagia, retrosternal chest pain
- CANDIDA - LINEAR YELLOW-WHITE PLAQUES –> PO FLUCONAZOLE
- CMV - LARGE SUPERFICIAL SHALLOW ULCERS –> GANCICLOVIR
- HSV - SMALL, DEEP ULCERS –> ACYCLOVIR
eosinophilic esophagitis
allergic, inflammatory eosinophilic infiltration of esophageal epithelium
- MC in children
- MC assoc w/ ATOPIC DZ (food allergy, non food allergy, asthma, eczema, etc)
- sx- dysphagia +/- reflux or feeding difficulties
- dx- endoscopy - normal +/- MULTIPLE CORRUGATED RINGS, +/- white exudates
- tx- remove foods w/ allergic response; inhaled topical corticosteroids (w/out spacer)
pill-induced esophagitis
MC w/ NSAIDs, BISPHOSPHONATES, potassium chloride, iron pills, vit C, BB, CCB
- sx- odynophagia, dysphagia
- dx- endoscopy - small, well-defined ulcers of various depths
- tx- take pills w/ at least 4 oz water, avoid recumbency for 30-60 min
caustic (corrosive) esophagitis
ingestion of corrosive substances: alkali (drain cleaner, lye, bleach) or acids
- sx- odynophagia, dysphagia, hematemesis, dyspnea
- dx- endoscopy to see extent of damage or complications (perforation, stricture, fistula)
- tx- supportive, pain med, IV fluids
GERD
transient relaxation of LES / INCOMPETENT LOWER ESOPHAGEAL SPHINCTER, esophageal motility disorders, delayed gastric emptying +/- hiatal hernia
-complications: esophagitis, stricture, Barrett’s, adenocarcinoma
- sx- HEARTBURN (PYROSIS), often retrosternal and post-prandial (30-60 min), increased in supine position, relieved w/ antacids; REGURGITATION, DYSPHAGIA, cough at night (acid aspiration into lungs)
- atypical sx: hoarseness, aspiration pneumonia, “asthma” broncospasm from acid, NON-CARDIAC CHEST PAIN (mc cause), weight loss
- ALARM SX: DYSPHAGIA, ODYNOPHAGIA, WL, BLEEDING (suspect malignancy or cx)
- dx- clinical
1. ENDOSCOPY - often used 1st if persisetent sx or complications of gerd
2. ESOPHAGEAL MANOMETRY - dec LES PRESSURE
3. 24 AMBULATORY PH MONITORING GOLD STD
-tx-
Stage 1: lifestyle modification
Stage 2: “as needed” pharmacotherapy - antacids, OTC H2 receptor antagonists (famotidine, ranitidine)
Stage 3: scheduled therapy - H2RA, PPI, prokinetic agents
PPI DRUG OF CHOICE IN MOD-SEV DZ; NISSEN FUNDO IF REFRACTORY
BARRET’S*
esophageal ADENOCARCINOMA
-RELATED TO GERD
epithelium replaced by precancerous metaplastic columnar cells from cardia of the stomach (more used to acidic enviro but don’t belong there)
achalasia*
idiopathic proximal loss of GANGLION CELLS IN AUERBACH’S PLEXUS –> INC LES PRESSURE –> obstx + lack of peristalsis
(esophageal wall ganglion cells in auerbach’s plexus normal produce nitric oxide –> relaxes smooth muscle)
-MC in 50s
- sx-
- DYSPHAGIA TO BOTH SOLIDS + LIQUIDS, malnutrition, WL, dehydration, REGURGE, chest pain, cough (btw 25-60yo)
- esophageal dilation may occur if left untreated
- dx-
- ESOPHAGEAL MANOMETRY - GOLD STD, shows inc LES pressure >40mmHg, dec peristalsis
- DOUBLE-CONTRAST ESOPHAGRAM “BIRD’S BEAK APPEARANCE OF LES” (narrowing)
- ENDOSCOPY may be needed to r/o carcinoma or other etiologies
- tx- decrease pressure –> botox injection (6-12 mo), nitrates, CCBs, pneumatic dilation of LES, esophagomyomectomy
- ddx- diffuse esophageal spasm or zenker’s diverticulum
diffuse esophageal spasm*
strong non-peristaltic esophageal contractions
- sx- stabbing, chest pain worse w/ HOT OR COLD liquids/foods
- dx- esophagram shows “corkscrew” esophagus
- tx- nitrates, CCBs
zenker’s diverticulum
pharyngoesophageal diverticulum/pouch (false diverticulum - only involves mucosa)
- sx- dysphagia, globus sensation, neck mass, regurge of foods, cough, halitosis (old trapped food in pouch)
- dx- BARIUM ESOPHAGRAM
- tx- diverticulectomy, cricopharyngeal myotomy; observe if small + asymptomatic
nutcracker esophagus
etio unknown; may be assoc w/ GERD
-EXCESSIVE CONTRACTIONS DURING PERISTALSIS
-sx- dysphagia (liq/solids), chest pain, asymtomatic
-dx- MANOMETRY - INC PRESSURE DURING PERISTALSIS
normal EGD/esophagram
-tx- lower esophageal pressure w/ CCB, nitrates, botox, sildenafil
boerhaave syndrome
FULL THICKNESS RUPTURE OF DISTAL ESOPHAGUS, assoc w/ REPEATED, FORCEFUL VOMITING or perf during endoscopy
- sx-RETROSTERNAL CHEST PAIN WORSE W/ DEEP BREATHING OR SWALLOWING, hematemesis
- CREPITUS ON CHEST AUSCULTATION due to PNEUMOMEDIASTINUM
- dx-
- CHEST CT/XRAY - pneumomediastinum, eso thickening
- CONTRAST ESOPHAGRAM - DEFINITIVE + leakage,
- tx-
- small/stable: IV fluids, NPO, abx, H2 blockers
- large/severe: surgical repair
Patient will be complaining of severe chest pain
PE will show Hamman crunch (mediastinal crackling with each heartbeat)
Chest X-ray will show pneumomediastinum
Diagnosis is made by esophogram with water-soluble oral contrast
Most commonly caused by a full-thickness esophageal rupture due to IATROGENIC> forceful vomiting
Most common location is left posterolateral distal esophagus
Treatment is emergent surgical consult and broad-spectrum antibiotics
mallory-weiss syndrome (tears)*
UGI bleeding from longitudinal mucosal lacerations @ gastroesophageal junction or the gastric cardia
-sudden rise in intragastric pressure or gastric prolapse into esophagus (excessive vomitting or bulimic)
- sx- PERSISTENT RETCHING/VOMIT –> HEMATEMESIS AFTER ETOH BINGE, melena, hematochezia, syncope, abdominal pain, hydrophobia
- dx- UPPER ENDOSCOPY –> SUPERFICIAL LONGITUDINAL MUCOSAL EROSIONS
- tx- SUPPORTIVE, acid suppression promotes healing
- severe bleeding –> epinephrine injection, sclerosing agent, band ligation, hemoclipping or balloon tamponade
esophageal webs + rings
web: thin membranes in mid-upper esophagaus
- may be congenital or acquired (ex complication of eosinophilic esophagitis)
- PLUMMER-VINSON SYNDROME: dysphagia, esophageal webs, iron def anemia, atrophic glossitis
- MC cauc F 20-60y
- SCHATZKI RING: lower esophageal web - MC assoc w/ sliding hiatal hernias
- sx- dysphagia esp to solids
- dx- BARIUM ESOPHAGRAM (SWALLOW)
- tx- ENDOSCOPIC DILATION IF SX BUT W/OUT REFLUX (antireflux surgery if not)
esophageal varices*
dilation of collateral submucosal veins as complication of PORTAL VEIN HTN
- RF: CIRRHOSIS MC CAUSE ADULTS (portal vein thrombosis mc in children)
- 90% w/ cirrhosis devo varices, 30% bleed (mortality rate 30-50% w/ 1st bleed) 70% rebleed w/in 1st year (1/3 rebleeds are fatal)
- sx- UPPER GI BLEED, may devo s/s hypovolemia
- dx- UPPER ENDOSCOPY + “red wale” markings + cherry red spots –> inc risk of bleed
- TYPE/SCREEN, FLUIDS + NG TO EMPTY CONTENTS BEFORE ENDOSCOPY
HIATAL HERNIA TYPES
Type I: “SLIDING HERNIA” MC TYPE - 95%
- GE jx and stomach slide into mediastinum (inc reflux)
- tx- like GERD
Type 2: “rolling hernia” (paraesophageal)
- fundus of stomach protrudes through diaphragm w/ GE jx remaining in anatomic location - may lead to strangulation
- tx- surgical repair to avoid complications
esophageal neoplasms*
SQUAMOUS CELL - MC CAUSE ESOPHAGEAL CANCER WORLDWIDE (90%)
- MC upper 1/3; peaks 50-70yo
- RF: TOBACCO/ALCOHOL USE, decreased fruits/veg, achalasia, hot beverages, exposure to noxious stimuli, men, nitrates, inc incidence AA; dec incidence w/ NSAIDs + coffee
ADENOCARCINOMA - MC CAUSE IN UNITED STATES
- MC younger pt, obese, caucasians, MC lower 1/3
- ADENOCARCINOMA IS USUALLY COMPLICATION OF GERD leading to Barrett’s
- sx-
- DYSPHAGIA TO SOLID FOOD –> FLUIDS, odynophagia
- WL, chest pain, anorexia, cough, hoarse, reflux, hematemesis +/- virchow’s node
- hyperCa in pt w/ squamous cell (due to PTH)
- dx- UPPER ENDOSCOPY W/ BX TEST OF CHOICE, double contrast barium esophagram
- tx- resection, radiation, chemo (5-FU), depending on stg
gastritis*
superficial inflam/irritate of mucosa w/ mucosal injury
- inbalance btw aggressive and protective measures
- -> H. PYLORI MC
- -> NSAIDs/ASA 2nd mc
- -> acute stress (critically ill)
- -> others: heavy ETOH, bile salt reflux, meds, radiation, trauma, ischemia, pernicious anemia, portal HTN
- sx- MC ASYMPTOMATIC
- epigastric pain, N/V, anorexia +/- upper bleed (minimal)
-dx- ENDOSCOPY GOLD STD = thick, edmatous erosions <0.5cm –> h.pylori testing
-tx-
-H.pylori positive –> “CAP” = clarithromycin + amox + PPI
alt metronidazole
-H.pylori negative –> acid suppresion: PPI, H2 block, antacids
-pharm prohylaxis for pt at high risk for stress-related: IV PPI or H2
Acute: NSAIDs > alcohol
Type A chronic: pernicious anemia
Type B chronic : H. pylori
gastropathy
mucosal injury w/out evid of inflammation
peptic ulcer disease*
- DEC PROTECTIVE FACTORS IN GASTRIC ULCER
- dec mucus, bicarb, prostaglandins; NSAIDs
- mc in antrum of stomach; older pt 55-70y
- worse w/ meals
- INC DAMAGING FACTORS (ACID/PEPSIN) IN DUODENAL ULCER
- acid, pepsin, h.pylori
- 4x MC; younger pt 30-55yo
- better w/ meals
- H.PYLOR MC CAUSE
- NSAIDS 2ND MC - inhibit prostaglandin-mediated synthesis of protective mucus
- Zollinger-Ellison syndrome: gastrin-producing tumor
- etoh, smoking, stress (sev medical), M, elderly, steroids, malignancy
- SUSPECT GI MALIG (ZES, GASTRIC CANCER) IN NONHEALING GU
- sx- DYSPEPSIA = EPIGASTRIC PAIN, WORSE AT NIGHT
- ulcer-like or acid dyspepsia - relief w/ food, antacids, nocturnal sx –> assoc w/ DU
- food-provoked dyspepsia - pain 1-2 hrs after meals + weight loss –> assoc w/ GU
- PUD IS MC CAUSE OF UPPER GI BLEED
- complications: bleeding, perforation (esp anterior DU), penetration (esp posterior DU), obstruction
- dx- ENDOSCOPY GOLD STD + bx to rule out malignancy
- upper GI series - used w/ pt unable/willing to do endoscopy
- all GU seen must f/u w/ endoscopy to r/o malignancy and document healing (8-12 wks later)
- tx-
- H.pylori –> “CAP” clarithromycin + amox + PPI
-H.pylori neg –> PPI; H2 blocker, misoprostol, antacids, pepto, sucralfate
zollinger ellison syndrome
gastrinomas: gastrin-secreting neuroendocrine tumors –> gastric acid hypersecrete –> PUD
-MC in duodenal wall (45%), pancreas (25%)
>66% malignant
-sx- ABDOMINAL PAIN AND DIARRHEA, multiple peptic ulcers, refractory “kissing” ulcers
diarrhea
-dx- fasting gastrin level (best screening) = >1000pg/mL and gastric pH <2
+ SECRETIN TEST: inc gastrin release w/ secretin (normally inhibits)
- tx- local: surgical resection
- metastatic: PPIs, surgical resection if liver involved
gastric carcinoma
Patient will be a man
With a history of H. pylori infection
Complaining of loss of appetite, unintentional weight loss
PE will show left supraclavicular node (Virchow’s node), left axillary node (Irish node), periumbilical node (Sister Mary Joseph’s node)
Comments: Adenocarcinoma is most common
- MC males >40yo, presents late
- RF: H.PYLORI, salted, cured, smoked, pickled foods w/ nitrates/nitrites (converted by h.pylori?)
- dx- upper endoscopy w/ biopsy
- tx- gastrectomy, rad/chemo; poor prognosis
bilirubin metabolism
prehepatic:
- bilirubin produced from heme metabolism (80% old RBC, 20% turnover immature RBC, myoglobin)
- heme degraded by macrophages in liver + spleen
- heme –> biliverdin (green) –> bilirubin (red-orange) –> sent to liver for conjugation and excretion
- unconjugated (indirect) bilirubin isn’t soluble in water
intrahepatic phase:
- unconjugated/indirect bilirubin is conjugated w/ a sugar in hepatocytes via enzyme GLUCURONOSYLTRANSFERASE (UGT)
- conjugated (direct) bilirubin is now water-soluble (for bile excretion)
posthepatic phase:
- once soluble in bile, transported and stored in GB
- in intestine, conj bili is converted to urobilinogen which can go through 3 main pathways:
1. oxidized by intestinal bacteria into stercobilin (gives stool brown color)
2. small amount converted in kidney to urobilin and excreted (gives urine yellow color)
3. some recycled back to liver & bile for reuse - in dz where excess direct bilirubin –> excreted into urine (why dark urine and light stools are seen in elevated direct/conj bilirubin)
- in hemolysis (inc unconj/indirect bilirubin,) urine may be dark due to hemoglobinuria not bilirubinemia
jaundice
yellowing of skin, nail beds + sclera by tissue bilirubin deposition as a consequence of hyperbilirubinemia
-occurs when levels >2.5mg/dL
etiologies:
- inc bilirubin overproduction (hemolysis), dec hepatic bilirubin uptake, impaired conjugation, biliary obstruction, hepatitis
- inc bilirubin w/out inc LFTs –> suspect familial bilirubin disorders (dubin-johnson synd, gilbert synd) + hemolysis
dubin-johnson syndrome
"Dubin", "Direct bilirubinemia" "Dark liver" hereditary conjugaed (direct) hyperbilirubinemia due to dec hepatocyte excretion
-sx- consititutional sx, mild icterus
- dx- mild isolated conjugated (direct) hyperbilirubinemia (btw 2-5) but can increase w/ concurrent illness, pregnancy or OCPs
- grossly black liver on biopsy
-tx- none
ROTOR’S SYND - simlar but milder in nature; assoc w/ conj and unconj hyperbili and not assoc w/ grossly black liver on bx
crigler-najjar syndrome
hereditary unconjugated hyperbilirubinemia (0.6-1.0/million)
- glucuronosyltransferase (UGT) is enzyme needed to convert indrect to direct
- Type I: no UGT activity (auto recessive)
- Type II: very little UGT activity <10% normal
- sx- neonatal jaundice w/ severe progression in the 2nd week leading to kernicterus (bili-induced encephalopathy) –> hypotonia, deafness, oculomotor palsy + death by 15 mo
- dx- isolated indirect (unconj) hyperbilirubineia w/ normal LFTs; liver normal on bx
- tx-
- Type I: PHOTOTHERAPY plasmapheresis in crisis, liver transplant definitive
- Type II: not usually necessary, PHENOBARBITAL shown to inc UGT (but not in type I)
gilbert’s syndrome
hereditary unconjugated hyperbilirubinemia (relatively common 5-10% pop)
-reduced UGT activity –> dec bili uptake –> inc indirect bili
- sx- TRANSIENT EPISODES OF JAUNDICE DURING STRESS, FASTING, ETOH OR ILLNESS
- dx- slightly inc isolated indirect bili w/ normal LFT (often incidental finding)
- tx- none needed
patterns of liver injury
hepatocellular damage: inc ALT + AST
-ALT more sensitive for liver dz
cholestasis: inc levels of alk phos w/ inc GGT
- inc bilirubin greater than inc ALT/AST
liver “synthetic” fx
- PT depends on synthesis of coag factors (vit K dependant): 2,7,9,10
- PT is an earlier indicator of severe liver injury/prognosis than albumin (prolonged PT when 80% of protein synthesizing ability lost)
liver lab patterns: AST:ALT > 2
alcohol hepatitis
“S” in AST for “Scotch”
AST levels usually <500, AST found in mitochondria, ETOH causes direct mitochondrial injury = inc AST
liver lab patterns: ALT>AST
viral/toxic/inflam process (usually)
AST + ALT > 1000 –> usually acute viral hepatitis (A, B and rarely C)
-chronic hep b/c/d –> mildly inc ALT + AST (usually <400)
liver lab patterns: inc alk phos –> inc alk phos + GGT
biliary obstx or intrahepatic cholestasis
- GGT most sensitive indicatory of biliary injury
- if ALP inc w/out GGT, look for other sources (bone, gut)
liver lab patterns: inc ALT > 1000, + ANA, + smooth muscle AB, inc IgG
autoimmune hepatitis
-responds to corticosteroids, azathioprine
cholelithiasis
cholesterol 90%, pigmented 10%
black stones: hemolysis or etoh cirrhosis
brown stones: inc in asian pop, parasites/bacterial infx
RF: 5F’s, OCPs, natives, cirrhosis, infx, rapid WL, IBBD, fibrates, inc trigs
- sx- mc asymptomatic
- biliary “colic” = episode of abrupt RUQ/epigastric pain
-dx- US
choledocholithiasis*
gallstones in common bile duct
- primary: stones form in duct
- secondary: mc, stones pass from GB into duct
- sx- asymptomatic, or biliary colic w/ RUQ tender, +/- jaundice
- complications: acute pancreatitis, acute cholangitis
- dx-
- transabdominal US often initially
- ERCP DIAGNOSTIC TEST OF CHOICE (and treatment)
- magnetic resonance cholangiopancreatography (MRCP) and endoscopic US w/ pt w/ intermediate risk
-tx- ERCP extraction preferred over lapo choledocholithotomy
acute cholangitis*
Patient will be complaining of right upper quadrant pain, jaundice, fever (Charcot triad)
Diagnosis is made by RUQ ultrasound, CT scan, or ERCP (gold standard)
Most commonly caused by choledocholithiasis leading to bacterial infection, E. coli
Treatment is antibiotics, definitive treatment is ERCP with antibiotics typically an adjunct
(amp/sulbactam, pip/tazo OR ceftriaxone + metronidazole OR FQ + metronidazole)
Comments: Charcot triad + hypotension and AMS = Reynolds pentad, acute obstruction
acute cholecystitis*
gall bladder/duct obstx by stone –> inflam/infx
-MC e.coli, klebsiella, entercocci, b.fragilis
- sx- RUQ pain continuous, N, precipitated by fatty meals
- F, + murphy’s sign, palpable GB (30%), + boas sign - referred pain to right shoulder subscapular area (phrenic nerve irritation)
- dx-
- US initial test of choice
- HIDA SCAN GOLD STANDARD (pos = no visualization of GB)
- tx- NPO, IV fluids, Abx (ceftriaxone + metronidazole) –> cholecystectomy
- if non-operative –> cholecystostomy
chronic cholecystitis
assoc w/ gallstones
-strawberry GB: interior resembles strawberry 2ry to cholesterol submucosal aggregation –> porcelain GB (premalignant condition)
fulminant hepatitis (acute hepatic failure)
rapid liver failure + hepatic encephalopathy (often w/ coagulopathy)
-acute = w/in 8 wks after onset of liver injury in pt that was healthy prior
- ACETAMINOPHEN MC CAUSE, drug rx, viral hepatitis (A-E), Reye syndrome
- sx- ENCEPHALOPATHY (+asterixis), COAGULOPATHY
- dx- INC AMMONIA in serum, INC PT/INR (>1.5), HYPOGLYCEMIA
- tx-
- encephalopathy: LACTULOSE (converts to lactic acid by bacteria, neutralizes ammonia), RIFAXIMIN, NEOMYCIN (abx that decrease bacteria producing ammonia), PROTEIN RESTRICTION (reduces breakdown of protein into ammonia)
- LIVER TRANSPLANT only definitive tx
reye’s syndrome
fulminant hepatitis mc seen in children assoc w/ ASA use during viral infx (can occur w/out ASA)
-sx- rash (hands/feet), intractable vomiting, liver damage, encephalopathy, dilated pupils, multi-organ failure