GI Flashcards
Where do external hemorrhoids occur?
Distal to the pectinate line
Arise from ectoderm
Painful because they receive somatic innervation
Associated with squamous cell carcinoma
15 y/o presents with right sided facial swelling just beyond the angle of the jaw. Has been producing more saliva than usual. How would you describe the saliva?
Parotitis
Lower Potassium concentration than normal saliva
Initially saliva from duct acini is isotonic to plasma but intercalated ducts reabsorb sodium and chloride and add potassium and bicarb
A pt presents with hepatic encephalopathy (asrixis (flapping tremor), confusion, and lethargy) secondary to ammonia accumulation from cirrhosis. How would you treat?
Lactulose
When digested by bacteria lactulose acidifies the colon and converts ammonia (NH3; a weak base), to a non absorbable form (NH4)
24 hours post birth a child has failed to pass meconium. + chloride sweat test. What is the embryonic origin of the other structure that is involved?
Mesenephric duct
95% of CF pts are infertile due to improper development of the mesonephric duct (wolffian)
A pt with PUD is complaining of impotence and has gynecomastia on PE likely due to AE’s of his current treatment. What could he be switched to that would use the same mechanism as his current drug?
Ranitidine
Gynecomastia and impotence are associated with cimetidine (H2-blocker) but ranitidine doesn’t have the antiadrenergic effect
42 y/o japanese pt that recently immigarated presents to their oncologist with histology demonstrating signet ring cell carcinoma. Dx?.
Gastric cancer
Mucin displaces nuclei to the side making the signet righ. If found in the ovary, it is assumed the cell metastasized from the stomach (Krkenberg tumor)
Pt presents with abd pain, steatorrhea, weight loss, fatigue, joint pain. Bx shouls intraepithelial lymphoctyes, enterocyte damage, villous blunting. Dx and risk of developing?
Celiac dz
HLA-DQ2, HLA-DQ8
Risk of T-cell lymphoma
Ab against gliadin
Through which vessel would a vitamin A analog first enter the bloodstream
Thoracic duct
Fat soluble vitamins enter lacteals -> larger lmphatics -> thoracic duct -> subclavian v.
How do you treat PUD?
Amoxicilin, Clarithromycin, omeprazole
Pain improves with a meal = duodenal ulcer
78 y/o man presents with diarrhea, LLQ pain, fever. Small amount of blood in stool. Labs: WBC = 14, HCT 35%, Platelet = 250,000. Colonoscopy is contraindicated. Location of this condition?
Attenuated muscularis propria
Diverticulitis, often in sigmoid colon.
RF’s = low fiber diet and obesity
Note: diverticulitis can occur without bleeding
Normally when acidic chyme enters the duodenum, it will secrete secretin from duodenal S-cells. What does secretin do?
Stimulate release of bicarbonate from the pancreatic duct.
A 10 y/o boy presents with an X linked immunodeficiency, chronic GI inflammation, and negative nitroblue tetrazolium test. Which immune component is impaired?
Chronic granulomatous dz
Defect in NADPH oxidase in phagosomes (PMNs, Macrophages)
NADPH oxidase is located on the membrane and produces reactive oxygen species
70 y/o presents with 3 day LLQ pain, anorexia, constipation, leukocytosis. PE LLQ tenderness, guarding, rebound
diverticulitis (and possible perforation) due to increased intraluminal pressure leading to perforation of a bowel outpouching
Occurs in weaker part of the bowel.
53 y/o alcoholic has epigastric pain radiating to his back, n/v. Relief by leaning forward, elevated amylase, lipase. What would be found on PE?
Tapping over CN VII elicits a muscle twitch (Chvostek sign) and/ or carpopedal spasm during BP cuff inflation (Trousseau sign)
Dx - pancreatitis
Assoc with hypocalcemia
46 y/o IVDU with RUQ pain, yellow eyes, elevated LFT’s. HCV +. What is she likely to develop if left untreated?
Chronic Hep C
Fatigue, fever, jaundice, poor appetite, GI upset, ashy stools, dark urine, joint pain, cirrhosis
Only 20-50% of HCV positive develop cirrhosis
What type of cell does Salmonella infect in the GI?
Peyer Patches
M cells overlie the Peryer’s patch and act as APC’s
Salmonella attaches to M celland M cells initiate T cell response
A neonate presents with inability to swallow. She cough chokes and vomits during feeding. XR shows a tracheosphageal fistula. What abnormality would have been observed during pregnancy?
Polyhydramnios
Pr presents with abdominal pain and vomiting improved by bending forward. CT shows diffuse pancreatic enlargement with areas of necrosis. This is caused by inappropriate activation of which enzyme?
Trypsinogen
Pancreatic enzymes are synthesized by pancreatic acinar cells as zymogens. They drain into the ampulla of Vater in the descending duodenum. and t enterokinase cleaves trypsinogen into trypsin which can now activate the other pancreatic enzymes (chymotrypsin, elastase, carboxypeptidase etc)
Pancreatic obstruction or ischemia leads to abn activatation of trypsinogen causing acute necrotizing pancreatitis
Pt presents with progressive fatigue and pruritis x 6 mo. Elevated Alk Phos, ALT and positive antimitochondrial ab. Dx and what would the histology resemble?
Primary biliary cholangitis
Autoimmune mediated destruction of small and mid sized intrahepatic bile ducts causing cholestasis.
Bx = Lymphocytic inflammation and destruction of intrahepatic bile ducts with necrosis and micronodular regeneration. Similar to graft vs. host dz b/c T cells cause apoptosis of small intrahepatic bile ducts
A 4 week old with feeding intolerance is found to have pancreatic tissue encircling the duodenum. Cause?
Annular pancreas
ABN migration of the ventral pancreatic bud and fuse with the dorsal bud
Normally the ventral pancreatic bud gives rise to the uncinate process and main pancreatic duct
Usually asymptomatic but may present with duodenal obstruction or pancreatitis
How do you asses bioavailability of a po drug as compared to its IV abailability?
Bioavailability = fraction of administered drug that reaches the systemic circulation chemically unchanged.
Measure plasma concentration vs time and divide the area under the po curve by the area under the IV curve
A chronic alcoholic is presenting with cirrhosis. Before beginning this treatment which structure will have increased pressure?
Portal v.
progressive fibrosis causes portal HTN
Would also expect increased pressure in the superior mesenteric, portal, and splenic v.
Why does ascites occur in cirrhosis?
Kidneys sense decreased perfusion pressure due to partal HTN and activates the RASS system
tx - Na restriction and diruetics (furosemide and spironolactone)
Pt presents with GERD that is resistant to OTC antiacids. PE scattered telangiectasias, ulcers at the finger tips, calcium deposits in the soft tissue of the hands and elbows. Dx and Why the heartburn?
CREST syndrome
GERD due to fibrous replacement of the muscularis in the lower esophagus
CREST = Cacinosis, Raynoud, Esophageal dysmotility, sclerodactyly, telangiectasia
Increased risk of Barret’s esophagus and fibrous stricture formation
Following a cholecystectomy where will dietary lipids be absorbed?
Jejunum
Bile salts are secreted into duodenum where bile salts emulsify the end products of fat digestion and form micelles.
Micelles are passively reabsorbed in the jejunum
Removal of gallbladder doesn’t change this
A pt is seeking a drug for motion sickness. What side effects should she be warned about?
Antimuscarinic and antihistamines with antimuscarinic action (meclizine, dimenhydrinate)
AE’s = blurry vision, dry mouth, urinary retention, constipation
What 3 systems sense movement?
Vestibular
Visual
Somatosensory systems
A male presents with epigastric abdominal pain following binge-drinking. 4 weeks later has has a palpable upper abdominal mass and a cystic lesion on CT. Dx and histology?
Pancreatic pseudocyst (complication of acute pancreatitis) Collection of fluid rich in enzymes and inflammatory debbris. Histology = walls consist of granulation tissue and fibrosis Unlike a true cyst, pseudocysts are not lined by epithelium
Parietal cells secrete?
Gastric acid, IF
Chief cells secrete?
Pepsin
Mucosal cells secrete?
Bicarbonate
G cells secrete?
Gastrin. Stimulates digestion and is activated by phenylalanine, tryptophan and high calcium
Which Histamine receptor is active in digestion?
H2
H1 = allergies
A cholecytokinin stimulation test demonstrating incomplete gallbladder emptying. What finding would you expect in this pt?
Biliary sludge due to gallbladder hypomotility
Gallbladder actively abosorbs water from bile and hypomotility allows for the bile to concentrate and the sludge predisposes to gallstone formation with bile duct obstruction
A pt with PUD undergoes gastrectormy and they find enlargement of gastric rugal folds and parietal cell hyperplasia. What caused this?
Gastrin
Stimulates HCl secretion and trophic effect on parietal cells
Zollinger-Ellison syndrome
If the inferior mesenteric a. is ligated during a procedure, where does the left colon get collateral circulation from?
Superior mesenteric a.
What are the 3 main blood supplies to the GI tract?
Celiac trunk - stomach, duodenum, gallbladder, liver, spleen, pancreas
Superior mesenteric a. - SI and LI
Inferior mesenteric a. - SI and LI
A new born with drooling, feeding difficulties (choking, coughing), and cyanosis with feedings?
Tracheoesophageal fistula with esophageal atresia
Failure of primitive foregut to separate from airway
Polyhydramnios
CXR wouls show a stomach bubble
What testing can you use to confirm lactase deficiency?
Stool pH
Congenital = ar
Secondary = acquired resulting from inflammation or infection that causes injury to the mucosal brush border of the SI.
Incomplete hydrolysis of lactose leads to osmotic diarrhea and bacterial fermenatation will drop stool pH
A pt becomes hypotensive during a cholecystectomy and presents days later with abdominal pain and bloody diarrhea suggests injury where?
Ischemic colitisof the rectosigmoid junction (watershed b/w sigmoid a. and superior rectal a.)
In low flow states watershed areas become prone to ischemia. What are the 2 watershed areas in the GI tract?
Splenic flexure (SMA and IMA) Rectosigmoid junction (sigmoid a. and superior rectal a.)
Acute inflammation of the gallbaldder in the absence of gallstones
Acalculous cholecystitis
Occurs in critically ill adn has a high mortality. Tjhought to be secondary to gallbaldder stasis and ischemia.
Fever, RUQ pain, leukocytosis
Inflamed and enlarged gallbladder
In addition to being its own activator, trypsin also serves as?
Its own inhibitor by cleaving other trypsin molecules
What is hereditary pancreatitis?
Mutation in trypsinogen or SPINK1 genes
Leads to ABN trypsin that is not susceptible to inactivating cleavage by trypsin (becomes unregulated and causes autodigestion)
Recurrent attacks of acute pancreatitis
On endoscopy a pt bx reveals moderately differentiated tumor cells with keratin pearls and nests. Dx and RF’s?
Esophageal squamous cell carcinoma
Alcohol consumption and smoking
Presents with progressive solid food dysphagia
After initiating opioids for pain management a pt presents with new upper abdominal pain that makes it difficult to lie still. Whats going on?
mu opioids can cause cantraction of smooth muscle causing spasm of common bile duct (Sphincter of Oddi)
Can cause biliary colic (severe pain and cramping in RIQ)
D/c opioid and control pain with an NSAID
Pt presents with worsening fatigue and elevated alk phos. What should be checked next?
A moderately elevated Alk phos of unclear eitology should be followed up with gamma-glutamyl transpeptidase
GGP is predominantly present in hepatocytes and biliary epithelia and helps id if the alk phos is coming from the GI tract or bone
Following a gastrectomy a pt will require supplementation with?
Inj B12 due to the lack Intrinsic Factor
Pt presents with systemic skin and joint symptoms, hepatomegaly, and significantly increased transaminase levels. Also urticarial vasculitis rash and RUQ pain
Acute HBV
Sex and drugs
Look for elevated HBsAg and HBeAg and viral load
A pt is presenting with intermittent abdominal pain and a cholesterol-containing mass in the ileocecal valve dx and findings on cxr?
Gallstone ileus = a bowel obstruction caused when a large gallstone erodes into the intestinal lumen
CXR = pneumobilia (air in the biliary tract)
Pt presents with yellowing skin and SOB with exercise. Has been occuring since birth. CXR = hyperlucency of lung fields and flat diaphragm
Alpha1-antitrypsin deficiency
Panacinar emphysema + jaundice
A 3 wk old premy presents with abd distension, vomiting, and blood streaked stool. Abdominal XR shows thin curvilinear areas of lucency that parallel the bowel wall lumen. Dx?
Necrotizing enterocolitis (NEC) XR reveals pneumatosis intestinalis One of the most common GU emergencies in newborns esp preterms due to GI and immune immaturity. Impaired mucosal barrier allows bacteria to invade causing necrosis and the bowel begins to collect gas 30% die, survivors are at risk of bowel obstruction due to fibrosis
Older male pt presents with abd discomfort, loose stool, and weight loss. Bx stains brightly with PAS. Dx?
Tropheryma whippelii
PAS stains the glycoprotein in the cell wall of the actinomycete
An alcoholic presents with hematemesis and esophagus show varices. The bleeding is most likely coming from chronic shunting of portal blood to the systemic circulation through which v?
Left gastric
Which type of hernia can protrude into the scrotum and becomes larger with coughing?
Indirect
These are more common than direct hernias and tend to present on the right side.
Failure of the processus vaginalis to obliterate
Inferior epigastric vessels are medial
The excess of NADH due to excessive alcohol intake causes a decrease in which metabolic process?
Free fatty acid oxidation
NADH is formed by alcohol dehydrogenase and aldehyde dehydrogenase
Hepatic steatosis = trigllyceride accumulation within the hepatocellular cytoplasm
A gastric lesion is considered an erosion if it extends into, but not completely though, which layer?
Muscularis mucosa
Acute erosive gastropathy can cause upper GI hemorrhage that leads to melena
A 38 y/o man presents with steatorrhea despite a healthy diet, no travel, no occupational hazards, and no significant alcohol or smoking history. CBC, chem panel, and thyroid panels are WNL. What work up should be ordered next?
Stool test with Sudan III stain
Fats are typically the most severely affected macronutrient in malabsorption. Sudan III tests the stool for fat is is the most sensitive screen for malabsorptive disorders
A “moldy” grain in china can cause G to T mutation in p53 increases risk of?
Liver Cancer
aflatoxin causes G to T in p53 and increases risk of hepatocellular carcinoma
Aspergillus
45 year old construction worker presents with fatigue x 4 mo and SOB. PE - overweight, pale conjunctiva. Labs: low HCT, low MCV but Ferritin, Fe, and TIBC are WNL. Dx and what would be seen on smear?
Lead poisoning
Basophilic stippling
Tends to be through occupational exposure in adults. Syx of clicky abd pain, constipation, lead lines on gum, peripheral neuropathy, microcytic anemia with normal iron studies.
Lead inhibits the heme synthesis pathway by inhibiting gamma-aminolevulinate dehydratase
A pt has acute pancreatitis that resolves with fasting. He has no PMH and does not consume alcohol. What test should be ordered?
Serum triglycerides
Most cases of acute pancreatitis is caused by gallstones and chronic alcoholism.
Since he does not drink, it’s suspicious that the has inherited or acquired hypertriglyceridemia which causes acute pancreatitis when triglycerides are > 10
Which type of GI ulcer is very unlikely to be malignant?
Duodenal ulcers
Gastric ulcers can be malignant (MALT, gastric adenocarcinoma) and must be bx’d especially if they[re caused by H. pylori
Duodenal ulcers caused by H. pylori do NOT have a high risk of duodenal carcinoma and do not require bx
A 3 day old is brought in due to persistent vomiting and refusal to eat. Non bloody, green/yellow color. On laparotomy - normal duodenum with absence of large segments of jejunum and ileum and the remainder of the distal ileum winding around a thin vascular stalk. Dx and pathology?
Intestinal atresia
Atresia distal to the duodenum is due to vascular occlusion in utero.
“apple-peel” atresia is due to occlusion of the superior mesenteric and leads to a blind-ending proximal jejunum (a length of absent bowel and mesentery) and a terminal ileum spiraled around an ileocolic vessel.
What is the role of Somatostatin?
“Anti hormone”
Decreases activity/realease of: Gastrin, CCK, secretin, GIP, VIP, Insulin, Glucagon
Secreted by D cells (GI tract) and delta cells (pancreas)
What is the role of VIP?
Vasoactive intestinal peptide
Made by smooth muscle cells and PS ganglia and enteric nervous system
Rleaxaes smooth m. and sphincters throughout GI tract and increases secretion of electrolytes and water
VIPoma = high volume watery diarrhea
What is ileus?
When peristalsis is low
Tx with prokinetic agents:
1. Increase ACh (bethanechol, neostigmine)
2. Increase 5-HT (Metoclopramide, macrolides)
3. Increase d2 (also metoclopramide)
What are the retroperiteneal structures?
A DUCK Pear Adrenal glands Duodenum Ureters Colon Kidneys pancreas Esophagus Aorta Rectum
I cells of the stomach secrete?
CCK
Which ligament contains the portal triad?
Hepatoduodenal ligament
Which pancreatic structure is derived from the ventral primordium?
Main Pancreatic duct, inferior/posterior portion of the head
Dorsal pancreatic bud form the majority of the pancreatic tissue.
What occurs when the dorsal and ventral pancreatic buds fail to fuse?
Pancreas divisum
Pancreatic ductal systems remain separate and the accessory duct drains the majority of the pancreas
A pt is having his external hemorrhoids removed. Anesthesia would be needed to block which nerve?
Pudendal n.
External hemorrhoid below dentate line, covered by modified squamous epithelium and have cutaneous (somatic) inn from the inferior rectal n. (branch of pudendal n.)
Branches of pudendal inn perineum and external genitalia in males and females
What are the characteristics of internal hemorrhoids?
Above dentate line and are covered by columnar epithelium. Autonomic inn from inferior hypogastric plexus - sensitive to stretch but no pain, temp, or touch
What is the order of gene mutations in sporadic colon cancer?
- APC (early adenoma; normal mucosa to small polyp)
- K-ras (Late adenoma; polyps increase in size)
- p53 (Adenocarcinoma; malignant transformation)