March 16 - GI Flashcards
Osmotic laxatives
Polyethylene glycol, magnesium citrate
Pigment stones: two causes
- Infection of biliary tract with bacteria or helminths. Causes release of beta glucuronidase which increases unconjungated bilirubin by deconjugating bilirubin
2, Crhonic hemolytic anemia
Opioids and gallbladder
Opioids can cause contraction of sphincter of Oddi. This increases bile duct pressures causing biliary colic
Graft-vs-host disease: liver
Lymphatic infiltration and destruction of small intrahepatic bile ducts, similar to what is seen in PBC
Riboflavin deficiency
Riboflavin used to make FAD which is involved in TCA cycle and electron transport chain. In TCA cycle, needed for succinate dehydrogenase.
Def causes stomatitis, chelitits, glossitis, seborrheic dermatitis, anemia
TCA cycle steps
- pyruvate to oxaloacetate
- oxaloacetate to citrate
- citrate to isocitrate
- isocitrate to alpha ketoglutarate + NAD to NADH
- alpha ketoglutarate to succinyl coA + NAD to NADH
- succinyl coA to succinate + GDP to GTP
- succinate to fumarate + FAD to FADH2
- fumarate to malate
- malate to oxaloacetate + NAD to NADH
C diff colitis: toxins
enterotoxin A: causes watery diarrhea
cytotoxin B: causes colonic epithelial cell necoris and fibrin deposition
Both disrupt actin cytoskeleton, sirupting itght junctions
Lipid digestion: location
Digestion occurs in duodenum
Abosrption occurs in jejunum
Pus formation
Macrophages at site release IL-8 which calls in neutrophils
C3a vs C5a
C3a: chemotactic for basophils and eosinophils
C5a: chemotactic for neutrophils
Pancreatic pseudocysts
Occurs as complication of acute pancreatitis. Pancreatic enzymes leak out leading to inflammatory reaction. Granulation tissue forms and encapsulates fulid. Not a true cyst because it is lined by granulation tissue rather than epithelium. Over 4-6 weeks, granulation tissue develops into fibrosis.
Causes of intestinal atresia
Duodenal: failure of recanalization
Jejunal/ileal: vascular injury; decreased perfusion results in ischemia which results in narrowing or obliteration of a segment of bowel
Colonic: cause unknown
Arsenic poisioning: presentation, causes, treatment
Causes: insecticide ingestion, contaminated well water
Presentation
- acute: garlic odor, vomiting, profuse watery diarrhea, QT prolongation
- chronic: hypo or hyperpigmentation, hyperkeartosis, stocking glove neuropathy
Treatmnet: dimercaprol (chelator that increases urinary excretion)
Deferoxamine
Chelator for iron OD
CaNa2 EDTA
chelator for lead toxicity
Hydroxycobalaminin
antidote for cyanide poisoning
Methylene blue
treatment for methemoglobinemia
Hamartonatous polyps
Generally benign polys. Disorganized mucosal glands, smooth muscle, connective tissue. Sporadic or associated with Peutz Jehghers or juvenile polyposis.
Budd chiari syndrome: pathology and pathophysiology
Pathology: Dilation of sinusoids, perivenular hemoorhage
Cause: acute venous outflow obstruction in liver
Anal fissure: presentation and location
Presentation: sharp pain + bright red bleeding with defecation
Location: Posterior midline anus distal to dentate line
Gastric varices
Two causes
1) portal HTN as complication of cirrhosis
2) splenic vein thrombosis as complication of chronic pancreatitis or pancreatic cancer. Short gastrics drain the fundus to thrombosis of the splenic vein increases pressure in the short gastrics and causes gastric varices isolated to the fundus
Azygos veins and left gastric vein
Azygos: drains esophageal veins to SVC
L gastric: drains upper stomach and lower esophagus to portal vein
Crohns and gallbladder
Terminal ileum inflamed in Crohns. Can’t reabsorb bile acids, resulting in increased cholesterol to bile ratio and gallstone formation
PAS stain
Stains glycoproteins bright pink. Good for looking at fungal cell walls, mucus secretions, BMs. In GI good for looking for T whippelii in sm bowel (gram po actinomycete)
Portal vein thrombosis
Portal HTN with liver unacffected as it si a perisinusoidal process
CA19-9
Pancreatic cancer marker
CA 125
Ovarian cancer marker
Carcinoembryonic antigen
GI cancer marker
Crohns vs UC inflammation
Crohns: Th1 process resulting in granulomas
UC: Th2 process resulting in mucosal damage
Indirect inguinal hernia: population,anatomy, cause
Population: male infants
Anatomy: superior to inguinal ligament. Lateral to inferior epigastrics. Protrudes through deep and superficial rings and is coveretd by all three fascial laters
Cause: Patent processus vaginalis
Direct inguinal hernia: popualtion, anatomy, cause
Population: old men
Anatomy: superior to inguinal ligament. Medial to inferior epigastrics. Protrudes through Hesselbach’s triangle. Superficial ring only. Covered by external spermatic fascia only
Cause: weak transfersalis fascia
Femoral hernia: population, anatomy, cause
Population: women
Anatomy: protrudes through femoral ring, inferior to inguinal ligament
Cause: weak proximal femoral canal
Conjugated vs unconjugated bilirubin
Conjugated is water soluble and excess can be excreted in urine
Cavernous hemangioma
Most common benign tumor of liver. Most common in adults 30-50. Often asymtpomatic. No biopsy due to risk of bleeding.
Liver tumor associated with oral contraceptives
hepatic adenoma
Zenker diverticulum: pathophysiology and presentation
Pathophys: Abnormal action of cricopharyngeal muscles during swallowing (either spasm or failure to relax) results in increased pressure in the pharynx resulting in herniation of pharyngeal mucosa to form a false diverticulum
Presentation: dysphasia, coughing/choking sensation, halitosis, recurrent aspiration pneumonia
Biliary sludge
Forms due to gallbladder hypomotility. Precursro to gallstones
Cystinuria
Autosomal recessive. Increased urine cysteine. Early cysteine kidney stones.
Locations of heart chambers
LA: most posterior, can compress underlying esophagus
RV: lateral right heart
RA: anterior and superior
LV: left lateral heart
Diverticulitis: pathophys/pathology
Pulsion: increased pressure from straining leads to herniation of the mucosa and submucosa through weak areas of the muscularis
Most common in sigmoid colon
False diverciulum as does not include muscularis layer
Bethanechol
Muscarinic agonist
Cimetidine
H2 blocker
Reye syndrome
- Hepatic dysfunction: vomiting, hepatomegaly, and increased LFTs. On path, microvescular steatosis (small fat vacuoles in hepatocyte cytoplasm)
- Encephalopathy: due to increased ammonia
Two types of stomach cancer
- Diffuse type: signet ring cells (nucleus pushed to side), non-gland forming, diffuse involvement due to loss of e-cadherin
- Intestinal type: resembles colon cancer with well formed glands, grows as a well formed mass
Acute viral hepatitis: pathology
ballooning degeneration
councilman bodies: eosinophilic/acidophilic apoptotic hepatocytes
mononuclear infiltrate
Non-atrophic vs atrophic chronic gastritis
Non-atrophic: In antrum, usually due to H pylori, and leads to duodenal ulcers
Atrophic: inflammation in body and fundus leading to loss of acid producing cells, risk for cancer
Pathogenesis of cholesterol gallstones
Increased cholesterol
Decreased bile acids
Decreased phosphatidylcholine
Kaposi’s sarcoma in GI
Can cause diarrhea. Diagnosed by scope which shows red/violet maculopapular lesions to raised hemorrhagic nodules. Biopsy shows spindle cells and BV proliferation
NEcrotizing enterocolitis: presentation, pathogenesis, and diagnossis
Presentation: distension and bloody stools in a preemie.
Pathogenesis: feeding introduces bacteria to bowel which proliferate excessively, invade the wall, and cause inflammation and ischemic necrosis
Diagnosis: thin curvilinear areas of lucency that parallel gut lumen on x-ray
Pathogenesis of hepatic steatosis in alcoholics
Incareds NADH produced by EtOH metab
Results in decreased FFA oxidation and accumulation of TGs
