NBME HIGH YIELD QUESTIONS AND ANSWERS

What are sentinel lymph nodes? First group of lymph nodes draining a specific organ Describe the lymph node drainage of the GI tract *Trachea and esophagus => Mediastinal *Liver, spleen, pancreas, stomach, upper duodenum => Celiac *Lower duodenum, jejunum, ilecum, colon to splenic flexure => SMA *Colon from splenic flexure to upper rectum => IMA *Lower rectum to anal canal (above pectinate line) =>Internal Iliac Anal rectum (below pectinate line) =>Superficial inguinal What is the mechanism by which Lactulose is used to treat Hepatic Encephalopathy? *Lactulose is resistant to intestinal disaccharides *Metabolized by gut flora into lactic and formic acid. *These acids have an osmotic/laxative effect and cause an acidifying effect *Acids also cause NH3 to be trapped as NH4+ and cannot cross intestinal wall; excreted into feces What antimuscarinics are used to prevent postprandial abdominal pain of IBS patient Hyoscyamine,dicyclomine Which drugs are contraindicated in patients with glaucoma? Drugs that cause mydriasis: A1 agonists or M3 antagonists (antimuscarinics) A1 agonists: Epinephrine M3 antagonists:Atropine and other antimuscarinics Mydriasis pulls the iris to it's base, making the angle narrow What is the treatment of Atropione poisoning? What is the treatment of Organophosphate poisoning? Atropine poisoning: Physostigmine (crosses BBB) Organophosphate poisoning: Atropine first and then PAM *Important to distinguish between atropine overdose and TCA overdose. Both have symp