GI 2 Flashcards
What is a benign metabolism disorder that will present urine samples that are positive for a reducing sugar but negative for glucose?
Essential furctosuria - deficiency of fructokinase
What is an AR characterized by neonatal jaundice, bleeding diathesis, feeding intolerance, and hypotension d/t an absent function of galactose-1-phosphate uridyl transferase?
galactosemia
What enzyme deficiency can cause life-threatening failure to thrive, hepatomegaly, and cirrhosis d/t impaired metabolism of fructose-1-phosphate into dihydroxy acetone phosphate (DHAP) and glyceraldehyde?
aldolase B
What disease presents with hepatomegaly, cardiomegaly, and increased risk for cirrhosis with an acid alpha glucosidase (or acid maltase) deficiency?
Pompe diseae - glycogen storage disease II
What is the most common cause of selective carbohydrate malabsorption with GI Sx of gaseous distention and diarrhea after dairy products?
lactase deficiency
What tumors are composed of nests or sheets of uniform cells with an eosinophilic cytoplasm and oval-to-round stippled nuclei derived from enterochromaffin cells of the intestinal mucosa?
carcinoid tumors
What is distinctive about carcinoid tumors on histology?
minimal to no variation in shape and size of tumor cells
What is characteristic of intestinal carcinoids?
they are malignant transformations of enterochromaffin cells of the intestinal mucosa a part of the amine precursor uptake and decarboxylation (APUD) system
What is the most common location of intestinal carcinoids?
ileum
-also frequently in appendix and rectum
What is a good way to identify the esophagus on CT?
the radiolucency of the air in the trachea can be identified, and the esophagus will be behind it
Describe the Ras-MAP pathway?
a groth factor liganf binds to TK –> autophosphorylation –> phosphotyrosine interacts with many proteins that activates Ras –> activated Ras converts GDP to GTP and begins a phosphorylation cascade with actvation of Raf kinase –> activation of MAP kinase –> enters nucleus to influence gene txn
What does projectile nonbilious vomiting in a newborn with an olive-sized mass in the distal stomach or pyloric region suggest?
pyloric stenosis
What is the cause of pyloric stenosis?
hypertrophy of the pyloric muscularis mucosae - narrowing of pyloric channel is thought to be exacerbated by localized edema and inflammation
what does a Hx of dyspnea and cardiomegaly suggest?
cardiac dysphagia d/t LA enlargement which is is located posteriorly just over the esophagus; increased P in LA can cause distention and pressure on underlying esophagus
When does LA enlargement occur?
in mitral stenosis and LV failure
What is the most common type of malignancy in pts suffering from IBD, particularly ulcerative colitis?
colorectal carcinoma
What are 6 key features that distinguish colitis-associated carcinoma from sporadic colorectal carcinoma?
- affects younger pts
- progress from flat and non-polypoid dysplasia
- hsitologically appear mucinous and/or have signet ring morphology
- develop early p53 mutations and late APC gene mutations (opposite of sporadic)
- be distributed within the proximal colon (esp with Crohn or concurrent primary sclerosing cholangitis)
- be multifocal in nature
When does colorectal carcinoma in IBD pts occur?
after 10y of colitis; tend to be higher grade than sporadic
Explain how colitis-asoociated carcinomas are different from sporadic colorectal carcinomas
more likely to arise from non-polypoid dysplastic lesions, be multifocal in nature, develop early p53 mutations and late APC gene mutations, and be of high histological grade
What are the two arteries given off by the splenic a.? Which is more vulnerable to ischemia after splenic a. blockage?
short gastric aa. and left gastroepiploic a.
-short gastric aa. are more vulnerable to ischemic injury because they have very poor anastomoses, whereas the L gastroepiploic a. has a strong anastomosis with the R gastroepiploic a.
What artery supplies blood to the pylorus and the proximal part of the duodenum?
gastroduodenal a.
What artery supplies blood to the distal lesser curvature of the stomach?
R gastric a.
What artery perfuses the distal greater curvature of the stomach?
R gastroepiploic
What typically causes double-stranded breaks in DNA and what is the repiar mechanism?
exposure to ionizing radiation - repaired by non-homologous end joining
What is PPV?
TP/(TP+FP)
What does dusky red congested vowel with subserosal ecchymoses, edema, and/or well0defined areas of necrosis indicate?
mesenteric ischemia
What is characterized by the preseence of a defect in the intestinal wall along with signs of peritonitis?
intestinal perforation
What is characterized by a dull-appearing peritoneal surface with areas of viscous white-yellow suppurative exudate?
bacterial peritonitis