Gastro 8 - Large Intestine Part 1 Flashcards
What is the cause of Hirschsprung disease?
Caused by failure of neural crest cells migration, leads to megacolon due to dysfunctional Auerbach and Meissner plexuses in distal colon.
What are the GI problems associated with Down syndrome?
Duodenal atresia. Hirschsprung disease. Annular pancreas. Celiac disease.
What is a volvulus?
Twisting of the colon around its mesentery. Most common sites are cecum or at the sigmoid colon. Twisting interrupts blood flow, causing ischemia.
What is the most abundant flora in the large intestine?
Bacteroides fragilis.
What is common between all the bacteria in the colon?
They are G (-), facultative anaerobic bacteria. Ferment sugars to lactic acid.
What are the causes of Appendicitis In adults? Children?
Fecalith in adults. Viral infection causing hyperplasia of lymphoid tissue in children.
What are the symptoms of appendicitis?
Nausea, vomiting. Causes diffuse periumbilical pain that later localizes to the right lower quadrant (McBurney’s point: 2/3 of the way from umbilicus to ASIS-anterior superior Iliac spine).
What must be discarded in women of reproductive age with symptoms that look like appendicitis? How do we do it?
Ectopic pregnancy. Done with beta-hCG count.
What is the Pectinate line?
Demarcates the end of endoderm and beginning of ectoderm located in the anal region.
What is the name of the hemorrhoids proximal to the pectinate line?
Internal hemorrhoids.
Which type of hemorrhoids do not cause pain?
Internal hemorrhoids.
What is the blood supply of the proximal to the pectinate line?
Superior rectal artery, that is from the inferior mesenteric artery. Venous drainage is superior rectal vein. If cancer develops in this area, most likely adenocarcinoma.
What is the name of the hemorrhoids distal to the pectinate line?
External hemorrhoids.
What type of cancer most likely develops when distal to the pectinate line? What would be the cause?
Squamous cell cancer. Caused by HPV 16, 18, 31.
What would be blood supply distal to the pectinate line?
Inferior rectal artery which is a branch of the pudendal artery. The venous drainage is going to the inferior rectal vein.
