GI Section 1: Large Bowel/Rectum (Misc LB Pathology) Flashcards
Ulcerative colitis, and to a lesser degree Crohns, is the primary cause.
Clostridium difficile
Toxic Megacolon
Toxic Megacolon
Gaseous dilation distends the transverse colon (on upright films), and the right and left colon on supine films.
Lack of haustra and pseudopolyps are also seen
Why wont you do barium enema in toxic megacolon?
Risk of perfroration
Ulcers of the penis and mouth.
Behcets
Behcets
Can also affect GI tract (and looks like Crohns) - most commonly affects the ileocecal region
a cause of pulmonary artery aneurysms
Behcets
Epiploic Appendagitis
Epiploic appendages along the serosal surface of the colon can torse, most commonly on the left
There is not typically concentric bowel wall thickening (unlike diverticulifis).
Omental infarction
itypically a larger mass with a more oval shape and central low density.
Common on the right (R O I- right omental infarct). Both entities are self-limiting.
Classic pathway of appdendicitis
obstruction (fecalith or reactive lymphoid tissue) -> mucinous fluid builds up increasing pressure -> venous supply is compressed -> necrosis starts ->
wall breaks down -> bacteria get into wall -> inflammation causes vague pain (umbilicus) -> inflamed appendix gets larger and touches parietal peritoneum (pain shifts to RLQ).
most common mucinous tumor of the appendix.
Mucinous cystadcnomas
They look similar to cystadenocarcinomas and can perforate leading to pseudomyxoma peritonei
Appendix Mucocele
Appendix Mucocele
“Onion sign” - layering within a cystic mass
Colonic Volvulus different flavors:
Sigmoid
Cecal
Cecal Bascule
Most common adult form of colonic volvulus
Sigmoid
Sigmoid Volvulus
Coffee Bean sign (inverted 3 sign)
SIgmoid Volvulus
Frimann Dahl’s Sign
which refers to 3 dense lines (arrows) converging towards the site of obstruction (star).
Points to the RUQ. Recurrence rate after decompression = 50
Associated with people with a “long mesentery.” More often points to the LUQ. Much less common than sigmoid.
Cecal Volvulus
Anterior folding of the cecum WITHOUT twisting
Cecal Bascule
dilation o f the cecum in an ectopic position in the middle abdomen, without a mesenteric twist
terminal ileum is not involved
Younger Person - with prior surgery, a mass, or a 3rd Trimester Baby destined to wear the jeweled crown of Aquilonia upon a troubled brow
Extends Towards LUQ
Haustra is maintained
Small Bowel is dilated
Old Grandma - who needs to poop Extends Towards RUQ
Haustra is Lost
Ascending and Transverse
Colon might be Dilated
marked diffuse dilation of the large bowel, without a discrete transition point.
Colonic Pseudo-Obstruction
aka Colonic Ileus, Ogilvie Syndrome
Bacterial overgrowth in a blind loop which gets no poop (surgery that creates a blind loop without poop). Classic with pre-existing Inflammatory Bowl Disease.
Diversion Colitis /Pouchitis
2 types of Colitis Cystica
- Superficial
- Deep/Profunda
The superficial kind consists of cysts that are small in the entire colon. It’s associated with vitamin deficiencies and tropical sprue. Can also be seen in terminal leukemia, uremia, thyroid toxicosis, and mercury poisoning.
Superficial Colitis Cystica
These cysts may be large and are seen in the pelvic colon and rectum.
Deep/proifunda Colitis cystica
Phleboliths in the rectum
associated with
Klippel-Trenaunay-Weber and Blue Rubber Bleb.
Rectal Cavernous Hemangioma
Gossypiboma
Heterogeneous intra-peritoneal collection located behind anterior abdominal wall at the level of the surgical incision site. It shows thin enhancing wall with multiple small internal gas bubbles and hyperdense curvilinear structures.
