peritoneum and mesentery Flashcards
Most common bug in SBP?
E coli
With regards to bowel displacement, what processes moves them medial? posterior?
Medial - ascites
Posterior - intraperitoneal abscess
What is pseudomyxoma peritonei? What are the causes?
Gelatinous ascites from ruptured appendiceal mucinous tumor or other mucinous tumors
What are the differentiating features of pseudomyxoma compared to simple ascites
Pseudomyxoma will have a scalloped liver margin due to mass effect from mucinous implants. There will also be high attenuating septa and punctate “ring and arc” calcifications
Where are the most common sites of peritoneal carcinomatosis? why?
Due to the flow of ascites
Pelvic cul de sac
Right paracolic gutter
Mesenteric root at ileocecal junction
Sigmoid mesocolon
DDx for enhancing nodules along peritoneal surface with marked nodular thickening of the omentum
Peritoneal carcinomatosis
Mesothelioma
Tuberculous peritonitis
DDx for peripherally enhancing centrally necrotic masses intraperitoneally?
Colon cancer
Invasive peritoneal mets
Primary peritoneal tumor
Peritoneal abscess
How does primary peritoneal mesothelioma present?
Multiple enhancing soft tissue masses present along peritoneum IN CONTACT with peritoneum with large volume ascites
How does cystic peritoneal mesothelioma differ from primary? Who gets it?
Young women
Benign
Low attenuation/anechoic multiloculated cystic mass filling peritoneal cavity
Most common primary tumor of small bowel?
Caricinoid
What cells does carcinoid arise from?
Enterochromaffin cells of kulchitsky in crypts of lieberkuhn
DDx for calcified mesenteric mass with radiating strands and adjacent bowel wall thickening
Carcinoid
Retractile mesenteritis
Where do most small bowel carcinoid tumors arise?
Terminal ileum
How does one differentiate carcinoid from mesenteric mets?
Mets wont have desmoplastic reaction, will be multiple
What causes the desmoplastic reaction in carcinoid?
Thickening along neurovascular bundles
What is the cardiac complication with carcinoid? Why
Tricuspid valve insufficiency due to direct release of serotonin into the hepatic veins by metastatic carcinoid
What is retractile mesenteritis?
Idiopathic mesenteric mass with dense calcifications and bowel tethering and obstruction.
Similar to carcinoid, but wont have spokewheel thickening and small bowel wall thickening
DDx for a solitary, ill defined mass at root of small bowel mesentery with marked associated calcification and bowel tethering
Retractile mesenteritis
Carcinoid
Most common primary mesenteric tumor
Desmoid
Which lymphoma more commonly affects the mesentery?
NHL
Lobulated confluent soft tissue mass encasing superior mesenteric vessels
What is the sign? Dx?
Hamburger/sandwich sign
Mesenteric lymphoma
DDx for low attenuation mesenteric LN with perihperal enhancement?
Treated lymphoma
Infection (fungal, MAI)
Whipples
testicular mets
Which nodes does abdominal TB affect most often?
Mesenteric and peripancreatic
HIV patient with centrally low attenuating LN
TB
What clues help differentiate MAI vs TB when considering them for centrally necrotic LN
TB more often has focal hepatic or splenic abnormalities and peritoneal involvement
What make up the nodes in CMLNS?
Chylous fluid surrounded by a thin rim of fibrous tissue
Cystic mesenteric adenopathy in a patient with celiac disease?
Cavitary mesenteric lymph node syndrome
What are the two responses with a retained surgical sponge?
Fibrinous - foreign body granuloma
Exudative - abscess formation
What is a gossypiboma?
Masslike inflammatory response surrounding a surgical sponge
Where do spilled gallstones accumulate?
Subdiaphragmatic or hepatorenal recess
When do complications most often occur with spilled gallstones?
4 months, but can be 1month-20years
What are the three types of abdominal hernia?
External, internal, diaphragmatic
Which hernia is most common?
Indirect
Which inguinal hernia goes medial/lateral to the inferior epigastric vessels? How can you quickly tell the difference?
MD - medial, direct
Lateral, indirect
Direct will NOT extend to the scrotum
What are the defects in the inguinal hernia types?
Direct - directly protrudes through abdominal wall defect
Indirect - protrudes through inguinal canal and emerges at the external ring
What is an incarcerated hernia?
One that cannot be manually reduced
Femoral hernias are more common in which sex?
Female
Where does a femoral hernia extend?
ALWAYS below the inguinal ligament and lateral to the pubic tubercle
Immediately medial to the femoral vein
Which hernia is more common to strangulate?
Femoral (10x) more than inguinal
Obstruction with pain radiating down medial thigh suggest what kind of hernia?
Obturator (impingement on obturator nerve)
Which hernia has the highest rate of mortality if strangulated?
Obturator
What is a richter hernia?
Hernia with only a portion of the circumference of a bowel loop
What is a spigelian hernia?
Abdominal wall defect involving the linea semilunaris
What is the most frequent internal hernia?
Paraduodenal
Where do most paraduodenal hernias occur and why?
Left side, as a result of bowel herniating through a peritoneal reflection created by the inferior mesenteric artery. Bowel resides lateral to the ascending limb of the duodenum
How do paraduodenal hernias appear?
Mass of small bowel loops in LUQ appearing to be encapsulated
What is a foramen of winslow hernia? Which part of bowel is more commonly herniated through it?
Herniation into the lesser sac
Small bowel (70%) Ascending colon/cecum (30%)
What is the cause of infantile bochdalek hernia?
Failure of closure of the pleuroperitoneal canal
Which side do bochdalek usually occur?
Left, always posterior
What is a morgagni hernia?
Midline defect where right and left pleuoroperitoneal folds do not join. Substernal herniation often involving omentum
Which organ most commonly herniates through a traumatic diaphragmatic hernia?
Stomach!
Which side do most traumatic hernias usually occur?
Left
due to protective effect of liver
Which side do morgagni hernias usually occur?
Right, and anterior
What is the progression of infantile umbilical hernia?
Spontaneous closure
What is the differential for misty mesentery?
Fluid - CHF, portal hypertension, hypoalbuminemia, mesenteric arterial or venous thrombosis
Inflammation - pancreatitis, IBD, diverticulitis
Neoplasm - NHL
Retractile mesenteritis
Soft tissue stranding with the epicenter distinct from the colon wall or appendix along the antimesenteric border?
Epiploic appendigitis
Which side are omental infarcts more common?
Right side, due to longer length of right omentum
What is the key feature in differentiating diverticulitis/appendicitis and omental infarct?
Omental infarct will have a normal adjacent colon
