STRX Week 3 & 4 Flashcards
Identify the organs and explain the rationale
Left: Duodenum - presence of Brunner’s glands in submucosa
Middle: Jejunum - plica circulares (extensions of submucosa)
Right: Ileum - presence of Peyer’s patches (lymphatic nodules in submucosa)
What area of the small intestinal mucosa is most susceptible to injury during an ischemic event and why?
Surface epithelium - they depend on blood capillaries in lamina propria that travel along crypts - furthest from blood source - most susceptible
What are two characteristics of ischemic intestinal disease?
Attentuation/atrophy of the surface epithelium
Normal to hyperproliferative crypts
What type of necrosis do you expect to see in the intestine following ischemia? Why?
Coagulative necrosis due to firm texture of the tissue
What is transmural infarction? When does it usually occur?
Infarction (lack of blood supply) that involves mucosa, submucosa, and muscularis propria - occurs due to acute blockage of major blood vessel
Why is mortality after ischemia higher in patients with right-sided colonic disease?
Both the small intestine and the right side of the colon are supplied by the superior mesenteric artery.
What are some causes and the result of occlusive intestinal ischemia?
What are some causes and the result of non-occlusive?
Causes of Occlusive:
1. Thrombus/embolism of superior mesenteric artery/vein
2. Systemic vasculitis of small arteries
3. Extrinsic compression of vasculature due to tumors, adhesion, strictures, strangulation, volvulus,
intussusception, herniation
4. CMV infection, which can result in localized vascular obstruction
Resulting in acute mesenteric ischemia
Non-occlusive:
1. Diabetes
2. Chronic NSAID use
Usually results in chronic mesenteric ischemia
Describe the pathogenesis of intestinal ischemia.
Loss of blood flow to the intestinal tissue results in hypoxic damage; however, most damage occurs due to reperfusion
injury when blood supply is restored; Restoration of oxygen supply results in generation of reactive oxygen species,
eicosanoids, nitric oxide, endothelin and several cytokines, resulting in vasoconstriction, inflammation, complement
activiation, and finally, tissue destruction.
What is the prognosis of instestinal ischemia, and what factors influence the prognosis?
Poor
Prognostic indicators include coexisting COPD and persistence of symptoms for more than 2 weeks. Rapid diagnosis and relief form persistent vasoconstriction are keys to improve these results. Surgical revascularization, intraarterial perfusion with a thrombolytic agent or infusion of vasodilators, and simple systemic anticoagulation are choices of therapy
The multifocal, well-circumscribed tumor growths on the small intestine and the presence of monomorphic cells with characteristic stippled (“salt and pepper”) chromatin within round nuclei suggests what type of tumor?
Neuroendocrine
What immunohistochemical stains would be used to confirm diagnosis of neuroendocrine tumor of the small intestine?
Chromogranin and Synaptophysin
What is a carcinoid syndrome? Which 2 substances are elevated in patient with classic carcinoid syndrome?
Neuroendocrine tumors release biologically active amines and peptides into blood, which escape inactivation by the liver, and cause multiple symptoms.
Serotonin (5-hydroxy tryptamine) and its metabolite, 5-hydroxy indole acetic acid (5-HIAA) are normally elevated in these patients.
Neuroendocrine tumors in what location tend to metastasize?
Which location tend to be aggressive?
NET in what location tend to be benign?
Foregut metastasize
Midgut aggressive
Hindgut benign
What factors portend a worse prognosis in GI neuroendocrine tumors
Degree of histological differentiation
Mitotic rate
Ki-67 proliferative index
Behavior is also affected by size and location
Suppose this tumor secreted gastrin, what changes would you expect to see in the stomach?
This is an example of a gastrinoma, associated with
the Zollinger-Ellison syndrome.
Gastrin would drive the proliferation of parietal cells, resulting in increased acid production.
Describe the duodenum in terms of its anatomical relationships with surrounding structures and its different named parts.
Duodenum has 4 parts: superior, descending, horizontal, ascending
Anterior to horizontal: superior mesenteric a. and v.
Posterior to horizontal: aorta and IVC
What is an anatomical landmark used to differentiate an upper versus a lower GI bleed?
What is the function of that landmark?
Ligament of Trietz
Connects the diaphragm to the duodenojejunal flexure - widens and elevates it during breathing - facilitates movement of intestinal contents
The small intestine except for [what] is considered intraperitoneal?
2nd, 3rd, and 4th parts of the duodenum are retroperitoneal
Outline the blood supply to the duodenum proximal to entry of the major duodenal papilla.
Aorta → Celiac Trunk → Common Hepatic artery → Gastroduodenal artery → SUPERIOR Pancreaticoduodenal artery (Anterior & Posterior branches), Duodenal branches
Outline the blood supply to the duodenum distal to entry of the major duodenal papilla.
Aorta → Superior Mesenteric artery → INFERIOR Pancreaticoduodenal arteries (Anterior & Posterior branches)
How would a pt feel epigastric pain from the duodenum?
Via the sympathetic pathways
Periarterial* → Celiac or Superior Mesenteric Ganglia → Greater/Lesser Splanchnic Nerve → Paravertebral Ganglion → White Communicating Rami → Anterior Primary Rami → Spinal nerve → Dorsal Root → Cell bodies in Dorsal Root Ganglion → Dorsal Root → Dorsal Rootlets → Dorsal Horn (location of Synapse)
Periaterials:
Gastroduodenal artery → Superior Pancreaticoduodenal artery
Superior Mesenteric artery → Inferior Pancreaticoduodenal arteries
What is the structure and function of the mesentery?
fan-shaped fold of peritoneum that attaches the jejunum and ilium to the posterior abdominal wall
The jejunum has [longer/shorter] vasa recta as compared to the ileum?
Longer
How would a spinal cord injury at T8-10 affect the small intestine?
Loss of sympathetic innervation to the jejunum and ileum –> increased peristalsis and blood flow
Parasympathetics not affected bc it’s recieved from vagus n
Color: Red — Pink
Wall: Thicker — Thinner
Vascularity: Greater — Less
Vasa recta: Longer — shorter
Arterial arcades: Larger and fewer — smaller and more
Fat in mesentery: Less, pale — more, encroaching
Plicae circulares: Prominent — Sparse
Characterize Primary Biliary Cholangitis and outline expected laboratory findings
Autoimmunity and inflammation of extrahepatic bile ducts leading to cholestasis and biliary fibrosis
Predominately in females
Florid duct lesions
Associated with sjogren syndrome and thyroid disease
Expected labs:
Elevated bilirubin, ALP, GGT (cholestatis pattern)
Positive Antimitochondrial antibodies
A pt’s labs show positive AMA and the following histologic findings:
What is the likely diagnosis? Interpret the histological findings
Primary Biliary Cirrhosis (PBC)
Destruction of bile duct
Characterize Primary Sclerosing Cholangitis and outline expected laboratory findings
Autoimmune disease with progressive inflammatory and sclerosing destruction of intrahepatic and extrahepatic bile ducts
Predominately male
Associated with IBD and Pancreatitis
Fibrotic Duct Obliteration with strictures and beading on biliary imaging
Unpredictable clinical course
Expected labs:
Elevated bilirubin, ALP, GGT (cholestatis pattern)
Elevated assay for pANCA
Negative AMA
A pt’s labs show negative AMA, elevated pANCA and the following histologic findings:
Primary Sclerosing Cholangitis (PSC)
Onion skin lesion, tombstone scar
Characterize Autoimmune hepatitis and outline expected laboratory findings
Autoimmune disorder of antibodies attacking hepatocytes
Predominately females
Associated with Lupus, rapidly progressive
Normal biliary imaging with plasma cell-rich infiltrates and Regenerative Rosettes on biospy
Most likely to present in fulminant failure
Expected labs:
Dramatically elevated AST, ALT (hepatocellular pattern)
Positive ANA, Anti-smooth muscle Abs with elevated serum IgG
A pt’s labs show elevated AST/ALT, positive ANA, and elevated serum IgG, and the following histologic findings:
Autoimmune hepatitis
Plasma cell infiltrates, Regenerative Rosettes
After SER, where do triglyceride droplets migrate to?
What happens in those organelles?
RER then Golgi
Assembling of chylomicrons
What cells are seen in the crypt of small intestine?
Enterocytes
Goblet cells
Paneth cells
Enteroendocrine cells
Does this CT have contrast?
What is the abnormality?
Yes
Cirrhosis:
Ascites in the abdomen
Small, scalloped liver
Splenomegaly
Explain the following 3-phase image series
Top left is no contrast
Top right is arterial (contrast in aorta)
Bottom left is portal-venous (contrast getting into portal vein lighting up liver)
Bottom right is delayed contrast
Interpret this ultrasound
Simple cyst in the liver
Well-circumscribed, hypoechoic, enhanced brightness in shadow area
Interpret the CT
Small Bowel Follow Through/ Barium
Irregularly thickened small bowel mucosal folds
How would you differentiate the pancreas from the parotid gland?
Presence of islets of Langerhans
Absence of striated ducts
Label the following:
Acinar cells
Centroacinar cells
Intercalated ducts
Identify the Islets of Langerhans
What is the encircled stricture?
What’s a possible outcome of it?
Rokitansky-Aschoff sinus
Invagination of mucous membrane into muscularis externa due to hyperplasia of epithelial cells through fibromuscular layer of gallbladder wall
Risk factor for formaiton of pigmented gallstones
Identify the tumor type for each picture and explain why
Pink: HCC tumor - cells that look like hepatocytes but have no portal tracts and thin trabeculae
Purple: adenocarcinoma - fibrotic tissue forming abnormal ducts or glands
What’s the difference between these two images?
Left: Enteric contrast
Right: Enteric and IV contrast
Imaging modality, body region, abnormality
MRCP - Magentic Resonance Cholangiopancreatography
Angiogram of liver without contrast
Cholangiocarcinoma
What are the imaging modality and body
parts depicted?
Endoscopic retrograde cholangiopancreatogram (ERCP)
