Pancreas Pathophys Flashcards

Question

the endocrine pancreas

Answer 1

Endocrine pancreas * The pancreas is also made of endocrine cells, which are a number of different cells that are within the Islet of Langerhans * These are polygonal cells that develop sometime around week 9 of embryonic development * They are separated by a thin capillary network from the bulk of the pancreatic parenchyma * Recall: the majority of the parenchyma is exocrine * You can see the Islet of Langerhans in the H&E stain and TEM very nicely

Answer 2

•The minor or accessory duct, which has 10% of the flow, is called the duct of Santorini

Answer 3

debridement, abx ## Footnote * For necrotic pancreatic parenchyma, certain necrosis is a set-up for infection (because any de-vitalized (?) tissue is a set-up for infection) * This has to be debrided and then antibiotics are indicated * Debridement means removing dead tissue. (Think of it as debris that needs to be scraped away either endoscopically, surgically, or through interventional radiology)

Answer 4

•For body or tail and more distant disease, you can do a partial pancreatectomy (sometimes done with a splenectomy and sometimes not).

Answer 5

* Generally a benign process * Has a higher pre-malignant potential, and can be anywhere from completely benign to borderline to malignant (which is then called a cystadenocarcinoma) * These are larger cystic structures, so mucinous cystadenoma is sometimes called macrocystic cystadenoma * It is filled with mucin, a thick fluid, that is secreted by the lining cells of the cysts. * This generally shows up in patients in their 50-60s but can be variable * These have a higher pre-malignant potential. So when they are found we generally recommend surgery if the patient is an appropriate candidate.

Answer 6

We’re going to look at a little bit of embryology * What’s this yellow structure here (1)? Yes, that’s the pancreas (lol) * What’s the green structure (2)? Gallbladder * 3 = Common bile duct * 4 = Cystic duct

Answer 7

The entire body and tail of the pancreas gets its arterial supply from branches of the splenic artery

Answer 8

Activation of proenzymes * Once these proenzymes come into the duodenum, on the brush border there is an enzyme called enterokinase, which is the main catalytic player that starts a whole cascade. * Enterokinase cleaves and activates trypsinogen (proenzyme form of trypsin) into trypsin * Then in a snowball effect, trypsin will lead to the cleaving of more trypsin from trypsinogen, and the activation of other proenzymes into its active form (i.e. chymotrypsinogen à chymotrypsin) * So, enterokinase is a key player

Answer 9

* In week 4 of embryonic development, there are 2 buds that develop as outpouchings from the endodermal lining. They are called the dorsal bud and the ventral bud, or the dorsal pancreas and ventral pancreas. * These are essentially outpouchings of the endodermal lining of the early nascent GI tract. * The dorsal pancreas eventually gives rise to the body and tail of the pancreas, and a small amount of the head. * Most of the head and the uncinate process come from the ventral pancreas * The two buds then rotate around what becomes the luminal GI tract, the duodenum. The buds then fuse sometime in week 7, forming the ductal system

Answer 10

* If pancreatic CA is in HOP and the patient is an appropriate surgical candidate (i.e. not sick from comorbid conditions or metastatic disease that it doesn’t make sense to think about surgery), the definitive surgery is called the Whipple procedure (pancreaticoduodenectomy). * They resect the distal stomach, the HOP, the gallbladder, biliary tree, and part of the duodenum * It is a pretty big surgery. * After this is resected, there are 3 anastomoses made between the biliary tree and the jejunum (called the choledochojejunostomy), between the remnant pancreas (pancreaticojejunostomy), and between the gastric remnant to the jejunum (gastrojejunostomy) (figure 2) * So, there are 3 anastomoses for the HOP. This is called the Whipple procedure.

Answer 11

* The most important things to know are that the nerves run along with the arteries and the vascular supply. * The nerves include the vagus and its branches, and the splanchnics (efferents and afferents) * These link with the ENS (which known as the “brain of the gut”) * The ENS has a number of important effects in terms of: * Endocrine secretion * Exocrine secretion * Modulating blood flow to the pancreas * And modulation of afferent pain sensation

Answer 12

* The main functional unit of the exocrine pancreas is the acinus * The acinus contains proenzymes (inactive enzyme precursors) * The proenzymes are stored in an inactive state and in response to a variety of signals, these can be released. Their contents flow down the ductal system (into the duct of Wirsung) and into the duodenum where they can cleave proteins, lipids, and so on. * These are maintained in an inactive state to prevent auto-activation and pancreatitis

Answer 13

* Almost exclusively a benign process that can affect people in their 50-60s (or sometimes earlier) * You have these tiny little microcystic structures, which is why serous cystadenoma is sometimes called a microcystic adenoma * They are lined by cuboidal epithelium * They secrete a glycogen rich but thin fluid * These are almost always benign and are generally found incidentally on imaging * They can cause symptoms though. We often leave them alone, but if they are large or causing symptoms from compression or causing pain, then if the patient is an appropriate surgical candidate, we recommend surgery.

Answer 14

* There are nociceptive pain receptors that mediate the pain from acute tissue injury and inflammation. * In chronic pancreatitis and pancreatic cancer, there is a longer lasting pain called neuropathic pain. This is from direct injury to the nerve. The mechanisms are very controversial.

Answer 15

Don’t drink alcohol, try not to tax pancreas with high fat diets. We give analgesics where appropriate, and it is almost always necessary. If patients are markedly deficient in terms of exocrine function (they have steatorrhea, diarrhea, malabsoprtion), pancreatic enzyme supplements may be indicated. We give insulin if they become diabetic from endocrine insufficiency.

Answer 16

* 1) Cephalic phase: mediated by the vagus nerve * 2) Gastric phase: mediated by peptides in the duodenum * 3) Intestinal phase: mediated by acid that comes from the stomach into the intestine, and leads to the release of an enzyme called secretin * Secretin mediates the release of a bicarbonate fluid from the ductal cells * This is important because in order for the enzymes to work in an optimal pH, there must be a neutralization of the acid that comes from the stomach into the duodenum

Answer 17

Sometimes these two ducts don’t fuse properly = pancreas divisum * This happens in 1 out of every 10 people. 10% of people have a condition called pancreas divisum (pancrease divided) * The two ducts don’t fuse properly * What happens is that too much of the pancreatic fluid goes through the minor duct (duct of Santorini) and it can predispose to recurrent attacks of acute pancreatitis * But, its clinically silent in the majority of people who have it – so you may never know you have it • •

Answer 18

* , you can elicit tenderness on palpation of the abdomen * Sometimes you can have rebound tenderness. * What does rebound tenderness imply? It means that this is a peritoneal sign (57 points to Peter!)

Answer 19

* Gallstone disease and alcohol are definitely #1 and #2 causes and account for the vast majority. * Drug-induced pancreatitis * Things to always think about for any disease: you ALWAYS want to know what other medications they are on since there are so many other drug-induced conditions besides pancreatitis * Iatrognic * Sometimes we do things that cause pancreatitis * A number of abdominal and cardiac surgeries can cause it from low blood flow states and ischemia * ERCP (endoscopic retrograde cholangiopancreatography): relieves obstruction of bile duct from stones * This procedure can also lead to pancreatitis sometimes * Metabolic * There are a number of metabolic issues including hypertriglyceridemia * Neoplastic * Pancreatic cancer can predispose to pancreatitis (less commonly, but can) * Structural * Some structural issues related to embryonic development can also cause pancreatitis (which we talked about)

Answer 20

* Pseudocyst is a false cyst. It is not epithelial lined. It is NOT a cyst. * It is essentially a bag of necrotic pancreatic parenchyma, pancreatic enzymes, tissue, and blood * Note that there is a lot of blood in the H&E stain. * CT scan * 1 = liver * 2 = gallbladder * 3 = pancreas * 4 = pseudocyst * This is much larger than the pancreas and is a pseudocyst * Why could this be important? There are a number of reasons. What’s right in front of the pancreas? The stomach (5). The pseudocyst is compressing the stomach. Even if the pseudocyst is completely benign and resolved, the patient can’t eat, can’t drink, and probably has nausea and vomiting. Something needs to be done. This is something that can develop in the acute and long term phase. * Question (can’t hear). Answer: The reason it is a pseudocyst is that it is not epithelial lined. It is essentially dead tissue that gets inflammatory cells around it and over 4-8 weeks becomes walled off. Because it’s not an epithelial lining, it’s not technically a cyst. That is why this is a pseudocyst, a sequelae of pancreatitis.

Answer 21

steroids work!! ## Footnote * When they looked at it under the microscope, there were just lymphocytes everywhere. * So, we are increasingly seeing this as autoimmune pancreatitis, and if you remember what I said about pancreatitis being a systemic disorder, this is the same idea here. This can involve the pancreas, but it can also be associated with other organs and autoimmune disorders like PSC, rheumatoid arthritis, and Sjogren’s syndrome. Some of these patients have salivary gland disease, xeropthalmia, xerostoma, and other manifestations of autoimmune disease. * If you treat them like an autoimmune disease with steroids, then the patients are cured (for a certain amount of time, since it is a relapsing remitting condition) * So, we’re very careful with these patients before sending them for resection even though statistically it is more commonly going to be a malignancy. BUT, this still should be at the back of your mind!

Answer 22

endoscopic cystgastrostomy

Answer 23

* The two main causes are gallstone disease (aka biliary pancreatitis) and alcohol * Alcohol is the #2 cause worldwide, and #1 cause in USA * There are also a lot of other etiologies: * Medications (quite common) * Ischemic pancreatitis * Hypertriglyceridemia associated pancreatitis * Scorpion sting (relevant in other parts of the world, and also a favorite exam question!) * Dr. Popper’s has not seen many cases of this.

Answer 24

* Less commonly is glucagonoma * It can be benign or malignant * It classically presents with necrotizing migratory erythematous rash

Answer 25

Regions of the pancreas (listed from right to left): * Head of the pancreas * Uncinate process: small outpouching of the pancreas * Neck * Body * Tail

Answer 26

* Most classically **amylase and lipase** (pancreatic enzymes that are released during pancreatitis/destruction of the pancreas) are elevated. * These elevated enzymes are not what is causing the damage. These are what’s released and what we are detecting during pancreatitis. * There can also be l**eukocytosis (elevated WBCs)** * Liver function tests (**LFTs**) may be elevated * May have **hypocalcemia, saponification, hyperglycemia, and a lot of electrolyte and metabolic abnormalities** may occur in the setting of acute pancreatitis

Answer 27

In gallstone pancreatitis, gallstones travel from the gallbladder via the cystic duct to the common bile duct and they are impacted at the ampulla of Vater. There will be activation and recruitment of leukocytes, release of pro-inflammatory cytokines, and destruction of the pancreas. stone = back P at level of pancreatic duct - premature activation of enzymse

Answer 28

endocrine tumors ## Footnote * Like cystic lesions of the exocrine pancreas, they can either be benign or malignant (high grade or low grade) * Malignant tumors can invade locally or metastasize * They are much less common than the exocrine neoplasms * They are more commonly in the body and tail * They can affect people of all ages * There are several types (which we will talk about) insulinoma, gastrinoma, glucagonoma

Answer 29

Ectopic or heterotopic pancreas * Generally a benign condition * There is heterotopic or abnormal placement of pancreatic tissue à (failure of complete migration of pancreatic tissue during development) * The pancreatic tissue can appear in various places within the luminal GI tract (i.e. stomach and in this picture, the duodenum) * It can be clinically silent or be an incidental finding on endoscopy * It can lead to pancreatitis * So you can have a patient with pancreatitis of pancreatic tissue in the stomach or the duodenum •

Answer 30

•Most of the head and the uncinate process come from the ventral pancreas

Answer 31

head (60%) ## Footnote * This is important because it affects both how it presents clinically and what kind of options we have for patients. * The majority of patients develop pancreatic adenocarcinoma in the head of the pancreas (HOP). It develops less commonly in the body, tail, and elsewhere. * In the HOP, it is diagnosed relatively early and characterized by painless obstructive jaundice * You get jaundice if you have pancreatic cancer in the HOP due to a mechanical reason. Cancer in the HOP will block biliary drainage and presents as obstructive jaundice. * These patients can be fluorescent – their bilirubin is sky high! These patients are picked up earlier than they would be with cancer elsewhere in the organ.

Pancreas Pathophys Flashcards

(55 cards)