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Flashcards in Pancreas Deck (25):
1

Acinar cells
Small Ductules
Large Ducts
Islet of Langerhans

Acinar cells-secrete digestive enzymes and proenzyme(cuboidal)
Small Ductules-bicarbonate
Larger Ducts-mucin
Islet of Langerhans-insulin, glucagon, somatostatin, PP, VIP, and serotonin

2

What is self digestion of the pancreas prevented by?

-inactive proenzymes are synthesized
-enzymes are in membrane bound zymogen granules
-activation of proenzymes requires activation of trypsinogen to trypsin
-trypsin inhibitors are present
-trypsin can inactivate itself
-resistance of acinar cells

3

acute pancreatitis

AUTODIGESTION of pancreatic substance by inappropriately activated pancreatic enzymes
-acute inflammatory process of the pancreas
-usually associated with acinar injury
-usually nonprogressive
-range from mild self limited disease to life threatening acute inflammatory process

Clinical:
abdominal pain resulting from enzymatic necrosis and inflammation of the pancreas
**80% of cases associated with biliary tract disease or alcoholism
Female 3X biliary tract disease
Male 6X alcoholism

4

What things can cause acute pancreatitis ?

1. obstruction of pancreatic ductal system
-gallstones
-periampullary neoplasms
2. Alcohol
3. Drugs
4. Trauma
5. Hypermetabolic
-hypertriglyceridemia, hyperparathyroidism-hypercalcemia
6. vascular (ischemia)
-shock, emboli, vasculitis (PAN)
7. Infectious
-mumps
8. Genetic
-mutations in cationic trypsinogen and trypsin inhibitor gene

5

What is the clinical picture for acute pancreatitis?

abdominal pain
elevated plasma amylase and lipase
diffuse fat necrosis-->hypocalcemia (less calcium more severe)
-ARDS
-acute renal failure
-disseminated intravascular coagulation DIC
-fluid sequestration

Treatment:
supportive
-analgesia
-IV
-correct electrolyte abnormalities

6

What are sequelae of acute pancreatitis?

5% death
pancreatic abscess
pancreatic pseudocyst pancreatic necrosis surrounded by granulation tissue (not lined by epithelium tissue)
infected necrotic debris

7

What are predisposing factors to Chronic pancreatitis?

1. long term alcohol abuse
2. long standing obstruction
-biliary tract disease/calculi
-pancreatic divisum
-neoplasm, pseudocysts
3. tropical pancreatitis-Africa and Asia
4. Hereditary Pancreatitis
5. Cystic fibrosis transmembrane conductance regulator gene mutation
6. idiopathic (up to 40%)

8

What are some proposed mechanisms for chronic pancreatitis?

1. hypersecretion of protein; insufficient ductal bicarbonate
-plug-->calcification & stone formation, or scar-->further obstruction
2. direct toxic effect
3. antioxidant imbalance-generation of free radicals in stressed acinar cells--> injury
4. profibrogenic cytokines

9

What happens in Chronic pancreatitis

1. fibrosis
2. reduced number and size of acini (exocrine pancreas)
3. obstruction and dilation of pancreatic ducts
-protein plugs
4. late stage loss of islets of langerhans (endocrine pancreas)
5. pseudocyst formation
6. calcified concretions

10

What are clinical signs of chronic pancreatitis?

1. recurrent attacks of abdominal pain
-radiation of pain to back
Triggers: ETOH, overeating, opiates
2. recurrent attacks of jaundice or vague indigestion
3. Exocrine pancreatic insufficiency
-steatorrhea
4. diabetes mellitus
5. pancreatic calcification on imaging

11

Pancreatic psuedocyst

-localized collections of pancreatic secretions in pancreatic interstitium as a result of damaged ducts

12

Pancreatic carcinoma

ductal adenocarcinoma of the pancreas
4th most frequent cause of cancer death in US

Pathogenic factors:
1. Pancreatic intraepithelial neoplasia (PanIN)
-precursor lesions
2. Smoking
3. Familial clustering
4. chronic pancreatitis
5. diabetes mellitus-produce more insulin, insulin is a growth factor

13

What is the molecular carcinogenesis of PanIN?

Pan1
Pan1b
-telomere shortening
-mutation of KRAS
Pan2
inactivation of p16
pan3
-inactivation of p53, SMAD4, BRCA2

-->invasive carcinoma

14

WHere is pancreatic carcinoma mostly found? What is the hsitology

head 60%
diffuse (20%)
body (15%)
tail (5%)
-gritty gray white solid firm masses

Histology
Adenocarcinoma
-poorly formed infiltrating glands
-majority of ductal origin
Dense stromal fibrosis
-desmoplastic response

15

Where does pancreatic carcinoma invade locally? What about distant metastases?

Local:
adjacent nerves--->SEVERE BACK PAIN
spleen, adrenals, transverse colon, stomach, vertebral column
-lymph nodes: peripancreatic, gastic, mesenteric, omental, portahepatic

Distal metastases:
-liver, lungs, bone

16

How does pancreatic carcinoma present?

-remain clinically silent until tumor impinges on other structures
-obstructive jaundice
-pain is usually first symptom
-weight loss, anorexia, malaise, weakness---signs of advanced disease

Tumor makers: CA19-9 and CEA-monitoring tool

Less than 20% of tumors are resectable at time of diagnosis

17

What happens if the pancreatic carcinoma is in the head of the pancreas? Body and tail?

HEAD
-tumor obstruction ampullary region/ common bile duct
-obstruction prevents conjugated bile from entering duodenum, bile pressure increases in the biliary tract and conjugated bile enters the vascular space
-distention of biliary tree

Body and tail
-does not impinge on biliary tract
-silent for long time
-large locally invasive and disseminated at time of diagnosis

18

What is trousseau sing?

migrating thrombophlebitis
-spontaneously appearing and disappearing venous thrombosis
-10% of patients
-attributed to elaboration of platelet aggregating factors and procoagulants from tumor

-mucin in blood vessel causes intravascular coagulation

19

What are 3 cystic neoplasms of the pancreas?

1. serous cystadenoma
2. mucinous cystic neoplasm
3. Intraductal papillary mucinous neoplasms

20

Serous Cystadenoma
Behavior
Gross morphology
Histology Clinical

Benign
Small cysts-clear, straw colored fluid
lined with CUBOIDAL cells which are glycogen rich
femaleX2
70s
nonspecific symptoms

21

Mucinous cystic neoplasms
Behavior
Gross morphology
Histology Clinical


Mucinous cystadenoma=benign
Mucinous cystadenocarcinoma=malignant


Cysts filled with thick mucin-not connected to main pancreatic duct
-cysts lined by COLUMNAR epithelium
-cytologically benign to severely dysplastic
-MAJORITY FEMALE!
-body/tail pancreas
-painless slowly growing masses

22

Intraductal papillary mucinous neoplasms

benign to malignant
-arise in main pancreatic duct or major branch
-lined by COLUMNAR epithelium
-various degrees of dysplasia
-Men>women
-head of pancreas

23

What is an annular pancreas?

ring of pancreatic tissue encircles duodenum

24

What is pancreas divisum?

failure of fetal duct to fuse
-3-10% of population
-increased pancreatic pressure
-possible chronic pancreatitis

25

Ectopic Pancreas

Pancreatic tissue in other tissue
stomach and duodenum, jejunum, meckel's diverticulum, ileum
-submucosa
-asymptomatic or pain, mucosal bleeding
2% of islet cell neoplasms