Chapter 97 Pancreas Flashcards
What % of pancreatic mass is made up of exocrine pancreas?
98%
What is the name of the islands of polygonal cells that make up the endocrin epancreas?
Islets of Langerhans
What are the fours disctinct cell types within pancreatic islets? What do they each synthesise?
Alpha cells –> Glucagon
Beta cells –> Insulin
Delta cells –> Somatostatin
F or PP cells –> Pancreatic polypeptide
Label the diagram
What is the innervatioon to the pancreas?
Enteric to blood vessels, vagal to acinar and islet cells
What are the anatomic and ‘other’ names for the two canine pancreatic ducts?
Where do they open?
Pancreatic ducts aka Duct of Wirsung. Opens at major duodenal papilla
Accessory pancreatic duct aka Duct of Santorini. Opens at minor duodenal papilla
List 2 possible anatomic pancreatic duct variations in dogs.
Presence of accessory duct only
Presence of three openings
How does feline pancreatic duct anatomy differ from canine?
80% of cats have only pancreatic duct (i.e. only 20% have accessory pancreatic duct)
Conjoined opening of pancreatic duct + CBD at major duodenal papilla.
Briefly decribe effect of insulin on:
Glucose
Fatty acids
Amino acids
Promotes intracellular conversion as follows:
Glucose –> glycogen
Fatty acids –> Triglycerides
Amino acids –> Protein
In 1 sentence describe function of glucagon
Mobilizes energy stores by increasing glycogenolysis, gluconeogenesis and lipolysis
List 4 ‘digestive’ (i.e. not related to glucose metabolism) functions of pancreas
- Digestive enzymes (as inactive zymogens)
- Production of co-factors that facilitate absorbtion of cabalamin, zinc and colipase C
- Secretion of bicarb for neutralization of gastric acid
- Inhibit bacterial proliferation within duodenum
What does intrinsic factor do?
Facilitates absorbtion of cobalamin (B12) in ileum
Describe cycle of trypsinogen in duodenum.
Activation of trypsinogen to trypsin by enterokinase (produced by the enterocytes).
Trypsin then converts the other proenzymes to active forms through proteolytic cleavage.
What are the three primary mechanisms for prevention of pancreatic autodigestion?
- Proteolytic and phospholipolytic enzymes sythesized, stored and secreted as inactive zymogens/pro-enzymes.
- Segregated storage of zymogens as membrane bound granules
- Acinar cells synthesise pancreatic secretory trypsin inhibitor –> prevents premature activation of pancreatic zymogens
What are the roles of secretin and cholecystekinin?
Where are they secreted from?
Secretin –> bicarb-rich fluid secretion
Cholecystekinin –> digestive enzyme secretion (+ gall bladder contraction)
Secreted from duodenal mucosal cells
What is necrotizing pancreatitis characterised by?
- Extensive acinar necrosis
- Peripancreatic fat necrosis
- Interstitial microabcess formation
- Microvascular thrombosis and local haemorrhage
How do alpha 2 agonists affect BG/insulin?
Alpha 2 agonists –> hypoinsulinaemia and hyperglycaemia
List 4 methods used for partial pancreatectomy
- Suture fracture
- Blunt dissection + ligation
- Vessel sealing devices
- Stapling
How much of pancreas can be removed without impairment of exocrine or endocrine function (provided remaining duct intact)
75-90%!!
List 3 potential complications of pancreaticoduodenectomy
EPI
DM
Ulceration
+ usuals
What is most common disease process of exocrine pancreas?
Pancreatitis and associated complications (e.g. abcess, pseudocyst)
Define acute panreatitis, acute recurrent pancreatitis and chronic pancreatitis
- Acute pancreatitis:* Inflammation of pancreas that is sudden in onset and reversible
- Acute recurrent pancreatitis:* Repeated episodes of pancreatic inflammation with no permanent histopathological change.
- Chronic pancreatits:* Continuous, often sub clinical inflammation of pancreas accompanied by irreversible histological changes that typically include fibrosis and atrophy.
Vomiting is hallmark c/s of pancreatitis in dogs - what % of cats with pancreatitis vomit?
40%
What blood work change can be seen wiht necrotizing pancreatitis?
Hyperglycaemia
Reportedly due to stress related release of cathecholamines and cortisol –> hyperglucagonaemia
HO ware amylase and lipase excreted?
Renal
i.e. any reduction in GFR –> increased values
TLi used for dx of EPI. Why not for panc?
Also renally excreted (like amylase and lipase therefore any cause for reduced GFR –> increased value)
What si most sens/spec text for dx of canine pancreatitis?
Pancreatic lipase immunoreactivity (cPLI)
What are possible radiographic lesions seen with pancreatitis?
Loss of serosal detail R cranial quadrant
Mass effect i.e.
- widening of angle between pyloric antrum and proximal duodenum
- L displacement of stomach
- R displacement of descending duodenum
- mass effect medial to descending duodenum
What US findings with pancreatitis?
- Hypoechoic pancreas (hyper with fibrosis)
- Mass lesion in pancreas
- Hyperechoic surrounding mesentery
*
List 4 indications for surgical intervention in pancreatitis cases
- Infection
- Local complications e.g. biliary obstruction, pancreatic abcess
- Confirmation of diagnosis with biopsy
- Lack of response to aggressive medical management
How should pancreatic abcess be managed (n.b. most veterinary ones are sterile (cf humans)
Surgery; partial pancreatectomy, biopsy, provision of drainage, cholecystoenterostomy, duodenal R+A
Comment re culture results from oancreatic abcess cases
Abcess culture often sterile but abdominal cavity culture positive i.e. submit specimans from multiple sites
What radiography sign may be seen with pancreatic abcess?
Gas in pancreas
What is reported survival following sx for pancreatic abcess?
15-50%
Define pancreastic pseudocyst
Collection of pancreatic secretions and debris within no-epithelialised fibrous sac
How is pancreatic pseudocyst diagnosed?
US + pancreatic enzyme concentration of cyst fluid > serum
where are the majority of pancreatic pseudocyst located?
L limb
List 3 tx options for pancreatic pseudocyst
What was overall survival (caes treated by any of the 3 methods)
Monitor for a few weeks - may resolve spontaneously
US guided aspiration
Sx if above fail or patient worsens
75% survival
In what part of pancreas has torsion been reported?
L limb in puppy
What is most common tumour of exocine pancreas?
Carcinoma
What paraneoplastic sign has been reported in cats with pancreatic carcinoma?
Alopecia
On contrast enhanced ultrasonography, how does pancreatitis differ from pancreatic carcinoma from insulinoma?
Pancreatitis: Delayed peak perfusion and prolonged enhancement
Pancreatic carcinoma: Hypoechoic and hypovascular lesions
Insulinoma: Uniformly hypervascular
Where do pancreatic carcinomas commonly metastasize to?
Liver and LNs
What % of insulinaomas are carcinoma vs adenoma?
60% carcinoma, 40% adenoma
What % of insulinoma dogs ahve metastasis at timem of diagnosis?
Where to usually?
50%
Liver + LNs
Bwloe what BG level is insulin secretion usually inhibited?
< 80 mg/dL (= 4.4 mmol/L)
In insulinoma cases, name a common association (in terms of history) with hypoglycaemic episodes
Often precipitated by excitement, exercise or fasting
Name a PE finding that may be related to chronic hypoglycaemia /9i.e. in insulinoma)
Peripheral neuropathy
How is insulinoma diagnosed?
Serum insulin measurmement during period of hypoglycaemia. If insulin high or normal = highly siggestive of insulinoma
Can also get idea from fructosamine
HOw does insulinoma cytology differ from normal exocrine pancreatic cytology?
Insulinoma cells lack the pink zymogen granules seen in cytoplasm of pancreatic exocrine cells
What type of CT should be used for dx insulinoma
Dual phase angiography
What radioisotpe is used for scintigraphy in insulinoma?
Radio-labelled somatostatin
List 2 pre-op management treatements for insulinoma
Glucocorticoid –> increased hepatic glucose production and decreases cellular glucose uptake
Regular small meals
Small pre-GA meal 2-3 hour before
(CRI glucagon if intractable hypoglycaemia)
What % of insulinoma odgs have a solitary nodule?
80%
What factor was associated with shorter sx and hospitalisation time for sx treatment of insulinoma
Use of vessel sealing device (rather than suture fracture technique).
N.B. vessel sealing device did not –> clinical signs of pancreatitis
What additional procedure shoudl be carried out with insulinoma excision?
LN and liver biopsy.
If primary insulinoma lesioon cannot be identified, what can be doen to aid localisation?
When is maximal staining achieved?
IV methylene blue
(3 mg/kg of 1% methylene blue diluted in 250 ml in sterile saline, administered over 30 mins)
Maximal staining 30 mins after administration
What is a potential complication of methylene blue administration
Heinz body anaemia
How can persistent hypoglycaemia (following insulinoma sx) be managed?
What were 2 most common side effects?
Streptozocin (a nitrosourea abx) selectively destroys beta cells in the pancreas and at metastatic sites.
- Give with saline as risk nephrotoxicity
- S/e: GI toxicity 60% and DM 40%
What was median duration of normoglycaemia and survival time in insulinoma dogs treated with streptozocin (for hyperglycaemia after insulinoma sx)?
median normoglycaemia 160 d
MST 300 d
Name 4 potential drugs for use in persistent/recurrent hyperglycaemia due to insulinoma
- Streptozocin: selectively destroys beta cells in the pancreas and at metastatic sites
- Glucocorticoids: –> increased hepatic glucose production and decreases cellular glucose uptake
- Diazoxide (benzothiadiazine derivative –> inhibits insulin secretion, stimulated hepatic gluconeogenesis and glycogenolysis and inhibits ude of glucose)
- Octreotide (Long acting somatostatin analogue –> inhibits insulin synthesis and secretion)
What was median euglycaemia period for dog with vs without mets at time of sx?
And MST mets vs no mets
Euglycaemia:
- Mets 2.5 months
- No mets: 14 months
MST:
- Mets 7-9 months
- No mets 2-4 years
What 3 factors were associated with poor prognosis in insulinoma cases?
- Tumours >2cm
- LN and liver mets
- Ki76 index >2.5%
Aside from insulinoma, name 2 other tumours of endocrine pancreas
Gastrinoma
Glucagonoma
What is the dyndome name for
Non-beta cell neuroendocrine tumour in pancreas
+
Hypergastrinaemia
+
GI ulceration
Zollinger-Ellison syndrome
Aside from pancreas - where else can gastrinomas arise from?
Duodenum, mesentery, peripancreatic LNs
What is met rate for gastrinoma?
70%
What % of gastrinoma patients have GI ulceration?
80%
What biochemical value is highly suggestive of gastrinoma?
Increased fasting serum gastrin concentration
(especially with gastric hyperacidity pH <3)
Lesion usualy v small so may not be visible on imaging. Histo for definitive dx.
What paraneoplastic syndrome is associated with glucagonoma?
What are c/s of this?
What is typical histo finding?
Superficial necrolytic dermatitis (also associated with advanced liver disease = hepatocutaneous syndrome)
C/s: Erythema, ulcerations, excoriations, foot pad hyperkeratosis, foot pad fissures, skin thickening/crusting
Histo: red, white, blue.
Upper layer—the stratum compactum—appearing red
Middle layer of ballooning degeneration in the stratum spinosum appearing white
Lower layer of hyperplastic basal cells of the epidermis appearing blue.
How is glucagonoma diagnosed?
increased serum glucagon concentration or histo (IHC positive for glucagon)
Tx = surgery but prognosis poor
