PATHOLOGY - Pancreatic Disease Flashcards
Describe the anatomy of the exocrine pancreas
The pancreas consists of a central body with a right and left limb. The functional units of the exocrine portion of the pancreas consist of acini which contain acinar cells, and the pancreatic ducts which are lined with pancreatic duct cells
Describe the anatomy of the pancreatic ducts in the dog
The dog has a pancreatic duct and an accessory duct. The pancreatic duct is the smaller of the two and drains into the major duonenal papilla and the accessory duct drains into the minor duodenal papilla, both distal to the entry of the common bile duct
Describe the anatomy of the pancreatic duct in the cat
The cat has a singular pancreatic duct which merges with the common bile duct before entering the duodenum at the major duodenal papilla
What are the functions of the exocrine pancreas?
Production and secretion of pancreatic enzymes
Production and secretion of bicarbonate
Production and secretion of intrinsic factor involved in vitamine B12 (cobalamin) absorption
Production and secretion of antibacterial proteins
Which cells produce and secrete pancreatic enzymes?
Acinar cells
Which pancreatic enzymes are produced by the acinar cells?
Proteolytic zymogens (inactive precursors)
Amylase
Lipase
Which cells produce and secrete bicarbonate?
Pancreatic duct cells
What stimulates the production and secretion of bicarbonate by the pancreatic duct cells?
The pancreatic duct cells produce and secrete bicarbonate in response to secretin which is produced by the duodenum. The bicarbonate is secreted into the duodenum where it neutralises the acidic ingesta which has travelled from the stomach
What are the pancreas’ defence mechanisms against autodigestion?
- Proteolytic enzymes are synthesised as zymogens (inactive precursors)
- Zymogens are packaged into granules and released from the acinar cells via exocytosis
- Pancreatic secretory trypsin inhibitors are packaged into the zymogen granules to prevent premature activation of trypsinogen into trypsin
- Lipase and amylase are packaged within lysosomes to seperate them from the zymogen granules
What are the systemic defence mechanisms agaisnt the release of pancreatic enzymes into the bloodstream?
The plasma contains systemic anti-proteases which scavange any free pancreatic enzymes released into the circulation
Describe the pathophysiolgy of acute pancreatitis
Acute pancreatitis is described as acute pancreatic necrosis in pathology
Lysosomes containing amylase and lipase fuse with the zymogen granules, forming vacuoles. The enzymes within the lysosomes activate trypsinogen into trypsin and the vacuoles will rupture, releasing the trypsin into the acinar cells where they will activate other zymogens and cause pancreatic necrosis and autodigestion. Inflammatory mediators and cytokines with cause inflammation and exacerbate the necrosis. Systemically, the plasma anti-proteases will become overwhelmed resulting in systemic inflammatory response syndrome (SIRS) which can progress to disseminated intravascular coagulation (DIC)
What are the risk factors for acute pancreatitis in dogs?
Middle aged to old
Female
Breed
Obesity/hyperlipidaemia
Quantity and quality of dietary lipids
Drugs
Hyperadrenocorticism (Cushing’s disease)
Hypothyroidism
Hypercalcaemia
Which dog breeds are at increased risk of acute pancreatitis?
Yorkshire Terrier
Silky Terrier
Minature Schnauzer
Minature Poodle
Cocker Spaniel
Give an example of a drug which increases the risk of acute pancreatitis in dogs
Potassium bromide
What are the risk factors for acute pancreatitis in cats?
Abdominal trauma
Acute hypercalcaemia
Ductul reflux of duodenal contents
Organophosphate poisoning
What are the clinical signs of acute pancreatitis?
Anorexia
Vomiting
Diarrhoea
Abdominal pain
Lethargy
Dehydration
Pyrexia
Jaundice
(T/F) Patients with acute pancreatitis are more likely to present with diarrhoea than vomiting
FALSE. Patients with acute pancreatitis are more likely to present with vomiting than diarrhoea, so if a patient has diarrhoea with no vomiting, this should put pancreatitis lower on your differential diagnoses list
Why do cats more commonly present with jaundice due to acute pancreatitis than dogs?
Cats more commonly present with jaundice due to acute pancreatitis than dogs as the feline pancreatic duct merges with the common bile duct, so inflammation and necrosis of the pancreas can cause post-hepatic jaundice
How can you diagnose acute pancreatitis?
Assess history, signalement and clinical signs
Haematology
Biochemistry
Serum lipase and amylase
Trypsin-like immunoreactivity (TLI)
Pancreatic specfic lipase (PLI)
Diagnostic imaging
Pancreatic biopsy
What changes on haematology can indicate acute pancreatitis?
Inflammatory leukogram
What are the characteristics of an inflammatory leukogram?
Leukocytosis
Neutrophilia
± Left shift
What changes on biochemistry can indicate acute pancreatitis?
Increased liver enzymes (ALP and GGT tend to increase more than ALT and AST)
Hyperbilirubinaemia
Hypocalcaemia
Hypokalaemia
Why does acute pancreatitis cause hypocalcaemia?
Acute pancreatitis can cause fat saponification as lipase is released which will break down the mesenteric fat surrounding the pancreas into fatty acids which can bind to calcium, reducing the free calcium in the bloodstream resulting in hypocalcaemia
What changes in serum amylase and lipase can indicate acute pancreatitis?
Increased serum amylase and lipase can indicate acute pancreatitis
What are the limitations of serum lipase and amylase for diagnosing acute pancreatitis?
Serum lipase and amylase have low sensitivity and specificity for pancreatitis as serum amylase and lipase can also increase in patients with decreased glomerular filtration rate as these enzymes are excreted renally. Furthermore, amylase and lipase originate in extra-pancreatic locations such as the gastric and intestinal mucosa so increases in these enzymes can indicate other disease processes outside the pancreas. Lipase can also increase following steroid administration, however the mechanism for this is unknown
What changes in a trypsin-like immunoreactivity test (TLI) can indicate acute pancreatitis?
Increased trypsin-like immunoreactivity test can indicate acute pancreatitis
What are the limitations of a trypsin-like immunoreactivity test for diagnosing acute pancreatitis?
Serum trypsin-like immunoreactivity (TLI) has a low sensitivity for acute pancreatitis as it will increase very early into acute pancreatitis, however it has a short half life which can result in false negative results. Furthermore, serum trypsin-like immunoreactivity (TLI) tests have to be sent to an external lab and thus have limited usefulness for some patients
What are the two forms of canine pancreatic specific lipase (cPL) tests?
SNAP cPL
SPEC cPL
What are the benefits and limitations of a SNAP cPL test for the diagnosis of acute pancreatitis?
There is an in-house SNAP cPL test available which can be used as a rapid point-of care test which is specific to acute pancreatitis. SNAP cPL has a good sensitivity and specificity for acute pancreatitis, however positive results should be confirmed using a quantitative SPEC cPL test
What are the benefits and limitations of a SPEC cPL test for the diagnosis of acute pancreatitis?
A SPEC cPL test has to be done in an external lab however it if a good confirmatory test for acute pancreatitis. SPEC cPL has a good sensitivity and specificity for acute pancreatitis, however there is potential for false positives in patients with a decreased glomerular filtration rate as these enzymes are excreted renally, and in patients treated with steroids, however the mechanism for this is unknown
What should you note when using feline pancreatic specific lipase to investigate acute pancreatitis?
Note that though the sensitivity of feline pancreatic specific lipase is up to 100% for moderate to severe acute pancreatitis however the sensitivity decreases to 54% for mild acute pancreatitis. Thus it is important to combine these results with other diagnostic tests and clinical judgement
What should you note when using pancreatic specific lipase to investigate acute pancreatitis?
It is important to confirm that the clinical signs are due to acute pancreatitis and not due to any other pathology as pancreatic specific lipase can increase due to other disease processes (i.e. due to upper gastrointestinal foreign bodies which can cause peritonitis and inflammation of the pancreas). It is important to combine these tests with other diagnostics
Which diagnostic imaging techniques can be used to help diagnose acute pancreatitis?
Radiography
Ultrasound
Advanced imaging (CT an MRI)
How can radiography be used when investigating acute pancreatitis?
Radiography can be used to assess for changes associated with acute pancreatitis, however be aware this has low sensitivity, as well as rule out any concurrent causes of the clinical signs or consequences of the acute pancreatitis
What are the key signs of acute pancreatitis on radiography?
Increased soft tissue/fluid opacity in the right cranial quadrant
Displacement of the descending duodenum and transverse colon
Gas filled, distended duodenum
Why can the duodenum become gas filled and distended due to pancreatitis?
Pancreatitis can cause duodenal ileus which will result in gas accumulation within the duodenum
How can ultrasound be used when investigating acute pancreatitis?
Ultrasound can be used to assess for changes associated with acute pancreatitis as well as rule out any concurrent causes of the clinical signs or consequences of the acute pancreatitis
What are the key signs of acute pancreatitis on ultrasound?
Enlarged, ill-defined hypoechoic to heterogenous pancreas
Hyperechoic tissues surrounding the pancreas
Ileus of the duodenum
Ultrasound is more sensitive for acute pancreatitis than radiography
What should you be aware of when using ultrasound to help diagnose acute pancreatitis in cats?
Detecting acute pancreatitis on ultrasound has a lower sensitivity in cats compared to dogs
When are pancreatic biopsies indicated?
Pancreatic biopsies are indicated when there are recurrent clinical signs of pancreatitis. However it is important to note that pancreatic biopsies are rarely done
How do you manage acute pancreatitis?
Intravenous fluid therapy and correct electrolyte imbalances
Analgesia
Antiemetics
Gastroprotectants
Anticoagulants
Enteric nutritional support
Antibiotics (not used routinely)
Management of any complications of acute pancreatitis
Why is intravenous fluid therapy important in the management of acute pancreatitis?
Patients with acute pancreatitis often present with dehydration and hypovolaemia secondary to vomiting and diarrhoea
Which electrolyte and acid base imbalances can be seen with acute pancreatitis?
Hypokalaemia can be seen with acute pancreatitis as acute pancreatitis can cause dietary potassium loss through vomiting and diarrhoea, vomiting and diarrhoea can also cause metabolic acidosis due to bicarbonate loss
What should you consider when providing analgesia to patients with acute pancreatitis?
Acute pancreatitis is very painful and causes visceral pain which will require multimodal analgesia
Why should you use gastric protectants in the management of acute pancreatitis?
Acute pancreatitis can cause impaired blood flow to the duodenum and abnormal or decreased production of bicarbonate by the pancreatic duct cells which will reduce neutralisation of the gastric acid that is passed into the duodenum, increasing the risk of duodenal ulceration
When are anticoagulants indicated in the management of acute pancreatitis?
Anticoagulants are indicated when there is suspicion of thrombosis as acute pancreatitis can cause systemic inflammatory response syndrome (SIRS) which will put patients into a hypercoagulable state which can cause thrombosis and even disseminated intravascular coagulation (DIC)
How would you apporoach nutritional support in patients with acute pancreatitis?
Place a nasogastric or nasoesophageal tube or place an oesophagostomy tube if the patient has to go for surgery for any complications of pancreatitis
Whan are antibiotics indicated in the management of acute pancreatitis?
Antibiotics are indicated in the management of acute pancreatitis when there is evidence of sepsis
When can plasma be indicated in the treatment of pancreatitis?
Plasma can be indicated to replenish the anti-proteases in severe cases of pancreatitis
|However be aware that this is not always effective and is expensive
What are the potential consequences of acute pancreatitis?
Systemic inflammatory response syndrome (SIRS)
Disseminated intravascular coagulation (DIC)
Pancreatic abscess
Necrotic masses
Pancreatic pseudocysts
Duodenal perforation and secondary septic peritonitis
Biliary tract obstruction
Most of these complications require referral surgery
What is the prognosis for acute pancreatitis?
The prognosis for acute pancreatitis is dependent on the severity of clinical signs and the development of complications
When should you suspect a patient has chronic pancreatitis?
Intermittent, low grade clinical signs of pancreatitis
Recurring episodes of acute pancreatitis
What are the potential consequences of chronic pancreatitis?
Exocrine pancreatic insufficiency (EPI)
Diabetes mellitus
How do you definitively diagnose chronic pancreatitis?
Pancreatic biopsy
How do you manage chronic pancreatitis?
Analgesia
Low fat diet
Vitamin B12 (cobalamin) supplementation
Appetite stimulants
Treat exocrine pancreatic insufficiency (EPI)
Treat diabetes mellitus
Why can a low fat diet be beneficial in the management of chronic pancreatitis?
A low fat diet can be beneficial in the management of chronic pancreatitis as hyperlipidaemia is a risk factor for pancreatitis
What is exocrine pancreatic insufficiency (EPI)?
Exocrine pancreatic insufficiency (EPI) is the inability to properly digest nutrients due to decreased secretory capacity of the exocrine pancreas and consequently decreased production of pancreatic enzymes
What is the main cause of exocrine pancreatic insufficiency (EPI) in dogs?
Juvenile pancreatic atrophy
Which dog breeds can have autosomal recessive inheritance of juvenile pancreatic atrophy?
German Shepherds
Rough collies
What is the main cause of exocrine pancreatic insufficiency (EPI) in cats?
Chronic pancreatitis
What are the clinical signs of exocrine pancreatic insufficiency (EPI)?
Weight loss
Increased appetite
Steatorrhoea
Diarrhoea
Undigested food in faeces
Poor coat quality
What is steatorrhoea?
Steatorrhoea is excessive fat in the faeces resulting in a greasy appearance which can occur due to the inadequate digestion of lipids
How can you diagnose exocrine pancreatic insufficiency (EPI)?
Trypsin like immunoactivity (TLI) test
|Trypsin will decreased with EPI
How do you manage exocrine pancreatic insufficiency (EPI)?
Pancreatic enzyme supplementation
Vitamin B12 (cobalamin) supplementation
How should you supplement pancreatic enzymes?
Pancreatic enzymes can be supplemented in powder or granules which should be mixed into every meal. However, these forms can be unpalatable to cats so you can feed them pancreas with their meals instead
What are the potential causes of poor responses to exocrine pancreatic insufficiency (EPI) treatment?
Not enough pancreatic enzyme supplementation
Gastrointestinal dysbiosis
Effect of gastric acid
Incorrect diet
Concurrent disease
What can be done to improve the response to exocrine pancreatic insufficiency (EPI) treatment?
Alter pancreatic enzyme supplementation
Antibiotic therapy
Gastroprotectants
Dietary change
Treat concurrent disease
What is the prognosis for exocrine pancreatic insufficiency (EPI)?
Excellent prognosis
