L93 Pathogenesis and Laboratory Detection of Pancreatitis

Pathogenesis of Pancreatitis

Direct injury to pancreatic acinar cells by bacteria, ischemia, hypoxia → Inappropriate activation of trypsinogen to trypsin → Premature activation of proelastase and phospholipase in acinar cells to → Elastase and phospholipase A

Causes digestion of:

Pancreatic tissue → release of cytokines and free radicals

Mesenteric fat → lipemic plasma

Blood vessels → hemorrhage into pancreas ± effusion into peritoneal cavity

Pancreatitis release of proteolytic enzymes into systemic circulation leads to:

Consumption of plasma protease inhibitors (α-macroglobulins)

Multisystemic involvement

DIC & shock

Causes / Risk Factors of Exocrine Pancreatic Inflammation - Pancreatitis in Dogs

Causes / Risk Factors of Feline Pancreatitis are Idiopathic

Infections (toxoplasma, coronavirus)

Hypotension due to anesthesia

Pancreatic trauma following road accidents, falls, surgery

risk factors for pancreatitis in cats

DM, Hepatic lipidosis, Enteropathies, Nephritis, IMHA

K-9 Pancreatitis: Clinical signs

Anorexia, depression, vomiting, diarrhea, weakness, abdominal pain

• Can be non-specific, Sometimes death, Lipemic blood samples

Dogs that survive acute phase may develop chronic low grade pancreatitis

Feline Pancreatitis: Clinical signs are non-specific (vague)

○ Lethargy, anorexia, vomiting, weight loss, diarrhea

○ Dehydration, abdominal pain

○ Dyspnea, ataxia

○ Samples not necessarily lipemic

Canine vs Feline Pancreatitis

Hematology Findings in Canine Pancreatitis

Laboratory Findings / Evaluation of Feline: Hematology Pancreatitis

Relative erythrocytosis due to anorexia and fluid loss

Acute inflammation and DIC

Feline pancreatitis: Serum chemistry

Increased hepatic enzyme activity due to concurrent hepatic lipidosis or cholangitis

Azotemia pre-renal (most likely) or renal

Hypo/hyperglycemia, Hypertriglyceridemia is absent

Feline pancreatitis: Ultrasonography - routine diagnostic imaging technique

Should be part of the minimum database

Assess co-morbidities including liver and GI

Additional US changes can occur later in the disease process

Dog with acute pancreatitis: clusters of exocrine cells, (arrows), non-degenerate neutrophils and RBCs

Cat with acute pancreatitis: a cluster of acinar cells (arrow), non-degenerate neutrophils(arrowhead) and RBCs

Amylase & Lipase in Pancreatitis Questionable diagnostic relevance in pancreatitis in dogs & especially cats

Half-life = Amylase 5 hours, Lipase 2 hours, Should be run together

Measurement completely useless in large animals and cats

Non-pancreatic sources including: Intestinal (70%) & hepatic Lipase also gastric, LPL

Amylase and lipase sensitivity in testing

Amylase Sensitivity 55%; specificity 80%

Lipase Sensitivity 90%; specificity 80%

Amylase & Lipase in Pancreatitis Increases can occur in:

Renal disease (Azotemia up to 10x increases reported)

Corticosteroids (↑ lipase up to 5x normal, but can ↓ amylase)

Hepatic disease, neoplasia

Intestinal FB

Testing of choice for pancreatitis is?

pancreatic specific tests Canine cPLI or Feline (fPLI)

Species Specific antibody directed to pancreatic lipase molecule

Pancreatic-specific; measures lipase of pancreatic origin only

• Pancreatic lipase Immunoreactivity (PLI)

Species-specific, thus fPLI (feline) and cPLI (canine)

Pancreatic lipase Immunoreactivity (snap and spec cPLI, fPLI)

Little enters blood in healthy pancreas vs larger amounts enter blood in pancreatic inflammation

No interference by hemoglobin, bilirubin, lipids, Not affected by sample transportation/ mailing

Precision testing: Measured by ELISA (or radioimmunoassay)

Snap PLI measured qualitatively in-house using ELISA

Spec PLI measured quantitatively in reference labs

High sensitivity (90%) & specificity (100%) for Acute pancreatitis

• Reduced sensitivity and specificity for Chronic pancreatitis

IdexxSnap cPL

Semi-quantitative

Sensitivity 90%; specificity 77%

Should be confirmed with spec cPL

VetScan cPL rapid Abaxis

Quantitative assay

Sensitivity 83%%; specificity 83%

No interference by hemoglobin, bilirubin, lipids

SNAP PLI vs Spec PLI

Acute Pancreatitis

Chronic Pancreatitis

Pancreatic disease in large animals(rare)

Amylase and lipase are meaningless

Horses - Amylase increases usually mild and can be with intestinal diseases

• 50% of horses with proximal enteritis

• 25% of horses with other causes of colic