Tip of the Month – November

Internal Medicine

Interpreting Pancreatic Lipase (PL) Results in Dogs with a Balanced Overview

Acute pancreatitis is a common cause of vomiting, inappetence, lethargy and abdominal pain in dogs, but confidently diagnosing pancreatitis can be a challenge.

Biochemical changes seen in acute pancreatitis can include liver enzyme elevation, hyperbilirubinaemia, mild hypoalbuminaemia and markers of dehydration, but these findings can be seen in many other diagnoses of course. Amylase and lipase, which are often included in standard biochemical panels lack both sensitivity and specificity for the demonstration of acute pancreatitis- in part because these enzymes are produced by many tissues, not only the pancreas. Development of pancreatic-lipase specific assays has made significant improvements to our ability to detect acute pancreatitis in dogs, but it is important to be aware that these assays are not perfect either. SpecPL is expected to be positive in 80-90% of dogs with acute pancreatitis, but it is important to consider the possibility of false positive results.

Other cranial abdominal pathology

The most common time to consider testing pancreatic lipase is of course in dogs with potentially consistent clinical signs: vomiting, inappetence, abdominal pain etc. While pancreatitis can cause such symptoms, many other cranial abdominal pathologies could also be responsible for such a patient’s signs: gastrointestinal pathologies (foreign body, mass, infection, inflammatory bowel disease etc), peritonitis, hepatobiliary disease etc. Unfortunately the prevalence of abnormal PL results in other compatible diagnoses is actually quite high:

• Trehy et al, 72% of dogs with gastrointestinal foreign bodies showed abnormal PL concentrations
• Kalli et al, 49% of dogs with parvoviral enteritis had abnormal PL concentrations
• Kathrani et al, 15% of dogs with inflammatory bowel disease showed equivocal/abnormal PL results.

It is of course possible that these dogs may have histopathological evidence of pancreatic inflammation, secondary to their main diagnosis, but as clinicians it is important to be aware that an abnormal PL result does not allow definitive diagnosis of acute pancreatitis when a dog presents with potentially compatible clinical signs. In the Haworth et al study, it was concluded that SNAP PL and Spec PL may provide a “false positive” diagnosis of pancreatitis in up to 40% of dogs presenting with acute abdominal signs in their hospital.

M.R. Trehy, D. Batchelor, P.J. Noble, P. Silvestrini, C.M. Elwood, I. Battersby, F. Adam, A.J. German. Serum Pancreas-Specific Lipase Concentrations In Dogs With Upper Gastrointestinal Foreign Bodies. (2014). Journal of Veterinary Internal Medicine 28: 711–744.

A. Kathrani, J. M. Steiner, J. Suchodolski, J. Eastwood, H. Syme, O. A. Garden, K. Allenspach. Elevated canine pancreatic lipase immunoreactivity concentration in dogs with inflammatory bowel disease is associated with a negative outcome. (2009). Journal of Small Animal Practice 50: 126–132.

I.V. Kalli, K.K. Adamama-Moraitou, M.N. Patsikas, D. Pardali, J.M. Steiner, J.S. Suchodolski, G. Menexes, G.D. Brellou, T.S. Rallis. Prevalence Of Increased Canine Pancreas-Specific Lipase Concentrations In Young Dogs With Parvovirus Enteritis. (2017). Veterinary Clinical Pathology 46 (1): 111–119.

M. D. Haworth, G. Hosgood, K.L. Swindells, C.S. Mansfield. Diagnostic Accuracy Of The SNAP And Spec Canine Pancreatic Lipase Tests For Pancreatitis In Dogs Presenting With Clinical Signs Of Acute Abdominal Disease. (2014). Journal of Veterinary Emergency and Critical Care 24(2): 135–143.

Azotaemia

Lipase is excreted renally, thus dogs with renal dysfunction may have elevated PL results. It is of course possible that dogs with marked azotaemia may have histopathological pancreatitis, as we know that the presence of azotaemia can cause changes in other organs (uraemic pneumonitis, uraemic encephalitis etc), but we certainly see elevated PL results in azotaemic patients without clinical signs suggestive of acute pancreatitis. Research into the prevalence of elevated PL results in azotaemic patients has shown mixed results, with prevalence 12-62% reported. There is not a good correlation between the degree of azotaemia and PL concentrations.

J.M. Steiner, D.R. Finco, S.R. Gumminger, D.A. Williams. Serum Canine Pancreatic Lipase Immunoreactivity (Cpli) In Dogs With Experimentally Induced Chronic Renal Failure. (2001). Journal of Veterinary Internal Medicine 15: 311.

S.E. Hulsebosch, C.A. Palm, G. Segev, L.D. Cowgill, P.H. Kass, and S.L. Marks. Evaluation of Canine Pancreas-Specific Lipase Activity, Lipase Activity, and Trypsin-Like Immunoreactivity in an Experimental Model of Acute Kidney Injury in Dogs. (2016). Journal of Veterinary Internal Medicine 30: 192–199.

K. Takada , C.A. Palm , S.E. Epstein, and L.D. Cowgill. Assessment of Canine Pancreas-Specific Lipase and Outcomes in Dogs with Hemodialysis-Dependent Acute Kidney Injury. (2018). Journal Veterinary Internal Medicine 32: 722–726.

Steroid excess

Elevated PL readings in dogs without clinical signs consistent with acute pancreatitis have been reported in both untreated hyperadrenocorticism (35% >400 ug/l) and dogs receiving immunosuppressive doses of prednisolone (50%, small study). The mechanism for these findings is unknown.

D.I. Mawby, J.C. Whittemore, and K.A. Fecteau. Canine Pancreatic-Specific Lipase Concentrations in Clinically Healthy Dogs and Dogs with Naturally Occurring Hyperadrenocorticism. (2014). Journal of Veterinary Internal Medicine 28: 1244–1250.

H. Ohta, T. Morita , N. Yokoyama , T. Osuga , N. Sasaki, K. Morishita, K. Nakamura, M. Takiguchi. Serial Measurement Of Pancreatic Lipase Immunoreactivity Concentration In Dogs With Immune- Mediated Disease Treated With Prednisolone. (2017). Journal of Small Animal Practice 58: 342– 347.

Congestive heart failure

Pancreatic lipase levels in dogs with degenerative mitral valve disease have been assessed, and those in congestive heart failure have significantly increased levels of PL: 5/15 congestive heart failure dogs had PL >400 ug/l, and 5/15 had equivocal elevations (PL 200- 400 ug/l). None of these dogs had clinical signs suspicious for acute pancreatitis. Hypoperfusion associated with the congestive heart failure is postulated to be a relevant factor.

D. Han, R. Choi, C. Hyun. Canine Pancreatic-Specific Lipase Concentrations in Dogs with Heart Failure and Chronic Mitral Valvular Insufficiency. (2015). Journal of Veterinary Internal Medicine 29: 180–183.

Intervertebal disc disease

On occasion, abdominal pain and spinal pain can be difficult to distinguish, this it is important to note that PL elevations are frustatingly also seen in dogs with intervertebral disc disease. In Scheuler et al, 45% of dogs with disc disease had PL levels in the equivocal or abnormal range (>200 ug/l). PL concentrations did not significantly correlate with clinical gastrointestinal disease, neurolocalisation or the preadmission administration of corticosteroids or NSAIDs.

R.O. Schueler, G. White, R.L. Schueler, J.M. Steiner, A. Wassef. Canine pancreatic lipase immunoreactivity concentrations associated with intervertebral disk disease in 84 dogs. (2018). Journal of Small Animal Practice 59 (5): 305-310.

Although pancreatic lipase assays are a very useful biomarker for the diagnosis of acute pancreatitis, and offer huge diagnostic advantage over biochemistry and imaging alone… it is important to be aware of the potential for positive PL results in scenarios other than acute pancreatitis.