BASICS

DEFINITION
Serum amylase and lipase activities higher than laboratory reference ranges.

Pathophysiology
• Only alpha amylase is present in animals. The pancreas, liver, and small intestine serve as sources of serum amylase. In healthy animals, serum amylase is derived primarily from extrapancreatic sources. Considerable serum amylase activity (up to 1000 IU/L) is normal in healthy animals. Hyperamylasemia can develop in animals with pancreatitis, gastrointestinal inflammation, and renal disease.
• Serum lipase is derived from the pancreas and gastric mucosa, and its activity is optimal when the pH is alkaline. Hyperlipasemia can develop in animals with pancreatitis, renal disease, hepatic disease, and after the administration of dexamethasone.
• Both amylase and lipase are inactivated by the kidneys and eliminated from the body in urine.

Systems Affected
Hyperamylasemia and hyperlipasemia have little to no effect on other organ systems.

SIGNALMENT
Breeds at risk for acute pancreatitis:
• Dogs--middle-aged and older miniature schnauzers, miniature poodles, and cocker spaniels
• Cats--middle-aged Siamese cats

SIGNS

General Comments
Clinical signs vary depending on the cause and organ system involved.

Historical Findings
• Pancreatitis--lethargy, depression, anorexia, vomiting, and diarrhea
• Hepatic disease--anorexia, altered mentation, icterus, weight loss, vomiting, diarrhea, PU/PD, and abdominal distention
• Renal disease--PU/PD, lethargy, anorexia, weight loss, vomiting, and diarrhea
• Gastrointestinal disease--vomiting, diarrhea, anorexia, and weight loss
• Exogenous glucocorticoids--PU/PD, polyphagia, and weight gain

Physical Examination Findings
• Pancreatitis--lethargy, dehydration, abdominal pain, fever, and icterus (more common in cats)
• Hepatic disease--icterus, hepatomegaly, depression, abdominal pain, weight loss, and peritoneal effusion
• Renal disease--weight loss, mucus membrane pallor, dehydration, and normal-sized to small, irregular kidneys
• Gastrointestinal disease --weight loss, dehydration, palpable mass lesion or foreign body, and variable fecal consistency

CAUSES

Pancreatitis and Hyperamylasemia
• Serum amylase activity increases in most dogs with pancreatitis; activity > 5000 IU/L is highly suggestive of acute pancreatitis.
• Although high amylase activity is a sensitive indicator of pancreatic inflammation, it can also be caused by nonpancreatic disease (poor specificity).
• Serum amylase activity is best interpreted in light of serum lipase activity. Amylase activity in dogs with pancreatitis does not correlate with lipase activity until serum lipase values exceed 800 IU/L.
• Serum amylase activity in cats with acute pancreatitis decreases, and therefore is not recommended.

Pancreatitis and Hyperlipasemia
• Serum lipase activity consistently increases several fold in dogs with pancreatitis. If serum lipase activity of > 500 IU/L is used as a cutoff, the sensitivity of the test for pancreatitis is 98%.
• Serum lipase activity is also affected by a variety of nonpancreatic disorders The specificity of the test for pancreatitis is 78% if a value of 500 IU/L is used as a cutoff.
• Serum lipase activity in cats with pancreatitis is normal to high.
• Normal serum lipase activity does not rule out pancreatic disease. Up to 15-20% of animals with acute pancreatitis have normal lipase and/or amylase activity.
• In general, lipase activity is a more reliable marker of pancreatitis in dogs and cats than amylase activity.

Renal Disease
• Renal failure is associated with hyperamylasemia and hyperlipasemia.
• High serum activities may result from impaired renal degradation or inadequate clearance due to a reduction in glomerular filtration.

Hepatic Disease
• The source of high lipase activity observed in animals with liver disease is not known.

Gastrointestinal Disease
• High serum amylase activity is observed in some dogs with enteritis, small intestinal obstruction, and gastrointestinal perforation.

Miscellaneous
• A 3-fold or more increase in serum lipase activity may occur after routine laparotomy in dogs without clinical signs or gross evidence of pancreatitis.
• Hyperlipasemia and decreases in serum amylase activity have been reported in dogs after the administration of corticosteroids.

RISK FACTORS
• Obesity and the ingestion of highfat diets in animals with pancreatitis
• Presence of underlying renal disease
• Presence of underlying hepatic disease
• Nonspecific gastrointestinal inflammation
• Previous administration of dexamethasone


DIAGNOSIS

DIFFERENTIAL DIAGNOSIS
• If vomiting, depression, fever, and abdominal pain are observed, rule out pancreatitis.
• If PU/PD, anorexia, weight loss, vomiting, anemia are observed, rule out chronic renal disease.
• If icterus, hepatomegaly, vomiting, PU/PD, and altered mentation are observed, rule out hepatic disease.
• If vomiting, diarrhea, anorexia, and palpable abnormalities of intestinal loops are observed, rule out gastrointestinal disease.

LABORATORY FINDINGS

Drugs That May Alter Lab Results
• Corticosteroids increase serum lipase activity and decrease serum amylase activity, but do not alter validity of laboratory results.

Disorders That May Alter Lab Results
• Serum amylase activity should be measured by an amyloclastic method that measures the disappearance of starch from the assay. Maltase activity in the plasma of dogs is high; and use of a saccharogenic method (measuring the appearance of glucose in the assay) indicates falsely high amylase activity, since maltase contributes to glucose formed in the assay.
• Measurement of serum lipase activity requires more time and the test is technically more cumbersome to perform.
• Hemolysis inhibits lipase activity.
• Lipemia falsely decreases serum lipase activity as measured by kinetic assays.

Valid if Run in Human Lab? Yes

CBC/BIOCHEMISTRY/URINALYSIS
• Pancreatitis--leukocytosis with a left shift, anemia in cats, hyperlipidemia, high ALT and ALP activities and total bilirubin, and prerenal azotemia
• Renal disease--anemia (nonregenerative), renal azotemia, hyperphosphatemia, hypokalemia (cats), and impaired urinary concentrating ability.
• Hepatic disease--high ALT and ALP activities and total bilirubin, hypoproteinemia, hypoalbuminemia, low BUN, and impaired urinary concentrating ability
• Gastrointestinal disease--vary depending on cause.

OTHER LABORATORY TESTS
• Measurement of serum trypsinlike
immunoreactivity or ELISA for trypsinogen activation peptide in dogs with pancreatitis
• Bile acid assay to assess hepatobiliary function in dogs and cats with hepatic disease
• Tests to assess gastrointestinal inflammation including serologic testing for infectious agents and fecal culture

IMAGING
• Pancreatitis--abdominal radiographs show peritoneal effusion, focal soft tissue opacity in right cranial abdominal compartment, and gas retention in proximal duodenum; ultrasound shows the presence of a pancreatic mass and loss of normal pancreatic echogenicity.
• Renal disease--abdominal radiographs may show normal sized to small kidneys, irregularity of renal cortical margins, and skeletal osteodystrophy; ultrasound may show small, irregular kidneys and increased renal cortical echogenicity.
• Hepatic disease--abdominal radiographs may show peritoneal effusion or hepatomegaly; ultrasound may show hepatomegaly and alterations in hepatic parenchymal echogenicity.
• Gastrointestinal disease--abdominal radiographs may show radiopaque foreign body, obstructive lesion, increase in diameter of bowel loops, mucosal irregularity (contrast), and ulcer (contrast); ultrasound findings vary but may show foreign body, obstructive lesion, and intramural infiltrative lesion.

OTHER DIAGNOSTIC PROCEDURES
• Renal biopsy (via laparotomy, laparoscopy, or ultrasound-guidance) to confirm diagnosis of renal disease
• Hepatic biopsy (via laparotomy, laparoscopy, or ultrasoundguidance) to confirm diagnosis of liver disease
• Laparotomy for full thickness intestinal biopsy
• Endoscopy for intestinal mucosal biopsy


TREATMENT

• Treatment varies depending on the underlying cause for high serum amylase and/or
lipase activity.
• Patients should be hospitalized for initial medical management.
• Restricted activity is required in most patients.
• Dietary management and fluid therapy are important treatment modalities in these patients.
• Surgical considerations include laparotomy to remove gastrointestinal foreign body, drain pancreatic abscesses, or provide open peritoneal drainage.


MEDICATIONS

DRUGS AND FLUIDS
• Patients with pancreatitis--NPO; lactated Ringer's solution is the fluid of choice and should be given IV; add potassium chloride to fluids in animals with profuse vomiting; use parenteral antibiotics (penicillin or ampicillin) if sepsis is present; use antiemetics (phenothiazine derivatives) if intractable vomiting occurs; use corticosteroids if patient is in shock.
• Renal Disease--lactated Ringer's solution or 0.9% saline are appropriate, first-choice rehydration fluids; fluids should be given IV in severely azotemic patients; treat signs of uremia with antiemetics (metoclopramide) and antihistamines (ie, H2-blockers such as cimetidine); transfusion may be required in animals with severe anemia.
• Hepatic disease--lactated Ringer's solution is used in animals with acute hepatopathy; use 0.45% saline in animals with chronic liver disorder; potassium supplementation in fluids is important in patients with chronic liver disease; lactulose and metronidazole can be used to reduce signs of hepatic encephalopathy.
• Gastrointestinal disease--NPO if patient is vomiting; lactated Ringer's solution should be used to correct hydration and electrolyte deficits; add potassium to fluids if necessary; avoid antibiotics unless hemorrhagic diarrhea is present; avoid anticholinergic drugs which can cause ileus; avoid antiemetics unless profuse vomiting is present.

CONTRAINDICATIONS
• Avoid the use of azathioprine, chlorothiazide, estrogens, furosemide, tetracycline, and sulfamethazole in patients with pancreatitis.
• Avoid aminoglycosides in patients with renal disease. Adjust the dosage or dosing interval appropriately for all other drugs that are eliminated by the kidneys.
• In animals with liver disease, adjust the dosage of drugs that require hepatic biotransformation or hepatic degradation.
• Avoid metoclopramide in animals with gastrointestinal obstruction.

PRECAUTIONS
• Since pancreatitis is the most common cause of markedly high activity of both serum amylase and lipase, the following drugs should be used cautiously:
(1) Corticosteroids since they may aggravate lesions of pancreatitis
(2) Phenothiazine antiemetics since they have hypotensive properties and may exacerbate pancreatic ischemia
(3) Dextrans since high dosages may promote bleeding in patients with hemorrhagic pancreatitis

POSSIBLE INTERACTIONS N/A

ALTERNATE DRUGS N/A


FOLLOW-UP

PATIENT MONITORING

Pancreatitis
• Evaluate patient's hydration status closely for the first 48 hours.
• Repeat biochemistry analysis and measurement of lipase activity as needed.
• Gradually reintroduce oral alimentation.

Other Conditions
Patient followup is extremely variable
depending on the organ system involved and extent of disease.

POSSIBLE COMPLICATIONS
Severe episodes of pancreatitis can cause death.


MISCELLANEOUS

ASSOCIATED CONDITIONS N/A

AGERELATED FACTORS N/A

ZOONOTIC POTENTIAL N/A

PREGNANCY N/A

SYNONYMS N/A

SEE ALSO
Pancreatitis

ABBREVIATIONS

ALP = alkaline phosphatase

ALT = alanine aminotransferase

BUN = blood urea nitrogen

NPO = nothing per os

PU/PD = polyuria/polydipsia

References

Strombeck DR, Guilford WG. The pancreas. In: Strombeck DR, Guilford WG eds. Small animal gastroenterology. 1st Ed. Davis, CA: Stonegate Publishing, 1990.

Polzin DJ, Osborne CA, Stevens JB, et al. Serum amylase and lipase activities in dogs with chronic primary renal failure. Am J Vet Res 1983; 44:404410.

Murtaugh RJ. Acute pancreatitis: diagnostic dilemmmas. Sem Vet Med Surg Small Anim 1987; 2:282295.

Author Albert E. Jergens

Consulting Editor Albert E. Jergens