Wallach's Interpretation of Diagnostic Tests: Pathways to Arriving at a Clinical Diagnosis (128 page)

>10% decrease in Hct

Serum calcium <8.0 mg/dL

Increase in BUN >5 mg/dL

Arterial pO
₂
<60 mm Hg

Metabolic acidosis with base deficit >4 mEq/L

   Mortality

1%, if 3 signs are positive

15%, if 3 to 4 signs are positive

40%, if 5 to 6 signs are positive

100%, if ≥7 signs are positive

   Degree of amylase elevation has no prognostic significance.

   CT scan, MRI, and ultrasound are useful for confirming diagnosis or identifying causes or other conditions.

Suggested Readings

Papachristou GI, Whitcomb DC. Inflammatory markers of disease severity in acute pancreatitis.
Clin Lab Med.
2005;25:17.

Whitcomb DC. Acute pancreatitis.
N Engl J Med.
2006;354:2142.

PANCREATITIS, CHRONIC

   See also Malabsorption.

   Laboratory Findings

Laboratory findings are often normal.

Imaging studies
: CT, ultrasound, and ERCP are most accurate for diagnosing and staging chronic pancreatitis. Radioactive scanning of the pancreas (selenium) yields variable findings in different clinics.

Cholecystokinin–secretin test
: Measures the effect of IV administration of cholecystokinin and secretin on volume, bicarbonate concentration, and amylase output of duodenal contents and increase in serum lipase and amylase. This is the most sensitive and reliable test (gold standard) for chronic pancreatitis especially in the early stages. However, it is technically difficult and is often not performed accurately; gastric contamination must be avoided. Some abnormality occurs in >85% of patients with chronic pancreatitis. Amylase output is the most frequent abnormality. When all three are abnormal, there is a greater frequency of abnormality in the tests listed below.

   Normal duodenal contents:

   Volume: 95–235 mL/hour

   Bicarbonate concentration: 74–121 mEq/L

   Amylase output: 87,000–276,000 mg

   Serum amylase and lipase increase after administration of cholecystokinin and secretin in approximately 20% of patients with chronic pancreatitis. They are more often abnormal when duodenal contents are normal. Normally serum lipase and amylase do not rise above normal limits.

   Fasting serum amylase and lipase are increased in 10% of patients with chronic pancreatitis.