34. Laboratory diagnosis of acute pancreatitis
Acute pancreatitis is a reversible inflammatory condition of the pancreas that varies in intensity from just oedema and adiponecrosis to widespread parenchymal necrosis. It occurs when something causes the digestive enzymes to be activated in the pancreas itself, which self-digest the organ. The disease has a relatively high mortality, around 5%.
Etiology
The most common causes are alcoholism and gallstones in the biliary tract distal to the pancreatic duct. These two factors are responsible for 80% of all cases of acute pancreatitis.
There are multiple possible causes, memorised by the acronym "I GET SMASHED"
- Idiopathic
- Gallstones
- Ethanol (Alcoholism)
- Trauma
- Steroids
- Mumps (and Coxsackie) Virus
- Autoimmune
- Scorpion venom
- Hypercalcaemia, hypertriglyceridaemia
- ERCP
- Drugs
Diagnosis and evaluation
The diagnosis of acute pancreatitis is made when two of the following three are present:
- Acute, persistent, severe epigastric pain (often radiates to the back)
- Elevation in serum lipase or amylase to > 3 the upper normal limit
- Characteristic findings of acute pancreatitis on imaging
In case of jaundice, elevated bilirubin, elevated liver tests or cholestatic enzymes, gallstone or another obstruction of the biliary tree is the likely cause.
Etiology
After the diagnosis is made, the underlying cause must be sought. This includes a thorough history to look for risk factors, serum triglyceride level, calcium level, and abdominal ultrasound for gallstone. Endoscopic ultrasound may be used if initial investigations does not reveal the etiology.
Severity assessment
The severity of the pancreatitis must be assessed, both based on clinical assessment and the SIRS score. Haemodynamic instability, hypoxaemia, acid-base disorder, altered mental status, are all features of severe acute pancreatitis. High CRP (> 100 mg/L) suggests necrotising pancreatitis. Important to note that serum lipase/amylase are not predictors of severity, and so the degree of enzyme elevation does not correlate with the severity of the disease.