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Etiology of Acute Pancreatitis

Causes of Acute Pancreatitis include:

• Gallstones (most cases)
• Alcohol (most cases)
• Idiopathic
• Hypercalcemia
• Hyperlipidemia
• Autoimmune
• Post ERCP
• Trauma
• Mumps
• Drugs (e.g., azathioprine,steroids or diuretics)

The causes of acute pancreatitis can be recalled from the mnemonic GET SMASH’D: gallstones, ethanol, trauma, steroids, mumps, autoimmune diseases, scorpion stings, hypertriglyceridemia, and drugs (e.g., azathioprine or diuretics).

Clinical Features of Acute Pancreatitis

There may be a history of cholecystitis or other complications of gallstones. Alcohol intake should be ascertained.

The patient complains of:

• Severe abdominal pain radiating to the back or shoulder, which may be relieved by sitting forward
• There may be associated nausea and vomiting

On examination there is:

• abdominal tenderness with guarding and rebound tenderness
• tachycardia
• fever
• jaundice
• hypotension, and sweating
• bruising around the umbilicus (Cullen’s sign) or in the flanks (Grey-Turner’s sign)

Differential Diagnosis

• Any cause of an acute abdomen (e.g., cholecystitis, mesenteric ischemia, and intestinal perforation).
• Myocardial infarction
• Dissecting aortic aneurysm

Investigations

The following investigations are important in the patient with acute pancreatitis:

• Serum amylase: markedly raised (over 1000 IU/mL). Amylase is also raised with cholecystitis and perforated peptic ulcer, but usually to a lesser extent. Serum lipase is also elevated and is more specific than amylase.
• Abdominal x-ray: gallstones, pancreatic calcification indicating previous inflammation, an absent psoas shadow due to retroperitoneal fluid, and a distended loop of jejunum (“sentinel loop”).
• Serum calcium: may be low.
• White cell count: usually raised.
• ECG: to exclude myocardial infarction.
• Arterial blood gases: metabolic acidosis.
• CXR: widened mediastinum in aortic dissection; gas under the diaphragm in perforated peptic ulcer.
• Abdominal CT: assess severity.

READ MORE: Imaging of Acute Pancreatitis – to Image or Not to Image

Management of Acute Pancreatitis

Management is usually conservative.

• Intravenous fluids should be given to maintain the circulating volume, and a central venous catheter may be helpful for assessing the volume of fluid required. If the patient is in shock (systolic blood pressure <90 mmHg), plasma expanders will be required.

• Pain relief is with intravenous or intramuscular opiates (e.g., pethidine, 50-150 mg 4 hourly, or pentazocine, 30-60 mg 4 hourly, meperidine, fentanyl, or morphine with an antiemetic such as prochlorperazine, 12.5 mg 8 hourly).

• A nasogastric tube should be inserted. TPN may be required.

• Blood tests, especially metabolic panel, glucose, and calcium, should be monitored.

• Surgery should be considered for suspected hemorrhagic necrosis of the pancreas.

• Some give H2-receptor antagonists, prophylactic antibiotics, or peritoneal lavage, although these measures are of unproven value.

READ MORE: Recognizing and Treating Severe Acute Pancreatitis (SAP)

Complications and Prognosis

Ranson’s criteria are used to predict the severity of acute pancreatitis. Mortality is 5-10%, but recurrence is uncommon in patients who recover.

Complications include :

• shock
• renal failure
• sepsis
• respiratory failure
• hypocalcemia due to the formation of calcium soaps
• transient hyperglycemia
• pancreatic abscess requiring drainage
• pseudocyst (i.e., fluid in the lesser sac presenting as a palpable mass)
• persistently raised serum amylase or liver function tests, and fever

Patients should be investigated to exclude gallstones, and alcohol should be avoided.