Acute pancreatitis (AP) is a common cause of abdominal pain, and the diagnosis is based primarily on the patient's history and clinical examination findings. The severity of the disease may range from mild local inflammation to multisystem organ failure secondary to a systemic inflammatory response. Cholelithiasis and alcohol abuse are the most common causes, but there are many potential etiologies. Patients without risk factors often develop pancreatitis secondary to medications or severe hyperlipidemia. Commonly used medications associated with pancreatitis include acetaminophen, carbamazepine, enalapril, estrogens, erythromycin, furosemide, hydrochlorothiazide, opiates, steroids, tetracycline, and trimethoprim-sulfamethoxazole.
The most common symptom is a midepigastric, constant, boring pain radiating to the back, which is often associated with nausea, vomiting, abdominal distention, and exacerbation in the supine position. Low-grade fevers, tachycardia, and hypotension may be present. Epigastric tenderness is common, whereas peritonitis is a late finding.
Physical finding are dependent on the severity of disease. Physical examination findings include epigastric tenderness but tenderness may localize more to the right or left upper quadrant of the abdomen. Bowel sounds may be diminished and abdominal distention may be present secondary to ileus. Refractory hypotensive shock, renal failure, fever, altered mental status, and respiratory failure may accompany the most severe disease.
Diagnosis and Differential
The diagnosis should be suspected by the history and physical examination. The presence of two of the three following features makes the diagnosis more likely: (1) history and examination findings consistent with acute pancreatitis, (2) lipase or amylase levels at least 2 to 3 times the upper limit of normal, or (3) imaging findings consistent with pancreatic inflammation. Serum lipase and amylase are the most common tests used to assist in the diagnosis but lipase is the preferred diagnostic test as it is more accurate. There are many sources of extrapancreatic amylase, making it relatively nonspecific. Normal serum amylase does not exclude the diagnosis of acute pancreatitis. There is no benefit to ordering both tests. The absolute levels do not correlate with the severity of disease.
A CBC will identify leukocytosis or anemia. Liver studies can demonstrate associated biliary involvement. An elevated alkaline phosphatase level suggests biliary disease and gallstone pancreatitis. Persistent hypocalcemia (<7 milligrams/100 mL), hypoxia, increasing serum urea nitrogen, and metabolic acidosis are associated with a potentially complicated course.
Imaging can help confirm the diagnosis of pancreatitis, evaluate biliary involvement, and exclude causes of abdominal pain. Abdominal CT scan is preferred over ultrasound as the latter is often limited by bowel gas overlying the pancreas. In the face of a typical clinical picture and laboratory results, emergency imaging may not be needed.
The differential diagnosis includes referred chest pain secondary to ischemic heart disease, pulmonary pathology such as pneumonia or empyema, hepatitis, cholecystitis or biliary colic, ascending cholangitis, renal colic, small bowel obstruction, peptic ulcer disease or gastritis, and acute aortic pathology such ...