acute pancreatitis

acute pancreatitis
Field	Gastroenterology, General surgery

acute pancreatitis is a sudden inflammation of the pancreas that can lead to significant local and systemic complications. It is a common gastrointestinal emergency requiring hospital admission, with a wide spectrum of severity from mild, self-limiting disease to severe, life-threatening illness. The condition is most frequently triggered by gallstones and alcohol abuse, and its management involves supportive care, treatment of the underlying cause, and management of complications.

Signs and symptoms

The hallmark symptom is severe, constant epigastric pain that often radiates to the back and is typically relieved by sitting forward. Patients frequently experience nausea and vomiting. On examination, signs may include tachycardia, hypotension, and fever; severe cases can present with Grey Turner's sign or Cullen's sign. The systemic inflammatory response can lead to tachypnea and hypoxia, indicating potential acute respiratory distress syndrome. Abdominal findings range from mild tenderness to severe peritonitis with abdominal distension and ileus.

Causes

The two most common etiologies are gallstones, which cause obstruction at the ampulla of Vater, and chronic alcohol abuse. Other identifiable causes include hypertriglyceridemia, hypercalcemia (often from hyperparathyroidism), and certain medications like azathioprine and furosemide. Structural abnormalities such as pancreas divisum or tumors, traumatic injury from procedures like endoscopic retrograde cholangiopancreatography, and infections like mumps are also recognized. In many cases, particularly at institutions like the Mayo Clinic, a significant portion is classified as idiopathic.

Pathophysiology

The process begins with premature activation of pancreatic zymogens, particularly trypsinogen, within the acinar cells. This leads to autodigestion of the pancreatic parenchyma and release of inflammatory mediators such as cytokines and chemokines. The local injury triggers a systemic inflammatory response syndrome, which can progress to multi-organ dysfunction affecting the lungs, kidneys, and cardiovascular system. Severe cases involve pancreatic necrosis and the development of collections like acute necrotic collections, which can become infected by organisms such as Escherichia coli.

Diagnosis

Diagnosis is primarily based on a combination of characteristic clinical presentation and elevated serum levels of lipase or amylase, typically more than three times the upper limit of normal. Imaging with contrast-enhanced computed tomography is the gold standard for assessing severity and complications like necrosis. Magnetic resonance imaging and transabdominal ultrasound are also valuable, with ultrasound particularly useful for detecting gallstones. The Atlanta classification and Ranson's criteria are commonly used scoring systems to stratify severity, alongside the APACHE II score in intensive care settings.

Treatment

Initial management is supportive and includes aggressive intravenous fluid resuscitation, analgesia (often with opioids like hydromorphone), and nutritional support, with early enteral nutrition preferred over parenteral nutrition. Treatment of the underlying cause is critical, such as endoscopic retrograde cholangiopancreatography for gallstone pancreatitis. In severe necrotizing pancreatitis, interventions for infected necrosis may be required, including percutaneous drainage or minimally invasive necrosectomy techniques pioneered at centers like the University of Pittsburgh Medical Center. Antibiotics like carbapenems are reserved for proven infection.

Prognosis

The prognosis varies widely; mild interstitial pancreatitis has a mortality rate of less than 1%, while severe necrotizing pancreatitis carries a mortality rate of 20-40%. Early predictors of severe disease include persistent organ failure and extensive pancreatic necrosis on imaging. Long-term complications can include pancreatic pseudocyst formation, endocrine and exocrine pancreatic insufficiency, and recurrent episodes leading to chronic pancreatitis. Outcomes are heavily influenced by the development of systemic complications and the timeliness of interventions, as studied extensively by organizations like the American Gastroenterological Association.

Category:Digestive system