What are the causes of prolonged fever in pancreatitis?

Causes of Prolonged Fever in Pancreatitis

The most common causes of prolonged fever in pancreatitis are infected pancreatic necrosis, other local complications such as pseudocysts, and non-pancreatic infections including pneumonia, urinary tract infections, and catheter-related infections.

Local Pancreatic Causes

Infected Pancreatic Necrosis

• Infected necrosis is the most serious local complication of severe pancreatitis and a major cause of prolonged fever 1
• A sudden high fever may indicate the development of infection, although this can arise from sources other than the pancreatic area 1
• Infected necrosis requires intervention to debride all cavities containing necrotic material 2

Sterile Pancreatic Necrosis

• An unremitting low to moderate grade fever is commonly seen in necrotizing acute pancreatitis and does not necessarily indicate deterioration 1
• Sterile necrosis can cause persistent inflammatory response with associated fever 3

Pseudocysts and Fluid Collections

• Acute fluid collections occur in 30-50% of severe pancreatitis cases 1
• Symptomatic collections (causing pain, mechanical obstruction, or fever) may require percutaneous aspiration 1
• An epigastric mass with vomiting suggests an acute fluid collection that may persist to form a pseudocyst 1

Non-Pancreatic Causes

Respiratory Complications

• Pneumonic consolidation and pleural effusions can be detected on chest x-ray 1
• Acute respiratory distress syndrome (ARDS) can develop as a complication of severe pancreatitis 1

Catheter-Related Infections

• Invasive monitoring equipment such as central lines may serve as a source of subsequent sepsis in the presence of pancreatic necrosis 1
• Strict asepsis should be observed in the placement and care of invasive monitoring equipment 1

Cholangitis in Gallstone Pancreatitis

• Severe gallstone pancreatitis with signs of cholangitis (fever, rigors, positive blood cultures) requires immediate therapeutic ERCP 1
• Biliary obstruction can lead to persistent fever and requires urgent intervention 2

Diagnostic Approach for Prolonged Fever

Clinical Assessment

• Increasing leucocyte and platelet counts, deranged clotting, an increase in the APACHE II score, and/or elevated CRP concentration indicate possible sepsis 1
• The onset of cardio-respiratory or renal failure are signs of septic complications 1
• A patient who is "failing to thrive" with features of hypermetabolism and a catabolic state suggests development of complications 1

Radiological Assessment

• Dynamic CT should be repeated in severe acute pancreatitis on a regular basis, usually every two weeks, or more frequently if there are indications of sepsis 1
• Plain abdominal x-ray may rarely reveal free gas in the retroperitoneum—a late sign indicative of infection with gas-forming organisms 1
• Ultrasound is useful for evaluation and serial monitoring of fluid collections 1

Bacteriological Assessment

• If sepsis is suspected, blood cultures should be obtained 1
• CT-guided fine needle aspiration of pancreatic necrosis for Gram stain and culture can differentiate between infected and sterile necrosis 1

Management Implications

Antibiotics

• Prophylactic antibiotics may be considered in severe acute pancreatitis 1
• Intravenous cefuroxime provides a reasonable balance between efficacy and cost for prophylaxis 1
• Imipenem has been shown to reduce the rate of septic complications in severe pancreatitis 4
• Piperacillin/tazobactam shows effective penetration into necrotic pancreatic tissue 5
• Recent evidence suggests limiting routine use of prophylactic antibiotics, with procalcitonin-based algorithms being investigated to distinguish between inflammation and infection 6

Interventions

• Infected necrosis requires intervention, preferably using minimally invasive approaches 7
• Asymptomatic fluid collections should not be drained due to risk of introducing infection 1
• For gallstone pancreatitis with cholangitis, urgent ERCP with sphincterotomy should be performed 2

Common Pitfalls

• Mistaking persistent low-grade fever in sterile necrosis for infected necrosis 1
• Unnecessary drainage of asymptomatic fluid collections, which increases the risk of introducing infection 1
• Failure to recognize non-pancreatic sources of infection such as central line infections or pneumonia 1
• Overuse of prophylactic antibiotics, which can lead to selection of resistant microbes and fungi 4, 7