Pancreatitis

Introduction

• 15-30% have recurrent disease and 5-25% end up with chronic pancreatitis
• 80% of cases involve only mild inflammation of the pancreas (mortality rate <1%), which resolves with supportive care
• Severe pancreatitis has mortality up to 30%
• Alcohol-induced pancreatitis more common in men and gallstone pancreatitis is more common in women
• Risk factors include alcohol, smoking, obesity and DM
• Alcohol
  • Complicated correlation with some authors stating large binge is causative while others claim at least 5 years of heavy use is required before alcohol can reliably be considered the cause

Causes

• Gallstones (35-75%)
• Alcohol (25-35%)
• Idiopathic (10-20%)
• Uncommon
  • Hypertriglyceridaemia (>1000mg/dL) (1-4%)
  • ERCP
  • Drugs (1.4-2%)
• More uncommon
  • Abdominal trauma
  • Post-operative
  • HyperPTH
  • Infection (bacterial, viral, parasitic)
  • Autoimmune
  • Tumor
  • Hypercalcaemia
  • Cystic fibrosis
• Rare
  • Ischaemia
  • Posterior penetrating ulcer
  • Toxins (<2% of cases)
• Congenital abnormalities

Drugs associated with pancreatitis

• Paracetamol
• Amiodarone
• Cannabis
• Carbamazepine
• Hydrochlorothiazide
• Codeine
• Dexamethasone
• Enalapril
• Oestrogens
• Erythromycin
• Frusemide

Drugs associated with pancreatitis

• Losartan
• Metronidazole
• Simvastatin
• Procainamide
• Tetracycline
• Bactrim
• Dapsone, isoniazid, rifampicin
• Antiretrovirals
• Chemotherapeutics – L-asparaginase, cisplatin, ifosfamide,
• Mercaptopurine and tamoxifen
• Azathioprine

Pathophysiology

• Trypsinogen converted to trypsin within the pancreatic acinar cells leading to unregulated activation and subsequent activation of other digestive enzymes, complements, kinins and autodigestion
• Mild, interstitial, oedematous pancreatitis is most common
• Acute necrotising pancreatitis involves surrounding tissues and SIRS and is responsible for associated mortality

Clinical features

• Pain may worsen lying supine or with oral intake
• Pain described as lower abdominal pain or dull/colicky pain is highly unlikely to be pancreatic in origin
• Rare late findings include Cullen’s sign (umbilical haemorrhage), Grey-Turner sign (red-brown flanks) and erythematous skin nodules from focal subcutaneous fat necrosis

Diagnosis

• 2 out of 3 of:
  • Clinical presentation consistent with acute pancreatitis
  • Serum lipase/amylase above ULN
  • Imaging findings consistent with pancreatitis (IV contrast-enhanced CT/MRI or USS)
• Lab studies
  • Guidelines suggest amylase or lipase should be 3x ULN, 2x ULN or just above ULN
  • Amylase
    • Rises within hours, peaks at 48 hours and normalises in 3-5 days
    • 20% of patients (mostly alcohol or triglyceride-associated pancreatitis) have normal amylase levels
    • Sensitivity only 70% and PPV of 15-72%
      Can also be elevated by renal insufficiency, salivary gland disease, acute appendicitis, cholecystitis, intestinal obstruction, intestinal ischaemia and gynaecological disease
  • Lipase
    • More specific and remains elevated for longer
    • Can be elevated at baseline in diabetics and renal disease, appendicitis and cholecystitis but much more rarely
    • More sensitive in delayed presentation and alcohol/triglyceride-associated pancreatitis
  • No evidence that adding amylase to a non-diagnostic lipase improves diagnostic accuracy
  • ALT > 150 within the first 48 hours of symptoms predicts gallstone pancreatitis with a >85% PPV

Imaging

• TA-USS
  • For suspected gallstone pancreatitis
• CXR
  • For severe pancreatitis or those with respiratory complaints
• CT
  • Routine use is not recommended if pancreatitis diagnosed
  • No evidence that this improves outcomes
  • Peripancreatic fluid collections or pancreatic necrosis rarely require any treatment and complete extent of these complications is usually not appreciated until 3 days of symptoms
  • Magnitude of morphological change on CT does not correlate with disease severity
  • IV contrast can worsen pancreatitis, renal function and allergy
  • If diagnosis is in doubt however, contrast-enhanced abdo CT may show characteristic findings:
    • Pancreatic parenchymal inflammation with or without peripancreatic fat stranding
    • Pancreatic parenchymal necrosis or peripancreatic necrosis
      • Appears as loss of normal lobulation and loss of enhancement
    • Peripancreatic fluid collection
    • Pancreatic pseudocyst
    • Lack of normal contrast enhancement of gland or portion thereof consistent with necrosis
    • Necrosis of pancreatic head alone = whole pancreas in terms of severity
    • Distal pancreatic necrosis has better outcomes
    • May show black holes of duct dilatation at head of pancreas

Imaging

• Indications for CT
  • Diagnosis unclear
  • Hyperamylasaemia and severe clinical pancreatitis, abdominal distension, tenderness, high fever >39 and leukocytosis
  • Ranson score >3
  • Lack of improvement after 72 hours of initial conservative therapy
  • Acute deterioration following initial improvement

Treatment

• Early aggressive hydration decreases morbidity and mortality
• Most patients require 2.5-4L of fluid with 1/3 delivered in first 12-24 hours
• NBM, IV fluids, antiemetics, opioids
• Prolonged bowel and pancreatic rest increases gut atrophy and bacterial translocation, leading to infection and increases morbidity and mortality
  • If nausea, vomiting and pain subside, can start small amounts of oral food and oral analgesia
  • Low-fat solid food diet has more calories than liquid diet and is safe
  • In ICU, trial of EN should be initiated via jejunal tube if possible and TPN initiated if 5-7 days of EN trials have failed
• Antibiotics only recommended if source of infection is demonstrated

Treatment

• Antibiotics
  • Carbapenems have been shown in meta-analysis to reduce sepsis by 21% and mortality by 12.3% in severe pancreatitis
  • Currently reserved for confirmed infected pancreatic necrosis (by FNA)

Severity classification

• Moderately severe acute pancreatitis (5% mortality)
  • Transient organ failure (<48 hours)
  • Local complications or systemic complications
• Severe acute pancreatitis (30% mortality)
  • One or more local or systemic complications
  • Persistent organ failure >48 hours
• Critical acute pancreatitis
  • Persistent organ failure and infected pancreatic necrosis
• Local complications
  • Acute peripancreatic fluid collections, pancreatic pseudocyst, acute pancreatic/peripancreatic necrosis, walled off necrosis, gastric outlet obstruction, splenic or portal vein thrombosis and colonic inflammation/necrosis
  • Suspect local complications if worsening symptoms, recurrent symptoms, rise in lipase after initial improvement, new or worsening organ dysfunction or sepsis

Extrahepatic complications

• Cardiovascular – Hypotension, hypovolaemia, myocardial depression, MI, pericardial effusion
• Pulmonary – Hypoxaemia, ARDS, atelectasis, pleural effusion, pulmonary infiltrates, respiratory failure
• DIC
• GI – Peptic ulcer disease, stress ulcer, GI perforation, GI bleeding, gastric outlet obstruction, splenic infarction
• Renal – Oliguria, azotaemia, acute renal failure, renal artery/vein thrombosis
• Metabolic – Hyperglycaemia, hypocalcaemia, hypertriglyceridaemia

Predicting severity

• SIRS at admission and persistent at 48 hours predicts severe acute pancreatitis and is far simpler and just as accurate as other scoring systems
  • SIRS at admission and mortality
    • Sensitivity 100%; Specificity 31%
  • SIRS at 48 hours
    • Sensitivity 77-89%; Specificity 79-86%
• Patient characteristics – Age >55, obesity, ALOC, comorbidities
• Labs – BUN >20mg/dL or rising, Hct >44% or rising, increased creatinine
• Imaging – Many or large extrapancreatic fluid collections, pleural effusions, pulmonary infiltrates

Disposition and follow-up

• Consider admission for:
  • First episode
  • Any biliary pancreatitis
  • IV pain relief requirement
  • Not tolerating oral intake
  • Persistently abnormal vital signs
  • Any signs of organ insufficiency
• Early cholecystectomy for gallstone pancreatitis
  • Cholecystectomy if NOT gallstone pancreatitis is associated with increased recurrence of acute pancreatitis
• Patients with cholangitis or known biliary obstruction on admission may benefit from early ERCP
  • Early ERCP in patient without cholangitis or known obstruction does not provide benefit

Ranson’s score

• On admission
  • Age >55
  • WCC >16
  • Glucose >11
  • LDH >400
  • AST >250
• Within 48 hours of admission
  • Decrease in Hct >10%
  • Increased BUN >1.8
  • Calcium <2
  • PaO2 <8kPa
  • Base deficit >4
  • Fluid deficit >6L

Ranson’s score
(for gallstone pancreatitis)

• At presentation
  • Age >70
  • WCC >18
  • Glucose >12.2
  • LDH >400
  • AST >250
• Within 48 hours
  • BE >5
  • Hct drop >10%
  • Rise in urea >2
  • PaO2 <60
  • Ca <2
  • Fluid deficit >4L

Glasgow criteria

• At presentation
  • Age >55
  • WCC >15
  • BSL >10
  • Urea >16 with no response to IV fluids
  • PaO2 <76
• Within 48 hours
  • Ca <2
  • Albumin <34
  • LDH >600
  • AST >200

Modified Glasgow Criteria

• Within 48 hours
  • PaO2 <60
  • Age >55
  • Neutrophils, WCC >15
  • Ca <2
  • Renal, urea >16
  • Enzymes, LDH >600, AST >200
  • Albumin <32
  • Sugar, BSL >10
• If 3 or more = severe

Chronic pancreatitis

• Mostly seen with alcoholic acute pancreatitis
• Attacks are similar to acute pancreatitis
• Goals of treatment are the same
• Mortality risk is generally lower than acute pancreatitis

Surgery for severe pancreatitis

• Accepted indications
  • Differential diagnosis
  • Persistent biliary pancreatitis
  • Infected pancreatic necrosis (based on FNA)
  • Pancreatic abscess
• Controversial
  • Stable but persistent necrosis
  • Deterioration in clinical course
  • Organ system failure
  • Abdominal compartment syndrome
• If severe pancreatitis is a ‘chance’ diagnosis at laparotomy, a T-tube should be inserted into the common bile duct + feeding jejunostomy tube (Oh’s)

Infected pancreatic necrosis

• Undisputed indication for surgery
• Multiple different methods of drainage have been attempted and no clear winner

Sterile pancreatic necrosis

• Conservative approach recommended as intervention risks infection

Pancreatic abscess

• Circumscribed collections of pus with little or no pancreatic necrosis
• Often occur 3-4 weeks after onset of severe pancreatitis
• Diagnosed most accurately on CT scan
• Percutaneous vs. open approach

ERCP

• For severe biliary pancreatitis
• Studies have shown ERCP + papillotomy shows benefit in severe cases of biliary pancreatitis

Last Updated on March 27, 2024 by Andrew Crofton