Acute Pancreatitis

Pancreas

Acute Pancreatitis

·        = Inflammation in pancreas and peripancreatic tissues (sometimes with haemorrhage and necrosis)

Causes

·        90% caused by either (grog or gravel):

o  Gallstones blocking the ampulla (60%)

o  Alcoholic (more chronic than acute) (30%).  Pathogenesis unclear - ?duct obstruction

·        Also: trauma, ERCP, drugs

·        Types:

o  Interstitial or oedematous pancreatitis: mild, self-limiting

o  Acute haemorrhagic (necrotising) pancreatitis: severe

Pathogenesis

·        Activation of pancreatic enzymes ® cellular injury, release of enzymes and cytokines ® ischaemia. Secondary bacterial infection possible. May also follow ERCP – catalysts from duodenum activate pancreatic enzymes while still in the pancreatic duct

·        Macroscopic appearance:

o   Variegated: blue-black haemorrhage, yellow-white fat necrosis 

o   Peritoneal „Chicken-Broth Ascites‟: layer of clear fat floating on turbid liquid – lipase has digested abdominal fat

o   With resolution: fibrosis, calcification, pseudocysts

·        Microscopic appearance: If mild, periductal inflammation. Proteolytic destruction of the pancreatic substance. Necrosis of blood vessels ® haemorrhage

Presentation

·        Upper abdominal constant (ie inflammatory) pain + lumbar back pain

·        Nausea, vomiting

·        Peritoneal irritation, ileus

·        Jaundice, especially in gallstone induced

·        Tachycardia

·        Signs (due to haemorrhagic fluid in the extra peritoneal space):

o   Cullen‟s Sign: Discolouration around the umbilicus

o   Greg-Turner‟s Sign: Discolouration around the flanks

·        If severe:

o   Shock: enzymes into blood, acute peritonitis, massive inflammation

o   Respiratory failure, circulatory failure

·        Complications: shock, ARDS, acute renal failure, abscess, duodenal obstruction

Investigations

·        ­Serum or urine amylase. Height of amylase does not correlate with severity. Other conditions may cause raised amylase. ­Lipase 

·        Also possibly ­ glucose, ­WBCs, ­creatinine, ¯calcium, ­faecal elastase

·        CXR to exclude gastrointestinal perforation (air under diaphragm)

·        Ultrasound/ERCP, ALT and bilirubin to check for stones 

·        CT to determine extent of inflammation/necrosis. Use contrast – necrotic tissue doesn‟t light up as it‟s not perfused

·        Also FNA

Differential

·        Abdominal catastrophe: perforation, ectopic pregnancy, infarction, ruptured aneurysm, obstruction, appendicitis

·        MI

·        Acute cholecystitis

Progression

·        Most fully recover in 4 – 6 days with IV fluids, O₂, analgesia 

·        If severe, up to 50% mortality. Treat for renal, cardiac and respiratory failure. Surgery for infected necrosis

·        Treat cause: e.g. ECRP + sphincterotomy, later cholecystectomy, alcohol abstinence, etc 

·        Supportive treatment: IV fluids, pain relief, inotropic support if ¯BP or renal hypoperfusion despite fluids