Acute pancreatitis

acute pancreatitis

Introduction• Acute pancreatitis is a condition in which

activated pancreatic enzymes leak into the substance of the pancreas and initiate the auto-digestion of the gland.

introduction

EtiologyCommon (90%)• Gall stones• Alcohol• IdopathicRare • Metabolic: hypercalcemia, hypertrigyceridemia• Drugs: thiazide, azathioprine, sodium valporate, pentamidine• Infection: mumps, coxsackie virus• Post ERCP (due to back pressure of contrast into ductal system)• Trauma• Organ transplantation• Post surgical

etiology

etiology

Pathophysiology• The pancreas secretes the digestive enzymes as proenzymes which

are activated in the intestinal lumen.

• Acute pancreatitis may result when activation occurs in pancreatic duct system or acinar cells. May include edema or obstruction of the ampulla of Vater resulting in reflux of bile into pancreatic ducts or direct injury to the acinar cells.

• The pancreas show edema and necrosis. The release of enzymes

lead to fat necrosis both in the pancreas and in the peritoneal cavity.

• Premature activation of trypsinogen into trypsin while it is still in pancreas. Resulting in auto digestion of the pancreas.pathophysiology

Proenzymes

Activated proteolytic enzymes

Defective intracellular transport and secretion

of pancreatic zymogens

Pancreatic duct obstruction (common

bile duct stones, tumors)

Acute pancreatitis

Hyperstimulation of pancreas (alcohol,

triglycerides)

Reflux of infected bile or duodenal contents into pancreatic duct (sphincter of Oddi

dysfunction)

Pancreatic secretory trypsin inhibitors

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pathophysiology

pathophysiology

Clinical presentation• Midepigastric pain with tenderness. Sudden severe pain

occurring often within 12-24 hours of a large meal or alcohol. The pain is persistent and radiates frequently through to the back to either shoulder or to one iliac fossa before spreading to involve the whole abdomen. Exacerbated on walking and lying supine. Relieved on sitting and leaning forward.

• Nausea and vomiting has always been the presentation of acute pancreatitis in the majority of cases.

• When pancreatitis is extremely severe, it mimics septic shock; fever, hypotension, respiratory distress from ARDS, elevation of the WBC and a rigid abdomen.

clinical presentation

clinical presentation

Abdominal examination• Tenderness in epigastrium

• Although severe pain, there may be little or no guarding of abdominal muscles at first. Later the upper abdomen becomes tender and rigid as peritoneal irritation increases.

• Mild abdominal distention if paralytic ileus develops.

• Severe advanced cases may develop bruising and discoloration in the left flank (Grey Turner’s sign due to tissue catabolism of Hb) and around the umbilicus (Cullen’s sign due to hemoperitoneum). These are the rare and late signs of extensive pancreatic destruction.

abdominal examination

Cullen’s sign

Grey Turner’s sign

abdominal examination

Complications of acute pancreatitisComplications Causes and features

Shock and renal failure Pancreatic failure is associated with leakage of fluid in the pancreatic bed also ileus with fluid filled loops of bowel leading to pre-renal azotemia and then acute tubular necrosis.

Hypoxia ARDS due to micro thrombi in pulmonary vessels.

Hyperglycemia Due to disruption of pancreatic islets.

Hypocalcemia Sequestration of calcium in fat necrosis.

Hypoalbuminemia Increased capillary permeability.

complications

Complications of acute pancreatitisPancreatic complications Causes and features

Necrosis

Abscess Rising fever, leukocytosis, localized tenderness and epigastric mass. It may be associated with left sided pleural effusion and enlarged spleen due to splenic vein thrombosis.

Pseudocyst Encapsulated fluid collection with high enzyme content. Usually less than 6cm sized pseudocysts resolve spontaneously. They may become secondarily infected requiring drainage of abscess.

Ascites Gradual increase in abdominal girth and persistent elevation of serum amylase in the absence of frank abdominal pain. It results from rupture of pancreatic duct or drainage of pseudocyst into the pancreatic cavity.

complications

complications

complications

Pseudocyst on CT scan

Complications of acute pancreatitis

Gastrointestinal complications Causes and features

Upper GI bleeding Gastric or duodenal erosion

Duodenal obstruction Compression by pancreatic mass

Obstructive jaundice Compression of common bile duct

complications

InvestigationsSerum amylase• Increased level of 3-fold or more the normal value indicates

acute pancreatitis, however other causes of elevation should be excluded such as mumps and perforation or infarction of the intestine.

• Levels turn normal after 48-72 hrs even with the continuing of pancreatitis, serum lipase should also be sent that remains high for 7-14 days.

• Persistent elevation suggests pseudocyst, pancreatic abscess or non pancreatic causes (intestinal obstruction, mumps, narcotics)

investigations

Serum lipase• Remains elevated for 7-14 days. It is diagnostic.

Other laboratory findings• WBC: 15000 – 30000• Glucose : high• BUN: may be elevated• Serum calcium: low in 25% of cases• AST, bilirubin, alkaline phosphatase are transiently elevated.

Serum albumin is low in 10% of patients and indicates severe pancreatitis.

• Markedly elevated LDH (>500U/dl) suggests poor prognosis• Serial assessment of C-reactive is a good indicator of

progress• ABGs show hypoxia investigations

Plain x-ray abdomen• It may show gall stones, sentinel loop, colon cut off sign,

features of paralytic ileus, left pleural effusion or collapsing of lung

CT scan• Useful in detecting large pancreas, pseudocyst, abscess,

hemorrhagic pancreas• Presence of gas bubbles indicate abscess

Ultrasound• To detect gallstone and biliary obstruction and serial

assessment of pseudocysts, although in the earlier stages the gland may not be grossly swollen and may be missed on US.

investigations

Acute exudative pancreatitis CT scan

Acute necrotizing pancreatitis CT scan

investigations

Differential diagnosis

• Perforated peptic ulcer• Acute cholecystitis and biliary colic• Acute intestinal obstruction• Renal colic • Myocardial infarction• Vasculitis• Pneumonia• Diabetic ketoacidosis

differential diagnosis

Management• In most patients it is a mild disease that subsides spontaneously

within several days. Withhold food and liquids by mouth, bed rest and in patients with severe pain and ileus nasogastric suction.

Supportive treatment• Bed rest NPO• IV fluids; saline or whole blood• Nasogastric suctioning; if severe nausea, vomiting or

development of paralytic ileus• Pethidine 3-4 hourly to control pain, avoid morphine• Oxygen for hypoxia, ventilator may be required for ARDS• Dopamine may be required for shock nonresponsive to fluid

management

• Calcium gluconate IV only if hypocalcemia is associated with tetany

• Fresh frozen plasma for coagulopathy• Serum albumin for hypoalbuminemia• Insulin for hyperglycemia• Total parenteral nutrition for severe cases• Antibiotics; prophylactic broad spectrum antibiotic is

given even in sterile pancreatitis to prevent infection• Imipenem 500mg IV 8 hourly or cefuroxime 1.5g IV 8

hourly• ERCP; when severe pancreatitis results from stone in

biliary tract; particularly if there is jaundice or cholangitis ERCP with endoscopic sphincterotomy and stone extraction is indicated

management

management

Surgery • Cholecystectomy should be undertaken within 2

weeks of resolution of pancreatitis.

• Patients with necrotizing pancreatitis or abscess require urgent endoscopic or minimally invasive retroperitoneal pancreatic (MIRP) necrosectomy to debride all cavities of necrotic material.

• Pancreatic pseudocysts can be treated by draining into stomach, duodenum or jejunum. Performed after 6 weeks, once capsule matures, by surgery or endoscopic cystogastrostomy.

management

management

References

• Davidson’s principles and practice of medicine 22nd edition

• Short textbook of medical diagnosis and management 11th international edition (Inam Danish)

• Kaplan medical USMLE step 2 CK internal medicine lecture notes

references

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