TOC   |  GI   

ACUTE PANCREATITIS

• Types  |  Findings |  DX |  Diff. DX  |  Causes |  Ranson/Imrie Criteria  |  Complications |  RX  
• Hyperamylasemia 

Types:

• Edematous pancreatitis: usually a mild & self-limited disorder.
• Necrotizing pancreatitis: Sx correlates with the degree of pancreatic necrosis.
• Hemorrhagic pancreatitis: variable amount of interstitial hemorrhage can be found in pancreatitis.

Sx of pancreatitis:

• Epigastric or periumbilical pain, often radiates to the back as well as to the cheest, flanks, & lower abd.
• The pain is more intense when pt is supine, often less by sitting with the trunk flexed & knees drawn up. N&V, abd. distention & chemical peritonitis Sx.
• Low grade fever, tachycardia, hypotension are fairly common. In 10-20% pt may have pulm. Sx as rales, atelectasis, or pleural effusion. A faint blue discoloration around the umbilicus (Cullen's sign) may occur as the result of hemoperitoneum, & a blue-red-purple or green-brown discoloration of the flanks (Turner's sign) reflects tissue catabolism of hemoglobin. The uncommon signs indicate the presence of a severe necrotizing pancreatitis. Erythematous skin nodules from subc. fat necrosis may occur.

Lab:
increased serum amylase & lipase, marked increased peritoneal or pleural fluid amylase > 1500 u/dL; leukocytosis, hyperglycemia, hypocalcemia (in 25% of pts), hyperbilirubinemia (in 10% of pts), transient elevation of LFT, decreased albumin, hypoxemia (in 25% of pts); ECG occasionally show ST-segment & T-wave abnormalities simulating myocardial ischemia. Plain abd. x-ray may show ileus, GB stone, or pancrease calcification; ultrasound of abd; Abd. CT scan; ERCP findings; pancreatic biopsy with US or CT guidance.

DX:
abd. pain, N&V, fever, tachycardia, elevated amylase & lipase, leukocytosis.

Diff-DX:    See also   Hyperamylasemia   
Perforated PUD or viscus, acute cholecystitis & biliary colic, acute intestinal obstruction, mesenteric vascular occlusion, renal colic, myocardial infarction, dissecting aortic aneurysm, connective tissue disorders with vasculitis, pneumonia, diabetic keoacidosis.

CAUSES of Pancreatitis:

1. Alcoholic pancreatitis
2. Biliary tract/gall stone pancreatitis
3. Post abdominal/nonabdominal surgery
4. Post ERCP procedure pancreatitis
5. Pancreatic tumor/ carcinoma or trauma
6. Metabolic: Hypertriglyceridemia, Hyperparathyroidism, Renal failure, Acute fatty liver of pregnancy.
7. Hereditary pancreatitis
8. Infections: mumps, viral hepatitis, mycoplasma, other virus, parasites
9. Connective tissue disorders with vasculitis: Lupus, Necrotizing angiitis, TTP, Schonlein Henoch purpura
10. Drug associated pancreatitis: * Definite association: azathioprine, sulfonamides, thiazide, furosemide, estrogens (oral contraceptives), tetracycline, valproic acid. * Probable association: chlorthalidone, ethacrynic acid, procainamide, L asparaginase, methyldopa, iatrogenic hypercalcemia * Equivocal association: corticosteroids
11. Pancreatic ampulla of vater obstruction: Regional enteritis, Duodenal diverticulum
12. Penetrating duodenal ulcer
13. Pancreas divisum
14. Recurrent bouts of acute pancreatitis without obvious cause: Consider occult disease of the gallbladder, biliary tree, pancreas, pancreatic ducts; drugs; hypertriglyceridemia, pancreas divisum, hereditary pancreatitis, Sphincter of Oddi dysfunction, cystic fibrosis.
15. Truly idiopathic

Factors adversely affecting survival in acute pancreatitis:
Ranson/Imrie Criteria:

• At admission or diagnosis: age >55, leukocytosis>16,000, hyperglycemia >200 mg/dL, LDL>400 IU/L, AST>250 IU/L
  
• During initial 48H: Hct fall >10%, fluid sequestration >400 mL, hypocalcemia <8.0 mg/dL, hypoxemia pO2<60mmHg, BUN rise >1.8 mmol/L or >5mg/dL after IV fluid, hypoalbuminemia <3.2 g/dL. APACHE II score >12, hemorrhagic peritoneal fluid, key indicators: Hypotension BP<90 or tachycardia>130/min,, oliguria <50mL/h or increasing BUN, Creat, Serum Ca++ <8.0 mg/dL, or serum albumin <3.2 g/dL.

LOCAL COMPLICATIONS of acute pancreatitis:

• Pancreatic phlegmon (solid mass of swollen, inflamed pancreas often containing patchy areas of necrosis), pancreatic abscess, pancreatic pseudocyst (pain, rupture, hemorrhage, infection, obstruction of GI tract); pancreatic ascites; involvement of contiguous organs by necrotizing pancreatitis (massive intraperitoneal hemorrhage, thrombosis of blood vessels, bowel infarction); obstructive jaundice.
• SYSTEMIC COMPLICATIONS of acute pancreatitis:
  Pulm: pleural effusion, atelectasis, mediatinal abscess, pneumonitis, ARDS.
• CV: hypotension/hypovolemia, sudden death, nonspecific ST-T changes simulating MI, pericar. effusion.
• Heme: DIC,

• GI bleeding: PUD, erosive gastritis, hemorrhagic pancreatic necrosis iwth erosion into major bl.vessels, portal vein thrombosis, variceal hemorrhage.
• Renal: oliguria, azotemia, renal artery +/or vein thrombosis.
• Metab: hyperglycemia, hypertriglyceridemia, hypocalcemia, encephalopathy, sudden blindness (Purtscher's retinopathy from retinal artery occlusion).
• CNS: psychosis, fat emboli.
• Fat necrosis: subc. erythematous nodules, bone, misc. )mediastinum, nervous system).

RX of acute pancreatitis:

• In 85-90% of pts, the disease is self-limited & subsides spontaneously,usually within 3-7 days after Rx is instituted.
• Conventional med. Rx include (1) analgesics for pain, (2) IV fluid & lytes to maintain normal intravascular volume, (3) no oral alimentation, PIN as needed & (4) NG suction prn to decrease gastrin release from the stomach & prevent gastric contents from entering the duodenum.
• Appropriate antibiotic Rx of established infection is quite important in secondary infection of necrotic pancreatitis (phlegm, abscess, pseudocyst) or in cholangitis.

Contrast-Enhanced CT scan provides valuable information on the severity & prognosis of acute pancreatitis:

Grade of Acute Pancreatitis:

• Normal pancrease 0 point
• Pancreatic enlargment alone 1 point
• Inflammation compared with pancreas/peripancreatic fat 2 points
• One peripancreatic fluid collection 3 points
• Two or more fluid collections 4 points

Degree of Pancreatic Necrosis:

• No necrosis 0 point
• Necrosis of one-third of pancreas 2 points
• Necrosis of one-half of pancreas 4 points
• Necrosis > one-half of pancreas 6 points

Pts with CT severity index scores of 3-6 are unlikely to have prolonged pancreatitis or a serious cojplication is negligible. Pts with scores of 7-10 had a 92% morbidity & 17% mortality. A CE-CT scan is indicated in pts with 3 or more Ranson's signs, in all seriously ill pts, & in pts who show evidence of clnical deterioration.

Laparotomy with adequate drainage & removal of necrotic tissue should be considered if conventional Rx does not halt the pt's deterioration.

Pts with severe fallstone-induced pancreatitis may improve dramatically if paipillotomy is carried out within the first 36-72 h of the attack.

Pancreatic Phlegmon

It should be suspected if abd. pain, fever, leukocytosis, & hyperamylasemia persist for >5days & esp. if an abd. mass is also present. Occasionally, extensive necrosis develops in phlegmons & require incision & drainage, esp. if infected. Phlegmons also may be secondarily infected, resulting in abscess in 10% of pts. The early dx of pancreatic infection can be accomplished by CT-guided needle aspiration.

The characteristic signs of abscess are fever, leukocytosis, ileus, and rapid deterioration in a pt initially recovering from pancreatitis. Drainage of pancreatic abscesses by nonsurgical percutaneous catheter techniques under CT-guidance has 50-60% resolution rate. Accordingly, laparotomy with radical sump drainage & possibly resection of necrotic tissue is usually required because the mortality rate for undrained pancreatic abscess approaches 100%. Multiple abscesses are common.

Pancreatic Pseudocysts are collections of tissue, fluid, debris, pancreatic enzymes, & blood which develop over a period of 1-4 weeks in approximately 15% of pts. They do not have epithelial lining. Abd. pain is the usual presenting complaint. a palpable, tender mass may be present. The serum amylase is elevated in 75% of pts. Sonogram is reliable in detecting pseudocysts. CT scan complements the use of sonogram in the dx of pseudocyst, esp. when it is infected. They resolved in 25-40% of pts. Those >5cm & that persist for >6weeks rarely disappear.

The complications of pseudocysts are: pain caused by expansion of the lesion & pressure on other viscera, rupture with peritonitis & shock, hemorrhage (triad of findings: increase in mass size, localized bruit over the mass, & a sudden decrease in Hgb & Hct without obvious signs of external blood loss), & abscess.

Sterile chronic pseudocysts can be treated safely with single or repeated needle aspiration or more prolonged catheter drainage with 45-75% success rate. Pts not responding to drainage require surgical Rx with internal or external drainage of the cyst.

Pseudoaneurysms develop in up to 10% of pts with acute pancreatitis, involving splenic artery, followed by the inferior & superior pancreatic duodenal arteries. The dx should be suspected in pts with pancreatitis who develop either UGI bleeding without an obvious cause in in whom a contrast-enhanced lesion is demonstrated within or adjacent to a suspected psudocyst as determined by thin-cut CT scan. Arteriography is ncecessary to confirm the dx.

Pancreatic Ascites & Pancreatic Pleural Effusions

Pancreatic ascites is usually due to disruption of the main pancreatic duct, or a leaking pseudocyst. The dx is suggested by elevated serum amylase, elevated ascitic fluid amylase & albumin >3.0 g/dL. In addition, ERCP will often demonstrate passage of contrast material from a major pancreatic duct or a pseudocyst into the peritoneal cavity. The diff-dx include intraperitoneal carcinomatosis, TB peritonitis, constrictive pericarditis, & Budd-Chiari syndrome.

Rx of pancreatic ascites inludes NG suction & PIN., paracentesis. Octreotide which inhibits pancreatic secretion is also useful in pancreatic ascites & pleural effusion. If ascites continues to recur after 2-3 weeks of med. Rx, surgery following pancreatography to define the anatomyh of the abnormal duct should be done.