Acute pancreatitis

Background

Pancreatic anatomy

• Acute inflammatory process that may involve surrounding tissue and remote organ systems
• Disease can range from mild inflammation to severe necrosis and multi-organ failure

Etiology

• Gallstones (including microlithiasis) - 35-40% of cases in most parts of the world
• Alcohol (acute and chronic consumption) - 30% of cases in the US
• Hypertriglyceridemia
• ERCP
  • Most common post-ERCP complication, usually from mechanical injury from instrumentation of the pancreatic duct or hydrostatic injury from contrast injection
• Drugs (Azathioprine, cisplatin, furosemide, tetracycline, thiazides, sulfa, valproate, didanosine, pentamidine, etc)
• Autoimmune disease (SLE, Sjögren, etc)
• Abdominal trauma
• Postoperative complications
• Infection
  • Bacterial: Legionella, Leptospirosis, Mycoplasma, Salmonella
  • Viral: Mumps, coxsackie, CMV, echo, Hep B
  • Parasitic: ascaris, cryptosporidium, toxoplasma
• Hypercalcemia
• Hyperparathyroidism
• Ischemia
• Posterior penetrating ulcer
• Scorpion venom (Caused by the genre Tityus and Leiurus which are distributed in Central/South America and North/East Africa, respectively
• Organophosphate insecticide
• Pancreatic or ampullary tumor
• Pancreas divisum with ductular narrowing on pancreatogram
• Oddi sphincter dysfunction
• Idiopathic (15-20% of cases)

Clinical Features

• Pain is the most common symptom and is often characterized by:
  • Persistent
  • Localizes to epigastric area, around waist, RUQ, or occasionally LUQ
  • Radiates to back
  • The onset may be less abrupt and the pain poorly localized
• Nausea/vomiting noted in most
• Abdominal distention is frequent complaint
• Cullen sign (ecchymosis of periumbilical region) - intrabdominal hemorrhage
• Turner sign (ecchymosis of flanks) - retroperitoneal hemorrhage
• Pulmonary Findings
  • Hypoxemia, ARDS, tachypnea
  • Indicates severe pancreatitis
    • Diaphragmatic inflammation, pancreatico-pleural fistula

Differential Diagnosis

Epigastric Pain

• Gastroesophageal reflux disease (GERD)
• Peptic ulcer disease with or without perforation
  • Zollinger-Ellison syndrome
• Gastritis
• Pancreatitis
• Gallbladder disease
  • Acute cholecystitis
  • Cholangitis
  • Symptomatic cholelithiasis
  • Acalculous cholecystitis
• Myocardial Ischemia
• Splenic Infarctionenlargement/rupture/aneurysm
• Pericarditis/Myocarditis
• Aortic dissection
• Hepatitis
• Pyelonephritis
• Pneumonia
• Pyogenic liver abscess
• Fitz-Hugh-Curtis Syndrome
• Hepatomegaly due to CHF
• Bowel obstruction
• SMA syndrome
• Pulmonary embolism
• Bezoar
• Ingested foreign body

Diffuse Abdominal pain

• Abdominal aortic aneurysm
  • Aortocaval fistula
• Acute gastroenteritis
• Aortoenteric fisulta
• Appendicitis (early)
• Bowel obstruction
  • Large bowel obstruction
    • Ogilvie's syndrome
  • Small bowel obstruction
  • Malignant bowel obstruction
• Bowel perforation
• Diabetic ketoacidosis
• Gastroparesis
• Hernia
• Hypercalcemia
• Inflammatory bowel disease
• Mesenteric ischemia
  • Mesenteric vein thrombosis
• Pancreatitis
• Peritonitis
• Sickle cell crisis
• Spontaneous bacterial peritonitis
• Volvulus

Evaluation

Ultrasound of acute pancreatitis with non-homogeneous, hypoechoic area in the body/tail projection attesting to extensive necrosis.

Complicated acute pancreatitis with large abscess in the projection of the tail.

Acute exudative pancreatitis on CT scan

Pancreattis with calcified pancreatic duct stones with some free intra-abdominal fluid

Work-Up

• Lipase
  • Amylase is both less sensitive and specific (sensitivity: 67-100%; specificity: 85-98%)
• CBC
• Chemistry
• LFTs
• ?Lactate
• ?Triglyceride

Ultrasound

• Edematous, swollen pancreas
• Gallstones
• Pseudocyst / pancreatic abscess

CT with IV contrast

• Little utility early on in disease and unlikely to affect the management of patients with acute pancreatitis during the first week of the illness
• Should be reserved for patients with persisting organ failure, severe pain and signs of sepsis

Diagnosis

Two of the following:

• Characteristic abdominal pain
• Lipase level >3x upper limit of normal
  • Sensitivity 82-100%, specificity 82-100%
  • Negative lipase does not exclude pancreatitis in chronic/recurrent disease
  • Absolute value not associated with prognosis or severity
• Characteristic findings on ultrasound or CT

Management

The core treatment involves supportive care to rest the pancreas. This can be achieved mainly through diet control.

Medical

Diet

• NPO (clears is probably ok for mild/moderate cases)
• When restarting diet, eat small, low-fat meals and gradually advance over 3 to 6 days as tolerated
• In patients with mild pancreatitis who are tolerating POs and can most likely be discharged. Instructions regarding a light diet and avoidance of alcohol is necessary

IV Fluids

• Volume resuscitation and constant monitoring of fluid status is important due to the risk of profound hypovolemia
  • Maintain urine output at 0.5 mL/kg

Analgesia and Antiemetics

• For example:
  • Dilaudid 1mg or morphine 4mg IV PRN
  • Zofran 4mg IV PRN

Electrolyte and Other Molecular Management

• Monitor for hypocalcemia and treat if symptomatic
• Monitor for development of hypoglycemia or hyperglycemia
• Consider albumin replacement if level <2g/dL
• See hypertriglyceridemia for management of high triglycerides

Antibiotics

Antibiotic use is often controversial and generally only required if there are obvious signs or sources of infection. Prophylactic use is not necessary

• Only indicated for necrosis, abscess, or infected pseudocyst / peripancreatic fluid
• Imipenem-cilastatin, meropenem, or (fluoroquinolone + metronidazole)

Procedural/Surgical

Bowel Decompression

• Consider placement of an NG tube only if SBO or ileus is present and symptomatic

ERCP

• Indicated for patients with gallstone pancreatitis with retained CBD stone or cholangitis (recommended within 24 hours)
• Alternative option for patients with gallstone pancreatitis who are poor operative candidates for cholecystectomy

Cholecystectomy

• Indicated for patients with biliary pancreatitis. Patients will generally will benefit from early cholecystectomy, as soon as the patient has recovered, preferably within the same hospital admission.

Fluid Collection Drainage

• Symptomatic walled-off pancreatic fluid collections should be evaluated for a drainage procedure.

Disposition

Discharge

• Mild case + no biliary disease + no systemic complication + tolerating clears
• Patients can be discharged when oral analgesics control their pain

Admit

• All other patients

Complications

Local

• Pancreatic necrosis
• Pancreatic pseudocyst / abscess
• Portal vein thrombosis
• Abdominal compartment syndrome
• Abdominal pseudoaneurysm
• Intra Abdominal hemorrhage

Systemic

• Cardiac dysfunction
• Renal failure
• Respiratory failure
• Shock
• Hypocalcemia (due to sequestration in necrotic fat)
• Hyperglycemia
• Pleural effusion with high amylase

Prognosis

APACHE-II

• Highest sensitivity and specificity in distinguishing mild from severe pancreatitis
• Can be used to estimate the risk of ICU mortality based on worse set of labs during a patient's first 24hrs

CT Severity Index

A extension of the Balthazar score with stratification of severity based on score.

• Balthazar grading of pancreatitis

A = normal pancreas - 0

B = enlargement of pancreas - 1

C = inflammatory changes in pancreas and peripancreatic fat - 2

D = ill defined single fluid collection - 3

E = two or more poorly defined fluid collections - 4

• Pancreatic necrosis

none - 0

less than/equal to 30% - 2

> 30-50 % - 4

> 50% - 6

• The maximum score that can be obtained is 10.

0-3: mild

4-6: moderate

7-10: severe

Ranson criteria

• Consist of 11 parameters. Five of the factors are assessed at admission, and six of the factors are assessed during the next 48 hours.
• Score of 3 or more indicates severe acute pancreatitis.

On admission

1. Age > 55
2. WBC > 16,000
3. Blood glucose >200mg/dL
4. Lactate dehydrogenase >350 U/L
5. Aspartate aminotransferase (AST) >250 U/L

48 hours

1. Hematocrit fall by > 10%
2. BUN increase by >5mg/dL
3. Serum Calcium <8mg/dL
4. pO2 < 60mmHg
5. Base deficit >4 MEq/L
6. Fluid Sequestation > 6L

BISAP

• Bedside Index for Severity in Acute Pancreatitis
• Decreased sensitivity, but outperforms in specificity as compared to Ranson and APACHE II
• Clinically more manageable to obtain, especially in the ED setting
  • BUN > 25 mg/dL
  • Impaired mental status, defined as disorientation, lethargy, somnolence
  • ≥2 SIRS Criteria
  • Age > 60 years
  • Pleural effusion
• Interpretation
  • Score of 0-2 had mortality < 2%
  • Score of 3-4 has mortality > 15%
  • Score of 5 has 22% mortality

See Also

• Pancreatitis Guidelines
• Chronic pancreatitis

External Links

• MDCalc - Ranson's Criteria
• MDCalc - Apache II Score
• MDCalc - BISAP Score for Pancreatitis Mortality