Infected Pancreatic Pseudocyst 12/10/2018

Leah presented a case of a young/early middle age man (45 years old) with a history of NIDDM2 and two prior episodes of pancreatitis (unclear etiology) presenting with worsening abdominal pain for 2 weeks, with associated nausea and vomiting. His appetite has also been poor for the past 3 months, subjectively losing 120lbs over this time period. For the 2-3 days prior to presentation, he started endorsing fever and chills in addition to worsening abdominal symptoms…

CT AP revealed  a necrotizing pancreatitis with large multilocular thick-walled infected pseudocyst with associated phlegmon and serpiginous fluid. Ultimately the patient likely has chronic pancreatitis complicated by development of pseudocyst and walled-off pancreatic necrosis.

Fortunately he is clinically stable, pending endoscopic necrosectomy for definitive management.


Since acute pancreatitis gets all the rage attention, we will actually spend some time on chronic pancreatitis and discuss potential complications from this condition.

Just a quick recap on acute pancreatitis though…

Acute Pancreatitis

Etiology (I GET SMASHED)

  • Idiopathic, IGG4
  • Gallstones (40%)
  • Ethanol (35%)
  • Trauma
  • Steroids
  • Mumps/Malignancy
  • Autoimmune
  • Scorpion stings
  • Hypercalcemia/Hypertriglyceridemia
  • ERCP (4% of pts who undergo ERCP)
  • Drugs (1%, thiazide, Lasix, HIV meds)

Diagnosis: 2/3 required

  • Acute epigastric pain
  • Elevated lipase or amylase 3x ULN, lipase has much better sensitivity and specificity
  • Imaging findings
    • US: 1st line, rule out GS, obstruction
    • CT with con pancreatic protocol: Indicated when suspecting necrotizing pancreatitis or clinical deterioration

General Management Strategies

  • Volume: aggressive fluid resuscitation, 250-500cc/hr
    • LR has improved outcomes vs NS! Check out this and this article.
  • Pain control
  • Nutrition
    • Mild cases: PO within 48 hours, low fat/low residue diet ok
    • Severe cases with organ damage: Start enteral nutrition via NJ or NG if not eating by 3-4 days, early nutrition improves outcome.
      • Consider TPN if unable to tolerate enteral feeding

Chronic Pancreatitis

Definition: Persistent inflammation of the pancreas, resulting in permanent functional and structural damage.

Epidemiology:

  • 50% from alcoholism, M > F, other risk factors include smoking.
  • A type of pancreatitis is more common in kids and young adults patients from tropical regions, known as tropical pancreatitis.
  • Certain genetic disposition

Pathophysiology: Not well understood but there are theories

  • Chronic pancreatic ductal obstruction due to protein plugs from protein-bicarb imbalance, overtime calcifies, overtime leading to fibrosis
  • Necrosis-fibrosis: Repeated attacks of acute pancreatitis with tissue necrosis. Fibrotic tissues gradually replace the necrotic tissue, leading to development of chronic inflammation.

Presentation

  • Might see the classic triad of abdominal pain, diabetes, and malabsorption.
  • Abdominal pain, chronic and often post-prandial, becomes more continuous as disease progresses.
  • Pancreatic insufficiency: steatorrhea, flatulence, distension, weight loss, fatigue, malnutrition

Complications

  • Pseudocyst (can occur 4 weeks after an acute episode or any time with chronic pancreatitis)
  • Bile duct or duodenal obstruction
  • Pancreatic ascites or pleural effusion due to disruption of the pancreatic duct
  • Splenic vein thrombosis, which can lead to gastric varices (which this patient actually has!)
  • Pseudoaneurysms of arteries
  • Inc risk of pancreatic adenocarcinoma. Those with hereditary or tropical forms are at high risk.

Diagnosis

  • XR: May see calcifications but only in 30% of cases
  • CT: also not sensitive, may be normal early on
  • MRCP is better than CT with IV Secretin
  • EUS: High sensitivity, low spec (low rate of false negative, high rates of false positive)
  • Pancreatic function test, usually indirect i.e. serum trypsinogen, 72H fecal fat after a high fat diet (demonstrates steatorrhea but cannot establish cause of the malabsorption), fecal chymotrypsin and elastase concentration)

Treatment

  • Pain control, often difficult, opiates, TCA, SSRI, gabapentin have been used with mixed results
  • Pancreatic enzyme supplements
  • Diabetes management
  • Smoking cessation, alcohol abstinence
  • Low fat diet (<25g/day) to reduce pancreatic enzyme secretion
  • ERCP

Prognosis: Generally prognosis is pretty poor once you have chronic pancreatitis


Pseudocyst

Epidemiology

  • Usually > 4 weeks after onset of acute episode, 5-16% of cases. Starts out as peripancreatic fluid collection, progresses to pseudocyst beyond 4 weeks.
  • Can occur in both acute and chronic pancreatitis
  • Alcohol use related chronic pancreatitis is associated with highest incidence of pseudocyst formation.

Pathophysiology

  • Encapsulated fluid collection, pseudo because the cyst wall lacks epithelial or endothelial cells.

Presentation

  • Uncomplicated: Asymptomatic to mild pain, can also lead to early satiety, nausea/vomiting
  • Complicated:
    • Gastric outlet or duodenal obstruction
    • Large vessel compression
    • CBD compression
    • Infected pseudocyst (10%)
    • Hemorrhage, UGIB
    • Pancreatico-pleural fistula

Diagnosis

  • CT: Well circumscribed, usually round or oval, homogeneous, all fluid
  • Transcutaneous or endoscopic US
  • ERCP (diagnostic and therapeutic in some cases)

Routine Management

  • Observe, with serial imaging.
    • Likelihood for resolution dec if persistent for  > 6 weeks, e/o chronic pancreatitis, pancreatic duct anomaly is present, or thicker-walled pseudocyst.
  • Supportive Care
    • Pain control
    • Nutritional support
    • PPI

Complication management

  • Drainage is indicated when:
    • Evidence of infection
    • Mass effect causing ductal or duodenal blockage or pancreatic ductal stricture
    • Perforation
  • Endoscopic drainage: Preferred over percutaneous
    • Criteria (higher chance of success if the following are met):
      • Fluid collection has to be mature with well defined wall and mostly liquid,
      • The wall of the cyst must be adherent to stomach or duodenum
      • Fluid collection must be at least 6 cm in size.
  • Drainage approaches:
    • Transmural: Drain out via the stomach or duodenum
    • Transpapillary: Drain via pancreatic duct
  • Contraindication of endoscopic intervention:
    • Pseudoaneurysm, associated with fatal hemorrhage, due to erosions of the gastroduodenal or splenic artery, suspect if drop in H&H or e/o GIB or sudden expansion.

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