Study Notes for Pancreatitis

Pancreatitis Study Notes

Introduction

  • The pancreas is a long flattened gland with two main functions:

    • Vital part of the digestive system

    • Critical controller of blood sugar levels

Anatomy and Function of Pancreas

  • Pancreatic Fluid Composition: Contains digestive enzymes (e.g., bicarbonate, amylase, lipase)

  • Types of Pancreatic Tissue:

    • Endocrine

    • Exocrine

  • Cell Types:

    • Acinar cells secrete inactive digestive enzymes (zymogens)

    • Pancreatic islets contain:

    • Alpha cells (produce glucagon)

    • Beta cells (produce insulin)

    • Delta cells (produce somatostatin)

Digestive Functions of the Pancreas

  • Cells in each acinus are filled with granules containing digestive enzymes which are secreted in an inactive form termed zymogens.

  • Zymogen activation:

    • Enterokinase in the duodenum activates:

    • Trypsinogen to Trypsin

    • Prolipase to Lipase

    • Amylase is activated in a similar manner.

  • Hormonal Influence on Secretion:

    • Secretin, cholecystokinin, and vasoactive intestinal polypeptide influence enzyme secretion.

    • Secretin and vasoactive intestinal polypeptide are released from S cells in response to gastric acid; they increase enzyme and bicarbonate secretion.

    • Cholecystokinin is released from I cells in response to long-chain fatty acids; it enhances secretin effects and induces gallbladder contraction.

Pancreatitis

  • Definition: Inflammation of the pancreas, can be acute or chronic.

  • Severity: Mild cases improve with treatment; severe cases may lead to life-threatening complications.

Acute Pancreatitis

Epidemiology

  • Condition Characteristics:

    • Inflammatory condition causing local injury, systemic inflammatory response syndrome, and organ failure.

  • Common gastrointestinal condition associated with significant suffering, hospitalizations, and healthcare costs.

  • Statistics:

    • 5% case fatality rate (higher in severe cases)

    • Increased incidence with age; more common in males and African Americans.

Etiology

  • Factors include:

    • Alcohol abuse (males > females)

    • Gallstones (females > males)

    • Hypertriglyceridemia (> 1000 mg/dL)

    • Post-endoscopic retrograde cholangiopancreatography (ERCP)

    • Trauma

    • Idiopathic causes

    • Ischemia

    • Drug-induced harm: Toxins like scorpion venom, medications such as valproic acid, estrogen, ACE inhibitors, tetracyclines, furosemide/thiazides, Exenatide.

Risk Factors for Drug-induced Pancreatitis

  • Hyperparathyroidism

  • Thyrotoxicosis

  • Malignancy

  • Vitamin D overdose

  • Hypercalcemia

  • AIDS and immunosuppression

  • Systemic Lupus Erythematosus (SLE)

  • Crohn’s disease and other autoimmune diseases

  • Concurrent use of estrogen

  • Hyperlipidemia

Alcoholic Pancreatitis

  • Alcohol affects pancreatic acinar cells and can cause:

    • Duct obstruction

    • Premature enzyme activation

    • Abnormal blood flow and sphincter motility issues

    • Increased secretion of cholecystokinin and secretin

  • Most commonly affects middle-aged individuals (incidence peaks at 45-55 years).

Gallstones-induced Pancreatitis

  • Gallstones may obstruct the pancreatic duct after passing into the common bile duct, causing pancreatic fluid accumulation and inflammation.

  • More common in women than men and across all age groups, especially older patients.

Signs and Symptoms of Acute Pancreatitis

  • Common Symptoms:

    • Acute abdominal pain:

    • Location: Epigastric

    • Character: Dull, steady, sudden onset, increasing severity

    • Radiation: May radiate to the back (50% of patients)

    • Nausea and vomiting

    • Anorexia

    • Diarrhea

    • Low-grade fever

Physical Examination Findings

  • General Signs:

    • Tachycardia

    • Abdominal tenderness/distention

    • Diminished bowel sounds (indicating ileus)

  • Severe Disease Indicators:

    • Fever

    • Hypotension

    • Tachypnea and crackles

    • Pale and diaphoretic

  • Warning Signs of Retroperitoneal Bleeding:

    • Cullen’s sign

    • Grey-Turner’s sign

  • Signs of Underlying Causes:

    • Hepatomegaly → Alcoholic pancreatitis

    • Scleral icterus or jaundice → Choledocholithiasis

    • Muscle spasms → Hypercalcemia

    • Xanthomas → Hypertriglyceridemia

Laboratory Evaluation

  • Key Tests:

    • Serum amylase ↑

    • Serum lipase ↑ (more specific)

    • ALT & bilirubin ↑ in gallstones-induced pancreatitis

    • BUN ↑ in severe disease due to third spacing

    • LDH and hematocrit ↑ in severe disease

    • CRP > 150 mg/L at 48 hours indicates risk of severe pancreatitis and organ failure

    • Triglyceride levels ↑ in hypertriglyceridemia

Diagnostic Criteria

  • Diagnosis of acute pancreatitis requires at least two of the following:

    • Acute onset of epigastric abdominal pain

    • Serum amylase or lipase > 3 times the upper limit of normal

    • Characteristic imaging findings:

    • Pseudocysts

    • Pancreatic inflammation

    • Pancreatic edema

    • Gallstones

    • Common bile duct dilation

    • Pancreatic necrosis

Prognostic Evaluation: Ranson’s Criteria

  • Widely used for assessing risk in acute pancreatitis.

  • Disadvantage: Takes 48 hours to complete the assessment.

Treatment Goals

  • Resolve:

    • Nausea, vomiting, abdominal pain, and fever

    • Normalization of serum amylase, lipase, and white blood cell count

    • Resolution of abscess, pseudocyst, or fluid collection (measured by CT scan)

Acute Management Strategies

  • Close monitoring of vital signs and fluid balance

  • Analgesia (mostly opioids)

  • Calcium gluconate for hypocalcemia

  • H2 receptor antagonist to reduce pancreatic juice secretion

  • Aggressive IV fluid resuscitation

  • Nil by mouth until tolerated (initial bowel rest)

  • Surgery if required

  • Early Nutritional Support:

    • Can begin as early as 24 hours if pain decreases

    • Linked to reduced morbidity

    • Low-residue, low-fat diet for mild cases as soon as tolerated

    • Enteral nutrition for severe cases if oral intake is not tolerated (start within 72 hours)

Treating the Etiology

  • Endoscopic Retrograde Cholangiopancreatography (ERCP)

  • Cholecystectomy after pancreatitis recovery for gallstones

  • Patient education on abstaining from alcohol

  • Goal triglyceride level < 500 mg/dL for hypertriglyceridemia:

    • IV insulin + dextrose with close glucose monitoring

    • Apheresis in certain severe cases (SIRS, hypocalcemia, multi-organ dysfunction)

Complications of Acute Pancreatitis

  • Infected pancreatic necrosis or abscess

  • Pseudocyst

  • Abdominal compartment syndrome

  • Pseudoaneurysm

  • Splanchnic venous thrombosis

Infected Pancreatic Necrosis or Abscess

  • Approximately ⅓ develop infection, fever, or increasing leukocytosis

  • Causative organisms: E. coli, Pseudomonas, Klebsiella, Enterococcus

  • Treatment:

    • Antibiotics:

    • Carbapenems

    • Fluoroquinolones with metronidazole

    • Cefepime or ceftazidime with metronidazole

    • Image-guided aspiration and drainage

    • Surgical necrosectomy when less invasive measures fail

Pseudocyst

  • An encapsulated fluid collection with a well-defined inflammatory wall that occurs days to weeks after pancreatitis onset

  • Most are asymptomatic, but symptoms can include abdominal pain, early satiety, and jaundice

  • Diagnosis: US, CT, or MRI

  • Treatment Options:

    • Observation for minimal/no symptoms

    • Drainage for symptomatic or infected pseudocysts (wall maturation takes weeks)

Abdominal Compartment Syndrome

  • Definition: Sustained intra-abdominal pressure leading to organ failure due to edema and fluid resuscitation

  • Presenting symptoms:

    • Tense, distended, painful abdomen

    • Progressive oliguria

    • Hemodynamic instability

    • Pulmonary decompensation

  • Diagnosis: Measuring intra-abdominal pressure

  • Treatment:

    • Hemodynamic support

    • Pain control

    • Surgical decompression

Pseudoaneurysm

  • Definition: Unexplained gastrointestinal bleeding and anemia due to erosion of gastroduodenal or splenic artery into a pseudocyst

  • Rare but life-threatening

  • Diagnosis by angiography and treatment via embolization

Splanchnic Venous Thrombosis

  • Thrombosis affecting splenic, portal, or superior mesenteric veins

  • Often found incidentally via imaging

  • Treatment:

    • Address underlying pancreatitis

    • Anticoagulation if hepatic function or bowel perfusion is compromised

Chronic Pancreatitis

Definition

  • Defined as a persistent, chronic, irreversible inflammation of the pancreas characterized by morphological changes.

  • Leads to chronic abdominal pain and impairment of endocrine and exocrine functions.

  • Clinically presents with chronic abdominal pain, normal/mildly elevated pancreatic enzyme levels, and can lead to diabetes mellitus and steatorrhea due to loss of pancreatic function.

Pathophysiology

  • Fibrogenesis: Response to pancreatic injury involving growth factors, cytokines, chemokines, leading to extracellular matrix deposition and fibroblast proliferation.

  • Transforming growth factor beta (TGF-beta) is critical in stimulating mesenchymal cell growth and matrix protein synthesis following pancreatic injury.

Etiology

  • Causes include:

    • Intraductal plugging and obstruction (e.g., ethanol abuse, stones, tumors)

    • Direct toxins and metabolites

    • Oxidative stress

    • Necrosis-fibrosis due to recurrent acute pancreatitis that heals with fibrosis

    • Ischemia

    • Autoimmune diseases

Clinical Presentation

  • Pain: Starts in the epigastrium, can be sharp or dull, radiates to the back, not relieved by antacids, can be provoked by alcohol or fatty meals.

  • Symptoms may include:

    • Nausea and vomiting

    • Food avoidance

    • Weight loss

    • Steatorrhea

    • GI bleeding

    • Icterus or cholangitis due to common bile duct obstruction

Complications

  • Common Complications:

    • Pseudocyst formation

    • Mechanical obstruction of the duodenum and common bile duct

  • Less Frequent Complications:

    • Pancreatic ascites or pleural effusion

    • Splenic vein thrombosis with portal hypertension

    • Pseudoaneurysm formation of the splenic artery

Management

  • Goals of Medical Treatment:

    1. Modify behaviors that may worsen the condition

    2. Enable the pancreas to heal and reduce abdominal pain

    3. Determine and alleviate the cause of abdominal pain

    4. Restore digestion and absorption to normal

    5. Diagnose and treat endocrine insufficiency

Symptomatic Treatment

  • Essential: Abstinence from alcohol

  • Pharmacologic Interventions:

    • Long-acting morphine, oxycodone, or transdermal fentanyl for pain

    • Antiemetics:

    • Oral ondansetron, prochlorperazine, or promethazine as needed

Nutritional Support

  • Goals:

    • Maximize caloric intake while minimizing steatorrhea

    • Frequent smaller meals, possible fat-soluble vitamin supplementation

    • Enteral or parenteral nutrition in severe cases, as needed

    • Use of Pancreatic Enzyme Replacement Therapy (PERT):

    • Take immediately before meals and snacks to assist in digestion/absorption

    • Administer with antacids or PPIs for effectiveness in alkaline conditions

Conclusion

  • Ongoing management of both acute and chronic pancreatitis focuses on addressing underlying causes, optimizing nutrition, and symptomatic relief to improve patient quality of life.