Pancreatitis & Pancreatic Cancer for the ABIM Exam
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Pancreatitis & Pancreatitis for the American Board of Internal Medicine Exam
Overview
- Pancreatitis is an inflammation of the pancreas, classified into acute and chronic forms.
- Acute pancreatitis is a reversible condition, while chronic pancreatitis leads to irreversible damage and fibrosis of the pancreas.
Acute Pancreatitis
Etiology
- The most common causes of acute pancreatitis are:
- Gallstones: Cause biliary obstruction and pancreatic ductal injury.
- Alcohol abuse: Direct toxic effect on pancreatic acinar cells.
- Other causes include:
- Hypertriglyceridemia (>1000 mg/dL).
- Hypercalcemia, trauma, medications (e.g., thiazides, azathioprine), infections (e.g., mumps), and post-ERCP.
Pathophysiology
- Pancreatic enzymes (trypsin) become activated prematurely within the pancreas, leading to autodigestion, inflammation, and necrosis.
- Severe cases involve systemic inflammatory response syndrome (SIRS), leading to multi-organ failure.
Clinical Presentation
- Epigastric pain: Severe, constant, radiating to the back.
- Nausea and vomiting.
- Physical exam:
- Epigastric tenderness.
- Signs of hemorrhagic pancreatitis: Cullen’s sign (periumbilical ecchymosis) and Grey Turner’s sign (flank ecchymosis).
Diagnosis
- Requires 2 out of 3 criteria:
- Characteristic abdominal pain.
- Serum amylase or lipase >3 times the upper limit of normal (lipase is more specific).
- Imaging findings: CT or MRI showing pancreatic inflammation or necrosis.
- CT abdomen with contrast: Identifies pancreatic necrosis, fluid collections, and pseudocysts.
- Ultrasound: First-line for evaluating gallstone-induced pancreatitis.
Complications
- Local: Necrosis, pancreatic pseudocyst, abscess.
- Systemic: Acute respiratory distress syndrome (ARDS), acute kidney injury, shock, and multi-organ failure.
Management
- Supportive care:
- IV fluids: Aggressive hydration with isotonic crystalloid (e.g., lactated Ringer’s).
- Pain control: Opioids are commonly used.
- NPO (nil per os): Allows the pancreas to rest.
- Antibiotics: Not routinely used unless there is evidence of infected pancreatic necrosis.
- Gallstone pancreatitis: Requires cholecystectomy after recovery to prevent recurrence.
- ERCP: Indicated for cholangitis or persistent biliary obstruction.
Chronic Pancreatitis
Etiology
- Chronic pancreatitis is primarily caused by:
- Alcohol abuse (most common in adults).
- Cystic fibrosis (most common in children).
- Other causes: Autoimmune pancreatitis, recurrent acute pancreatitis, and hereditary factors.
Pathophysiology
- Chronic inflammation leads to fibrosis, ductal obstruction, and progressive loss of pancreatic exocrine and endocrine function.
Clinical Presentation
- Chronic epigastric pain: Often radiates to the back, worsened by eating, and may be relieved by leaning forward.
- Pancreatic insufficiency: Results in steatorrhea, fat-soluble vitamin deficiencies, and diabetes mellitus due to loss of islet cell function.
- Weight loss: Due to malabsorption.
Diagnosis
- Imaging:
- CT scan or MRI: Show calcifications, pancreatic atrophy, or ductal dilation.
- Endoscopic ultrasound (EUS): Can detect early changes.
- Fecal elastase: A non-invasive marker of exocrine pancreatic insufficiency.
Complications
- Pancreatic pseudocyst: Fluid collection that may become infected.
- Pancreatic cancer: Chronic inflammation increases the risk.
Management
- Pain control: Acetaminophen or NSAIDs, opioids for refractory pain.
- Pancreatic enzyme supplementation: For malabsorption and steatorrhea.
- Dietary modification: Small, frequent meals low in fat.
- Surgical intervention: For refractory pain or complications (e.g., pseudocysts, ductal obstruction).
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Pancreatic Cancer
Overview
- Pancreatic cancer is primarily pancreatic adenocarcinoma, arising from the exocrine pancreas. It is associated with a poor prognosis due to late-stage diagnosis.
Risk Factors
- Smoking: The most established risk factor.
- Chronic pancreatitis: Increases the risk, particularly with hereditary causes.
- Diabetes mellitus: Particularly new-onset diabetes in older adults.
- Genetic syndromes: BRCA1/BRCA2 mutations, Lynch syndrome, familial pancreatitis.
- Obesity and a diet high in fat.
Clinical Presentation
- Painless jaundice: Due to obstruction of the common bile duct by a tumor in the pancreatic head.
- Weight loss, anorexia, fatigue.
- Abdominal pain: Vague and epigastric, often radiating to the back.
- New-onset diabetes: Particularly in older adults without prior risk factors.
- Courvoisier’s sign: Palpable, non-tender gallbladder in the presence of jaundice.
Diagnosis
- CT scan with contrast: The preferred initial test to evaluate the pancreas, detect masses, and assess for metastasis.
- Endoscopic ultrasound (EUS): Used for obtaining biopsies and staging.
- CA 19-9: A tumor marker that can aid in diagnosis and monitor treatment response but is not specific for pancreatic cancer.
- ERCP: Can be used to relieve biliary obstruction with stenting.
Staging and Prognosis
- Staging is based on the TNM system (tumor size, nodal involvement, metastasis).
- Resectable: Tumors confined to the pancreas with no major vessel involvement.
- Locally advanced: Tumor involvement of major vessels or adjacent organs without distant metastases.
- Metastatic: Spread to distant organs such as the liver, lungs, or peritoneum.
- The prognosis is poor, with a 5-year survival rate of around 10% due to the advanced stage at diagnosis.
Management
Surgical
- Pancreaticoduodenectomy (Whipple procedure): The treatment of choice for tumors in the pancreatic head that are resectable.
- Distal pancreatectomy: For tumors in the body or tail of the pancreas.
- Surgery is only possible in about 20% of cases due to the late presentation of the disease.
Chemotherapy
- Gemcitabine-based regimens are used for both resectable and unresectable disease.
- FOLFIRINOX (combination of 5-FU, irinotecan, leucovorin, and oxaliplatin) may be used in patients with good performance status.
Palliative Care
- Biliary stenting: For relief of jaundice in non-resectable patients.
- Pain management: Often requires opioids due to the severity of cancer-related pain.
- Nutritional support: Patients often suffer from cachexia and require dietary interventions.
Key Points
- Acute pancreatitis is most commonly caused by gallstones and alcohol abuse, presenting with epigastric pain and elevated lipase levels.
- Chronic pancreatitis leads to irreversible pancreatic damage, resulting in steatorrhea, diabetes, and chronic pain.
- Pancreatic cancer often presents late with painless jaundice, weight loss, and abdominal pain, leading to a poor prognosis.
- CT scan is the primary diagnostic tool for both pancreatitis and pancreatic cancer.
- Surgical resection (Whipple procedure) is the only curative treatment for pancreatic cancer but is feasible in only a minority of patients due to late-stage detection.