Pancreatitis & Pancreatic Cancer for the USMLE Step 1
Pancreatitis & Pancreatic Cancer for the USMLE Step 1
Overview
- Pancreatitis is the inflammation of the pancreas, classified into:
- Acute pancreatitis: Reversible pancreatic inflammation.
- Chronic pancreatitis: Irreversible damage with fibrosis and loss of function.
Acute Pancreatitis
Etiology
- Most common causes include:
- Gallstones: Cause biliary obstruction.
- Alcohol abuse: Directly toxic to pancreatic cells.
- Other causes: Hypertriglyceridemia, hypercalcemia, drugs (e.g., thiazides), and post-ERCP.
Pathophysiology
- Premature activation of pancreatic enzymes leads to autodigestion of pancreatic tissue, causing inflammation and possible necrosis.
Clinical Presentation
- Severe epigastric pain: Radiates to the back, worsened by lying flat.
- Nausea and vomiting.
- Signs of severe disease include Cullen’s sign (periumbilical ecchymosis) and Grey Turner’s sign (flank ecchymosis).
Diagnosis
- Requires 2 of 3 criteria:
- Epigastric pain.
- Serum lipase or amylase >3 times normal (lipase is more specific).
- Imaging: CT or ultrasound showing pancreatic inflammation.
- CT scan with contrast: Identifies complications like necrosis or pseudocyst formation.
Management
- Supportive care: IV fluids, pain control, and bowel rest (NPO).
- ERCP: Indicated if gallstones are involved or for biliary obstruction.
- Antibiotics: Only for infected necrosis, not routine.
Chronic Pancreatitis
Etiology
- Most common causes:
- Alcohol abuse.
- Cystic fibrosis in children.
- Pathophysiology involves progressive fibrosis and destruction of the pancreas.
Clinical Presentation
- Chronic epigastric pain, often worsened by eating.
- Pancreatic insufficiency: Results in steatorrhea (fat malabsorption) and diabetes mellitus (loss of endocrine function).
Diagnosis
- CT scan: Shows calcifications, atrophy, and ductal dilation.
- Fecal elastase: Marker of exocrine insufficiency.
Management
- Pancreatic enzyme replacement for steatorrhea.
- Pain management with NSAIDs or opioids.
- Surgery is reserved for complications or intractable pain.
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Pancreatic Cancer
Overview
- Pancreatic adenocarcinoma is the most common type of pancreatic cancer, with a poor prognosis due to late detection.
Risk Factors
- Smoking and chronic pancreatitis are the major risk factors.
- Genetic syndromes: BRCA1/BRCA2 mutations, Lynch syndrome.
- Obesity and diabetes mellitus also increase risk.
Clinical Presentation
- Painless jaundice: Caused by obstruction of the common bile duct.
- Weight loss, anorexia, and fatigue.
- Epigastric pain: Often radiates to the back.
- New-onset diabetes in an older adult can be a sign of pancreatic cancer.
Diagnosis
- CT scan with contrast: Preferred initial test to identify masses and assess for metastasis.
- Endoscopic ultrasound (EUS): Used for biopsy and staging.
- CA 19-9: A tumor marker that aids in diagnosis and monitoring but is not specific.
Management
- Whipple procedure (pancreaticoduodenectomy): The treatment for resectable tumors in the pancreatic head.
- Chemotherapy: Gemcitabine or FOLFIRINOX is used in advanced or metastatic disease.
- Palliative care: Includes biliary stenting for jaundice and pain management.
Key Points
- Acute pancreatitis is most commonly caused by gallstones and alcohol, presenting with severe epigastric pain and elevated lipase levels.
- Chronic pancreatitis leads to fibrosis and pancreatic insufficiency, causing steatorrhea and diabetes.
- Pancreatic cancer presents with painless jaundice, weight loss, and abdominal pain, often with a poor prognosis.
- CT scan is the key diagnostic tool for both pancreatitis and pancreatic cancer.
- Surgical resection (Whipple procedure) is the only curative option for pancreatic cancer, but many patients present with unresectable disease.