Pancreas
Pancreas Review
Pancreas
Anatomy & Physiology
- Parts: head (incl. uncinate), neck, body, tail. Uncinate rests on aorta, behind SMV. PV forms behind neck (SMV + splenic v.).
- Arterial supply: head—superior (off GDA) & inferior (off SMA) pancreaticoduodenal a.’s; body/tail—great, inferior, dorsal pancreatic a.’s (off splenic).
- Venous drainage: into portal system. Lymphatics: celiac & SMA nodes.
- Ductal cells secrete HCO₃⁻; acinar cells secrete digestive enzymes (amylase, lipase, trypsinogen, chymotrypsinogen, carboxypeptidase).
- Exocrine pearls: amylase only pancreatic enzyme secreted in active form; trypsin activates other zymogens.
- Endocrine islet cells: α (glucagon), β (insulin), δ (somatostatin), PP cells (pancreatic polypeptide).
- Blood flow sequence: islets → acini (“islet–acinar portal system”).
- Hormonal control: secretin ↑ HCO₃⁻; CCK ↑ enzymes; ACh ↑ both; somatostatin & glucagon ↓ exocrine function.
- Sphincter of Oddi: CCK & glucagon relax; morphine contracts.
Congenital & Structural Variants
- Annular pancreas: duodenal obstruction (double-bubble). Assoc. with Down syndrome. Tx: duodenojejunostomy or duodenoduodenostomy (± sphincteroplasty). Pancreas not resected.
- Pancreas divisum: failed duct fusion; minor papilla drains majority; can cause pancreatitis from accessory duct stenosis. Dx: ERCP—long minor duct; Tx: ERCP with minor papilla sphincteroplasty ± stent; open sphincteroplasty if endoscopic fails.
- Heterotopic pancreas: often duodenum; usually incidental; resect if symptomatic.
Acute Pancreatitis
- Common causes: gallstones, alcohol (others: hyperTG, hyperCa, ERCP, meds, trauma, scorpion, autoimmune, genetic).
- Dx: 2 of 3—typical pain; lipase ≥3× ULN; imaging findings.
- Initial care: aggressive IV fluids (first 24 h), analgesia, early enteral nutrition. Avoid TPN unless necessary.
- Gallstone pancreatitis: clear duct if cholangitis/obstruction (ERCP). Perform cholecystectomy same admission when clinically improved.
- Abx: not indicated for uncomplicated pancreatitis or sterile necrosis. Use for infected necrosis (fever, leukocytosis, sepsis, gas on CT, positive cultures). Imipenem commonly used.
- Imaging: CT for complications (necrosis, collections). US to assess stones/CBD.
Ranson Criteria (Non-Gallstone; initial & 48 h)
| Time | Criterion |
|---|---|
| Admission | Age >55; WBC >16; Glucose >200; AST >250; LDH >350 |
| At 48 h | Hct ↓ >10%; BUN ↑ >5; Ca <8; PaO₂ <60; Base deficit >4; Fluid sequestration >6 L |
Interpretation: more criteria → higher mortality; use for trend/comparison (not sole management driver).
Revised Atlanta – Post-Pancreatitis Fluid Collections
| <4 weeks | ≥4 weeks | Contents | Wall | Typical term | Notes |
|---|---|---|---|---|---|
| Acute peri-pancreatic fluid collection | Pseudocyst | Fluid only | None → Mature | Pseudocyst | Many resolve; treat if symptomatic, infected, or >6 cm persisting |
| Acute necrotic collection | Walled-off necrosis (WON) | Fluid + necrosis | None → Mature | WON | Intervene if infected or symptomatic |
Necrotizing Pancreatitis & Step-Up
- Infected necrosis suspected with sepsis, persistent organ failure, gas in collection, or positive culture (FNA rarely required if obvious).
- Preferred strategy: delay until demarcation → percutaneous or endoscopic drainage → VARD/endoscopic necrosectomy if needed → open necrosectomy only if failure/instability.
- Nutrition: enteral (post-pyloric if needed).
Infected Necrosis – Step-Up Pathway
| Clinical state | First step | If inadequate | Last resort | Rationale |
|---|---|---|---|---|
| Stable, suspected infection | Broad-spectrum abx; percutaneous or EUS-guided drainage | VARD / endoscopic necrosectomy | Open necrosectomy | Staged source control lowers morbidity/mortality |
Pancreatic Pseudocyst
- More common with chronic pancreatitis; can follow acute.
- Observe ≥6 weeks (many resolve; wall maturation).
- Indications for intervention: symptoms (pain, infection, bleeding, obstruction), size >6 cm persisting, rapid growth.
- Image duct first (ERCP or MRCP).
- Approaches: endoscopic transpapillary stenting (if duct communication), EUS-guided transmural drainage (cystgastro/duodenostomy), or surgical (lap/open) cystgastrostomy.
Pancreatic Fistulas & Pancreatic Pleural Effusion
- Postop fistulas: most close spontaneously (esp. <200 cc/d). Tx: drain, NPO, TPN if needed, octreotide. If persistent → ERCP with sphincterotomy ± pancreatic stent; remove stent after closure.
- Pancreatic pleural effusion/ascites: retroperitoneal leak from duct or pseudocyst; amylase >1000 in fluid. Tx: thoracentesis/drainage + conservative care (NPO, TPN, octreotide). Most close without surgery.
Chronic Pancreatitis
- Etiologies: alcohol (MCC), idiopathic, biliary disease, autoimmune; genetic (PRSS1 in young). ↑ risk pancreatic CA.
- Symptoms: chronic pain → back, weight loss; exocrine malabsorption/steatorrhea; endocrine DM.
- Dx: CT—atrophy, calcifications, ductal dilation (“chain of lakes”); US (duct >4 mm, cysts, atrophy); ERCP/MRCP detail anatomy.
- Medical: pain control, pancreatic enzymes, nutrition; celiac block PRN.
- Surgery—match morphology:
- Dilated duct ≥6 mm, head normal: Puestow (longitudinal pancreaticojejunostomy).
- Head-dominant disease (± duct dilation): Frey (LPJ + limited head “coring”).
- Duodenum-preserving head resection: Beger (end-to-end or side-to-side PJ).
- Distal duct stricture with normal head: Distal pancreatectomy (consider spleen-preserving).
- Minimal-change disease: bilateral thoracoscopic splanchnicectomy for pain; resection/drainage ineffective.
- Complications to know: CBD stricture → hepaticojejunostomy or choledochojejunostomy (exclude malignancy first). Splenic vein thrombosis → isolated gastric varices (bleeding) → splenectomy.
Hereditary Pancreatitis & Insufficiency
- Hereditary pancreatitis: unexplained recurrent pancreatitis <35 y → consider PRSS1 testing; ↑ lifetime pancreatic CA risk.
- Exocrine insufficiency: steatorrhea, weight loss; fecal fat testing. Tx: high-carb/high-protein, low-fat diet + pancreatic enzymes. Endocrine function often preserved until late.
Cystic Neoplasms
- Serous cystadenoma: very low malignant risk; microcystic, central scar; low CEA; resect if symptomatic/growing.
- Mucinous cystic neoplasm (MCN): thick-walled, septated, ovarian-type stroma, body/tail; high CEA; resect all fit patients.
- IPMN: main-duct, branch-duct, or mixed; mucin at fish-mouth papilla pathognomonic for main-duct.
- Cyst fluid: CEA >192 → mucinous; high amylase → duct communication (pseudocyst/IPMN).
IPMN – Fukuoka-Guided Management
| Category | Criteria | Action |
|---|---|---|
| High-risk stigmata | Obstructive jaundice; enhancing solid component/mural nodule ≥5 mm; main duct ≥10 mm | Resect (if fit) |
| Worrisome features | Cyst >3 cm; thickened/enhancing wall; non-enhancing mural nodule; lymphadenopathy; MPD 5–9 mm; abrupt MPD change with distal atrophy; rapid growth; pancreatitis | EUS ± FNA → Resect if concerning EUS/cytology or patient/size risk (e.g., young with >2 cm) |
| Low-risk BD-IPMN | None of the above | Surveillance (interval by size/center protocol) |
Age heuristic: Daughter = solid pseudopapillary, Mother = mucinous, Grandmother = serous.
Pancreatic Neuroendocrine Tumors (PNETs)
- Epidemiology: 1–2% of pancreatic tumors; nonfunctional common (60–90% malignant; often late presentation).
- Localization: multiphase CT/MRI → EUS; somatostatin receptor imaging for most (not great for insulinoma); selective arterial testing if needed.
- Principles: resect locoregional disease; enucleate small benign-appearing tumors away from duct; formal resection for malignant/high-risk; cholecystectomy if long-term somatostatin analogs anticipated.
Functional PNET Snapshot
| Tumor | Key features | Labs/Tests | Typical location | Operation |
|---|---|---|---|---|
| Insulinoma (MC functional) | Whipple triad (fasting hypoglycemia, neuroglycopenia, relief w/ glucose); 90% benign | 72-h fast: glucose <55 with ↑ insulin, C-peptide, proinsulin, low β-hydroxybutyrate; ↑ glucose after glucagon | Throughout pancreas | Enucleation if small/benign; formal resection if malignant |
| Gastrinoma | Refractory PUD ± diarrhea/weight loss; gastrin >1000 with low pH; secretin test ↑ >200 | FSG, secretin test; SSTR imaging/EUS | Gastrinoma triangle (cystic–CBD junction; 2nd–3rd duodenum; neck–body pancreas) | Enucleation if small noninvasive; Whipple if large/invasive; node dissection |
| Glucagonoma | 4 D’s: dermatitis (necrolytic migratory erythema), DM, depression, DVT | Fasting glucagon 1000–5000 | Tail | Distal pancreatectomy + nodes |
| Somatostatinoma | Cholecystitis, DM, steatorrhea; often malignant | SSTR imaging | Head/duodenum | Formal resection + nodes; cholecystectomy |
| VIPoma | WDHA (watery diarrhea, hypokalemia, achlorhydria) | ↑ VIP during diarrhea | Body/tail; extra-pancreatic possible | Formal resection + nodes; cholecystectomy |
Pancreatic Adenocarcinoma
- Risk factors: smoking, heavy alcohol, chronic pancreatitis, ↑BMI, long-standing DM; common mutations KRAS, TP53, CDKN2A, SMAD4. CA 19-9 most useful marker (not screening).
- Imaging/staging: pancreatic-protocol CT; EUS for nodes/vessels; PET/CT selectively for suspected mets; staging laparoscopy in high-risk (borderline-resectable, high CA19-9, large primary, suspicious nodes).
- Biopsy: not required before upfront resection; required before neoadjuvant therapy or for unresectable/metastatic disease.
- Preop biliary drainage: no survival benefit; ↑ wound infections. For upfront surgery, drain only for severe pruritus, cholangitis, or coagulopathy. If neoadjuvant planned and jaundiced → drain. Self-expanding metal stents preferred (patency, easy placement).
- Venous resection: PV/SMV resection/reconstruction acceptable to achieve R0 if reconstructible.
- Adjuvant therapy: everyone after R0/R1 (e.g., modified FOLFIRINOX).
- Borderline-resectable: consider neoadjuvant chemo-RT (tissue via EUS-FNA first).
Resectability Criteria (CT-based)
| Category | Arterial | Venous (PV/SMV) | Distant disease |
|---|---|---|---|
| Resectable | No arterial tumor contact | ≤180° contact without contour irregularity | Absent |
| Borderline-resectable | Contact <180° with SMA or celiac; or common hepatic contact permitting safe resection/recon | Involvement amenable to resection/recon; short-segment occlusion allowed if reconstructible | Absent |
| Unresectable | >180° contact with SMA/celiac or unreconstructable arterial involvement | Unreconstructable PV/SMV involvement | Present (or peritoneal/liver mets) |
Pancreas Q&A Review (condensed)
- Two most common causes of acute pancreatitis? Alcohol, gallstones.
- Antibiotics in pancreatitis? No (unless infected necrosis). Imipenem if infection suspected.
- Gallstone pancreatitis timing? Clear duct if obstruction/cholangitis; cholecystectomy same admission when improved.
- Atlanta terms <4 vs ≥4 weeks? APFC/ANC → pseudocyst/WON.
- Infected necrosis management? Step-up (drain → VARD/endoscopic → open last).
- Chronic pancreatitis with dilated duct ≥6 mm? Puestow. Head-dominant? Frey. Distal stricture, normal head? Distal pancreatectomy. Minimal-change? Splanchnicectomy.
- Pseudocyst algorithm? Image duct first (ERCP/MRCP) → observe ≥6 wk unless symptoms/infection/>6 cm → endoscopic or surgical drainage.
- Cyst fluid CEA >192 suggests? Mucinous (MCN/IPMN). High amylase? Duct communication.
- IPMN high-risk stigmata? Obstructive jaundice, mural nodule ≥5 mm, main duct ≥10 mm → resect.
- Insulinoma workup hallmark? 72-h fast: low glucose with ↑ insulin/C-peptide/proinsulin, low β-hydroxybutyrate; glucagon raises glucose.
- Gastrinoma test? Secretin paradox (↑ gastrin >200). Triangle borders? Cystic–CBD junction; 2nd–3rd duodenum; neck–body pancreas.
- VIPoma syndrome? WDHA. Glucagonoma rash? Necrolytic migratory erythema.
- Preop stent for pancreatic CA? Only for pruritus, cholangitis, coagulopathy (or neoadjuvant if jaundiced). Metal stents preferred.
- Arterial rule of resectability? >180° SMA/celiac contact = unresectable.
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