Pancreas/Biliary, in full.

Diagnose acute pancreatitis (AP) by the Atlanta criteria (2 of 3: characteristic epigastric/LUQ pain, lipase or amylase >3x ULN [lipase preferred for specificity/duration], or characteristic imaging). ACG 2024 stratifies severity risk using SIRS on admission plus bedside risk factors, rising/elevated BUN, rising/elevated hematocrit (>44), obesity (BMI>30), extrapancreatic fluid collections/pleural effusion/infiltrates, altered mental status, and older age/comorbidities, rather than mandating a formal BISAP or APACHE II composite score. Give moderately aggressive lactated Ringer's, most important in the first 6-12 hours, reassessing volume status/BUN/HCT at 6 hours (further aggressive hydration has little added benefit after 24-48h). Start oral low-fat solid food within 24-48h as tolerated in mild disease; if enteral feeding is needed for moderately severe/severe disease, prefer nasogastric over nasojejunal with small-peptide/medium-chain-triglyceride formula and continuous (not bolus/cyclic) feeding; avoid parenteral nutrition if possible. Do not give prophylactic antibiotics, even in severe disease or sterile necrosis; reserve antibiotics for suspected infected necrosis (typically arising 10-14 days in), and choose agents that penetrate pancreatic necrosis while together covering both gut-derived gram-negative enterics and anaerobes, a carbapenem supplies this as monotherapy, whereas a fluoroquinolone or a third-or-higher-generation cephalosporin must be combined with metronidazole; metronidazole alone (anaerobic cover only), or a cephalosporin or a quinolone alone, does not adequately treat infected necrosis. Perform cholecystectomy preferably before discharge for mild acute biliary pancreatitis, and after a second unexplained AP episode even without identified gallstones; reserve ERCP within 24h for AP complicated by cholangitis, with rectal indomethacin +/- pancreatic duct stent and periprocedural hydration to reduce post-ERCP pancreatitis risk. Check triglycerides when gallstones/alcohol are absent (>1000 mg/dL supports a hypertriglyceridemia etiology). For stable pancreatic necrosis, defer surgical, radiological, or endoscopic intervention 4-6 weeks to allow walling-off (step-up approach).

Per NCCN Neuroendocrine and Adrenal Tumors v2.2025: Work up a suspected pancreatic NET with multiphasic pancreatic-protocol contrast CT and/or MRI; consider EUS with biopsy (FNB) for tissue; use somatostatin-receptor imaging with 68Ga- or 64Cu-DOTATATE PET/CT when it will change management. Obtain biochemical/hormonal evaluation only when a functional syndrome is clinically suspected (not routine for nonfunctioning tumors). Grade by mitotic count and Ki-67 under the WHO classification of neuroendocrine neoplasms (G1 <3%, G2 3-20%, G3 >20%). Consider genetics referral/germline testing for inherited syndromes, principally MEN1 and VHL (less commonly NF1, TSC). LOCALIZED well-differentiated G1/G2: for an incidentally found sporadic nonfunctioning tumor <=2 cm without high-risk features, that is, none of the worrisome imaging/pathologic features that favor resection: main pancreatic-duct dilation (>3 mm) or biliary-duct obstruction, pathologic regional lymphadenopathy on cross-sectional imaging, or vascular encasement/invasion of adjacent structures (grade, functional/symptomatic status, size >2 cm, and interval growth are addressed separately below), NCCN lists BOTH observation and surgery as options; observed lesions are followed with multiphasic CT/MRI (± SSTR-PET as indicated) at 3-12 months, then every 6-12 months if stable. For tumors >2 cm, functional/symptomatic, higher-grade, or enlarging on surveillance, surgical resection (enucleation, distal pancreatectomy, or pancreaticoduodenectomy by location) is recommended and can be curative. ADVANCED/METASTATIC well-differentiated: somatostatin analogs (octreotide LAR or lanreotide) are a preferred first-line option for SSTR-positive, lower-grade/lower-proliferation tumors. 177Lu-DOTATATE PRRT is now also a first-line option for SSTR-positive disease on the strength of NETTER-2, whose population was newly diagnosed grade 2/3 GEP-NET with Ki-67 10-55% (median PFS 22.8 vs 8.5 months), keep the Ki-67 10-55% window and SSTR-positivity as the qualifiers, not an open-ended 'Ki-67 >=10%.' Subsequent-line options for progressive disease include everolimus, sunitinib (pancreatic primary), CAPTEM (capecitabine + temozolomide), PRRT if not already used, and cabozantinib, FDA-approved March 26, 2025 and included by NCCN as a category 1 option for previously treated, unresectable/locally advanced/metastatic well-differentiated pancreatic NET (the FDA label specifies only 'previously treated,' without a required prior-drug sequence).

Confirm chronic pancreatitis on CROSS-SECTIONAL IMAGING, CT for late calcific disease, MRI/MRCP (with secretin where available) for earlier ductal and parenchymal change, EUS an acceptable alternative; per ACG 2020, "Diagnosis is made usually on cross-sectional imaging, with modalities such as endoscopic ultrasonography and pancreatic function tests playing a secondary role". Fecal elastase does NOT confirm chronic pancreatitis: it is a test of exocrine FUNCTION and is the appropriate initial test for the exocrine pancreatic insufficiency (EPI) that chronic pancreatitis causes, a consequence of the disease, not the diagnosis of it. A normal fecal elastase does not exclude chronic pancreatitis and a low one does not establish it. Per AGA 2023, fecal elastase must be run on a semi-solid or solid stool specimen; below 100 mcg/g is good evidence of EPI and 100-200 mcg/g is indeterminate (below 200 mcg/g is the cutoff commonly used to screen). Then manage with smoking and alcohol cessation, PERT for exocrine insufficiency titrated to symptoms, fat-soluble vitamin and bone surveillance, and individualized type 3c diabetes control, considering insulin early in patients with marked hyperglycemia or symptoms of insulin deficiency. Treat pain with a stepwise ladder from scheduled acetaminophen and neuromodulators to EUS-guided celiac plexus block and endoscopic/surgical intervention, referring early for surgery per ESCAPE 2020 in candidates with main pancreatic duct obstruction. Screen for PDAC per lifetime risk and pursue etiologic workup via TIGAR-O v2, including genetic testing and autoimmune pancreatitis evaluation.