Special Surgery 14. Acute and Chronic Pancreatitis: Symptoms, Diagnosis, Treatment, Complications

I. Acute Pancreatitis

Definition

Acute inflammation of the pancreas
Caused by premature activation of digestive enzymes → autodigestion
Clinical spectrum: mild self-limited disease → necrotizing pancreatitis with organ failure

Etiology

Gallstones / cholelithiasis
Alcohol, especially binge drinking
Hypertriglyceridemia
Post-ERCP pancreatitis
Drugs: azathioprine, thiazides, valproate, steroids and others
Trauma
Viral infections: mumps, Coxsackie, CMV, HIV
Hypercalcemia
Autoimmune pancreatitis
Idiopathic

Pathogenesis

Acinar cell injury or duct obstruction → premature trypsinogen activation
Activated pancreatic enzymes → autodigestion of pancreatic tissue
Inflammatory cytokine release + endothelial/vascular injury
Vasodilation + increased capillary permeability → third spacing
Hypovolemia → tachycardia, hypotension, distributive/hypovolemic shock pattern
Untreated hypoperfusion → organ failure + pancreatic necrosis
Lipase-mediated fat necrosis → free fatty acids bind Ca2+ → hypocalcemia

Classification

1. Morphology

Acute interstitial / edematous pancreatitis:

Inflammation and pancreatic enlargement
No necrosis
Usually milder

Acute necrotizing pancreatitis:

Pancreatic parenchymal and/or peripancreatic necrosis
May be sterile or infected
Higher risk of organ failure and local complications

2. Severity

Mild: no organ failure, no local/systemic complications
Moderately severe: transient organ failure < 48 h and/or local complications
Severe: persistent organ failure > 48 h, single or multiple organs

Clinical Features

Sudden severe epigastric pain
Radiates to the back → belt-like pain
Worse after meals and when supine
Improves sitting up / leaning forward
Nausea, vomiting
Abdominal tenderness, distension, guarding
Fever, tachycardia, hypotension in severe disease
Signs of severe/hemorrhagic pancreatitis:

Cullen sign: periumbilical bruising
Grey-Turner sign: flank discoloration

Diagnosis

2 out of 3 Criteria

Typical abdominal pain
Serum amylase or lipase >= 3x upper limit of normal
Imaging consistent with acute pancreatitis

Laboratory Tests

Lipase more specific than amylase
WBC, CRP: inflammation/severity follow-up
BUN/creatinine and hematocrit: dehydration/severity
Calcium: hypocalcemia in severe fat necrosis
Glucose: stress hyperglycemia or endocrine dysfunction
Liver enzymes and bilirubin:

ALT/GPT elevation suggests biliary etiology
Bilirubin/ALP/GGT elevation suggests CBD obstruction

Triglycerides if no obvious cause or severe lipemia

Imaging

Transabdominal ultrasound:

Evaluate gallstones and biliary duct dilation
Limited pancreas view if bowel gas

Contrast-enhanced CT:

Not routinely needed immediately if diagnosis is clear and mild
Use if diagnosis uncertain, broad differential, severe disease or no improvement after 48-72 h
Shows necrosis, collections, hemorrhage, abscess, complications

MRCP or EUS:

Suspected CBD stone when ERCP indication is uncertain
Idiopathic/recurrent pancreatitis workup

ERCP:

Therapeutic, not routine diagnostic test
Indicated urgently if gallstone pancreatitis with cholangitis or persistent biliary obstruction

Severity Scores

BISAP
Ranson criteria
APACHE II
Organ failure assessment and clinical course are more important than a score alone

II. Acute Pancreatitis Treatment and Complications

Initial Treatment

Hospital admission and severity assessment
Early IV fluid resuscitation:

Balanced crystalloid such as Ringer lactate often preferred
Normal saline also used
Goal-directed: monitor pulse, BP, urine output, BUN/hematocrit, respiratory status
Avoid both under-resuscitation and fluid overload

Analgesia:

Opioids commonly required
NSAIDs can be used in selected mild cases if renal/GI risk allows

Antiemetics and oxygen if needed
ICU if persistent organ failure, shock, respiratory failure or severe SIRS

Nutrition

Mild pancreatitis:

Early oral feeding within 24-48 h as tolerated
Low-fat solid diet can be started; prolonged NPO is not necessary

Moderately severe/severe pancreatitis:

Enteral nutrition is preferred over parenteral nutrition
Nasogastric or nasojejunal feeding are both acceptable
Parenteral nutrition only if enteral route impossible or inadequate

Antibiotics

No prophylactic antibiotics for sterile necrosis or predicted severe pancreatitis
Use antibiotics if:

Cholangitis
Infected pancreatic necrosis suspected/proven
Extrapancreatic infection: pneumonia, UTI, catheter infection, bacteremia

Infected necrosis clues:

Gas in collection on CT
Sepsis
Bacteremia
Clinical deterioration after initial improvement

Use agents penetrating necrosis, e.g. carbapenem or quinolone + metronidazole depending on local protocol/resistance

Treat the Cause

Gallstone Pancreatitis

Urgent ERCP if cholangitis or persistent biliary obstruction
No routine urgent ERCP if no cholangitis/jaundice and CBD stone only suspected; use MRCP/EUS first
Mild gallstone pancreatitis → laparoscopic cholecystectomy during same admission before discharge
Severe gallstone pancreatitis → delay cholecystectomy until inflammation/collections stabilize

Other Causes

Alcohol: abstinence support and withdrawal prevention
Hypertriglyceridemia: insulin infusion/plasmapheresis in selected severe cases, then lipid control
Drug-induced: stop causative drug
Hypercalcemia: treat underlying cause

Local Complications

Timing / Type	Description	Management Logic
Acute peripancreatic fluid collection	Early fluid around pancreas, no wall, no necrosis	Usually conservative
Pancreatic pseudocyst	Encapsulated fluid collection, usually after >4 weeks, no solid necrotic material	Drain if symptomatic, infected, bleeding, obstructing or enlarging
Acute necrotic collection	Early collection with fluid + necrotic material	Conservative unless infected/symptomatic
Walled-off necrosis	Mature encapsulated necrotic collection after about 4 weeks	Step-up drainage/necrosectomy if infected or symptomatic

Other local complications:

Pancreatic abscess/infected necrosis
Hemorrhage / pseudoaneurysm
Pancreatic ascites
Pleural effusion
Splenic vein thrombosis
Gastric outlet or biliary obstruction from mass effect

Systemic Complications

SIRS / sepsis
Shock
ARDS
Acute kidney injury
DIC
Hypocalcemia
Hyperglycemia / diabetes mellitus
Multiorgan failure

Interventional / Surgical Treatment

Intervention should be delayed when possible in stable necrotizing pancreatitis, ideally about 4 weeks, to allow wall maturation
Indications:

Infected necrosis with sepsis or deterioration
Symptomatic walled-off necrosis
Abdominal compartment syndrome
Ongoing acute bleeding / pseudoaneurysm
Bowel ischemia or perforation
Obstruction due to mass effect

Step-up approach:

Antibiotics + supportive care
Percutaneous catheter drainage or endoscopic transmural drainage
Minimally invasive necrosectomy if drainage fails
Open necrosectomy only if less invasive methods fail or emergency indication exists

III. Chronic Pancreatitis

Definition

Long-standing/recurrent inflammation of pancreas
Irreversible destruction of pancreatic parenchyma
Replacement by fibrosis
Progressive exocrine and endocrine pancreatic insufficiency

Etiology

Chronic alcohol use: most common classical cause
Smoking: independent risk factor and accelerates progression
Recurrent acute pancreatitis
Idiopathic
Autoimmune pancreatitis
Hereditary/genetic:

PRSS1
SPINK1
CFTR
CTRC

Obstructive causes:

Pancreatic duct stricture
Pancreatic duct stone
Tumor
Pancreas divisum in selected recurrent cases

Pathomechanism

Repeated acinar cell injury and duct obstruction
Premature trypsinogen activation → intrapancreatic enzyme activation
Autodigestion and inflammation
Chronic toxin/inflammatory stimulation activates pancreatic stellate cells
Fibrosis + duct distortion + calcification
Loss of acinar cells → exocrine insufficiency
Loss of islet cells → endocrine insufficiency / pancreatogenic diabetes

Clinical Features

Chronic epigastric pain
Radiates to back → belt-like
Worse after meals and when supine
Improves leaning forward
Initially episodic, later persistent
Nausea, vomiting
Jaundice if distal bile duct stricture/compression
Exocrine pancreatic insufficiency:

Malabsorption
Steatorrhea
Weight loss
Fat-soluble vitamin deficiency: A, D, E, K

Endocrine insufficiency:

Diabetes mellitus
Brittle diabetes possible because glucagon response is also impaired

Diagnosis

Clinical history + imaging + functional testing
Labs:

Amylase/lipase can be normal in advanced chronic pancreatitis
Bilirubin/ALP/GGT if biliary obstruction
Glucose, HbA1c for endocrine function
Nutritional labs: albumin, vitamins, INR if malnutrition suspected

Exocrine function:

Fecal elastase low in pancreatic exocrine insufficiency
Fecal fat testing if diagnosis unclear

Imaging:

Contrast CT: calcifications, atrophy, duct dilation, pseudocyst
MRI/MRCP: ductal anatomy, strictures, stones, pseudocysts
Secretin-MRCP can assess ductal anatomy/function in selected centers
Endoscopic ultrasound: sensitive for early disease and excludes tumor
ERCP mainly therapeutic, not routine diagnostic

Complications

Exocrine pancreatic insufficiency
Endocrine insufficiency / diabetes mellitus
Pancreatic pseudocyst
Biliary obstruction from distal CBD stricture
Duodenal obstruction
Pancreatic duct stones/strictures
Bleeding from pseudoaneurysm
Splenic vein thrombosis and gastric varices
Pancreatic ascites / pleural fistula
Increased risk of pancreatic cancer

IV. Chronic Pancreatitis Treatment and Surgical Aspects

Conservative Treatment

Lifestyle

Complete alcohol cessation
Smoking cessation
Nutrition support and dietitian involvement

Nutrition and Enzyme Replacement

High-calorie diet if weight loss
Small frequent meals
Avoid severe fat restriction if it worsens malnutrition; treat steatorrhea with enzymes
Pancreatic enzyme replacement therapy:

For steatorrhea, weight loss or low fecal elastase with symptoms
Take with meals/snacks
Add PPI if response inadequate due to acid inactivation

Fat-soluble vitamins A, D, E, K and calcium/vitamin D replacement if deficient

Pain Management

Stepwise analgesia:

Paracetamol/NSAIDs if safe
Neuropathic agents such as pregabalin/amitriptyline in selected patients
Opioids only if needed, with dependence/constipation risk

Treat duct obstruction, pseudocyst or inflammatory mass if pain generator is structural

Diabetes Treatment

Insulin often required
Monitor for hypoglycemia because glucagon response may be impaired
Coordinate with nutrition/enzyme replacement

Endoscopic Treatment

Indications:

Painful obstructed main pancreatic duct
Pancreatic duct stones/strictures
Symptomatic pseudocyst within endoscopic reach
Benign biliary stricture due to chronic pancreatitis

Methods:

ERCP pancreatic duct stenting
Stone extraction
ESWL for large radiopaque pancreatic duct stones, then ERCP if needed
EUS-guided pseudocyst drainage
Biliary stenting for benign distal bile duct stricture

If endoscopic therapy fails or pain recurs, discuss surgical options early in MDT

Surgical Indications

Intractable pain despite optimal medical/endoscopic treatment
Dilated pancreatic duct with obstructing stones/strictures
Inflammatory pancreatic head mass
Symptomatic pseudocyst not suitable for endoscopic treatment
Biliary or duodenal obstruction
Bleeding complications not controlled by radiology/endoscopy
Suspicion of pancreatic cancer

Surgical Procedures

Drainage Procedure

Puestow / Partington-Rochelle procedure:

Longitudinal pancreaticojejunostomy
Indication: pain with dilated main pancreatic duct, usually without dominant head mass
Drains pancreatic duct along its length into Roux-en-Y jejunal limb

Resection Procedures

Pancreaticoduodenectomy / Whipple procedure:

For pancreatic head-dominant disease, suspicion of malignancy or duodenal/biliary obstruction
Includes pancreatic head, duodenum, distal CBD, gallbladder and reconstruction

Distal pancreatectomy:

For isolated body/tail disease or suspected tumor in distal pancreas

Hybrid / Duodenum-Preserving Head Procedures

Frey procedure:

Local pancreatic head coring/resection + longitudinal pancreaticojejunostomy
Good for inflammatory head mass + dilated duct

Beger procedure:

Duodenum-preserving pancreatic head resection
Preserves duodenum and bile duct if feasible

Total pancreatectomy:

Last resort only
Not routine for pain because causes brittle diabetes and complete exocrine insufficiency