Chronic Pancreatitis

Definition
Chronic pancreatitis, is a continuing, chronic inflammatory process of the pancreas, characterized by irreversible histological and functional changes.

Epidemiology
35–45 years (usually related to alcohol)
M>F

Aetiology
TIGAR-O Classification: Risk Factors Associated with Chronic Pancreatitis:

Toxic-metabolic	chronic alcohol use (70% of pt), chronic renal failure, Hypercalcemia (hyperparathyroidism), Hyperlipidemia (rare), Medications, Tobacco, Toxins
Idiopathic	Early and late onset Tropical pancreatitis (tropical calcific pancreatitis and fibrocalculous pancreatic diabetes)
Genetic	Autosomal dominant, or Autosomal recessive modifier genes- eg  CTFR in cystic fibrosis (commonest cause in children)
Autoimmune	Autoimmune chronic pancreatitis associated with inflammatory bowel disease, Sjögren syndrome, primary biliary cirrhosis Isolated autoimmune chronic pancreatitis
Recurrent/severe acute pancreatitis	Postirradiation, Postnecrotic (severe acute pancreatitis), Recurrent acute pancreatitis, Vascular ischemia
Obstructive	Pancreas divisum Sphincter of Oddi disorders Duct obstruction (pancreatic or ampullary tumors, posttraumatic pancreatic duct fibrosis)

Pathophysiology
CBD obstruction leads to biliary stasis,bacterial overgrowth, suppuration, and biliary sepsis.
Causes: choledocholithiasis (60%), biliary tract manipulation, pancreatic or biliary neoplasm

Presentation

• intermittent attacks of severe pain, often in the mid or left upper abdomen and occasionally radiating in a bandlike fashion or localized to the mid back. The pain may occur either after meals or independently of meals, but it is not fleeting or transient and tends to last at least several hours.
• erythema ab igne’s mottled dusky greyness), bloating, steatorrhoea, ↓ weight, brittle diabetes. Symptoms relapse and worsen

Differential diagnosis
Acute cholecystitis
Acute pancreatitis
Intestinal ischemia or infarction
Obstruction of common bile duct
Pancreatic tumors
Peptic ulcer disease
Renal insufficiency

Investigation

FBC	Elevated with infection, abscess
amylase, lipase	non-specific for chronic pancreatitis. Llipase may not be ↑
Fecal tests	> 7 g fat per day is abnormal; quantitative; requires 72 hours; should be on a diet of 100 g fat per day Maldigestion and malabsorption if >90% of pancrease is destroyed
Faecal elastase	< 200 mcg per g (0.20 g per kg) of stool is abnormal; noninvasive; exogenous pancreatic supplementation will not alter results; requires only 20 g of stool
Pancreatic function tests	Direct tests: Determination in duodenal aspirate and pancreatic juice Indirect tests:  oral administration of a complex substance that is hydrolyzed by a specific pancreatic enzyme to release a marker substance
Secretin stimulation test	Peak bicarbonate concentration < 80 mEq per L (80 mmol per L) in duodenal secretion; best test for diagnosing pancreatic exocrine insufficienc
Serum trypsinogen	< 20 ng per mL (0.83 nmol per L) is abnormal
LFT	Alk Phos, Bilirubin ↑ in biliary pancreatitis and ductal obstruction by strictures or mass
breath test	13C-hiolien - for PUD
Lipid panel	Significantly elevated triglycerides are a rare cause of chronic pancreatitis
Calcium	Hyperparathyroidism is a rare cause of chronic pancreatitis
IgG4	For autoimmune: ESR, IgG4, rheumatoid factor, ANA ↑
AXR	speckled pancreatic calcification is pathognomonic (3% of cases)
Abdominal U/S	shows changes in the size, shape contour, and echotexture of the pancreas Picture: Transverse sonogram shows an echogenic, enlarged pancreas with multiple small hyperechoic nonshadowing foci in the pancreas *Endoscopic ultrasonography (EUS) is more sensitive
CT	sensitivity: 80% and spesificity: 85% Focal enlargement associated with calcification or ductal dilatation in a mass is suggestive of chronic pancreatitis. Normal finding does not rule out chronic pancreatitis
MRI	In most patients, a normal pancreatic duct is seen characteristic beaded appearance ( round filling defects) of the pancreatic duct
ERCP	Endoscopic retrograde cholangiopancreatography: ERCP Advantages: most accurate visualization of the pancreatic ductal system, therapeutic Disadvantages :invasive, expensive, requires complete opacification of the pancreatic duct to visualize side branches, and carries a risk of pancreatitis.
MRCP	Magnetic resonance cholangiopancreatography (MRCP ) Advantages: safe, reasonably accurate, noninvasive, fast, and very useful in planning surgical or endoscopic intervention, can visualize pancreatic parenchyma Disadvantages: Not therapeutic
FDG-PET	rule out pancreatic carcinoma

Management

Medical	Analgesics (stepwise approach) hydration, electrolyte correction, broad spectrum Ab. Antidepressants (treatment of concurrent depression) Cessation of alcohol and tobacco use Denervation (celiac nerve blocks, transthoracic splanchnicectomy) long-term insulin therapy (for pancreatic diabetes) Low-fat diet and small meals lipase (eg Creon) Pancreatic enzymes with proton pump inhibitors or histamine H2 blockers Steroid therapy (in autoimmune pancreatitis) Vitamin supplementation (A, D, E, K, and B12)
Endoscopic	Extracorporeal shock wave lithotripsy with or without endoscopy Pancreatic sphincterotomy and stent placement for pain relief Transampullary or transgastric drainage of pseudocys
Surgical	Indication Biliary or pancreatic stricture Duodenal stenosis Fistulas (peritoneal or pleural effusion) Hemorrhage Intractable chronic abdominal pain Pseudocysts Suspected pancreatic neoplasm Vascular complications Types: Decompression Lateral pancreaticojejunostomy (most common) Cystenterostomy Sphincterotomy or sphincteroplasty Resection Distal or total pancreatectomy Pancreatoduodenectomy (Whipple procedure, pylorus-preserving, duodenum-preserving) Click here for details of surgery
Not recommended	Allopurinol (Zyloprim) Antioxidant therapy (vitamin C, vitamin E, selenium [Selepen*], methionine [Uracid]) Octreotide (Sandostatin) Prokinetic agents (erythromycin)

Complications

Complication	Incidence (%)
Acute pancreatitis	Recurrent
Chronic pain	80 to 90
Diabetes mellitus	> 40
Weight loss	> 40
Pancreatic cancer	15 to 40
Pseudocyst	25 to 30
Malabsorption and steatorrhea	10 to 15
Bile duct, duodenal, or gastric obstruction	5 to 10
Pancreatic ascites or pleural effusion	< 10
Splenic or portal vein thrombosis	< 1
Pseudoaneurysm, especially of splenic artery	< 1
Vitamin deficiency (A, D*, E, K and B12)	Rare