Chronic Pancreatitis

Definition And Pathophysiology

Persistent, destructive pancreatic inflammation causing irreversible acinar and ductal structural changes.
Sentinel acute pancreatitis event (SAPE) initiates inflammatory cascade.
Recurrent acinar cell injury activates pancreatic stellate cells, driving progressive fibrosis.
Progressive damage yields corresponding loss of exocrine and endocrine function, alongside intractable pain.

Pediatric etiology differs significantly from adult disease; genetic and structural anomalies dominate over toxic exposures.

Category	Specific Risk Factors
Toxic/Metabolic	Medications (L-asparaginase, valproic acid, azathioprine), hypertriglyceridemia, hypercalcemia, chronic renal failure.
Idiopathic	Diagnosed when exhaustive evaluation excludes known causes.
Genetic	PRSS1 (hereditary pancreatitis, autosomal dominant), CFTR, SPINK1 (disease modifier), CTRC, CPA1. Present in up to 73% of pediatric cohorts.
Autoimmune	Type 2 (idiopathic duct-centric) predominates in children. Serum IgG4 often normal. Responds well to corticosteroids.
Recurrent/Severe Acute	History of recurrent or severe acute pancreatitis episodes driving fibrotic progression.
Obstructive	Pancreas divisum, gallstones, biliary cysts, anomalous pancreaticobiliary junction. Present in up to 33% of patients.

Intermittent or continuous abdominal pain (epigastric or mid-abdomen), often radiating to back.
Pain frequently triggered or exacerbated by food ingestion.
Associated nausea, vomiting, anorexia, and weight loss.
Progressive exocrine pancreatic insufficiency causing steatorrhea, failure to thrive, and fat-soluble vitamin deficiencies.
Progressive endocrine insufficiency manifesting as pancreatogenic (type 3c) diabetes mellitus.
“Burned-out” phase: Intractable pain persists during exacerbations without corresponding elevations in serum amylase or lipase due to severe parenchymal atrophy.

Confirmation requires minimum one of the following criteria:

Abdominal pain consistent with pancreatic origin plus suggestive imaging findings.
Evidence of exocrine pancreatic insufficiency plus suggestive imaging findings.
Evidence of endocrine pancreatic insufficiency plus suggestive imaging findings.

Modality	Clinical Utility And Findings
Ultrasonography	First-line, noninvasive screening. Demonstrates dilated duct, calcifications, parenchymal atrophy, pseudocysts.
MRCP	Preferred cross-sectional imaging avoiding radiation. Secretin stimulation enhances sensitivity for detecting early ductal changes and side branches.
Endoscopic Ultrasound (EUS)	Highly accurate for detecting subtle early parenchymal/ductal changes. Facilitates fine-needle aspiration/biopsy.
ERCP	Diagnostic use decreased due to post-ERCP pancreatitis risk. Reserved primarily for therapeutic intervention or clarifying ductal anomalies.

Exocrine Function: Fecal elastase-1 concentration (<200 ug/g indicates insufficiency) or 72-hour fecal fat collection (coefficient of fat absorption <90%). Secretin-stimulated direct duodenal fluid testing provides highest sensitivity but requires invasive intubation.
Endocrine Function: Fasting plasma glucose ( $\geq$ 126 mg/dL) or standard oral glucose tolerance test.

Analgesia: Implement stepwise approach. Initiate non-opioid analgesics (acetaminophen, NSAIDs). Advance to weak opioids (tramadol) for refractory pain. Incorporate neuromodulators (gabapentin, pregabalin, amitriptyline) to target central sensitization/neuropathic pain and spare opioid reliance.
Enzyme Replacement: Pancreatic enzyme replacement therapy (PERT) mitigates exocrine insufficiency, prevents malnutrition, and may provide negative feedback reducing pain (specifically utilizing non-enteric coated preparations).
Psychological Support: Cognitive behavioral therapy (CBT) enhances coping mechanisms, addresses concomitant mood disorders, and improves overall functional quality of life.

ERCP indicated for targeted obstructive pathology (pancreas divisum, obstructing stones).
Therapeutic modalities include sphincterotomy, ductal dilatation, stent placement, and stone extraction.
Yields significant pain relief in appropriately selected pediatric candidates.

Drainage Procedures: Lateral pancreaticojejunostomy (Puestow procedure) decompresses ductal strictures; indicated primarily for large duct disease.
Resection Procedures: Pancreaticoduodenectomy (Whipple) or combined drainage/resection (Beger/Frey procedures) indicated for predominant pancreatic head mass or intractable focal disease.
Total Pancreatectomy with Islet Autotransplantation (TPIAT): Definitive therapy for refractory pain failing maximal medical and endoscopic management. Simultaneous islet autotransplantation prevents brittle diabetes. Highly effective for eliminating pain, particularly in younger children with defined genetic etiologies (PRSS1).

Local complications include pseudocyst formation, biliary/pancreatic duct strictures, and splenic vein thrombosis resulting in portal hypertension.
Carries significant long-term risk for pancreatic adenocarcinoma; lifetime risk approaches 50% specifically in patients harboring PRSS1 mutations.