Chronic pancreatitis — diagnosis, investigation and management

a) Clinical diagnosis and principle (2 marks)

The combination of recurrent epigastric pain radiating to the back, steatorrhoea, new-onset diabetes and weight loss in a heavy drinker is the classic triad of chronic pancreatitis (CP) — a progressive, fibrotic, inflammatory disease producing irreversible loss of exocrine and endocrine function.^[1][2]

The reticular brown abdominal discolouration is erythema ab igni — chronic heat-pad use, a bedside sign of chronic pancreatic pain. The diagnostic principle is that no single test is gold-standard: diagnosis rests on a combination of structural imaging (calcification, ductal change, atrophy) and functional testing (exocrine insufficiency). Pancreatic cancer must always be actively excluded, because CP and cancer coexist and CP is itself a cancer risk factor.^[1]

b) Investigations (3 marks)

Structural imaging:

• Abdominal X-ray — pancreatic calcification is pathognomonic when present (found in 30 to 50 percent).
• Contrast CT pancreas (the most useful single test) — parenchymal calcification, dilated main pancreatic duct, gland atrophy, pseudocysts, inflammatory head mass; excludes cancer; graded by the Cambridge classification (mild / moderate / marked).
• MRCP / secretin-MRCP or endoscopic ultrasound (EUS) with the Rosemont criteria if early / equivocal.
• The 'chain of lakes' / 'string of pearls' ductal appearance (alternating strictures and dilatation) is classic on ERCP (now used mainly therapeutically).

Functional tests:

• Faecal elastase-1 — under 200 microg/g = exocrine insufficiency (moderate); under 100 = severe; not affected by PERT.
• Fasting glucose / HbA1c — type 3c diabetes (low C-peptide).

Adjuncts:

• LFTs, coagulation, CA 19-9, and EUS-FNA of any mass — to exclude pancreatic cancer.
• Fat-soluble vitamins (A, D, E, K), B12, folate, calcium, magnesium, zinc — deficiency from malabsorption.
• IgG4 — if autoimmune pancreatitis suspected (painless jaundice, 'sausage' pancreas).
• DEXA scan — osteoporosis / osteomalacia; genetic testing (PRSS1, SPINK1, CFTR) if young / familial / idiopathic.

c) Management — definitive and stepwise (3 marks)

1. Correctable causes and conservative measures — complete alcohol abstinence (slows progression, improves survival) and smoking cessation (independent benefit); small, frequent, low-fat, high-protein diet with medium-chain triglycerides (MCTs); nutritional supplements and fat-soluble vitamins; thiamine 100 mg daily (alcoholic).
2. Pancreatic enzyme replacement therapy (PERT) — pancreatin (Creon) 25,000 to 40,000 units of lipase with each main meal, 10,000 to 25,000 with snacks, with a PPI (omeprazole 20 to 40 mg daily); taken WITH food, throughout the meal. Treats both steatorrhoea and (via CCK negative feedback) pain.
3. Stepwise analgesia (WHO ladder) — paracetamol 1 g 6-hourly; then NSAID (ibuprofen 400 mg 8-hourly, with caution); then tramadol 50 to 100 mg 4 to 6-hourly; then a strong opioid (morphine or fentanyl patch) — pethidine is NOT preferred. Add a neuromodulator (pregabalin, amitriptyline) for the neuropathic component; refer to a chronic-pain service to limit opioid harm.
4. Type 3c diabetes — insulin (often low doses); avoid sulfonylureas (hypoglycaemia).
5. Endoscopic therapy if refractory pain from large calcified ductal stones (over 5 mm) — ESWL; stricture stenting and sphincterotomy.
6. Surgery for dilated-duct (over 7 mm) disease failing endoscopy — lateral pancreaticojejunostomy (Puestow); resection (Beger, Frey, Whipple) for an inflammatory head mass; total pancreatectomy with islet autotransplantation (TPIAT) for intractable small-duct disease.

d) Complications and prognosis (2 marks)

• Complications: pancreatic pseudocyst (drain if symptomatic / infected / over 6 cm), bile-duct stricture (jaundice, cholangitis), duodenal obstruction, splenic vein thrombosis with isolated gastric fundal varices (left-sided portal hypertension; splenectomy is curative), visceral pseudoaneurysm (catastrophic bleed — angiography and embolisation), fat-soluble vitamin deficiency / osteoporosis, opioid dependence, and pancreatic cancer (cumulative risk about 4 percent at 20 years).^[3]
• Prognosis — CP is progressive and shortens life expectancy by about 10 to 20 years; the main drivers of mortality are diabetes, malnutrition, addiction, pancreatic cancer and cardiovascular disease. Annual follow-up reviews pain, glucose, nutrition, micronutrients, bone density and adherence.^[1]