Chronic Pancreatitis — Written Clinical Reasoning

Part A — Diagnosis, aetiology and staging

Diagnosis

The diagnosis is chronic pancreatitis, established by the combination of characteristic clinical features (chronic recurrent epigastric pain radiating to the back, steatorrhoea, weight loss, and new-onset diabetes), objective exocrine insufficiency (faecal elastase 65 micrograms per gram, indicating severe insufficiency), and characteristic irreversible imaging (a dilated irregular main pancreatic duct with calcifications and parenchymal atrophy on CT). No further diagnostic testing is required to confirm the diagnosis in this advanced case. The 2016 mechanistic consensus defines chronic pancreatitis as a pathological fibroinflammatory syndrome of the pancreas producing irreversible structural damage with permanent loss of exocrine and endocrine function [1].

Aetiological framework — the TIGAR-O classification

The aetiology should be classified using the TIGAR-O mechanistic framework [2]. This patient's disease is toxic-metabolic, driven by chronic heavy alcohol use, with smoking as the likely cofactor (which must be asked about, as it independently accelerates fibrosis and markedly increases pancreatic cancer risk). The other categories — idiopathic, genetic (PRSS1, SPINK1, CFTR, CTRC), autoimmune (type 1 IgG4-related, type 2), recurrent and severe acute pancreatitis, and obstructive — should be considered if the alcohol history is uncertain or atypical features are present (young age, a positive family history, painless obstructive jaundice suggesting autoimmune pancreatitis). In this patient the alcohol history is sufficient, but I would check a lipid panel, calcium, and serum IgG4 to exclude coexistent hypertriglyceridaemia, hypercalcaemia, and autoimmune pancreatitis.

Staging

The disease is in the burnt-out (insufficiency) phase: the steatorrhoea and type 3c diabetes indicate that the gland has lost more than 90 per cent of its exocrine secretory capacity and a large proportion of its endocrine function. The pain may eventually abate as the parenchyma is destroyed, but at present it remains a major problem. [1]

Part B — Assessment and management of exocrine insufficiency

Assessment

The faecal elastase of 65 micrograms per gram confirms severe exocrine insufficiency (a level below 200 indicates insufficiency and below 100 indicates severe insufficiency). Faecal elastase is the best non-invasive marker and is not affected by pancreatic enzyme replacement, but I would note that it is insensitive in mild disease — not a limitation here [3]. I would also screen for fat-soluble vitamin deficiency (vitamins A, D, E, and K), check a bone density scan (DEXA) for osteoporosis and osteomalacia, and assess nutritional status (BMI, weight trend).

Management — pancreatic enzyme replacement therapy

Pancreatic enzyme replacement therapy (PERT) with enteric-coated porcine pancreatin is the cornerstone. The meta-analysis by de la Iglesia-García confirmed that PERT improves the coefficient of fat absorption (from about 67 to 83 per cent), reduces faecal fat excretion, and improves nutrition and quality of life [7]. The prescription:

• 25,000 to 40,000 units of lipase with each main meal, and half that with snacks.
• Taken during or immediately after food, never before, so the enzymes are in the duodenum when chyme arrives.
• Add a proton pump inhibitor (omeprazole 20 mg daily or pantoprazole 40 mg daily) to protect the enzymes from gastric acid degradation and enhance efficacy.
• Titrate to symptoms — increase the dose until steatorrhoea and weight stabilise.
• Supplement the fat-soluble vitamins A, D, E, and K.
• Dietetic input — adequate calories, reduced fat, with medium-chain triglycerides as a calorie source.

Part C — Assessment and management of endocrine insufficiency — type 3c diabetes

Why this is type 3c diabetes

The HbA1c of 58 mmol per mol confirms diabetes, and in the context of chronic pancreatitis with severe exocrine insufficiency and characteristic imaging, this is type 3c (pancreatogenic) diabetes. The Ewald criteria — exocrine insufficiency, pathological pancreatic imaging, and absence of type 1 autoimmunity — are met [4].

Why it is dangerous and how it differs from type 2

Type 3c diabetes is different from type 2 because the gland loses both insulin-secreting beta cells and glucagon-secreting alpha cells. The diabetes is brittle with wide glucose excursions, and hypoglycaemia is particularly dangerous because the loss of glucagon counter-regulation means there is no endogenous recovery from insulin-induced hypoglycaemia. Severe hypoglycaemia is a leading cause of death [4].

Management

• Insulin is the mainstay. A basal-bolus regimen, titrated cautiously.
• Avoid metformin in this malnourished, exocrine-insufficient patient (lactic acidosis and weight loss risk), and avoid sulphonylureas (hypoglycaemia risk).
• Relax the glycaemic target so that avoidance of hypoglycaemia takes priority over tight control. Self-monitoring of blood glucose is essential, with structured education on hypoglycaemia recognition and management.
• PERT improves glycaemic control by restoring nutrient absorption. [1]

Part D — Pain management

Pain is addressed with a stepped approach [3]:

1. Eliminate precipitants — complete alcohol abstinence and smoking cessation.
2. Non-opioids — paracetamol and NSAIDs (with gastroprotection and renal monitoring).
3. Neuropathic adjuncts — pregabalin or gabapentin, and a tricyclic antidepressant, targeting the neuropathic component of chronic pancreatic pain.
4. Opioids — weak then strong (tramadol, then low-dose oral morphine or oxycodone), titrated with a clear dependency-minimising plan and addiction-medicine input.
5. Definitive therapy for refractory pain.

His dilated main pancreatic duct with multiple stones and a dominant distal stricture makes him a candidate for endoscopic ERCP therapy (stricture stenting, stone removal, often combined with extracorporeal shock wave lithotripsy to fragment large calculi), and if that fails or for durable relief, surgery (Puestow longitudinal pancreaticojejunostomy, or a Frey procedure if the head is diseased). The Cahen NEJM 2007 trial showed that surgery provided superior durable pain relief to endoscopic drainage in obstructive dilated-duct disease (75 versus 32 per cent partial or complete relief at two years) [8]; the decision is individualised in a multidisciplinary setting, and endoscopy is a reasonable first step in selected patients with a dominant stricture.

Part E — Complications and surveillance

I would assess for and counsel on the complications: pancreatic pseudocyst, biliary obstruction (a fibrotic head causing cholestasis), splenic vein thrombosis (left-sided portal hypertension with gastric varices — splenectomy is curative if bleeding occurs), and osteoporosis from malabsorption. [1]

Regarding pancreatic cancer: chronic pancreatitis carries a modest long-term increased risk. Any change in symptoms — new weight loss, a change in the pain pattern, or new jaundice — mandates investigation to exclude pancreatic cancer, because the two diseases coexist and mimic each other [5]. Surveillance imaging is selective (hereditary and genetic subgroups), not universal, but smoking cessation is essential because smoking magnifies the cancer risk [2].

Part F — Excluding the mimics

Before attributing all findings to alcoholic chronic pancreatitis, I would actively exclude autoimmune pancreatitis (check serum IgG4 — a diffuse sausage-shaped gland with painless jaundice and a dramatic steroid response would redirect management entirely) [6] and pancreatic adenocarcinoma (Ca 19-9 and EUS-fine-needle aspiration if there is an inflammatory head mass or a change in symptoms). These are the two diagnoses that must not be missed.