Pancreatitis
Pancreatitis
Overview
Pancreatic inflammation + acinar cell injury. ACUTE and CHRONIC = distinct entities.
Acute pancreatitis
“ACUTE ABDOMEN” presentation. Severe form w/ macroscopic haemorrhage+fat necrosis = ACUTE HAEMORRHAGIC PANCREATITIS/pancreatic necrosis. Age 40-70, commoner FEMALES.
Sudden onset post-alcohol/heavy meal. Pain, vomiting, collapse — differentiate from appendicitis/perforated PUD/cholecystitis/mesenteric infarction. AMYLASE ↑ within 24hrs; LIPASE ↑ after 3-4 days, MORE SPECIFIC. Glucosuria 10%.
Etiology: ALCOHOLISM + CHOLELITHIASIS = >80% of cases (2 leading causes). Less common: trauma, ischaemia, shock, adjacent inflammation extension, bacterial/viral infection, drugs(thiazides/sulfonamides/OCPs), hypothermia, hyperlipoproteinaemia, hypercalcaemia(hyperparathyroidism). Rare: familial. Some idiopathic.
Pathogenesis: enzyme liberation+activation. 3 main destructive groups (of >20 secreted):
- PROTEASES(trypsin/chymotrypsin) — most important, proteolysis. Trypsin→kallikrein→activates kinin+clotting+complement systems→inflammation/thrombosis/haemorrhage
- LIPASES/PHOSPHOLIPASES — degrade lipids/membrane phospholipids
- ELASTASES — destroy vascular elastic tissue
Activation mechanisms:
- Acinar cell damage(alcohol/viruses/drugs/ischaemia/trauma)→intracellular enzyme release
- Duct obstruction(cholelithiasis/alcoholism/other)→enzyme leakage into interstitium
- Exocytosis block(nutritional)→lysosomal hydrolase activation
Morphology: Gross — early=swollen/oedematous. 1-2 days=VARIEGATED (grey-white necrosis + chalky-white fat necrosis + blue-black haemorrhage). Blood-stained ascites+fat necrosis flecks in omentum/mesentery. Resolved=fibrosis+calcification+ductal dilatation. Micro: lobule/duct necrosis, arterial/arteriolar necrosis+haemorrhage, fat necrosis, polymorph infiltrate.
Complications:
- Systemic: chemical/bacterial peritonitis, endotoxic shock, acute renal failure
- Local: pancreatic abscess, pseudocyst, duodenal obstruction
Mortality HIGH(20-30%) — shock, infection, renal failure, DIC.
Chronic pancreatitis
Progressive destruction from REPEATED MILD SUBCLINICAL acute attacks (“chronic relapsing”). Recurrent severe pain(months-years intervals), weight loss, jaundice. LATE=diabetes+steatorrhoea. XR: pancreatic calcification+ductal calculi.
Etiology: same factors as acute — MOSTLY chronic alcoholism+HIGH-PROTEIN diet, less often biliary disease. Familial hereditary=more often CHRONIC than acute. Rare: hypercalcaemia, hyperlipidaemia, dorsal-ventral duct fusion failure.
Pathogenesis: acute haemorrhagic pancreatitis RARELY→chronic — usually resolves to PSEUDOCYST instead (key distinction, avoids severity-spectrum misconception). Different mechanisms:
- ALCOHOLIC — alcoholism+high-protein diet→↑pancreatic juice protein→duct obstruction+damage
- NON-ALCOHOLIC(tropical) — protein-calorie malnutrition, ±genetic factors
Morphology: Gross=enlarged, firm, nodular, smooth grey cut surface, LOST lobulation, calcification foci(concretions→stones), ±pseudocysts. Micro (staged):
- Duct obstruction — wall fibrosis, protein plugs/stones in lumina
- Squamous metaplasia+dilatation of ducts
- Chronic infiltrate around lobules+ducts
- Acinar atrophy + marked interlobular fibrosis
- Islet involvement = LATE stage ONLY
Complications: diabetes, pancreatic insufficiency(steatorrhoea/malabsorption), pseudocyst.
Pancreatic pseudocyst
Localised collection: pancreatic juice+necrotic debris+haemorrhage. Follows acute pancreatitis OR trauma. Presents: abdominal mass+pain, ±intraperitoneal haemorrhage+peritonitis.
Morphology: Gross=within/adjacent to pancreas, usually solitary, unilocular, ≤10cm, thin/thick wall. Micro: dense fibrous wall+marked inflammation; haemosiderin/calcium/cholesterol crystals(preceding haemorrhage/necrosis evidence); serous/turbid lumen fluid. NO EPITHELIAL LINING = defining feature (distinguishes from true cyst).
Clinical relevance
Amylase(early,24hr)-vs-lipase(later,3-4d,MORE SPECIFIC) timing = single most actionable lab fact — lipase preferred when diagnosis delayed/amylase equivocal. Acute pancreatitis RARELY transitions directly to chronic — typical resolution=PSEUDOCYST; chronic builds from repeated SUBCLINICAL attacks instead — avoids treating acute/chronic as one severity spectrum. Pseudocyst’s NO epithelial lining = key differentiator from true cyst (default “cyst” assumption otherwise implies lining). Alcohol+gallstones(>80% of acute cases) = distinct mechanisms (acinar toxicity vs duct obstruction) converging on same enzyme-activation endpoint.
Pancreatitis
Overview
Pancreatic inflammation + acinar cell injury. ACUTE and CHRONIC = distinct entities.
Acute pancreatitis
“ACUTE ABDOMEN” presentation. Severe form w/ macroscopic haemorrhage+fat necrosis = ACUTE HAEMORRHAGIC PANCREATITIS/pancreatic necrosis. Age 40-70, commoner FEMALES.
Sudden onset post-alcohol/heavy meal. Pain, vomiting, collapse — differentiate from appendicitis/perforated PUD/cholecystitis/mesenteric infarction. AMYLASE ↑ within 24hrs; LIPASE ↑ after 3-4 days, MORE SPECIFIC. Glucosuria 10%.
Etiology: ALCOHOLISM + CHOLELITHIASIS = >80% of cases (2 leading causes). Less common: trauma, ischaemia, shock, adjacent inflammation extension, bacterial/viral infection, drugs(thiazides/sulfonamides/OCPs), hypothermia, hyperlipoproteinaemia, hypercalcaemia(hyperparathyroidism). Rare: familial. Some idiopathic.
Pathogenesis: enzyme liberation+activation. 3 main destructive groups (of >20 secreted):
- PROTEASES(trypsin/chymotrypsin) — most important, proteolysis. Trypsin→kallikrein→activates kinin+clotting+complement systems→inflammation/thrombosis/haemorrhage
- LIPASES/PHOSPHOLIPASES — degrade lipids/membrane phospholipids
- ELASTASES — destroy vascular elastic tissue
Activation mechanisms:
- Acinar cell damage(alcohol/viruses/drugs/ischaemia/trauma)→intracellular enzyme release
- Duct obstruction(cholelithiasis/alcoholism/other)→enzyme leakage into interstitium
- Exocytosis block(nutritional)→lysosomal hydrolase activation
Morphology: Gross — early=swollen/oedematous. 1-2 days=VARIEGATED (grey-white necrosis + chalky-white fat necrosis + blue-black haemorrhage). Blood-stained ascites+fat necrosis flecks in omentum/mesentery. Resolved=fibrosis+calcification+ductal dilatation. Micro: lobule/duct necrosis, arterial/arteriolar necrosis+haemorrhage, fat necrosis, polymorph infiltrate.
Complications:
- Systemic: chemical/bacterial peritonitis, endotoxic shock, acute renal failure
- Local: pancreatic abscess, pseudocyst, duodenal obstruction
Mortality HIGH(20-30%) — shock, infection, renal failure, DIC.
Chronic pancreatitis
Progressive destruction from REPEATED MILD SUBCLINICAL acute attacks (“chronic relapsing”). Recurrent severe pain(months-years intervals), weight loss, jaundice. LATE=diabetes+steatorrhoea. XR: pancreatic calcification+ductal calculi.
Etiology: same factors as acute — MOSTLY chronic alcoholism+HIGH-PROTEIN diet, less often biliary disease. Familial hereditary=more often CHRONIC than acute. Rare: hypercalcaemia, hyperlipidaemia, dorsal-ventral duct fusion failure.
Pathogenesis: acute haemorrhagic pancreatitis RARELY→chronic — usually resolves to PSEUDOCYST instead (key distinction, avoids severity-spectrum misconception). Different mechanisms:
- ALCOHOLIC — alcoholism+high-protein diet→↑pancreatic juice protein→duct obstruction+damage
- NON-ALCOHOLIC(tropical) — protein-calorie malnutrition, ±genetic factors
Morphology: Gross=enlarged, firm, nodular, smooth grey cut surface, LOST lobulation, calcification foci(concretions→stones), ±pseudocysts. Micro (staged):
- Duct obstruction — wall fibrosis, protein plugs/stones in lumina
- Squamous metaplasia+dilatation of ducts
- Chronic infiltrate around lobules+ducts
- Acinar atrophy + marked interlobular fibrosis
- Islet involvement = LATE stage ONLY
Complications: diabetes, pancreatic insufficiency(steatorrhoea/malabsorption), pseudocyst.
Pancreatic pseudocyst
Localised collection: pancreatic juice+necrotic debris+haemorrhage. Follows acute pancreatitis OR trauma. Presents: abdominal mass+pain, ±intraperitoneal haemorrhage+peritonitis.
Morphology: Gross=within/adjacent to pancreas, usually solitary, unilocular, ≤10cm, thin/thick wall. Micro: dense fibrous wall+marked inflammation; haemosiderin/calcium/cholesterol crystals(preceding haemorrhage/necrosis evidence); serous/turbid lumen fluid. NO EPITHELIAL LINING = defining feature (distinguishes from true cyst).
Clinical relevance
Amylase(early,24hr)-vs-lipase(later,3-4d,MORE SPECIFIC) timing = single most actionable lab fact — lipase preferred when diagnosis delayed/amylase equivocal. Acute pancreatitis RARELY transitions directly to chronic — typical resolution=PSEUDOCYST; chronic builds from repeated SUBCLINICAL attacks instead — avoids treating acute/chronic as one severity spectrum. Pseudocyst’s NO epithelial lining = key differentiator from true cyst (default “cyst” assumption otherwise implies lining). Alcohol+gallstones(>80% of acute cases) = distinct mechanisms (acinar toxicity vs duct obstruction) converging on same enzyme-activation endpoint.
Pancreatitis
Overview
Pancreatitis is pancreatic inflammation with acinar cell injury, classified into distinct acute and chronic forms.
Acute Pancreatitis
Acute inflammation presenting clinically as an “acute abdomen.” The severe form, with macroscopic haemorrhage and fat necrosis in/around the pancreas, is termed acute haemorrhagic pancreatitis (acute pancreatic necrosis). Occurs in adults aged 40–70, commoner in females.
Sudden onset, typically after an alcohol bout or heavy meal. Presents with abdominal pain, vomiting, collapse — must be differentiated from other acute-abdomen causes (acute appendicitis, perforated peptic ulcer, acute cholecystitis, mesenteric vessel occlusion/intestinal infarction). Serum amylase rises within the first 24 hours; serum lipase rises after 3–4 days and is more specific for pancreatic disease. Glucosuria occurs in 10% of cases.
Etiology: the two leading causes — alcoholism and cholelithiasis — together account for >80% of cases. Less common causes: trauma, ischaemia, shock, extension of inflammation from adjacent tissues, blood-borne bacterial infection, viral infections, drugs (thiazides, sulfonamides, OCPs), hypothermia, hyperlipoproteinaemia, hypercalcaemia (hyperparathyroidism). Rarely familial pancreatitis. A proportion remain idiopathic.
Pathogenesis: destructive changes result from liberation and activation of pancreatic enzymes. Three main destructive enzyme groups (of >20 secreted):
- Proteases (trypsin, chymotrypsin) — most important for proteolysis. Trypsin also converts prekallikrein to kallikrein, activating the kinin system, and thereby clotting and complement systems — resulting in inflammation, thrombosis, tissue damage, and the haemorrhages of acute haemorrhagic pancreatitis.
- Lipases/phospholipases — degrade lipids and membrane phospholipids.
- Elastases — destroy vascular elastic tissue.
Activation/release mechanisms:
- Acinar cell damage (alcohol, viruses, drugs, ischaemia, trauma) → intracellular enzyme release.
- Duct obstruction (cholelithiasis, chronic alcoholism, other obstructing lesions) → enzyme leakage from ductules into interstitial tissue.
- Block in exocytosis (nutritional causes) → intracellular enzyme activation by pancreatic lysosomal hydrolases.
Morphology: Gross — early: swollen, oedematous pancreas; within 1–2 days: characteristic variegated appearance — grey-white pancreatic necrosis, chalky-white fat necrosis, blue-black haemorrhages. Typically, blood-stained ascitic fluid and white fat-necrosis flecks in the omentum/mesentery/peripancreatic tissue. Resolved lesions show fibrosis, calcification, ductal dilatation. Micro: pancreatic lobule/duct necrosis; arterial/arteriolar necrosis with haemorrhage; fat necrosis; polymorph-predominant inflammatory reaction around necrosis/haemorrhage.
Complications:
- Systemic: chemical/bacterial peritonitis, endotoxic shock, acute renal failure.
- Local: pancreatic abscess, pancreatic pseudocyst, duodenal obstruction.
Mortality is high (20–30%); death from hypotensive shock, infection, acute renal failure, DIC.
Chronic Pancreatitis
Progressive pancreatic destruction from repeated mild, subclinical acute pancreatitis attacks (“chronic relapsing pancreatitis”). Most present with recurrent severe abdominal pain at intervals of months to years; weight loss and jaundice often accompany. Later: diabetes mellitus and steatorrhoea. Abdominal X-ray may show pancreatic-region calcification and ductal calculi.
Etiology: mostly the same factors as acute pancreatitis — most commonly chronic alcoholism with a protein-rich diet, less often biliary tract disease. Familial hereditary pancreatitis (uncommon) more often presents chronically than acutely. Rare causes: hypercalcaemia, hyperlipidaemia, developmental failure of dorsal-ventral pancreatic duct fusion.
Pathogenesis: acute haemorrhagic pancreatitis seldom progresses to chronic pancreatitis — instead it typically resolves into a pancreatic pseudocyst. Alcoholic and non-alcoholic chronic pancreatitis arise via different mechanisms:
- Alcoholic — chronic alcoholism + high-protein diet → increased pancreatic juice protein concentration → duct obstruction and damage.
- Non-alcoholic (tropical chronic pancreatitis) — from protein-calorie malnutrition in tropical countries; genetic factors contribute in some cases.
Morphology: Gross — enlarged, firm, nodular pancreas; smooth grey cut surface with lost normal lobulation; frequent calcification foci (tiny concretions to visible stones); ± pseudocysts. Micro (stage-dependent):
- Duct obstruction — wall fibrosis, protein plugs/stones in the lumina.
- Squamous metaplasia and dilatation of some inter-/intralobular ducts.
- Chronic inflammatory infiltrate around lobules and ducts.
- Acinar tissue atrophy with marked interlobular fibrosis increase.
- Islet tissue involvement only in late stage.
Complications: diabetes mellitus, pancreatic insufficiency with steatorrhoea/malabsorption, pancreatic pseudocyst formation.
Pancreatic Pseudocyst
A localised collection of pancreatic juice, necrotic debris, and haemorrhage, developing after acute pancreatitis or trauma. Presents as an abdominal mass with pain, ± intraperitoneal haemorrhage and generalised peritonitis.
Morphology: Gross — within or adjacent to the pancreas; usually solitary, unilocular, up to 10 cm, thin- or thick-walled. Micro: dense fibrous wall with marked inflammatory reaction; evidence of preceding haemorrhage/necrosis (haemosiderin, calcium, cholesterol crystal deposits); lumen contains serous/turbid fluid. No epithelial lining — this is the defining feature distinguishing it from a true cyst.
Clinical Relevance
- The amylase-vs-lipase timing distinction (amylase rises first within 24 hours; lipase rises later but is more specific) is the single most clinically actionable lab fact here — lipase is preferred when the diagnosis is delayed or amylase is equivocal.
- Acute pancreatitis rarely transitions directly into chronic pancreatitis — the typical resolution path after a severe acute attack is a pseudocyst, not chronic disease; chronic pancreatitis instead builds from repeated subclinical attacks. This distinction avoids a common conceptual error of treating acute and chronic pancreatitis as points on one continuous severity spectrum.
- The pseudocyst’s defining absence of an epithelial lining is the key differentiator from a true pancreatic cyst — worth anchoring precisely, since “cyst” terminology otherwise implies an epithelial lining by default.
- Alcohol and gallstones jointly explaining >80% of acute pancreatitis cases is worth pairing with their distinct mechanisms (acinar cell toxicity for alcohol vs duct obstruction for gallstones) — both converge on the same enzyme-activation endpoint via different upstream routes.
Pancreatitis
Overview
Pancreatitis is pancreatic inflammation with acinar cell injury, classified into distinct acute and chronic forms.
Acute Pancreatitis
Acute inflammation presenting clinically as an “acute abdomen.” The severe form, with macroscopic haemorrhage and fat necrosis in/around the pancreas, is termed acute haemorrhagic pancreatitis (acute pancreatic necrosis). Occurs in adults aged 40–70, commoner in females.
Sudden onset, typically after an alcohol bout or heavy meal. Presents with abdominal pain, vomiting, collapse — must be differentiated from other acute-abdomen causes (acute appendicitis, perforated peptic ulcer, acute cholecystitis, mesenteric vessel occlusion/intestinal infarction). Serum amylase rises within the first 24 hours; serum lipase rises after 3–4 days and is more specific for pancreatic disease. Glucosuria occurs in 10% of cases.
Etiology: the two leading causes — alcoholism and cholelithiasis — together account for >80% of cases. Less common causes: trauma, ischaemia, shock, extension of inflammation from adjacent tissues, blood-borne bacterial infection, viral infections, drugs (thiazides, sulfonamides, OCPs), hypothermia, hyperlipoproteinaemia, hypercalcaemia (hyperparathyroidism). Rarely familial pancreatitis. A proportion remain idiopathic.
Pathogenesis: destructive changes result from liberation and activation of pancreatic enzymes. Three main destructive enzyme groups (of >20 secreted):
- Proteases (trypsin, chymotrypsin) — most important for proteolysis. Trypsin also converts prekallikrein to kallikrein, activating the kinin system, and thereby clotting and complement systems — resulting in inflammation, thrombosis, tissue damage, and the haemorrhages of acute haemorrhagic pancreatitis.
- Lipases/phospholipases — degrade lipids and membrane phospholipids.
- Elastases — destroy vascular elastic tissue.
Activation/release mechanisms:
- Acinar cell damage (alcohol, viruses, drugs, ischaemia, trauma) → intracellular enzyme release.
- Duct obstruction (cholelithiasis, chronic alcoholism, other obstructing lesions) → enzyme leakage from ductules into interstitial tissue.
- Block in exocytosis (nutritional causes) → intracellular enzyme activation by pancreatic lysosomal hydrolases.
Morphology: Gross — early: swollen, oedematous pancreas; within 1–2 days: characteristic variegated appearance — grey-white pancreatic necrosis, chalky-white fat necrosis, blue-black haemorrhages. Typically, blood-stained ascitic fluid and white fat-necrosis flecks in the omentum/mesentery/peripancreatic tissue. Resolved lesions show fibrosis, calcification, ductal dilatation. Micro: pancreatic lobule/duct necrosis; arterial/arteriolar necrosis with haemorrhage; fat necrosis; polymorph-predominant inflammatory reaction around necrosis/haemorrhage.
Complications:
- Systemic: chemical/bacterial peritonitis, endotoxic shock, acute renal failure.
- Local: pancreatic abscess, pancreatic pseudocyst, duodenal obstruction.
Mortality is high (20–30%); death from hypotensive shock, infection, acute renal failure, DIC.
Chronic Pancreatitis
Progressive pancreatic destruction from repeated mild, subclinical acute pancreatitis attacks (“chronic relapsing pancreatitis”). Most present with recurrent severe abdominal pain at intervals of months to years; weight loss and jaundice often accompany. Later: diabetes mellitus and steatorrhoea. Abdominal X-ray may show pancreatic-region calcification and ductal calculi.
Etiology: mostly the same factors as acute pancreatitis — most commonly chronic alcoholism with a protein-rich diet, less often biliary tract disease. Familial hereditary pancreatitis (uncommon) more often presents chronically than acutely. Rare causes: hypercalcaemia, hyperlipidaemia, developmental failure of dorsal-ventral pancreatic duct fusion.
Pathogenesis: acute haemorrhagic pancreatitis seldom progresses to chronic pancreatitis — instead it typically resolves into a pancreatic pseudocyst. Alcoholic and non-alcoholic chronic pancreatitis arise via different mechanisms:
- Alcoholic — chronic alcoholism + high-protein diet → increased pancreatic juice protein concentration → duct obstruction and damage.
- Non-alcoholic (tropical chronic pancreatitis) — from protein-calorie malnutrition in tropical countries; genetic factors contribute in some cases.
Morphology: Gross — enlarged, firm, nodular pancreas; smooth grey cut surface with lost normal lobulation; frequent calcification foci (tiny concretions to visible stones); ± pseudocysts. Micro (stage-dependent):
- Duct obstruction — wall fibrosis, protein plugs/stones in the lumina.
- Squamous metaplasia and dilatation of some inter-/intralobular ducts.
- Chronic inflammatory infiltrate around lobules and ducts.
- Acinar tissue atrophy with marked interlobular fibrosis increase.
- Islet tissue involvement only in late stage.
Complications: diabetes mellitus, pancreatic insufficiency with steatorrhoea/malabsorption, pancreatic pseudocyst formation.
Pancreatic Pseudocyst
A localised collection of pancreatic juice, necrotic debris, and haemorrhage, developing after acute pancreatitis or trauma. Presents as an abdominal mass with pain, ± intraperitoneal haemorrhage and generalised peritonitis.
Morphology: Gross — within or adjacent to the pancreas; usually solitary, unilocular, up to 10 cm, thin- or thick-walled. Micro: dense fibrous wall with marked inflammatory reaction; evidence of preceding haemorrhage/necrosis (haemosiderin, calcium, cholesterol crystal deposits); lumen contains serous/turbid fluid. No epithelial lining — this is the defining feature distinguishing it from a true cyst.
Clinical Relevance
- The amylase-vs-lipase timing distinction (amylase rises first within 24 hours; lipase rises later but is more specific) is the single most clinically actionable lab fact here — lipase is preferred when the diagnosis is delayed or amylase is equivocal.
- Acute pancreatitis rarely transitions directly into chronic pancreatitis — the typical resolution path after a severe acute attack is a pseudocyst, not chronic disease; chronic pancreatitis instead builds from repeated subclinical attacks. This distinction avoids a common conceptual error of treating acute and chronic pancreatitis as points on one continuous severity spectrum.
- The pseudocyst’s defining absence of an epithelial lining is the key differentiator from a true pancreatic cyst — worth anchoring precisely, since “cyst” terminology otherwise implies an epithelial lining by default.
- Alcohol and gallstones jointly explaining >80% of acute pancreatitis cases is worth pairing with their distinct mechanisms (acinar cell toxicity for alcohol vs duct obstruction for gallstones) — both converge on the same enzyme-activation endpoint via different upstream routes.
Pancreatitis
- Enzyme cascade diagram: acinar cell damage/duct obstruction/exocytosis block converging on protease/lipase/elastase activation and their distinct destructive effects
- Acute pancreatitis’s typical resolution path to pseudocyst vs chronic pancreatitis’s separate route via repeated subclinical attacks, shown as two diverging pathways
Pancreatitis
- Enzyme cascade diagram: acinar cell damage/duct obstruction/exocytosis block converging on protease/lipase/elastase activation and their distinct destructive effects
- Acute pancreatitis’s typical resolution path to pseudocyst vs chronic pancreatitis’s separate route via repeated subclinical attacks, shown as two diverging pathways
My Sticky Notes
Personal revision notes, mnemonics and reminders.
