Although acute and chronic pancreatitis sounds like short-term and long-term consequences of the same disease process, they are not. The pathology is totally different in those two conditions. Acute pancreatitis is a clinical syndrome, which results from the escape of activated pancreatic digestive enzymes from the duct system into the parenchyma leading to excessive destruction of the pancreatic and peripancreatic tissues. In contrast, chronic pancreatitis is characterized by progressive destruction of the pancreatic parenchymal tissues with chronic inflammation, fibrosis, stenosis and dilatation of the duct system and eventually leading to impairment of the pancreatic functions. This article points out the differences between acute and chronic pancreatitis with regard to their etiology, pathological changes, clinical features, complications, management and prognosis.
Acute Pancreatitis
Acute pancreatitis, which is the auto digestion of the pancreas by activated enzymes, is a medical emergency. In 25% of the cases, the etiology is unknown, but some of the associated factors have been identified. Biliary tract calculi are found to play a major role. Acute pancreatitis commonly occurs after a bout of heavy drinking, which is found to be its toxic effect on pancreatic acinar cells. Other causes are hypercalcaemia seen in primary hyperparathyroidism, Hyperlipidemias, shock, hypothermia, drugs and radiation.
When considering the pathogenesis of acute pancreatitis release of enzymes causing destruction of the pancreatic and peripancreatic tissues leads to acute inflammation, thrombosis, hemorrhage, vascular injury and fat necrosis. Depletion of the intra vascular volume can lead to shock. Wide spread necrosis of the tissues and hemorrhage are seen. Fat necrosis appears as chalky white foci that may be calcified. In severe cases, pancreatic abscess may form due to massive liquefactive necrosis. Neutrophils are the predominant inflammatory cell.
Clinically acute pancreatitis presents as a medical emergency. Patient may develop severe epigastric pain, frequently referred to back, relieved by leaning forward, accompanied by vomiting and shock. There is an immediate elevation of serum amylase, often 10-20 times the normal upper limit and returns to normal in 2-3 days. After 72 hours, serum lipase starts elevating.
Most patients with acute pancreatitis recover from the acute attack with proper supportive care. In severe cases, serious complications may occur such as pancreatic abscess, severe hemorrhage, shock, DIC or respiratory distress syndrome, which can lead to death.
Chronic Pancreatitis
It is the permanent injury to the pancreas where the exocrine and endocrine functions and morphological abnormalities occur in the gland. In most of the cases, there may be no obvious predisposing factor. Other causes include chronic alcoholism, biliary tract calculi, dietary factors and recurrent acute pancreatitis.
When considering the pathogenesis of chronic pancreatitis; after repeated attacks of pancreatitis, the pancreas becomes atrophic and fibrotic. The pancreatic duct gets stenosed with proximal dilatation with loss of parenchyma and replacement with scar tissue. Exocrine and endocrine functions deteriorate. Diffuse calcifications give a rocky-hard consistency to the gland. Microscopically variable lymphocytic infiltration is present.
Clinically patient is presents with upper abdominal pain, backache, jaundice, features of pancreatic failure such as gradual weight loss, anorexia, anemia, steatorrhoea and diabetes.
Here, the plain X ray of the abdomen may demonstrate pancreatic calcifications. Ultrasound and CT scan of the abdomen, pancreatic functions tests, Endoscopic retrograde cholangiopancreatography, angiography and pancreatic biopsy are other useful tests in chronic pancreatitis.
Treatment consists of management of pain either by drugs or surgical intervention, malabsorption by dietary supplements and diabetes by giving insulin if necessary. The complications of diabetes represent the main threat to life. Narcotic dependence is another problem.
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What is the difference between acute pancreatitis and chronic pancreatitis? • Acute pancreatitis is a medical emergency. • Etiologies and pathogenesis are different in the two conditions. • In acute pancreatitis, life-threatening conditions occur such as hemorrhage and shock, which can be severe enough to cause death, but chronic pancreatitis, is a slowly developing disease process. • High levels of serum amylase levels are seen in acute pancreatitis within 1-2 days of the attack. • Pancreatic calcifications and changes in the architecture occur in chronic pancreatitis, but acute pancreatitis morphological changes are reversible with good supportive care. • Permanent diabetes mellitus almost never follows a single attack of acute pancreatitis, but chronic pancreatitis results in diabetes mellitus where the patient may have to depend on insulin.
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