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Pancreatitis- definition, types, etiology, pathophysiology

DEFINITION AND TYPES

Pancreatitis, acute or chronic, is an inflammation and potential necrosis of the pancreas. It can be classified into 2 types

ACUTE PANCREATITIS

Acute pancreatitis ranges from a mild, self-limiting disorder to a severe, rapidly fatal disease that does not respond to any treatment. It is very sudden and last for a few days. Mild acute pancreatitis is characterized by edema and inflammation confined to the pancreas. Minimal organ dysfunction is present, and return to normal usually occurs within 6 months. Although this is considered the milder form of pancreatitis, the patient is acutely ill and at risk for hypovolemic shock, fluid and electrolyte disturbances, and sepsis. A more widespread and complete enzymatic digestion of the gland characterizes severe acute pancreatitis. The tissue becomes necrotic, and the damage extends into the retroperitoneal tissues.

CHRONIC PANCREATITIS

Chronic pancreatitis is an inflammatory disorder characterized by progressive anatomic and functional destruction of the pancreas. It occurs over many years and has multiple causes and painful symptoms. As cells are replaced by fibrous tissue with repeated attacks of pancreatitis, pressure within the pancreas increases. The end result is mechanical obstruction of the pancreatic and common bile ducts and the duodenum. Additionally, there is atrophy of the epithelium of the ducts, inflammation, and destruction of the secreting cells of the pancreas.

EPIDEMIOLOGY

The increased incidence of pancreatitis, coupled with new treatment options, poses a challenge for primary care physicians. Between 1960 and 1980, the incidence of acute pancreatitis increased 10-fold. Mortality secondary to pancreatitis ranges from 2 to 9 percent.

Acute pancreatitis can be a medical emergency associated with a high risk for life-threatening complications and mortality, whereas chronic pancreatitis often goes undetected until 80% to 90% of the exocrine and endocrine tissue is destroyed. Acute pancreatitis does not usually lead to chronic pancreatitis unless complications develop. However, chronic pancreatitis can be characterized by acute episodes. Typically, patients are men 40 to 45 years of age with a history of alcoholism or women 50 to 55 years of age with a history of biliary disease.

The rate of incidence for pancreatitis each year in the United States is over 300,000 people. Roughly 200,000 people are hospitalized each year for treatment of acute pancreatitis. Over 100,000 people a year see their doctor for treatment of chronic pancreatitis and there are over 50,000 hospitalizations in the United States for the chronic condition. The United States has one of the highest incidence rates of pancreatitis, most likely due to increased alcohol and high-fat food consumption.

The database compiled in January 2004 given by WHO, the rank of the highest incidence of Acute Pancreatitis in a country is as follows

RANK COUNTRIES AMOUNT
1 USA 2834 deaths
2 Brazil 1831 deaths
3 Poland 1544 deaths
4 Japan 1102 deaths
5 Spain 1070 deaths
6 Mexico 1037 deaths
7 Germany 983 deaths
8 Romania 908 deaths
9 Argentina 640 deaths
10 South Africa 367 deaths

 

Prevalence of Chronic Pancreatitis in India

The prevalence of tropical pancreatitis is estimated to be ~126/100,000 population) in southern India according to a survey conducted by Balaji et al from the department of Gastroenterology, AIIMS, New Delhi. This is in contrast to the estimated prevalence of chronic pancreatitis of around 10-15/100,000 population in several western industrialized countries and 45.4/100,000 population in Japan. Such a high prevalence of chronic pancreatitis in India suggests that it is an endemic zone for Chronic Pancreatitis (CP) and points towards a possible genetic and/or environmental factor as playing an important etiologic role. Most patients with CP are young in our experience, the mean age being 36.7 years. The majority of patients were male i.e. 80%. The duration of disease from the time of presentation to the hospital was 48 months. Pain was the most common mode of presentation, being present in 97% of patients. The prevalence of diabetes in patients with CP was 31% but the prevalence of clinical malabsorption (maldigestion) was much lower at 5%. Among the complications of CP, pseudocysts were present in 32% of patients, bile duct stricture in 3.5% of patients, and splenic vein thrombosis in 7% of patients.

 

ETIOLOGY

There are several possible causes of pancreatitis. The most common are gallstones, which block the duct of the pancreas (for acute pancreatitis), and excessive alcohol consumption (for chronic pancreatitis).

  • Certain drugs, including azathioprine, sulfonamides, corticosteroids, nonsteroidal anti-inflammatory drugs (NSAIDs), and antibiotics such as tetracycline
  • Infection with mumps, hepatitis virus, rubella, Epstein-Barr virus (the cause of mononucleosis), and cytomegalovirus
  • Abnormalities in the structure of the pancreas or the pancreatic or bile ducts, including pancreatic cancer
  • High levels of triglycerides (fats) in the blood
  • Surgery to the abdomen, heart, or lungs that temporarily cuts off blood supply to the pancreas, damaging tissue
  • Hereditary diseases, such as cystic fibrosis
  • Injury to the abdomen
  • Idiopathic

There are some less common causes of pancreatitis such as the adverse effects of some drugs, increased calcium level in the blood, markedly raised triglycerides (a fraction of fat) in blood, trauma, hyperparathyroidism, etc.

Pathophysiology

pathophysiology of pancreatitis

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