Acute cholecystitis is primarily caused by the presence of gallstones that obstruct the cystic duct, which is the duct that connects the gallbladder to the common bile duct. When the cystic duct becomes blocked, bile cannot flow out of the gallbladder, leading to the accumulation of bile and increased pressure within the gallbladder. This, in turn, triggers inflammation and irritation of the gallbladder wall, resulting in acute cholecystitis.
Gallstones are solid deposits that form in the gallbladder, primarily composed of cholesterol or bilirubin. The exact cause of gallstone formation is not fully understood, but certain factors contribute to their development. These factors include:
- Imbalance in bile components: Changes in the composition of bile, such as increased cholesterol or decreased bile salts, can promote gallstone formation.
- Gallbladder motility issues: Reduced gallbladder emptying or inefficient contraction of the gallbladder can lead to bile stasis, increasing the likelihood of gallstone formation.
- Obesity: Obesity is a significant risk factor for gallstone formation and subsequent acute cholecystitis. Excess weight and adipose tissue can contribute to an imbalance in bile composition.
- Age and gender: Gallstones are more common in older individuals, particularly females, due to hormonal influences. Estrogen, for instance, increases cholesterol secretion in bile.
- Rapid weight loss or fasting: A sudden and significant reduction in weight, as well as prolonged fasting or very low-calorie diets, can increase the risk of gallstone formation.
- Other risk factors: Certain medical conditions, such as diabetes, liver cirrhosis, and hereditary blood disorders like sickle cell anemia, can also predispose individuals to gallstone formation and acute cholecystitis.
While gallstones are the primary cause of acute cholecystitis, other factors can contribute to its development. These may include infections, trauma to the gallbladder, or rarely, tumors blocking the cystic duct.
It’s important to note that not all individuals with gallstones develop acute cholecystitis, and the condition can occur without the presence of gallstones in some cases, such as acalculous cholecystitis. However, gallstones remain the most common underlying cause of acute cholecystitis.