Gallbladder wall thickening refers to an increase in the thickness of the gallbladder’s wall. A normal gallbladder wall typically appears as a thin line; a thickness exceeding 3 millimeters is often atypical. This is not a diagnosis but a non-specific sign indicating various underlying conditions. Conditions may originate within the gallbladder or stem from issues elsewhere.
Inflammatory Conditions
Inflammation directly affecting the gallbladder is a frequent cause of wall thickening. Acute cholecystitis, often triggered by gallstones obstructing the cystic duct, leads to sudden inflammation. Patients commonly experience pain in the upper right abdomen, fever, and nausea. The gallbladder wall thickens due to edema and inflammation.
Chronic cholecystitis arises from repeated episodes of acute inflammation, typically associated with gallstones. This persistent irritation causes the gallbladder wall to become fibrotic and thickened. While symptoms might be less severe than acute cholecystitis, patients can still experience recurrent discomfort.
Acalculous cholecystitis involves gallbladder inflammation without gallstones. This condition frequently affects critically ill patients, such as those recovering from major surgery, trauma, or severe burns. It is believed to result from bile stasis and increased bile viscosity within the gallbladder.
Systemic and Extrabiliary Conditions
Gallbladder wall thickening can also stem from broader medical issues affecting other organs or fluid balance. Liver diseases, including hepatitis, cirrhosis, and portal hypertension, are common extrabiliary causes. In these conditions, fluid retention or increased pressure in the portal venous system can lead to edema.
Conditions affecting systemic fluid regulation, such as heart failure and kidney disease, can contribute to gallbladder wall thickening. These conditions often result in generalized fluid overload or impaired fluid excretion, leading to fluid accumulation in tissues. Low protein levels in the blood, known as hypoalbuminemia, can cause fluid to leak from blood vessels into surrounding tissues, resulting in edema. Additionally, severe infections like sepsis or inflammation of nearby organs, such as pancreatitis, can trigger reactive thickening.
Benign Structural Changes and Less Common Causes
Beyond inflammatory and systemic issues, certain benign structural changes and less common conditions cause gallbladder wall thickening. Adenomyomatosis is a benign condition characterized by an overgrowth of the gallbladder’s inner lining and muscle layers. This overgrowth often forms small pockets or diverticula within the wall.
Xanthogranulomatous cholecystitis is a rare, severe form of chronic inflammation that causes significant and irregular gallbladder wall thickening. Its appearance on imaging may resemble gallbladder cancer, posing a diagnostic challenge. Normal post-prandial thickening is a physiological phenomenon that occurs after eating. As the gallbladder contracts to release bile for digestion, its wall temporarily appears thicker, a normal physiological finding. This temporary thickening is often referred to as “pseudothickening” and is a key consideration to avoid misdiagnosis.
Malignant Causes
Gallbladder cancer is a serious, though less common, cause of gallbladder wall thickening. This malignancy manifests as either localized (focal) or widespread (diffuse) thickening. While inflammatory conditions are more frequent, cancer remains a concern. Imaging characteristics such as the pattern of thickening, the presence of masses, or infiltration into adjacent organs help differentiate malignant from benign causes. Therefore, when identified, further evaluation is often necessary to determine the precise cause and guide appropriate management.