The most common cause of cholecystitis are gallstones (90% of the cases). The bile becomes concentrated in the gallbladder. This later causes irritation and is probably the leading cause of inflammation (chemical inflammation). This invites infection, usually from colonization by gut organisms. 10% of the cases do not involve gallstones (achalculous cholecystitis).
Risk factors for calculous cholecystitis
- Gallstones are more common in women.
- Increasing age
- Obesity or rapid weight loss
- Native Americans are more prone. White people have a higher prevalence than black people. Scandinavians have a high prevalence of gallstones.
Acalculous cholecystitis is related to conditions associated with biliary stasis, including debilitation, major surgery, severe trauma, sepsis, long-term total parenteral nutrition (TPN), and prolonged fasting. Other causes of acalculous cholecystitis include cardiac events; sickle cell disease; Salmonella infections; diabetes mellitus; and cytomegalovirus, cryptosporidiosis, or microsporidiosis infections in patients with AIDS.
Cholecystitis is often accompanied by presence of gallstones. The classical patient with cholecystitis is described as "fat, forty, female and fertile". The main symptom is abdominal pain in the right upper part of the abdomen (right hypochondrium). Fever (from infection), nausea and vomiting may also occur.
The main clinical sign is tenderness in the right hypochondrium.
- Abdominal ultrasonography provides high sensitivity and specificity for detection of gallstones and cholecystitis. Findings suggestive of acute cholecystitis include pericholecystic fluid, gallbladder wall thickening and the presence of gallstones.
- Abdominal CT scan can also detect acute cholecystitis with sensitivity greater than 95%. MRI scans have a similar accuracy.
- A HIDA scan is the best tool in detection and diagnosis of acute cholecystitis.
- ERCP may be useful in patients at high risk for common duct gallstones if signs of common bile duct obstruction are present. It has the advantage of being therapeutic as well as diagnostic.
- Other tests include: abdominal x-ray, oral cholecystogram. A CBC shows infection by an elevated white blood cell count. All females of childbearing age should have pregnancy testing.
Initial treatment of acute cholecystitis is usually medical which usually consists of antibiotics (ampicillin, ampicillin/sulbactam, or piperacillin/tazobactam. In severe life-threatening cases Primaxin or meropenem) and supportive therapy (e.g. pain killers) followed by surgical removal of the gallbladder - cholecystectomy. Cholecystectomies can be performed as a laparotomy or laparoscopically although the established trend is for laparoscopic operations which has the benefit of shorter post-operation recovery times and smaller surgical scars.
Patients admitted for cholecystitis should receive nothing by mouth (NPO) because of expectant surgery. However, in uncomplicated cholecystitis, a liquid or low-fat diet may be appropriate until the time of surgery.