Posted by voda from IP 134.174.110.5 on April 03, 2006 at 07:54:51:
In Reply to: q posted by armal on March 31, 2006 at 16:28:07:
AAC most commonly occurs in hospitalized patients without prior gallbladder disease and severe concomitant medical and surgical conditions. Known populations at risk include patients who are postoperative (especially after abdominal surgery), patients with extensive burns, patients with trauma, and patients receiving prolonged parenteral nutrition. Other reported associations include prolonged fasting, use of high-dose opioid analgesics, and mechanical ventilation.
The most frequent physical and laboratory findings include fever, right upper quadrant (RUQ) pain, nausea, leukocytosis, and elevation of liver-associated enzymes and bilirubin. All of these clinical parameters are nonspecific. In almost all instances in which it can be evaluated, abdominal pain is present; however, it is often not localized to the RUQ. Fever is present in two thirds of patients, and leukocytosis and liver function abnormalities are present in approximately 80%.
Early imaging evaluation is required, and frequently, multiple diagnostic tests are performed. No single imaging study is ideal. The 3 primary imaging modalities often are complementary, with ultrasound (US) or CT providing anatomic information and evaluation of adjacent structures and cholescintigraphy providing functional information.
US and cholescintigraphy should be the initial imaging tests performed to evaluate possible AAC.
CT is preferred if other differential possibilities are more likely or if CT needs to be performed for another indication.
While it is unusual for acalculous cholecystitis to occur in the presence of a normal gallbladder, on both US and cholescintigraphy examinations, this finding can occur early in the course of the disease. In the patient with continued clinical deterioration who is either unable to be evaluated clinically or in whom clinical evaluation fails to demonstrate an alternative source, many authors recommend maintaining a low threshold for instituting empiric minimally invasive therapy in the form of percutaneous cholecystostomy.
Usually, sonography is the first examination performed in cases of possible acalculous cholecystitis
Hepatobiliary scintigraphy (HBS) is a physiologic test that evaluates hepatic bile formation, excretion, and ductal functional patency.
HBS is accurate in the diagnosis of calculous cholecystitis since the primary event is believed to be cystic duct obstruction. In acalculous cholecystitis, functional obstruction usually occurs in the disease process but is variable and is not the primary process. Not surprisingly, the sensitivity and specificity of the test are decreased in this setting.
In general, diagnostic quality studies with augmentation yield a sensitivity of 80-90% and a specificity of 90-100%.
Once the diagnosis of AAC is made, the gallbladder should be removed or drained.
Therapeutic options for acalculous cholecystitis include open and laparoscopic cholecystectomy, surgical cholecystostomy, percutaneous cholecystostomy or aspiration, and endoscopic transcystic drainage.