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. (See Etiology.) For more information, see the Medscape Reference article Acalculous Cholecystopathy.

Uncomplicated cholecystitis has an excellent prognosis, with a very low mortality rate. Once complications such as perforation/gangrene develop, the prognosis becomes less favorable. Some 25-30% of patients either require surgery or develop some complication.

The most common presenting symptom of acute cholecystitis is upper abdominal pain. Signs of peritoneal irritation may be present, and in some patients, the pain may radiate to the right shoulder or scapula. Frequently, the pain begins in the epigastric region and then localizes to the right upper quadrant (RUQ). Although the pain may initially be described as colicky, it becomes constant in virtually all cases. Nausea and vomiting are generally present, and patients may report fever.

Most patients with acute cholecystitis describe a history of biliary pain. Some patients may have documented gallstones. Acalculous biliary colic also occurs, most commonly in young to middle-aged females. The presentation is almost identical to calculous biliary colic with the exception of reference range laboratory values and no findings of cholelithiasis on ultrasound. Cholecystitis is differentiated from biliary colic by the persistence of constant severe pain for more than 6 hours.

Patients with acalculous cholecystitis may present similarly to patients with calculous cholecystitis, but acalculous cholecystitis frequently occurs suddenly in severely ill patients without a prior history of biliary colic. Often, patients with acalculous cholecystitis may present with fever and sepsis alone, without history or physical examination findings consistent with acute cholecystitis.

Elderly patients (especially patients with diabetes) may present with vague symptoms and without many key historical and physical findings. Pain and fever may be absent, and localized tenderness may be the only presenting sign. Elderly patients may also progress to complicated cholecystitis rapidly and without warning.

The pediatric population may also present without many of the classic findings. Children who are at higher risk for developing cholecystitis include patients with sickle cell disease, seriously ill children, those on prolonged TPN, those with hemolytic conditions, and those with congenital and biliary anomalies.

Bacterial proliferation within the obstructed gallbladder results in empyema of the organ. Patients with empyema may have a toxic reaction and may have more marked fever and leukocytosis.The presence of empyema frequently requires conversion from laparoscopic to open cholecystectomy.

In rare instances, a large gallstone may erode through the gallbladder wall into an adjacent viscus, usually the duodenum. Subsequently, the stone may become impacted in the terminal ileum or in the duodenal bulb and/or pylorus, causing a gallstone ileus.

Emphysematous cholecystitis occurs in approximately 1% of cases and is noted by the presence of gas in the gallbladder wall from the invasion of gas-producing organisms, such as Escherichia coli, Clostridia perfringens, and Klebsiella species. This complication is more common in patients with diabetes, has a male predominance, and is acalculous in 28% of cases. Because of a high incidence of gangrene and perforation, emergency cholecystectomy is recommended. Perforation occurs in up to 15% of patients. For more information, see the Medscape Reference article Emphysematous Cholecystitis. Other complications include sepsis and pancreatitis.

Treatment of cholecystitis depends on the severity of the condition and the presence or absence of complications. Uncomplicated cases can often be treated on an outpatient basis; complicated cases may necessitate a surgical approach. In patients who are unstable, percutaneous transhepatic cholecystostomy drainage may be appropriate. Antibiotics may be given to manage infection. Definitive therapy involves cholecystectomy or placement of a drainage device; therefore, consultation with a surgeon is warranted.

Consultation with a gastroenterologist for consideration of ERCP may also be appropriate if concern exists of choledocholithiasis.

Patients admitted for cholecystitis should receive nothing by mouth because of expectant surgery. However, in uncomplicated cholecystitis, a liquid or low-fat diet may be appropriate until the time of surgery.

For acute cholecystitis, initial treatment includes bowel rest, intravenous hydration, correction of electrolyte abnormalities, analgesia, and intravenous antibiotics. For mild cases of acute cholecystitis, antibiotic therapy with a single broad-spectrum antibiotic is adequate.

Outpatient treatment may be appropriate for cases of uncomplicated cholecystitis. If a patient can be treated as an outpatient, discharge with antibiotics, appropriate analgesics, and definitive follow-up care. Criteria for outpatient treatment include the following

• Afebrile with stable vital signs.
• No evidence of obstruction by laboratory values.
• No evidence of common bile duct obstruction on ultrasonography.
• No underlying medical problems, advanced age, pregnancy, or immunocompromised condition.
• Adequate analgesia.
• Reliable patient with transportation and easy access to a medical facility.
• Prompt follow-up care.

Laparoscopic cholecystectomy is the standard of care for the surgical treatment of cholecystitis. Studies have indicated that early laparoscopic cholecystectomy resulted in shorter total hospital stays with no significant difference in conversion rates or complications. The ACR 2010 criteria state that laparoscopic cholecystectomy is the primary mode of treatment for acute cholecystitis.

Early operation within 72 hours of admission has both medical and socioeconomic benefits and is the preferred approach for patients treated by surgeons with adequate experience in laparoscopic cholecystectomy.Immediate cholecystectomy or cholecystotomy is usually reserved for complicated cases in which the patient has gangrene or perforation.

Endoscopic retrograde cholangiopancreatography (ERCP) allows visualization of the anatomy and may be therapeutic by removing stones from the common bile duct.

Studies indicate that this procedure may be safe as initial, interim, or definitive treatment of patients with severe acute cholecystitis who are at high operative risk for immediate cholecystectomy.