Cholecystitis is commonly due to impaction (sticking) of a gallstone within the neck of the gall bladder, leading to inspissation of bile, bile stasis, and secondary infection by gut organisms, predominantly E coli and Bacteroides species.

The Gallbladder's wall becomes inflamed. Extreme cases may result in necrosis and rupture. Inflammation often spreads to its outer covering, thus irritating surrounding structures such as the diaphragm and bowel.

Less commonly, in debilitated and trauma patients, the Gallbladder may become inflamed and infected in absence of stone impaction.

Stones in the gallbladder may not cause obstruction and the accompanying acute attack. The patient might develop a chronic, low-level inflammation which leads to a chronic cholecystitis, where the gallbladder is fibrotic and calcified.

Cholecystitis usually presents as a pain in the right upper quadrant. This is usually a constant, severe pain. The pain may be felt to 'refer' to the right flank or right scapular region at first.

This is usually accompanied by a low grade fever, vomiting and nausea.

More severe symptoms such as high fever, shock and jaundice indicate the development of complications such as abscess formation, perforation or ascending cholangitis. Another complication, gallstone ileus, occurs if the gallbladder perforates and forms a fistula with the nearby small bowel, leading to symptoms of intestinal obstruction.

Chronic cholecystitis manifests with non-specific symptoms such as nausea, vague abdominal pain, belching, diarrhea.

Diagnosis

Cholecystitis is usually diagnosed by a history of the above symptoms, as well examination findings:

fever (usually low grade in uncomplicated cases)
tender right upper quadrant +/- Murphy's sign
Subsequent laboratory and imaging tests are used to confirm the diagnosis and exclude other possible causes.

This should be suspected whenever there is acute right upper quadrant or epigastric pain.
Other possible causes include:
Perforated peptic ulcer
Acute peptic ulcer exacerbation
Amoebic liver abscess
Acute amoebic liver colitis
Acute pancreatitis
Acute intestinal obstruction
Renal colic
Acute retrocolic appendicitis

Sonography is a sensitive and specific modality for diagnosis of acute cholecystitis; adjusted sensitivity and specificity for diagnosis of acute cholecystitis are 88% and 80%, respectively. The 2 major diagnostic criteria are cholelithiasis and sonographic Murphy's sign. Minor criteria include gallbladder wall thickening greater than 3mm, pericholecystic fluid, and gallbladder dilatation.

The reported sensitivity and specificity of CT scan findings are in the range of 90-95%. CT is more sensitive than ultrasonography in the depiction of pericholecystic inflammatory response and in localizing pericholecystic abscesses, pericholecystic gas, and calculi outside the lumen of the gallbladder. CT cannot see noncalcified gallbladder calculi, and cannot assess for a Murphy's sign.

Hepatobiliary scintigraphy with technetium-99m DISIDA (bilirubin) analog is also sensitive and accurate for diagnosis of chronic and acute cholecystitis. It can also assess the ability of the gall bladder to expel bile (gall bladder ejection fraction), and low gall bladder ejection fraction has been linked to chronic cholecystitis. However, since most patients with right upper quadrant pain do not have cholecystitis, primary evaluation is usually accomplished with a modality that can diagnose other causes, as well.

X-Ray during laparoscopic cholecystectomyFor most patients, in most centres, the definitive treatment is surgical removal of the gallbladder. Supportive measures are instituted in the meantime and to prepare the patient for surgery. These measures include fluid resuscitation and antibiotics. Antibiotic regimens usually consist of a broad spectrum cephalosporin such as ceftriaxone and an antibacterial with good cover against anaerobic bacteria, such as metronidazole.

Gallbladder removal, cholecystectomy, can be accomplished via open surgery or a laparoscopic procedure. Laparoscopic procedures can have less morbidity and a shorter recovery stay. Open procedures are usually done if complications have developed or the patient has had prior surgery to the area, making laparoscopic surgery technically difficult. A laparoscopic procedure may also be 'converted' to an open procedure during the operation if the surgeon feels that further attempts at laparoscopic removal might harm the patient.

In cases of severe inflammation, shock, or if the patient has higher risk for general anesthesia (required for cholecystectomy), the managing physician may elect to have an interventional radiologist insert a percutaneous drainage catheter into the gallbladder ('percutaneous cholecystostomy tube') and treat the patient with antibiotics until the acute inflammation resolves. The patient may later warrant cholecystectomy if their condition improves.

Gall bladder perforation (GBP) is a rare but life-threatening complication of acute cholecystitis. The early diagnosis and treatment of GBP are crucial to patient morbidity and mortality.

Approaches to this complication will vary based on the condition of an individual patient, the evaluation of the treating surgeon or physician, and the facilities' capability. It can happen at the neck from pressure necrosis of an impacted calculus, or at the fundus. It can result in a local abscess, or perforation into the general peritoneal cavity; if the bile, is infected diffuse peritonitis supervenes readily and rapidly. Death can result.

A retrospective study looked at 332 patients who received medical and/or surgical treatment with the diagnosis of acute cholecystitis. Patients were treated with analgesics and antibiotics within the first 36 hours after admission (with a mean of 9 hours), and proceeded to surgery for a cholecystectomy. Two patients died and 6 patients had further complications. The morbidity and mortality rates were 37.5% and 12.5%, respectively in the present study. The authors of this study suggests that early diagnosis and emergency surgical treatment of gallbladder perforation are of crucial importance