Cholecystitis overview

# Overview
Cholecystitis is inflammation of the gallbladder.

# Historical Perspective
Xanthogranulomatous cholecystitis (XGC) is a rare form of gall bladder disease which mimics gallbladder cancer although it is not cancerous. It was first discovered and reported in the medical literature in 1976 by J.J. McCoy, Jr., and colleagues.. Eosinophilic cholecystitis was first described in 1949..

# Classification

# Pathophysiology

# Causes

# Differentiating Cholecystitis overview from Other Diseases

# Epidemiology and Demographics

# Risk Factors

# Screening

# Natural History, Complications, and Prognosis

## Natural History

## Complications

## Prognosis

# Diagnosis

## History and Symptoms
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, and diarrhea.

## Physical Examination
Cholecystitis is usually diagnosed by a history of the symptoms, as well as examination findings like fever (usually low grade in uncomplicated cases) and a tender right upper quadrant +/- Murphy's sign. Subsequent laboratory and imaging tests are used to confirm the diagnosis and exclude other possible causes.

## Laboratory Findings
Laboratory values may be notable for an elevated alkaline phosphatase, possibly an elevated bilirubin (although this may indicate choledocholithiasis), and possibly an elevation of the WBC. CRP (C-reactive protein) is often elevated. The degree of elevation of these laboratory values may depend on the degree of inflammation of the gallbladder. Patients with acute cholecystitis are much more likely to manifest abnormal laboratory values, while in chronic cholecystitis the laboratory values are frequently normal.

## Electrocardiogram
Acute cholecystitis presents as pain in the epigastrium, which can be confused with an acute myocardial infarction. ECG can be useful in excluding an MI.

## CT
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.

## Ultrasound
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 includes gallbladder wall thickening greater than 3mm, pericholecystic fluid, and gallbladder dilatation.  

## Other Diagnostic Studies
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 gallbladder to expel bile (gallbladder ejection fraction), and a low gallbladder 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.  

## Diagnostic Criteria
The diagnostic criteria for acute cholecystitis according to Tokyo guidelines is as follows.
Diagnosis: The presence of one local sign or symptom, one systemic sign, and a confirmatory finding on an imaging test.

## Severity Grading
The severity grading for acute cholecystitis according to Tokyo guidelines is as follows.

# Treatment

## Medical Therapy

## Surgery

## Prevention