Emphysematous Cholecystitis

Published on 19/07/2015 by admin

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 Best modality for identifying intramural/intraluminal gallbladder (GB) gas (100% sensitive)

image Gas within pericholecystic abscess or free intraperitoneal air may be present with perforation
image Other CT findings similar to uncomplicated cholecystitis
• Ultrasound

image Gas in GB wall manifests as highly echogenic reflectors with dense posterior acoustic “dirty” shadowing
image Associated with “ring-down” or “comet tail” artifact
image Intraluminal gas bubbles rise up to nondependent portions of GB (champagne sign)
image Cholelithiasis (50%), GB wall thickening, pericholecystic free fluid, and Murphy sign
• Radiography: Insensitive for detection of ectopic gas
• MR: Intraluminal and intramural gas appear as signal voids on all pulse sequences

PATHOLOGY

• Infection of GB with gas-forming organisms such as Clostridium welchii   and  Escherichia coli
• Etiology may reflect vascular compromise of cystic artery
• Major contributing factors: Atherosclerosis, diabetes, advanced age, primary infection with gas-forming organism

CLINICAL ISSUES

• Atypical, mild, or insidious presentations (especially in diabetics or elderly) often delay diagnosis and treatment
• High risk of gangrene, perforation, and sepsis if untreated, with high mortality rate (15-25%)
• Definitive treatment: Urgent cholecystectomy + parenteral antibiotics

image Cholecystostomy (as bridge to cholecystectomy) in high-risk, poor surgical candidates
image
(Left) Ultrasound image in an elderly diabetic man with fever demonstrates echogenic reflectors image in the gallbladder (GB) wall with “dirty” acoustic shadowing and “ring down” artifact image, classic for emphysematous cholecystitis.

image
(Right) Axial CECT in a patient with melanoma shows widespread liver metastases image. Gas is present within the GB lumen image, and the GB wall appears to be perforated image. Gangrenous perforation of the GB was seen at surgery, possibly related to the patient’s chemotherapy.
image
(Left) Color Doppler ultrasound in a diabetic patient shows a distended GB containing heterogeneous material, including some foci of very high-intensity echoes within the lumen and wall of the GB, and virtually no flow within the GB wall.

image
(Right) Axial CECT in the same patient shows the distended GB with gas bubbles image within the wall and lumen corresponding to the echogenic foci identified on sonography, in keeping with emphysematous cholecystitis.

TERMINOLOGY

Synonyms

• Clostridial cholecystitis

Definitions

• Rare form of acute cholecystitis due to secondary infection by a gas-forming organism

IMAGING

General Features

• Best diagnostic clue

image Curvilinear intramural gas or intraluminal gas resulting in a gas-fluid level within the gallbladder (GB)
• Location

image Lumen or wall of GB
• Size

image Ranges from several bubbles to extensive intramural or intraluminal gas
• Morphology

image Curvilinear intramural gas or intraluminal gas resulting in a gas-fluid level

Imaging Recommendations

• Best imaging tool

image NECT or CECT
image Plain radiographs should not be utilized if there is high suspicion for this diagnosis

Radiographic Findings

• Radiography

image Intraluminal (rounded) or intramural (curvilinear) gas in expected position of GB

– Air-fluid level may be present in upright or decubitus films
image Insensitive for detection of emphysematous cholecystitis: Only identified 45% of cases in 1 series

– Cases where findings are apparent on radiography tend to be more severe

CT Findings

• Best modality for identifying intramural or intraluminal GB gas (100% sensitive)

image Gas within pericholecystic abscess or free intraperitoneal air may be present with perforation
image Rarely portal venous gas due to GB wall ischemia
image Extension of gas into remainder of biliary system suggests severe form of infection
• Gallstones seen in only ∼ 50% of patients: Acalculous cholecystitis carries higher risk
• Other findings are similar to uncomplicated cholecystitis

image GB wall thickening (> 3 mm)
image GB distension > 5 cm (in short axis)
image Pericholecystic free fluid and fat stranding
image Irregularity, ulcerations, and absent enhancement of GB wall due to gangrene

MR Findings

• Intraluminal and intramural gas appear as signal voids on all pulse sequences

image Floating signal void due to gas bubbles in nondependent portion of GB (unlike stones which are dependent)
image Low signal intensity rim around margin of GB due to intramural gas
image Gas causes field inhomogeneity and susceptibility artifact at air-tissue interface
• Irregular wall thickening with areas of heterogeneous T1 and T2 hyperintensity indicative of intramural hemorrhagic necrosis
• Other findings similar to uncomplicated cholecystitis

image Low signal (T1WI and T2WI) intensity stones in dependent portion of GB (particularly in neck and cystic duct)
image Wall thickening (> 3 mm), GB distension (> 5 cm), and pericholecystic fluid

Ultrasonographic Findings

• Gas in GB wall manifests as highly echogenic reflectors with dense posterior acoustic “dirty” shadowing

image Shadowing is not anechoic (as is seen with gallstones), but is of intermediate echogenicity
image Echogenic reflectors associated with “ring-down” or “comet tail” artifact
• Intraluminal gas bubbles should be mobile on real-time US and may rise up to nondependent portions of GB similar to bubbles of champagne (champagne sign)

image Gas may change position when patient is moved
• Cholelithiasis (in 50% of patients), GB wall thickening, pericholecystic free fluid, and pericholecystic echogenic fat (due to inflammation)
• US has high specificity, but lower sensitivity, for detection of emphysematous cholecystitis

image Echogenic gas in GB lumen may be misinterpreted as gas-filled bowel, stone-filled GB, or porcelain GB

DIFFERENTIAL DIAGNOSIS

Gangrenous Cholecystitis

• No evidence of ectopic intraluminal or intramural gas
• Ultrasound: Asymmetric GB wall thickening, intraluminal membranes and heterogeneous intraluminal material due to sloughed mucosa, and ulcerations of GB wall

image May be associated with decreased vascularity of GB wall (particularly at fundus) on color Doppler
image Sonographic Murphy sign absent in 1/3 of patients
• CECT: Hypoenhancement or nonenhancement of portions of GB wall

Gas-Forming Cholangitis

• Pneumobilia is very rare finding in ascending cholangitis and may be due to gas-forming organisms or choledochoenteric fistula
• Obstructing common duct stone, biliary ductal dilatation, high-density bile, and biliary duct wall thickening suggest cholangitis
• GB should appear normal (except for intraluminal gas)

Gas-Forming Hepatic Abscess

• Multiloculated, rim-enhancing fluid collection within liver, often with multiple “satellite” abscesses and surrounding low density parenchymal edema

image Adjacent THAD secondary to hepatic hyperemia on arterial phase imaging
• Internal gas within abscess will appear similar to gas elsewhere on US: Bright echogenic reflectors with “dirty” acoustic shadowing

image May be hypo-, iso-, or echogenic “mass”
image Avascular on color Doppler imaging
image Often associated with right pleural effusion and RLL atelectasis
image May have unilocular or multiseptate appearance

Gas in Biliary Tree from Biliary-Enteric Anastomosis or Post Sphincterotomy

• Identification of biliary-enteric anastomosis and clinical history are keys to diagnosis
• Pneumobilia and gas in GB are normal findings in this situation and do not imply infection
• Plain films

image Gas centrally in common bile duct and proximal ducts
• CT

image Gas in biliary tree
image Identification of enteric anastomosis, usually from Roux-en-Y procedure

Retroperitoneal Gas

• Gas in retroperitoneum may be secondary to a number of different entities, including perforated duodenal ulcer, emphysematous pyelonephritis, and emphysematous pancreatitis

Gallbladder Filled With Gallstones

• GB may not be discretely visualized on US with posterior acoustic shadowing, mimicking gas
• Wall-echo-shadow complex and “clean” posterior acoustic shadowing allow distinction between entities

Porcelain Gallbladder

• Dense posterior acoustic shadowing on US should be “clean” (unlike “dirty” shadowing with gas)
• Calcification along anterior and posterior wall may be visible on US

Bowel Gas in Right Upper Quadrant

• Bowel gas near expected position of GB may mimic emphysematous cholecystitis on US
• Bowel should demonstrate peristalsis in real time

PATHOLOGY

General Features

• Etiology

image Infection of GB with gas-forming organisms such as Clostridium welchii   (1/3 of cases) and  Escherichia coli

– Other common genera:  Staphylococcus, S treptococcus, Pseudomonas, Enterococcus, and Klebsiella
image Secondary infection of GB complicating acute calculous or acalculous cholecystitis
image Gallstones present in ∼ 50% of patients
• Pathogenesis is thought to be partially secondary to vascular compromise of cystic artery

image Contributing factors

– Vascular compromise (atherosclerosis of cystic artery)
– Cholelithiasis
– Impaired immunity (diabetes, advanced age)

image Up to 50% of affected patients are diabetic
– Infection with gas-forming organisms (primary or secondary)

Staging, Grading, & Classification

• Grading system based on distribution of gas within GB

image Stage 1: Gas in GB lumen
image Stage 2: Gas in GB wall
image Stage 3: Gas in pericholecystic space

Gross Pathologic & Surgical Features

• Gangrenous and necrotic GB

Microscopic Features

• Extensive hemorrhagic necrosis
• Diffuse edema
• Cystic spaces in GB wall from gas pockets
• Intramural abscesses
• Endarteritis obliterans

CLINICAL ISSUES

Presentation

• Most common signs/symptoms

image Symptoms similar to uncomplicated cholecystitis in most patients

– Right upper quadrant pain, low-grade fever, nausea, vomiting, and leukocytosis
image Clinical presentation may be atypical, mild, or insidious (especially in diabetic or elderly patients), potentially delaying diagnosis and treatment

– Atypical presentations much more common with emphysematous cholecystitis than with uncomplicated cholecystitis
• Other signs/symptoms

image Gram-negative septic shock and peritonitis in setting of perforation
image Abdominal wall crepitus due to dissecting gas (very rare)
• Clinical profile
• Laboratory findings

image Leukocytosis and mild to moderate hyperbilirubinemia (due to hemolysis induced by clostridial infection)

Demographics

• Age

image 50-70 years
• Gender

image M > F
• Epidemiology

image Includes 1% of all cases of acute cholecystitis
image More frequent in patients with acalculous cholecystitis
image More common in patients with diabetes (more prone to clostridial infection)
image Atherosclerosis with decreased flow in cystic artery may be a contributing factor

Natural History & Prognosis

• High risk of gangrene, perforation, and sepsis if untreated

image Necrosis and gangrene seen in 75% at surgery
image Perforation seen in 20% of cases (5x higher risk than uncomplicated cholecystitis)
• High mortality rate (15-25%) primarily due to high incidence of GB wall gangrene and perforation

Treatment

• Urgent cholecystectomy (definitive treatment)

image Can be performed using laparoscopic or open approach
image High rate of conversion to open cholecystectomy due to extensive inflammation in GB fossa
• Cholecystostomy (as bridge to cholecystectomy) in high-risk, poor surgical candidates
• Parenteral antibiotic therapy (adjuvant treatment)
• Hypothetical adjuvant role for hyperbaric oxygenation

DIAGNOSTIC CHECKLIST

Consider

• Distinguish emphysematous cholecystitis on US from other common mimics, including GB filled with stones, porcelain GB, and bowel gas

Image Interpretation Pearls

• Curvilinear gas in GB wall or intraluminal air-fluid level on CT
• Champagne sign: Effervescent gas bubbles on ultrasound
image
(Left) Axial NECT in an elderly diabetic woman demonstrates air within the wall image and lumen image of the GB, which has a thickened wall. Note the presence of significant surrounding fat stranding and ascites image,

image
(Right) Coronal NECT in the same patient demonstrates not only the gas within the GB wall image, but also gas image extending outside the GB, in keeping with perforation. Emphysematous cholecystitis carries a high risk of both wall gangrene and perforation.
image
(Left) Ultrasound of a 79-year-old man with right upper quadrant pain shows wall thickening image and nondependent linear intramural echogenicity image. Note the “dirty” posterior shadowing image, an ultrasound artifact characteristic of gas.

image
(Right) Transverse ultrasound of the same patient shows intramural gas image and posterior “dirty” shadowing image. Note the infiltrated omentum image adjacent to the GB and fine, layering gallstones image. Gangrenous cholecystitis was confirmed at pathology.
image
(Left) NECT of an elderly man with coronary artery disease, diabetes, and abdominal pain shows intraluminal image and intramural image GB gas. Note free intraperitoneal gas image, a manifestation of GB perforation. Transmural GB necrosis and gram-negative rods were shown at pathology.

image
(Right) Longitudinal grayscale ultrasound of the GB in an elderly diabetic patient reveals an edematous wall image and intramural gas image, characteristic findings in the setting of emphysematous cholecystitis.
image
Axial NECT in an elderly patient with abdominal pain shows gas within the GB lumen image, in keeping with emphysematous cholecystitis.

image
Axial NECT show gas image within the wall of a distended GB, in keeping with emphysematous cholecystitis. A perforated gangrenous GB was found at surgery.
image
Axial NECT in an elderly patient with fever and sepsis show gas within the lumen image and wall image of the GB. At the request of the referring physicians, a percutaneous pigtail catheter image was placed into the GB lumen with no benefit to the patient, who subsequently had an open cholecystectomy.
image
Coronal NECT of an 83-year-old man with diabetes, leukocytosis, and mental status changes shows gas within the wall of the GB image. Note peripheral portal venous gas image, a rare complication of emphysematous cholecystitis. The patient recovered after open cholecystectomy.
image
AP supine radiograph of a 72-year-old woman admitted with sepsis, right upper quadrant pain, and surgically confirmed emphysematous cholecystitis shows gas within the wall image and lumen image of the GB.
image
Axial CECT of a 76-year-old man with a history of ischemic cardiomyopathy, E. coli sepsis, and right upper quadrant pain shows gas within the wall image and lumen image of the GB.
image
Transverse grayscale ultrasound of the GB in a 76-year-old diabetic presenting with fever, RUQ pain, and gram-negative bacteremia shows multiple stones image and sludge image in the GB, as well as intramural gas image, which appears as “dirty” shadowing in the fundus.
image
Axial CECT of a 66-year-old diabetic man presenting with 2-day history of chills and fever, with marked RUQ guarding on physical exam shows the generalized thickening image and gas bubble image in the GB wall. There is also an adjacent fluid collection image, consistent with a pericholecystic abscess.
image
Axial CECT in the same patient reveals the site of perforation image and gas in the GB wall image. GB perforation was confirmed at surgery.
image
Axial NECT of a 63-year-old septic male shows gas image and layering high-attenuation clot image within the GB lumen. Hemorrhagic, gangrenous cholecystitis was confirmed at laparotomy.

SELECTED REFERENCES

1. Revzin, MV, et al. The gallbladder: uncommon gallbladder conditions and unusual presentations of the common gallbladder pathological processes. Abdom Imaging. 2014. [Epub ahead of print].

 

Oyedeji, FO, et al. Emphysematous Cholecystitis. Ultrasound Q. 2014. [ePub].

Narese, F, et al. Emphysematous cholecystitis: Imaging findings. Clin Ter. 2013; 164(6):e519–e522.

Patel, NB, et al. Multidetector CT of emergent biliary pathologic conditions. Radiographics. 2013; 33(7):1867–1888.

Charalel, RA, et al. Complicated cholecystitis: the complementary roles of sonography and computed tomography. Ultrasound Q. 2011; 27(3):161–170.

Wu, JM, et al. Emphysematous cholecystitis. Am J Surg. 2010; 200(4):e53–e54.

Elsayes, KM, et al. Gastrointestinal manifestations of diabetes mellitus: spectrum of imaging findings. J Comput Assist Tomogr. 2009; 33(1):86–89.

González Valverde, FM, et al. Emphysematous cholecystitis. Clin Gastroenterol Hepatol. 2007; 5(3):e9.

Sonmez, G, et al. Education and imaging. Hepatobiliary and pancreatic: emphysematous cholecystitis. J Gastroenterol Hepatol. 2007; 22(11):2035.

Watanabe, Y, et al. MR imaging of acute biliary disorders. Radiographics. 2007; 27(2):477–495.

Koenig, T, et al. Magnetic resonance imaging findings in emphysematous cholecystitis. Clin Radiol. 2004; 59(5):455–458.

Bennett, GL, et al. Ultrasound and CT evaluation of emergent gallbladder pathology. Radiol Clin North Am. 2003; 41(6):1203–1216.

Konno, K, et al. Emphysematous cholecystitis: sonographic findings. Abdom Imaging. 2002; 27(2):191–195.

Van Dyck, P, et al. Acute emphysematous cholecystitis. JBR-BTR. 2001; 84(2):77.

Coulier, B, et al. Images in clinical radiology. Extensive emphysematous cholecystitis. JBR-BTR. 1999; 82(5):245.

Wu, CS, et al. Effervescent gallbladder: sonographic findings in emphysematous cholecystitis. J Clin Ultrasound. 1998; 26(5):272–275.

Gill, KS, et al. The changing face of emphysematous cholecystitis. Br J Radiol. 1997; 70(838):986–991.

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