Summary: A 54-year-old woman with a history of diabetes mellitus
presented in diabetic ketoacidosis. A source of infection was not
found on the initial evaluation, despite an elevated white blood
cell count. The following day she began to complain of diffuse
abdominal pain. An abdominal ultrasound was performed, which was
unremarkable except for the fact that the gallbladder was not
visualized (figure 1). Because of worsening abdominal pain, supine
and left lateral decubitus radio-graphs of the abdomen were
performed (figure 2), followed by an abdominal computed tomo-graphy
(CT) scan (figure 3).
Diagnosis
Emphysematous cholecystitis
Findings
The ultrasound reveals highly reflective echoes in the
gallbladder fossa with associated reverberation artifact,
consistent with gas (figure 1). The supine radiograph of the
abdomen reveals curvilinear lucencies outlining the margin of the
gallbladder (figure 2A). On the left lateral decubitus radiograph,
a gas/fluid level is demonstrated within the lumen of the
gallbladder (figure 2B). The CT scan shows gas within the wall and
the lumen of the gallbladder, as well as within the extrahepatic
biliary system (figure 3).
Discussion
Emphysematous cholecystitis (EC) is a relatively rare form of
acute cholecystitis in which the gallbladder wall and/or lumen
contain gas. In some cases, the pericholecystic tissues and biliary
system also contain gas. The development of EC is attributed to
bacterial invasion of the gallbladder wall by gas-forming bacteria.
The most common micro-organisms implicated are Clostridium species.
Escherichia coli is also frequently present, either alone or as a
copathogen.1 EC is more common among patients with diabetes
mellitus (up to 50%) and is associated with increased morbidity and
mortality compared with acute non-emphysematous cholecystitis.2 The
increase in morbidity and mortality is likely related to the
increased prevalence of gangrene and perforation of the
gallbladder. Unlike nonemphysematous cholecystitis, EC is more
common in males than females. EC is less likely to be associated
with gallstones (80% have stones) than nonemphysematous
cholecystitis.3 Vascular insuf-ficiency has been suggested as the
primary insult in most cases, with the ischemic gallbladder
providing an opportunity for gas-forming micro-organisms to
proliferate.1-3
The clinical presentation of EC is usually similar to
nonemphysematous cholecystitis.1,2 However, there may be a
surprising paucity of symptoms in some patients. No author has
reported a case in which the diagnosis of EC was strongly suspected
before being made radiographically or surgically.1
Although plain radiographs are often not obtained in suspected
cases of cholecystitis, they provide an opportunity to identify
abnormal collections of gas in the gallbladder fossa. Plain
radiographic findings of EC have been described in three stages:
gas within the gallbladder lumen (stage 1), the wall (stage 2), and
the pericholecystic tissues (stage 3).1,2 The differential
diagnosis of air in the gallbladder lumen alone includes a fistula
between the gallbladder or biliary system and gastrointestinal
tract, enterobiliary anastomosis, incompetent sphincter of Oddi,
and recent endoscopic retrograde cholangiopancreatogram.4
Ultrasound is frequently the first modality utilized in a
patient with clinical suspicion of acute cholecystitis. Abnormal
ultrasound findings may be present before gas becomes visible on
plain radiographs.3,5,6 These findings include a reverberation or
"comet-tail" artifact caused by an abrupt change of acoustic
impedance at a soft tissue/gas interface.5 The gallbladder itself
is usually not visualized, due to reflection of sound waves by gas
collections within the wall and/or lumen. An "effervescent"
appearance of the gallbladder has also been described, with
multiple tiny echogenic foci (gas bubbles) rising from the
dependent portion of the gallbladder lumen. The appearance has been
described as being similar to "champagne bubbles."6
CT is frequently used to evaluate abdominal pathology and is
virtually diagnostic for EC. It may also serve to identify abnormal
collections of gas or calcifications that prevent sonographic
visualization of the gallbladder.
We would like to emphasize that failure to identify the
gallbladder during abdominal ultrasound of a fasting patient with
abdominal symptoms (particularly the diabetic and elderly) should
suggest the diagnosis of emphysematous cholecystitis. A careful
search for abnormal collections of gas in the gallbladder fossa
during ultrasound examination, or further study with plain
radiographs and/or CT may save valuable time during management of
patients with this condition.
- Jolly BT, Love JN: Emphysematous cholecystitis
in an elderly woman: Case report and review of the literature.
Emerg Med 11:593-597,1993.
- Gill KS, Chapman AH, Weston MJ: The changing
face of emphysematous cholecystitis. Br J Radiol 70:986-991,
1997.
- Wav LW, Sleisenger MH: Acute cholecystitis.
In: Sleisenger MH, Fordtran JS (eds): Gastrointestinal Disease, pp
1379-1380. Philadelphia: W.B. Saunders Company, 1983.
- Lee HM, Jeffrey RB:Emphysematous
pyelonephritis with resultant emphysematous cholecystitis secondary
to hematogenous dissemination. Abdom Imag 20:169-172, 1995.
- Franquet T, Bescos JM, Barberena J, Montes M:
Acoustic artifacts and reverberation shadows in gallbladder
sonograms: Their cause and clinical implications. GastroIntest
Radiol 15:223-228,1990.
- Nemcek AA Jr., Gore RM, Vogelzang RL, Grant M:
The effervescent gallbladder: A sonographic sign of emphysematous
cholecystitis. AJR Am J Roentgenol 150:575-577, 1980.