Diagnostic Ultrasound - Abdomen and Pelvis

Acute Acalculous Cholecystitis
Diagnoses: Biliary System
TERMINOLOGY
• Acute necroinflammatory disease of gallbladder (GB) not
related to gallstone
IMAGING
• GB wall thickening (> 4 mm)
• Hypoechoic, layered/striated appearance
• GB distension
• Positive sonographic Murphy sign
• Critical illness with sepsis, shock, recent surgery, trauma, or
burns
• Sonographic Murphy sign may not be elicited in patient
who is obtunded, unconscious, or sedated
• US is first-line
• HIDA for indeterminate ultrasound
• CT for complications
TOP DIFFERENTIAL DIAGNOSES
• Acute calculous cholecystitis
KEY FACTS
• Sympathetic GB wall thickening
• Hyperplastic cholecystosis
• Gallbladder mucocele
PATHOLOGY
• More commonly seen in critically ill patients with multiple
risk factors
• Acalculous cholecystitis constitutes ~ 10% of acute
cholecystitis
• Pathogenesis is multifactorial
• Combination of Increased bile viscosity and wall Ischemia
CLINICAL ISSUES
• Worse prognosis than acute calculous cholecystitis
• 40% develop complications such as gangrene, perforation,
and empyema
• Mortality rate up to 30%
(Left) Longitudinal oblique
ultrasound of acalculous
cholecystitis shows that the
gallbladder is distended with
sludge and wall thickening st.
A small amount of
pericholecystic fluid and no
gallstones are noted. (Right)
Left lateral decubitus
ultrasound of acalculous
cholecystitis shows sludge ſt,
wall thickening st, and a
pericholecystic collection .
No gallstones were found.
(Left) Transverse ultrasound of
perforated acalculous
cholecystitis shows an
irregularly thickened
gallbladder wall st with
intramural edema. There is
localized pericholecystic fluid
with an abscess that is not
shown. (Right) A 4-hour image
from a HIDA scan in a patient
with acalculous cholecystitis
shows lack of activity in the
gallbladder fossa ſt. Activity
is seen in small bowel st.
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