What is the diagnosis and treatment for a critically ill patient with a thickened edema and hyperemic appearing gallbladder without definitive evidence of cholelithiasis?

Acute Acalculous Cholecystitis (ACC)

The imaging findings of gallbladder wall thickening with edema and hyperemia without stones in a critically ill patient are highly suggestive of acute acalculous cholecystitis, which requires urgent diagnostic confirmation with Tc-99m cholescintigraphy and prompt surgical intervention (cholecystostomy or cholecystectomy) to prevent progression to gangrene and perforation. 1

Diagnosis

Clinical Context and Suspicion

• ACC is an underdiagnosed but serious complication in critically ill patients that progresses rapidly to spontaneous gallbladder gangrene and perforation without prompt treatment 1
• The condition most commonly follows trauma, biliary surgery, or occurs in critically ill/ventilated patients 1
• Localizing right upper quadrant pain and tenderness are often absent in sedated or ventilated patients, requiring a high index of suspicion 1
• The only differentiating laboratory features may be elevation in alkaline phosphatase or gamma-glutamyl transferase 1
• Unexplained fever may be the first sign in 25% of patients 2

Imaging Interpretation

Ultrasound findings of gallbladder wall thickening, edema, and hyperemia are suggestive but NOT diagnostic of ACC because these changes are frequently present in critically ill patients who do not develop ACC 1

Ultrasound Limitations:

• Single ultrasound sensitivity ranges from 29% to 92% with specificity of 96% 1
• Serial ultrasound examinations showing progression of abnormalities have excellent negative predictive value when initial diagnosis is uncertain 1
• Three key ultrasound findings (in absence of stones): thickened gallbladder wall, enlarged tender gallbladder, and pericholecystic fluid are present in almost 90% of ACC cases 2

Confirmatory Testing

Tc-99m cholescintigraphy (HIDA scan) is the imaging examination of choice for suspected acalculous cholecystitis 1

• Sensitivity of 80-90% for acute cholecystitis based on non-visualization of gallbladder within 60 minutes 1
• Most sensitive diagnostic test because ACC is typically associated with cystic duct obstruction 1
• Important caveat: Specificity may be limited in critically ill patients where non-visualization can occur without inflammation despite cholecystokinin administration 1
• Some ACC cases related to direct inflammation (not obstruction) may produce false-negative results 1

Alternative Advanced Imaging:

• CT with IV contrast can detect wall enhancement and adjacent liver parenchymal hyperemia, which is an early finding in ACC 1
• CT has superior sensitivity over ultrasound in some studies (92% vs 79%) 1
• MRI with MRCP may play a role when other imaging is equivocal, though often impractical in critically ill patients 1

Treatment

Surgical Intervention Urgency

ACC represents a surgical emergency due to rapid progression to advanced disease 2, 3

• 70% of patients have advanced disease (gangrene, empyema, or perforation) at operation 2
• 40% of patients operated >48 hours after symptom onset had gallbladder perforation versus only 8% when operated within 48 hours 2
• ACC is associated with high morbidity and mortality, particularly when perforation occurs 2, 3, 4

Surgical Options:

Two primary surgical approaches depending on patient condition and gallbladder viability:

1. Cholecystostomy (percutaneous or surgical tube drainage):

   • Preferred for critically ill patients who cannot tolerate cholecystectomy 1, 5
   • Can be performed under local anesthesia 3
   • Led to resolution of inflammatory process in all patients in one series 5
   • Both diagnostic and therapeutic 1

2. Cholecystectomy (laparoscopic or open):

   • Reserved for patients with extensive gallbladder necrosis 5
   • Can be performed laparoscopically at bedside in some units 1
   • Definitive treatment when patient condition permits 1

Supportive Management:

• Broad-spectrum antibiotics should be initiated, though no evidence supports improved outcomes from hepatically-excreted antibiotics specifically 1
• Fluid resuscitation and hemodynamic support 5

Critical Pitfalls

• Do not dismiss ultrasound findings as nonspecific in critically ill patients—maintain high clinical suspicion and proceed to HIDA scan 1
• Do not delay surgical intervention beyond 48 hours once diagnosis is established, as perforation risk increases dramatically 2
• Hypotension is central to ACC pathogenesis (mucosal ischemia with elevated intraluminal pressure), so ACC represents another organ failure in multiple organ dysfunction syndrome 5
• High-dose narcotic agents may be a contributory factor 1
• ACC can occur in otherwise healthy young patients, not exclusively in critically ill populations 6