Diagnostic Ultrasound - Abdomen and Pelvis

Dilated Gallbladder
912
Differential Diagnoses: Biliary System
DIFFERENTIAL DIAGNOSIS
Common
• Physiologic
• Acute Calculous Cholecystitis
• Acute Acalculous Cholecystitis
Less Common
• Mucocele/Hydrops
• Drugs
• Post Vagotomy
• Choledochal Cyst
• Gallbladder Carcinoma
• Gallbladder Hemorrhage
• Acute Hemorrhagic Cholecystitis
• Other Causes of Cholecystitis
○ Obstruction post biliary stenting
○ Ischemia post transarterial hepatic chemoembolization
or in the setting of severe hypotension or sepsis
○ Infections
Rare but Important
• Mucin Producing Gallbladder Carcinoma
• Torsion/Volvulus
• Systemic Lupus Erythematosus
ESSENTIAL INFORMATION
Key Differential Diagnosis Issues
• Determine if the gallbladder is obstructed or not
○ Look for an intrinsic lesion such as stone, polyp, or mass
○ Look for an extrinsic mass, collection, or inflammation
• Differentiate acute surgical from nonsurgical gallbladder
distension
• Look for secondary signs of inflammation
○ Wall thickness, pericholecystic fluid, or inflamed fat
• Correlate with patient history, signs, and laboratory results
Physiologic Dilatation
• Distended > 5 x 5 x 10 cm
• Otherwise normal appearing gallbladder
• Secondary to
○ Prolonged fasting
○ Postoperative state
○ Total parenteral nutrition
○ Post vagotomy
Acute Calculous Cholecystitis
• Distension with
○ Gallstones
○ Wall thickening
○ Pericholecystic fluid
• Presence of sonographic Murphy sign is key for diagnosis of
acute cholecystitis
Acute Acalculous Cholecystitis
• Distension without gallstones
• Sludge, wall thickening and gallbladder
• Ill patient with sepsis, postoperative or post trauma
• Increased risk of wall necrosis and gangrene
• Difficult diagnosis as sonographic Murphy sign may not be
elicited in obtunded or sedated patients
• Confirm with HIDA
• Or diagnostic/therapeutic percutaneous cholecystotomy
Drugs
• Various drugs may decrease gallbladder contraction
○ Including atropine, somatostatin, arginine, nifedipine,
progesterone, trimebutine, loperamide, and
ondansetron
Unusual Causes of Acute Cholecystitis
• Ischemic cholecystitis
○ Following transarterial hepatic chemoembolization for
liver malignancy
○ Following prolonged hypotension post trauma,
hemorrhage, sepsis
• Following metal bile duct stent placed for malignant biliary
stricture
○ Cholecystitis from cystic duct obstruction
Gallbladder Hemorrhage
• Mobile internal echoes
• Increasing echogenic luminal content over time if active
bleeding
• Retracting clot
• Post hepatobiliary intervention or biopsy
• Post trauma or surgery
• Secondary to neoplasms, anticoagulation or bleeding
disorder
• Post aneurysm rupture
• Present with
○ Pain
○ Jaundice
○ Hemobilia
○ Hematemesis
○ Hematochezia
Acute Hemorrhagic Cholecystitis
• Intraluminal hemorrhage with signs of acute cholecystitis
• Underlying
○ Atherosclerosis
○ Diabetes
○ Bleeding diathesis
○ Anticoagulation therapy
Gallbladder Carcinoma
• Typically thick irregular wall or solid tumor in lumen
• Extension into liver
• Gallstones typically present
• Mucin producing variant may produce distended mucin
filled gallbladder
○ Smaller mural/polypoid mass
Mucocele/Hydrops
• Distended gallbladder filled with watery mucoid material
• Thin gallbladder wall
• Secondary to Gallbladder outlet obstruction
○ Obstructing polyp or stone
○ Obstructing masses such as pancreaticobiliary and
ampullary carcinoma
○ Acute or chronic pancreatitis
• Courvoisier sign