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A 44-year-old woman is evaluated in the emergency department for severe, unremitting right upper quadrant abdominal pain that started 12 hours ago. The pain radiates to her right subscapular region and is associated with nausea and two episodes of bilious emesis. She has a history of diet-controlled type 2 diabetes mellitus and hyperlipidemia. Her temperature is 38.3°C (100.9°F), blood pressure is 135/85 mm Hg, pulse is 102/min, and respirations are 18/min. Physical examination demonstrates marked tenderness to palpation in the right upper quadrant with voluntary guarding, making deep palpation difficult. Laboratory results show:

TestValue
Leukocyte count14,500/mm³
Total bilirubin1.0 mg/dL
Alkaline phosphatase95 U/L
Aspartate aminotransferase (AST)32 U/L
Alanine aminotransferase (ALT)38 U/L
Amylase60 U/L

A transabdominal right upper quadrant ultrasound reveals multiple echogenic foci with posterior acoustic shadowing within the gallbladder. The gallbladder wall measures 2.5 mm in thickness, and there is no pericholecystic fluid. The common bile duct diameter is 4 mm. The sonographic Murphy sign cannot be definitively assessed due to the patient's guarding. The clinical suspicion for acute cholecystitis remains high.

Which of the following is the most appropriate next imaging study to establish the diagnosis?

  1. A
    Computed tomography of the abdomen and pelvis with intravenous contrast
  2. B
    Magnetic resonance cholangiopancreatography (MRCP)
  3. Hepatic iminodiacetic acid (HIDA) cholescintigraphyCevap
  4. D
    Repeat abdominal ultrasonography following a fatty meal
  5. E
    Endoscopic retrograde cholangiopancreatography (ERCP)

Cevap

Hepatic iminodiacetic acid (HIDA) cholescintigraphy
The correct answer is hepatic iminodiacetic acid (HIDA) cholescintigraphy. In patients presenting with a clinical picture highly suspicious for acute cholecystitis (e.g., severe right upper quadrant pain, fever, leukocytosis) who have an equivocal or non-diagnostic initial abdominal ultrasound, HIDA cholescintigraphy is the standard next step in diagnosis. While this patient's ultrasound demonstrated gallstones, it lacked definitive features of acute inflammation (such as a thickened gallbladder wall or pericholecystic fluid), and the sonographic Murphy sign could not be reliably assessed due to voluntary guarding. A HIDA scan involves the intravenous injection of a radiotracer that is taken up by the liver and excreted into the biliary tree. In acute cholecystitis, the cystic duct is typically obstructed by a gallstone, preventing the radiotracer from entering the gallbladder. Thus, non-visualization of the gallbladder on cholescintigraphy confirms the diagnosis of acute cholecystitis.

Adım Adım Çözüm

1
Analyze the clinical presentation and laboratory findings.
The patient has systemic signs of inflammation (fever, leukocytosis) and localized right upper quadrant pain, highly suggestive of acute cholecystitis. Normal liver chemistries and amylase lower the likelihood of choledocholithiasis or acute pancreatitis.
To establish the pretest probability of acute cholecystitis and rule out immediate alternate biliary pathologies.
2
Evaluate the findings of the initial right upper quadrant ultrasonography.
The ultrasound confirms cholelithiasis but lacks definitive secondary signs of acute cholecystitis (wall thickening >4 mm, pericholecystic fluid). The sonographic Murphy sign is indeterminate.
To determine if the primary diagnostic modality confirms the suspected diagnosis.
3
Determine the most appropriate next diagnostic step for high clinical suspicion with an equivocal ultrasound.
A HIDA scan is selected to directly evaluate cystic duct patency and confirm the diagnosis.
Because cholescintigraphy is highly sensitive and specific for acute cholecystitis when initial ultrasonography is non-diagnostic.

Anahtar Kavram

In patients with a high clinical suspicion for acute cholecystitis but equivocal findings on initial right upper quadrant ultrasonography, hepatic iminodiacetic acid (HIDA) cholescintigraphy is the most appropriate next imaging study to confirm the diagnosis.
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