Right upper quadrant pain with a negative Murphy sign
A 58-year-old woman presents with 2 days of right upper quadrant pain, fever of 38.4 °C, and vomiting. White cell count is 15.2 × 10⁹/L, bilirubin 1.8 mg/dL, and alkaline phosphatase is mildly raised. She received intravenous morphine in the emergency department 20 minutes before your scan. Ultrasound shows a distended gallbladder with a 4 mm wall and dependent sludge, but no shadowing stones and no pericholecystic fluid. She does not report tenderness when you press over the gallbladder, although she winces when you press over the adjacent liver. The referring team asks whether she needs surgery tonight.
1. What findings would push you toward acute cholecystitis rather than biliary colic, and how much weight do you give the negative sonographic Murphy sign?
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Acute cholecystitis is a constellation, not a single sign. Findings that raise probability:
- Wall thickness greater than 3 mm (here 4 mm, which is borderline but abnormal).
- Distension (roughly >8–10 cm long axis or >4–5 cm transverse).
- Pericholecystic fluid, echogenic fat, or mucosal sloughing.
- A sonographic Murphy sign.
- Failure of the gallbladder to contract, and sludge or stones.
Biliary colic usually has a thinner wall, no fever or leucocytosis, and resolves. This patient has fever, leucocytosis and a raised bilirubin, so the clinical picture already favours inflammation or obstruction.
The negative Murphy sign is one data point, not an exclusion. It has modest sensitivity and specificity, and is less reliable after opioid analgesia, in older or diabetic patients, and when the gallbladder is gangrenous. A negative sign should lower your confidence slightly, not overrule the rest of the picture. Look for secondary signs and correlate with the team.
2. What could explain the absent Murphy sign and how would you adjust your technique?
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Possible explanations:
- Morphine and other analgesia given 20 minutes earlier blunt the pain response.
- Atypical or blunted perception of pain.
- Gangrenous or perforated gallbladder, where the wall is denervated.
- The sign was not elicited properly - it requires graded pressure directly over the gallbladder under real-time observation.
Technique adjustments:
- Apply graded compression with the probe directly over the gallbladder while watching the patient's face, and compare with identical pressure over adjacent liver as a control.
- Ask the patient to point to the point of maximum pain.
- Repeat in the left lateral decubitus position, which moves the gallbladder and bowel.
- Scan the whole right upper quadrant for pericholecystic fluid, fat stranding and a dilated common bile duct (bilirubin 1.8 mg/dL warrants this).
- Do not rely on a single negative sign; state in the report that analgesia was recent.
3. If the gallbladder contains sludge but no stones, what is your differential and what do you recommend?
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Differential for sludge plus a thickened wall without stones:
- Acalculous cholecystitis - consider if the patient is critically ill, septic, or has had prolonged fasting; this patient is not obviously in that group, but it remains possible.
- Choledocholithiasis or biliary obstruction - bilirubin 1.8 mg/dL and raised alkaline phosphatase make this important; look for a dilated common bile duct.
- Hepatitis or pancreatitis - check liver enzymes and lipase.
- Peptic ulcer disease and right lower lobe pneumonia - can mimic right upper quadrant pain.
- Sludge alone can be an incidental finding and does not explain fever and leucocytosis.
Recommendation: if the ultrasound remains equivocal, a HIDA scan is the functional test of choice for acute cholecystitis. MRCP or CT is appropriate to exclude a common bile duct stone given the bilirubin. Give antibiotics and involve the surgical team; a normal ultrasound does not exclude acute cholecystitis and the decision should not be made on imaging alone.