Biliary Colic vs Cholecystitis: Ultrasound Findings & Antibiotics/OR Timing

Right-upper-quadrant pain is common—but only some patients need urgent surgery. This pathway separates biliary colic (transient cystic duct obstruction) from acute cholecystitis(persistent obstruction with inflammation), adds sensible labs and imaging, and clarifies antibiotics, ERCP/HIDA, and timing for laparoscopic cholecystectomy.

Typical Presentations

• Biliary colic: postprandial RUQ/epigastric pain, steady (not colicky), peaks within an hour, resolves within 6–8 h, afebrile, normal WBC.
• Acute cholecystitis: persistent RUQ pain (>6 h), fever, tachycardia, leukocytosis, focal peritoneal signs, positive Murphy sign on exam.
• Complications to keep in mind: choledocholithiasis (CBD stone), ascending cholangitis, gallstone pancreatitis.

Initial Workup

• Labs: CBC, CMP (AST/ALT, ALP, bilirubin), lipase, pregnancy test when relevant.
• Patterns: isolated leukocytosis suggests cholecystitis; cholestatic LFTs (↑ALP/↑bilirubin) imply CBD obstruction; elevated lipase suggests gallstone pancreatitis.
• ECG/troponin if atypical epigastric pain or risk factors—don’t miss cardiac mimics.

Ultrasound (first-line imaging)

• Stones/sludge within gallbladder.
• Sonographic Murphy sign: maximal tenderness when the probe is over the gallbladder.
• Wall thickening (≈>3 mm), pericholecystic fluid, distended gallbladder.
• CBD diameter: dilated duct raises concern for choledocholithiasis (context- and age-dependent).
• Interpretation:
  • Stones + typical pain but no inflammatory signs → biliary colic.
  • Stones + sonographic Murphy ± wall thickening/fluid → acute cholecystitis (highly likely).
  • No stones but strong clinical picture → consider acalculous cholecystitis (critically ill) or use HIDA.

When to Use HIDA, MRCP, or ERCP

• HIDA scan: if ultrasound equivocal and suspicion persists; nonvisualization of gallbladder supports cystic duct obstruction/cholecystitis.
• MRCP: noninvasive evaluation for suspected CBD stones when ultrasound is indeterminate.
• ERCP: therapeutic for confirmed or highly likely choledocholithiasis/cholangitis (fever, jaundice, RUQ pain ± sepsis); get GI/advanced endoscopy involved early.

ED/Initial Management

• NPO, IV access, analgesia (avoid meperidine dogma—use multimodal: acetaminophen, opioids if needed), antiemetics, IV fluids.
• Antibiotics for suspected cholecystitis or cholangitis (examples; follow local protocols/allergies):
  • Moderate severity: ceftriaxone + metronidazole or ampicillin–sulbactam.
  • Severe/septic or high local resistance: piperacillin–tazobactam or carbapenem per ID input.
• No antibiotics are needed for simple biliary colic without systemic signs.

Who Goes to the OR, and When?

• Acute cholecystitis: early laparoscopic cholecystectomy, ideally within the index admission (often within 24–72 h) after resuscitation and antibiotics.
• Biliary colic: elective lap chole to prevent recurrence; arrange timely outpatient surgery if symptoms are recurrent or quality of life impacted.
• High-risk/sick patients (sepsis, severe comorbidities, poor operative candidacy): consider percutaneous cholecystostomy for source control with interval surgery later.

Choledocholithiasis & Cholangitis Pathway (short version)

• High likelihood (visible CBD stone, bilirubin markedly elevated, cholangitis): antibiotics + urgent ERCP for duct clearance → lap chole during same admission when feasible.
• Intermediate likelihood: MRCP or EUS to confirm; proceed to ERCP if positive.

Gallstone Pancreatitis (brief)

• Resuscitation, analgesia, early enteral nutrition when tolerated; avoid routine prophylactic antibiotics.
• Early lap chole during the same hospitalization for mild cases after clinical improvement; delay if severe/necrotizing until stabilized.

Discharge vs Admission

• Biliary colic: discharge when pain controlled, tolerating PO, afebrile, normal labs; provide low-fat diet advice and surgical follow-up.
• Cholecystitis: admit for antibiotics, monitoring, and early surgery planning.

Pearls & Pitfalls

• Localized peritonitis or sepsis → don’t delay surgeon involvement.
• Normal LFTs do not exclude CBD stones; clinical context matters.
• Beware elderly/diabetic patients—attenuated exam but higher complication rates.

Patient FAQs

“Can I just pass the stone?” Gallbladder stones don’t “pass” from the gallbladder; they intermittently block the cystic duct. Recurrent pain is common until the gallbladder is removed.

“Why surgery if antibiotics help?” Antibiotics treat inflammation and infection but not the obstructing stones—definitive management is cholecystectomy.

References & Notes

Practical RUQ pathway: ultrasound first, use HIDA/MRCP selectively, give antibiotics for cholecystitis/cholangitis, clear the duct when needed (ERCP), and perform early laparoscopic cholecystectomy during the index admission. Local protocols vary—follow institutional guidance. Educational only.