A 40-year-old man underwent laparoscopic cholecystectomy 2 years earlier. He remains asymptomatic until 1 week before admission, when he complains of RUQ pain and jaundice. He develops a fever and has several rigor attacks on the day of admission. An ultrasound confirms the presence of gallstones in the distal CBD. The patient is given antibiotics. Which of the following should be undertaken as the next step in therapy?

**Core Concept**
The patient's symptoms and ultrasound findings suggest a biliary obstruction due to gallstones in the distal common bile duct (CBD), leading to ascending cholangitis, a bacterial infection of the bile duct.

**Why the Correct Answer is Right**
The patient is already receiving antibiotics to cover the bacterial infection. However, the definitive treatment for biliary obstruction due to gallstones involves relieving the obstruction. Endoscopic retrograde cholangiopancreatography (ERCP) with sphincterotomy is a minimally invasive procedure that allows for the removal of the gallstones and the creation of a temporary opening in the sphincter of Oddi to facilitate bile drainage. This procedure can be performed simultaneously with stone extraction, reducing the risk of recurrent obstruction.

**Why Each Wrong Option is Incorrect**
**Option A:** Administering more antibiotics alone is not sufficient to address the biliary obstruction, which is the underlying cause of the patient's symptoms.
**Option B:** Performing a percutaneous transhepatic cholangiogram (PTC) is a more invasive procedure that may be necessary in cases where ERCP is not feasible, but it is not the next step in therapy for this patient.
**Option D:** Repeating the ultrasound in 24 hours may provide additional information but does not address the urgent need to relieve the biliary obstruction.

**Clinical Pearl / High-Yield Fact**
When a patient presents with symptoms of ascending cholangitis, it is essential to promptly relieve the biliary obstruction to prevent further complications, such as sepsis and liver abscess formation.

**Correct Answer:** C. ERCP with sphincterotomy is the next step in therapy for this patient to relieve the biliary obstruction and prevent further complications.

✓ Correct Answer: D. ERCP with sphincterotomy and stone removal