MRCS-1501

A 41 year old lecturer is admitted with abdominal pain. He has suffered from repeated episodes of this colicky right upper quadrant pain. On examination, he has a fever with right upper quadrant peritonism. His blood tests show a white cell count of 22. An abdominal ultrasound scan shows multiple gallstones in a thick walled gallbladder, the bile duct measures 4mm. Tests show that his liver function is normal. What is the best course of action?