•Temperature 38°C, pulse 70 bpm, BP 129/64mmHg, SaO₂ 98-100% on RA.

•Hydration is satisfactory.

•Examination of the hands reveals no clubbing and normal-appearing palmar creases.

•Head and neck examination is unremarkable.

•Cardiovascular: HS dual, no murmur.

•His chest is clear on auscultation.

•Abdominal examination reveals a soft abdomen, with right upper quadrant tenderness. Murphy’s sign is negative.

•No signs of oedema.

Investigations

•CBC:

–WBC 11.7 x 10⁹/L;

–haemoglobin 13.3g/dL;

–platelets 294 x 10⁹/L.

•Bilirubin 35μmol/L.

•ALP 123 IU/L.

•ALT 221 IU/L.

•Clotting profile is normal.

•Amylase 98 IU/L.

•Blood gases: no acidosis.

•A screening chest X-ray and abdominal X-ray are also done which are normal.

What is your working diagnosis?

In view of the right upper quadrant pain, tea-coloured urine, fever and deranged liver function tests, biliary obstruction needs to be excluded.

Imaging including ultrasonography of the hepatobiliary and pancreatic system (USG HBP) or computed tomography with contrast of the abdomen are initial investigations for biliary obstruction.

A USG HBP is done, showing a 1.8cm dilated common bile duct and dilated intrahepatic ducts but the distal common bile duct is obscured.

What would you do next?