A 50 year old lady presented with history of pain upper abdomen, nausea, and decreased appetite for 5 days. She had undergone cholecystectomy 2 years back. Her bilirubin was 10 mg/d1, SGPT 900 1U/L SGOT 700 IU/L and serum alkaline phosphatase was 280 IU/L. What is the most likely diagnosis ?