Introduction

A 32 year-old man presented with complaints of nose bleeding and mild postprandial abdominal pain for 3 days. The patient had prior history of rheumatic heart disease. Four weeks prior to the onset of symptoms the patient had undergone a double mechanical valve replacement using a number 21 Masters St Jude valve in the aortic position and a number 29 Masters St Jude valve in the mitral position. He was started on warfarin at that time. A few days prior to admission, the patient developed an upper respiratory infection and was placed on a 4-day course of azithromycin. Physical examination was unremarkable. Rectal examination revealed no gross blood, however occult blood test was positive. At the time of this visit the haemoglobin was 14 g/dl and the International Normalised Ratio (INR) was 12. In view of these results the patient was given 5 mg of vitamin K orally and sent home with close follow-up. The following day . . . [Full text of this article]