1. Case report
A 65-year-old Chinese man with a history of prosthetic heart
valve replacement had been stabilized on warfarin anticoagulation
therapy for two years. He has no other medical conditions and his
onlymedication was warfarin. The patient was compliant regarding
the attendance of appointments and in taking the medication, and
maintained a therapeutic INR (1.7–2.5) on a maintenance daily dose
of 1.875 mg warfarin with monthly INR monitoring. The patient did
not exhibit symptoms of ecchymosis, nosebleeds, bleeding gums or
blood clots and denied drinking and smoking.
On the morning of November 10, 2013, the patient developed
macroscopic hematuria and consequently attended hospital. The
urine test results confirmed hematuria with an abnormal urinary
red blood cell count of 33201.5/l (the normal range is 0–23/l)
and an INR of 3.84. The patient did not report any change in the