[Vitamin K antagonist overdose induced blindness in an infant: an argument for a therapeutic educational program].

INTRODUCTION: Vitamin K antagonist (VKA) treatment is associated with significant risks and requires strict monitoring by measuring the international normalized ratio (INR), either by conventional methods or by self-measurement under medical supervision. We present a case of blindness occurring secondary to a moderate head injury, in a pediatric setting with no VKA therapeutic education.

CASE REPORT: A 7-year-old child with a single ventricle had been operated on for a total cavopulmonary shunt at the age of 5 years. He took VKA therapy with an INR target between 2 and 3. After a head trauma, he had a frontal hematoma. His parents did not request a medical exam and did not check his INR. Six days after the injury, the INR was 2.23. The parents went to the emergency ward because the child had bilateral orbital hematoma. At admission, the INR was 5.6. The orbital hematoma was surgically evacuated in the emergency setting. Unilateral blindness occurred and remains a sequelae of the overdose.

COMMENTS AND CONCLUSION: VKA treatment requires close supervision to prevent overdose, whose complications such as internal bleeding can have terrible consequences such as the case of blindness reported herein. This case report is a strong argument in favor of an educational program for children with VKA treatment.