Congenital Methemoglobinemia: Thinking Out of a Blue Box

Abstract

Though cyanosis in a new-born baby is very common in many congenital heart diseases, one of the causes of congenital cyanosis is congenital methemoglobinemia, which is a very rare entity. We are reporting a case of a 19-day-old male newborn who presented with complaints of increased frequency of stool, irritability, cyanosis, and tachypnea. Eventually, he was diagnosed with congenital methemoglobinemia based on his blood methemoglobin level, which was 6.5% of total hemoglobin, and successfully treated with intravenous methylene blue at 2 mg/kg. We discuss the importance of this rare case in the differential diagnosis of congenital cyanosis.