Methemoglobinemia in children as a differential diagnosis of cyanosis

: Methemoglobinemia is characterized by cyanosis with various degrees of severity. Symptoms range from asymptomatic to unconsciousness and death. Although cyanosis caused by methemoglobinemia is well-documented in the literature, it is rare and the consequences can be fatal. The cause of methemoglobinemia can be environmental, acquired, congenital or a combination of the above. Among the potential sources for methemoglobinemia are local anaesthetics that are in common use in hospitals and clinics, some of which can be purchased without prescription. Although these drugs are considered to be safe, they can still induce methemoglobinemia and can be life-threatening. In this review we describe patients admitted to the Pediatric Intensive Care Unit during the year 2000 suffering from cyanosis and diagnosed as having methemoglobinemia.