Introduction Acquired methemoglobinemia is due to various compounds (mainly nitrates in the water) that activate the oxidation of hemoglobin to form methemoglobin (which is unable to carry oxygen), thereby causing cyanosis when reaching levels of 15% or more. Young children and infants are more predisposed by a transient methemoglobin reductase deficiency. We present a unique case seen at the hospital over the past 6 years, of methemoglobinemia.
Case report A newborn of 29 days of age who presented generalized cyanosis within few hours of evolution, without apparent relationship with gastrointestinal or respiratory symptoms. The week before he was admitted with a similar picture (milder and self-limited) diagnosed as a possible gastroesophageal reflux. The mother related boiling bottles with celery greens (average trend to accumulate nitrates). A physical examination presented only central cyanosis saturating 93% to ambient air. The tests showed an additional 60% of methemoglobin. It was treated with intravenous 5 mg methylene blue, repeating the same dose about an hour later with post methaemoglobin of 1.1% and a normal acid base balance.
Discussion methemoglobinemia is one of the main causes to be considered in patients who presents a picture of central cyanosis with normal oxygen saturation. Its timely diagnosis allowed us to initiate treatment as soon as possible, obtaining a good response in cases of acquired methemoglobinemia.