title: A 5-hour-old male neonate with cyanosis.
abstract: Methemoglobin (MetHb) is a form of hemoglobin in which heme iron is oxidized and unable to bind oxygen; its normal basal production is counteracted by an efficient MetHb-reduction pathway. The causes of methemoglobinemia are classified as congenital or acquired. Shortly after his birth, the 5-hour-old male Caucasian neonate, whose case we present herein, developed central cyanosis that was unresponsive to supplemental oxygen. Oxygen saturation as determined via pulse oximetry was normal. In contrast, blood gas testing by multiwave CO-oximetry indicated decreased fractional oxyhemoglobin and an elevated MetHb fraction. The patient was subsequently diagnosed with a congenital cytochrome b5 reductase deficiency. This case emphasizes causes of methemoglobinemia and differences among analytical methods used to measure oxygen status when MetHb is present.
authors.affiliation: Departments of Clinical Pathology and.
authors.forename: Melkon
authors.initials: M
authors.lastname: DomBourian
authors.affiliation: Pediatrics, William Beaumont Hospital and Beaumont Children's Hospital, Oakland University William Beaumont School of Medicine, Royal Oak, Michigan.
authors.forename: Alok
authors.initials: A
authors.lastname: Ezhuthachan
authors.affiliation: Pediatrics, William Beaumont Hospital and Beaumont Children's Hospital, Oakland University William Beaumont School of Medicine, Royal Oak, Michigan.
authors.forename: Amitai
authors.initials: A
authors.lastname: Kohn
authors.affiliation: Pediatrics, William Beaumont Hospital and Beaumont Children's Hospital, Oakland University William Beaumont School of Medicine, Royal Oak, Michigan.
authors.forename: Brian
authors.initials: B
authors.lastname: Berman
authors.affiliation: Departments of Clinical Pathology and ESYKES@beaumont.edu.
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Sykes
mesh_terms: D001784:Blood Gas Analysis; D003490:Cyanosis / Q000097:blood* / Q000209:etiology*; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D008706:Methemoglobin / Q000378:metabolism; D008708:Methemoglobinemia / Q000150:complications*
chemical_list: D008706:Methemoglobin
keywords: CO-oximeter; arterial blood gas; clinical chemistry; congenital methemoglobinemia; cytochrome b5 reductase; pulse oximetry