Hereditary methemoglobinemia is an autosomal recessive disorder characterized by NADH-cytochrome b5 reductase (b5R) deficiency. In an attempt to clarify the molecular mechanisms involved in the enzyme deficiency, we isolated the b5R gene from a patient homozygous for hereditary methemoglobinemia, generalized type, and compared its nucleotide sequence with that of the normal NADHcytochrome b5R g...

INTRODUCTION Methemoglobinemia is a rare cause of hypoxemia, characterized by abnormal levels of oxidized hemoglobin that cannot bind to and transport oxygen. CASE PRESENTATION A 62-year-old male underwent bronchoscopy where lidocaine oral solution and Hurricaine spray (20% benzocaine) were used. He developed central cyanosis and his oxygen saturation was 85% via pulse oximetry. An arterial b...

A patient undergoing chemotherapy for relapsed non Hodgkin lymphoma developed tumor lysis syndrome, hypoxia and the abrupt onset of intravascular hemolysis. A past history of unexplained anemia and the finding of blister cells on peripheral smear led to the suspicion of congenital glucose phosphate dehydrogenase (G6PD) deficiency with intravascular hemolysis induced by the drug rasburicase. G6P...

A rare fatal case of self-poisoning with nitrobenzene following oral ingestion is reported. On presentation to the hospital, severe methemoglobinemia (70%) was observed in an 82-year-old male who had ingested 250 mL of an unknown substance in the previous 24 h. Methylene blue and exchange transfusion were the therapeutic methods applied in the treatment of the methemoglobinemia. Forty-eight hou...

The activity of NADH-cytochrome b5 reductase (NADH-methemoglobin reductase) is generally reduced in red cells of patients with recessive hereditary methemoglobinemia. To determine whether this lower activity is due to reduced concentration of an enzyme with normal catalytic properties or to reduced activity of an enzyme present at normal concentration, we measured erythrocyte reductase concentr...

BACKGROUND Methylene bis(thiocyanate) (MBT) is a microbiocidal agent mainly used in industrial water cooling systems and paper mills as an inhibitor of algae, fungi, and bacteria. CASE PRESENTATION We describe the first case of severe intoxication following inhalation of powder in an industrial worker. Profound cyanosis and respiratory failure caused by severe methemoglobinemia developed with...

Acute gastroenteritis remains a common medical problem in the pediatric population and diarrhea may be life threatening in the neonate. Organic aciduria has been observed in children with short bowel, malabsorption, and Hirschsprung’s disease,’6 and methemoglobinemia has been observed in children with acute diarrheal disease.7’5 The two infants described here, however, represent the mitial repo...

Hereditary methemoglobinemia is an autosomal recessive disorder characterized by NADH-cytochrome b5 reductase (b5R) deficiency. In an attempt to clarify the molecular mechanisms involved in the enzyme deficiency, we isolated the b5R gene from a patient homozygous for hereditary methemoglobinemia, generalized type, and compared its nucleotide sequence with that of the normal NADHcytochrome b5R g...

Methemoglobinemia is an uncommon but potentially fatal disorder. Most cases have no adverse clinical consequence and require no treatment, but methemoglobinemia is often overlooked as a cause of low oxygen saturation, and often mistaken for the more common causes of hypoxia by anesthesiologists despite simple bedside tests that indicate the presence of this treatable abnormality. We present a 6...