Long‐term Treatment with Methylene Blue in a Dog with Hereditary Methemoglobinemia Caused by Cytochrome b5 Reductase Deficiency

Journal of Veterinary Internal Medicine

  ^{1    1    1    2    2    2    3} 

[1] Department of Veterinary Medicine and Surgery, Veterinary Health Center, University of Missouri, Columbia, MO;Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO;Section of Medical Genetics, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA;

关键词: Cyanosis;    CYB;    Whole‐genome sequence;    Blood gas;   

DOI  :  10.1111/jvim.14843

来源: publisher

【 摘 要 】

A juvenile male mixed breed dog was presented for lethargy, exercise intolerance, and aggression when touched on the head. Cyanosis, tachycardia, and tachypnea were observed and persisted during oxygen supplementation. Arterial blood gas analysis by co‐oximetry identified an increased methemoglobin concentration (27%; normal, <2%) with normal arterial oxygen tension. The methemoglobinemia and associated clinical signs resolved after administration of methylene blue (1 mg/kg) IV, and the dog was discharged. The affected dog's whole‐genome sequence contained 2 potentially causal heterozygous CYB5R3 missense mutations suggesting that cytochrome b5 reductase deficiency was responsible for the methemoglobinemia. This hypothesis was confirmed by enzyme analysis that identified cytochrome b5 reductase activity in the affected dog's erythrocytes to only approximately 6% of that in a control sample. Clinical signs recurred 11 days after discharge but normalized and the methemoglobin concentration decreased with methylene blue administration PO (1.5 mg/kg, initially daily and then every other day).

【 授权许可】

Unknown