ABSTRACT
A 6-month-old mixed breed dog was referred for evaluation of a potential disorder of sex development (DSD) and lower than expected energy level. Genitourinary examination revealed ambiguous external genitalia, hypospadias, and a subtle pouch of skin that resembled an empty scrotum. Corrective surgery was planned and subsequently aborted after cyanosis was identified preoperatively and an arterial blood gas analysis by co-oximetry identified increased methemoglobin (MetHb) concentration (35%, normal <2%) with normal arterial oxygen tension. Ensuing investigations confirmed hereditary methemoglobinemia caused by cytochrome b5 reductase (CYB5R) deficiency via molecular genetic (Arg219Pro homozygous variant in CYB5R3 gene) and biochemical (cytochrome b5 reductase enzyme activity of 8% [normal, 100% activity] testing. Karyotyping and molecular analysis of sex chromosomes revealed the dog was genetically female with a normal female karyotype (78,XX), and was negative for the Y-linked SRY gene and positive for the X-linked androgen receptor gene. Methylene blue (MB, 3.3 mg/kg per os [PO] q24 h) was administered and the MetHb concentration decreased to 9% within 14 days. Urogenital revision surgery proceeded without complication and the dog was maintained on MB (3-4 mg/kg PO q24 h) long-term without adverse effects. This is the first report to describe the use of PO MB to decrease MetHb concentrations in a dog with CYB5R deficiency in preparation for anesthesia and highlights its potential as a viable alternative to the intravenous formulation for elective procedures. In addition, this report describes the clinical, molecular, imaging, surgical, and macroscopic and microscopic pathological features of a dog with SRY-negative, 78,XX testicular DSD.
Subject(s)
Dog Diseases , Methemoglobinemia , Animals , Cytochrome-B(5) Reductase/deficiency , Cytochrome-B(5) Reductase/genetics , Cytochrome-B(5) Reductase/therapeutic use , Dog Diseases/drug therapy , Dog Diseases/genetics , Dog Diseases/surgery , Dogs , Female , Male , Methemoglobinemia/diagnosis , Methemoglobinemia/drug therapy , Methemoglobinemia/genetics , Methemoglobinemia/veterinary , Methylene Blue/therapeutic use , Sexual DevelopmentABSTRACT
An 8-year-old male neutered domestic shorthair cat developed corneal lipidosis and marked hypertriglyceridemia approximately 36 hours after intravenous lipid therapy (IVLT) for the treatment of permethrin toxicosis. The cat's ocular changes resolved approximately 72 hours after IVLT without treatment. This study reports a rare complication of IVLT.
Hypertriglycéridémie et lipidose cornéenne transitoire chez un chat après une lipidothérapie intraveineuse pour une toxicose à la perméthrine. Un chat commun mâle stérilisé âgé de 8 ans a développé une lipidose cornéenne et une hypertriglycéridémie marquée environ 36 heures après une lipidothérapie intraveineuse (LTI) pour le traitement de la toxicose à la perméthrine. Les changements oculaires du chat se sont résorbés sans traitement environ 72 heures près la LTI. Cette étude signale une complication rare de la LTI.(Traduit par Isabelle Vallières).