felis - Articles
Retina: fluoroquinolone retinopathy
Introduction
- Cause: enrofloxacin administered at a systemic dose above the manufacturer's current dose recommendation can induce a toxic retinopathy.
- Signs: blindness.
- Diagnosis: history of systemic enrofloxacin administration at above the manufacturer's current dose recommendation during the preceeding three days.
- Treatment: withdrawal from enrofloxacin medication.
- Prognosis: retinal degeneration is permanent. In some cases, milder doses result in reduced vision but not blindness.
Presenting signs
- Poor vision - owner complains of cat bumping into things.
- Bilateral mydriasis.
- Negative menace response.
- May have normal dazzle reflex.
- May have pupillary light reflex although likely reduced in amplitude Eye: examination.
Age predisposition
- There are no age, sex or breed predispositions known.
Special risks
- Enrofloxacin is excreted through the kidney and liver. Therefore, cats with renal or hepatic disease may be at increased of toxicity, along with older or dehydrated animals.
Pathogenesis
Pathophysiology
- A molecular basis for susceptibility to the drug's effects has been documented in cats.
- The ABCG2 transporter protein normally functions to restrict distribution of fluoroquinolones across the blood-retinal barrier.
- Feline ABCG2 has been shown to be defective which is thought to allow for the potential build-up of photoactive and potentially retinotoxic fluoroquinolones within the retina.
Timecourse
- In experimental studies, ophthalmoscopic signs were visible by day 3, and progressive retinal degeneration over the first week can be observed with retinal blood vessel attenuation and tapetal hyperreflectivity.
Diagnosis
Subscribe To View
This article is available to subscribers.
Try a free trial today or contact us for more information.
Treatment
Subscribe To View
This article is available to subscribers.
Try a free trial today or contact us for more information.
Prevention
Subscribe To View
This article is available to subscribers.
Try a free trial today or contact us for more information.
Outcomes
Subscribe To View
This article is available to subscribers.
Try a free trial today or contact us for more information.
Further Reading
Publications
Refereed papers
- Recent references from PubMed and VetMedResource.
- Gelatt K N, Van Der Woerdt A, Ketring K L et al (2011) Enrofloxacin‐associated retinal degeneration in cats. Vet Ophthalmol 4 (2), 99-106 PubMed.
- Ramirez C J, Minch J D, Gay J M et al (2011) Molecular genetic basis for fluoroquinolone-induced retinal degeneration in cats. Pharmacogenetics and Genomics 21 (2), 66-75 PubMed.
- Messias A, Gekeler F, Wegener A et al (2008) Retinal safety of a new fluoroquinolone, pradofloxacin, in cats: assessment with electroretinography. Doc Ophthalmol 116 (3), 177-191 PubMed.
- Ford M M, Dubielzig R R, Giuliano E A et al (2007) Ocular and systemic manifestations after oral administration of a high dose of enrofloxacin in cats. Am J Vet Res 68 (2), 190-202 PubMed.
- Wiebe V, Hamilton P (2002) Fluoroquinolone-induced retinal degeneration in cats. JAVMA 221 (11), 1568-1571 PubMed.
- Turnidge J (1999) Pharmacokinetics and pharmacodynamics of fluoroquinolones. Drugs 58 (Suppl 2), 29-36 PubMed.
Other sources of information
- Natasha Mitchell & James Oliver (2015) Feline Ophthalmology - The Manual. Grupo Asis. ISBN 978-84-16315-11-6.