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Veterinary ophthalmology2025; doi: 10.1111/vop.70003

Mycotic Sphenopalatine Sinusitis With Concurrent Compression of the Optic Nerves and Chiasm and Severe Visual Impairment in A Horse.

Abstract: A 15-year-old Swiss Warmblood gelding was presented to the ophthalmology service of Zurich University due to severe visual impairment. Ophthalmic and neurologic examinations were performed, raising suspicion of post-retinal blindness. Standing contrast computed tomography (CT) of the head revealed a partially calcified, soft tissue attenuating mass in the sphenopalatine sinus with concurrent compression of the optic nerves and chiasm. Differential diagnosis included neoplasia and granulomatous disease. The horse was euthanized, and the head was subsequently examined by magnetic resonance imaging (MRI) followed by gross and histopathology. MRI showed compression of the optic nerves and chiasm. Histopathology revealed the formation of fibrous granulation tissue, osseous metaplasia, and pyogranulomatous inflammation in the sphenopalatine sinus. Periodic acid-Schiff reaction and Grocott silver staining demonstrated branching septated filament hyphae and fungal spores. The optic nerves and chiasm were evident of mild neuronal atrophy, showing mild gliosis, vacuolation, and mild lympho-plasmacytic inflammation. Mycotic sphenopalatine sinusitis should be considered as a more specific diagnosis for post-retinal blindness in horses due to the compression of the optic nerve(s) and chiasm.
© 2025 American College of Veterinary Ophthalmologists.
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Publication Date: 2025-03-07 PubMed ID: 40055139DOI: 10.1111/vop.70003Google Scholar: Lookup
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Summary

This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.

The research article describes a case where a 15-year-old horse was found to have severe visual impairment due to Mycotic Sphenopalatine Sinusitis, a fungus-based infection in its sphenopalatine sinus which was causing compression on its optic nerves and chiasm. This led the researchers to suggest that such sinusitis should be considered a more specific diagnosis for post-retinal blindness in horses.

Details of the Case

  • The horse, a Swiss Warmblood gelding, was presented to the ophthalmology service of Zurich University due to the severe visual impairment that it was experiencing.
  • An ophthalmic examination followed by a neurological examination was carried out. These examinations led the researchers to suspect that the horse was suffering from post-retinal blindness.

Diagnostic Procedures and Findings

  • The researchers conducted a standing contrast computed tomography (CT) scan of the horse’s head to get a detailed understanding of the issue.
  • The CT scan revealed a partially calcified, soft tissue attenuating mass in the sphenopalatine sinus of the horse. This mass was causing concurrent compression of the horse’s optic nerves and chiasm, which were contributing to the animal’s visual impairment.
  • In terms of differential diagnosis, the findings raised the possibility of it being a neoplastic (cancerous) or granulomatous (caused by inflammation) disease.

Post-Euthanization Examination and Histopathological Findings

  • After the horse was euthanized, the researchers conducted further tests including a magnetic resonance imaging (MRI) scan of the head, followed by gross and histopathological examination.
  • The MRI confirmed the earlier findings of compression of the optic nerves and chiasm. Histopathological examination revealed formation of fibrous granulation tissue, osseous metaplasia (transformation of normal tissue into bone), and a pyogranulomatous inflammation in the sphenopalatine sinus.
  • Upon performing Periodic acid-Schiff reaction and Grocott silver staining, fungus in the form of branching septated filament hyphae and spores was detected. In addition, the optic nerves and chiasm revealed mild neuronal atrophy, exhibiting mild gliosis (reactive astrocytosis), vacuolation (formation of vacuoles), and mild lympho-plasmacytic inflammation.
  • These findings led the researchers to conclude that the horse had been suffering from mycotic sphenopalatine sinusitis. This fungal sinus infection was causing the visual impairment by way of compressing the optic nerve and chiasm.

Significance of the Study

  • The study emphasizes the need to consider mycotic sphenopalatine sinusitis as a specific diagnosis for post-retinal blindness in horses.
  • Through this case study, it provides more information about how this fungal infection can lead to compression of critical optic structures and create consequent visual impairment.

Cite This Article

APA
Holz N, Suárez J, Hetzel U, Rampazzo A, Stoppini R. (2025). Mycotic Sphenopalatine Sinusitis With Concurrent Compression of the Optic Nerves and Chiasm and Severe Visual Impairment in A Horse. Vet Ophthalmol. https://doi.org/10.1111/vop.70003

Publication

Veterinary ophthalmology
ISSN: 1463-5224
NlmUniqueID: 100887377
Country: England
Language: English

Researcher Affiliations

Holz, Niklas
  • Ophthalmology Section, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland.
Suárez, José
  • Clinic for Diagnostic Imaging, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland.
Hetzel, Udo
  • Institute of Veterinary Pathology (IVPZ), Vetsuisse Faculty, University of Zurich, Zurich, Switzerland.
Rampazzo, Antonella
  • Ophthalmology Section, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland.
Stoppini, Riccardo
  • Ophthalmology Section, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland.

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This article includes 27 references
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Citations

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