Ethmoidal Infection with Aspergillus SPP in 3 Horses

Ethmoidal infection with Aspergillus spp. in 3 horses: successful treatment by transendoscopic removal of mycotic plaques alone or in combination with systemic itraconazole

Ethmoidal infection with Aspergillus spp. is rarely reported in horses. This case series describes three horses suffering from unilateral infection with Aspergillus spp. of the ethmoid with varying underlying conditions. Diagnosis was made by endoscopic evaluation of the ethmoid (presence of white mycotic plaques on a layer of thick yellow mucus) and confirmed by fungal culture (A. fumigatus) and/or cytology in all horses. Horse 1 and 2 had a progressive ethmoid hematoma (PEH). Both horses were treated for over 5 months with repeated formalin injections (one horse after initial surgical debulking of the PEH that also invaded the maxillary and sphenopalatine sinuses) before the infection with Aspergillus occurred. The third horse showed (congenital) abnormal anatomy of the right dorsal nasal passage and right ethmoid and was presented with complaints of poor performance and nasal discharge. In the two horses with PEH the mycotic plaques were removed successfully transendoscopically. After 6 weeks the infection was no longer present at endoscopy in the first horse (follow up: no relapse >10 months).

The second horse is currently 5 weeks post treatment and therefore it is still too early to determine outcome. In horse number 3 it was not possible to remove all mycotic plaques, therefore systemic treatment with itraconazole (3mg/kg q12h for 8 weeks orally) was started. After 8 weeks the Aspergillus infection had cleared as confirmed by endoscopy and the clinical signs had resolved (follow up: no relapse >8 months). No side effects were seen with systemic itraconazole treatment. This case series shows that in horses with underlying ethmoidal conditions, clinical infection with Aspergillus spp. may occur as complication. Transendoscopic removal of the mycotic plaques alone may be successful. If this approach is not feasible or unsuccessful, systemic treatment with itraconazole can be considered. […]