Fungal Rhinosinusitis and Disseminated Invasive Aspergillosis in Cats

Successful Treatment of Sino-Orbital Aspergillus udagawae Infection Using Oral Posaconazole in a Cat

A 10 yr old spayed female ragdoll cat presented with sudden onset of sneezing, nasal discharge, and stertor. There was no improvement in clinical signs despite treatment with antibiotics, feline interferon, and nebulization. A computed tomography (CT) scan revealed findings consistent with chronic rhinitis, and a tissue biopsy obtained by rhinoscopy led to a histopathologic diagnosis of sinonasal aspergillosis. Polymerase chain reaction amplification identified the causative agent as Aspergillus udagawae. Oral itraconazole therapy was initiated. However, the cat's clinical signs progressed to include left exophthalmos, nictitating membrane protrusion, and lacrimation. A second CT scan revealed a soft-tissue attenuating structure extending into the left retrobulbar space, confirming progression to sino-orbital aspergillosis (SOA). The oral medication was changed to posaconazole and continued for 5 mo, resulting in resolution of the clinical signs. The cat has remained asymptomatic over 24 mo since initial diagnosis. This case represents the first successful treatment of feline SOA caused by A udagawae infection with posaconazole. A udagawae is the second most common cause of SOA and is known to be intractable because of its low susceptibility to antifungal agents and poor response to topical clotrimazole. Posaconazole may be a valuable treatment option for SOA caused by A udagawae.

Invasive Fungal Infections and Oomycoses in Cats: 1. Diagnostic approach

CLINICAL RELEVANCE

In contrast to superficial fungal infections, such as dermatophytosis, invasive fungal infections (IFIs) are characterised by penetration of tissues by fungal elements. Disease can spread locally within a region or can disseminate haematogenously or via the lymphatics. The environment is the most common reservoir of infection. Since fungal spores are airborne, indoor cats are also susceptible to IFIs. Some environmental fungi are ubiquitous and present globally, while others are endemic or hyperendemic within specific geographic regions. Zoonotic pathogens include Microsporum canis, Sporothrix schenckii and Sporothrix brasiliensis.

AIM

In the first of a two-part article series, the approach to the investigation of feline IFIs and oomycoses is reviewed. As well as tips for diagnosis, and information on the ecological niche and distribution of fungal pathogens, the review covers clinical presentation of the most common IFIs, including cryptococcosis, histoplasmosis, blastomycosis, coccidioidomycosis, sporotrichosis, phaeohyphomycosis, aspergillosis and dermatophytic pseudomycetoma, as well as the oomycoses pythiosis, lagenidiosis and paralagenidiosis. In Part 2, the spectrum of activity, mechanisms of action, pharmacokinetic and pharmacodynamic properties and adverse effects of antifungal drugs are reviewed, and the treatment and prognosis for specific IFIs and oomycoses are discussed.

EVIDENCE BASE

The review draws on published evidence and the authors' combined expertise in feline medicine, mycology, dermatology, clinical pathology and anatomical pathology.

Invasive fungal infections and oomycoses in cats 2. Antifungal therapy

CLINICAL RELEVANCE

Invasive fungal infections (IFIs) and oomycoses (hereafter termed invasive fungal-like infections [IFLIs]) are characterised by penetration of tissues by fungal elements. The environment is the most common reservoir of infection. IFIs and IFLIs can be frustrating to treat because long treatment times are usually required and, even after attaining clinical cure, there may be a risk of relapse. Owner compliance with medication administration and recheck examinations can also decline over time. In addition, some antifungal drugs are expensive, have variable interpatient pharmacokinetic properties, can only be administered parenterally and/or have common adverse effects (AEs). Despite these limitations, treatment can be very rewarding, especially when an otherwise progressive and fatal disease is cured.

AIM

In the second of a two-part article series, the spectrum of activity, mechanisms of action, pharmacokinetic and pharmacodynamic properties, and AEs of antifungal drugs are reviewed, and the treatment and prognosis of specific IFIs/IFLIs - dermatophytic pseudomycetoma, cryptococcosis, sino-orbital aspergillosis, coccidioidomycosis, histoplasmosis, sporotrichosis, phaeohyphomycosis, mucormycosis and oomycosis - are discussed. Part 1 reviewed the diagnostic approach to IFIs and IFLIs.

EVIDENCE BASE

Information on antifungal drugs is drawn from pharmacokinetic studies in cats. Where such studies have not been performed, data from 'preclinical' animals (non-human studies) and human studies are reviewed. The review also draws on the wider published evidence and the authors' combined expertise in feline medicine, mycology, dermatology, clinical pathology and anatomical pathology.

ABBREVIATIONS FOR ANTIFUNGAL DRUGS

AMB (amphotericin B); FC (flucytosine); FCZ (fluconazole); ISA (isavuconazole); ITZ (itraconazole); KCZ (ketoconazole); PCZ (posaconazole); TRB (terbinafine); VCZ (voriconazole).

Clinical remission of feline sino-nasal aspergillosis despite evidence of persistent infection

Case summary

Feline sino-nasal aspergillosis is a rare condition with only sparse heterogeneous reports in the literature regarding its treatment. This report describes the presentation, treatment and outcome of a cat with sino-nasal aspergillosis treated by meticulous debridement in combination with topical and systemic azole therapy. Diagnosis was based on MRI, in combination with rhinoscopic assessment and visualisation of fungal plaques, followed by histopathology, fungal culture and panfungal PCR. The cat was treated by debridement of fungal plaques via anterior rhinoscopy and frontal sinusotomy and local instillation of 1% clotrimazole solution, followed by a 4-week course of oral itraconazole. Histopathology confirmed fungal rhinitis and culture identified Aspergillus fumigatus and Aspergillus versicolor. Clinical remission was achieved after treatment; however, evidence of persistent infection was confirmed in the post-mortem examination 8 months after the cat was euthanased for unrelated reasons.

Relevance and novel information

Despite clinical remission, the persistence of fungal infection post mortem highlights the challenges of monitoring the response to treatment and illustrates that the resolution of clinical signs does not necessarily equate with a disease cure.

Sino-orbital aspergillosis with obstructive cervical lymphadenopathy in a cat caused by Aspergillus viridinutans complex

Case summary

This report describes an indoor-only cat with a rare form of sino-orbital aspergillosis (SOA) with cervical lymphadenopathy causing local obstruction. Extensive work-up on initial presentation failed to identify the underlying etiology and the diagnosis was not determined until the disease progressed during a prolonged course of glucocorticoid therapy.

Relevance and novel information

SOA caused by Aspergillus viridinutans complex is increasingly recognized as a significant cause of mortality in cats in recent years, with most cases reported in Australia, Europe and Asia. Feline SOA carries a poor prognosis owing to its invasive nature and resistance to antifungal therapy. This case demonstrates the importance of clinical awareness of SOA as a differential for cats with chronic nasal signs and exophthalmos in the USA. Moreover, it demonstrates a rare form of presentation and potential difficulty in achieving a correct diagnosis.

Ventral cervical subcutaneous Aspergillus species fungal granuloma in a cat

Case summary

An 8-year-old domestic longhair cat was evaluated for a right ventral subcutaneous cervical mass. Serial bloodwork and contrast-enhanced cranial and thoracic CT initially lacked ethmoturbinate lysis and showed a progressive, vascularized, right ventral cervical mass involving local lymph nodes. The mass was removed surgically on two occasions. Histopathology and fungal culture were diagnostic for a recurring sclerosing fungal granuloma and pyogranulomatous and eosinophilic lymphadenitis, consistent with Aspergillus species. The cat was treated with oral itraconazole; however, owing to the owner’s non-compliance in administering the medication and disease progression, the cat was humanely euthanized 3 years after diagnosis.

Relevance and novel information

The development of a cervical subcutaneous fungal granuloma of Aspergillus species in a domestic longhair cat before obvious maxillary, orbital or ethmoturbinate lysis on initial diagnostics is rare and suggests an early onset of lymphatic or hematogenous spread from a suspected nidus of infection within the sinonasal cavity.

CT findings of nasal cryptococcosis in cats and dogs: A case series

Cryptococcus spp. can cause chronic rhinitis in cats and dogs. Computed tomography (CT) descriptions of imaging features of nasal cryptococcosis are limited. This retrospective single-center consecutive case series aimed to describe the CT features of lesions in cats and dogs with nasal cryptococcosis. Ten cats and 12 dogs with a diagnosis of nasal cryptococcosis confirmed with cytology, histopathology, and/or serology that had undergone a head CT from 2010 and 2020 were included. Images were evaluated by a veterinary radiologist for the presence of a nasal or nasopharyngeal mass, regional destruction, intracranial extension, and lymphadenopathy. The majority of cats (8/10 [80%]) had nasal lesions with most cases described as non-destructive rhinitis (7/8 [88%]). Three cats (3/10 [30%]) had a nasal mass. All cats had a nasopharyngeal mass, and in most cases (8/10 [80%]) the nasopharyngeal mass was centered caudally near the temporomandibular joints. None of the cats had cribriform plate lysis or meningeal enhancement. All dogs had nasal lesions. Eleven dogs (11/12 [92%]) had destructive rhinitis with lysis of nasal conchae. Most dogs (8/12; 67%) had a nasal mass, of which in seven dogs the caudal nasal mass extended into the rostral nasopharynx. Most dogs had cribriform plate lysis (9/12 [75%]), of which four dogs (44%) had mass extension into the cranium. Our findings support potential differences in CT features between dogs and cats with nasal cryptococcosis. Nasal cryptococcosis should be considered a differential diagnosis in dogs and cats with nasal and nasopharyngeal masses.

First Case Report of Aspergillary Rhinopharyngitis in a Foal From Chile

We present the first case of rhinopharyngitis due to Aspergillus fumigatus in a purebred Chilean horse. Clinically, manifested mucopurulent discharge from both nostrils, inflammation of the nasal, ocular, and ear mucosa; associated with decay and hyporexia. Based on the clinical signs and analysis of the mycological and molecular transtracheal aspirate sample, the present case was diagnosed as Aspergillus fumigatus rhinopharyngitis. After the antifungal susceptibility test, oral itraconazole treatment was maintained for 45 days, showing no clinical sign.

Complete clinical response to combined antifungal therapy in two cats with invasive fungal rhinosinusitis caused by cryptic Aspergillus species in section Fumigati

Cryptic species in Aspergillus section Fumigati are increasingly reported to cause invasive aspergillosis in humans and animals. These infections are often refractory to treatment because of intrinsic antifungal resistance. We report two cases of invasive fungal rhinosinusitis in domestic cats caused by A. udagawae and A. felis. Clinical signs resolved after combined therapy including posaconazole, caspofungin and terbinafine. Both cases remained asymptomatic more than 2 years from initial presentation.

Disseminated invasive aspergillosis caused by Aspergillus felis in a cat

A 2‐year‐old male desexed Ragdoll cat with a 1‐year history of sneezing and nasal discharge presented with a large subcutaneous cervical mass, identified as the right medial retropharyngeal lymph node on computed tomography (CT). A right orbital mass, destructive sino‐nasal cavity disease and multiple pulmonary nodules were also identified. Aspergillus felis was cultured from the lymph node. After treatment with posaconazole and liposomal amphotericin B the lymph node enlargement and orbital mass resolved but left frontal sinus involvement and pulmonary lesions persisted despite additional caspofungin therapy. The cat was euthanized 14 months after diagnosis with dysphagia and chronic progressive exophthalmos. A meningeal granuloma with intravascular fungal hyphae was identified at post‐mortem and A felis was cultured from the left frontal sinus and a right retrobulbar fungal granuloma. This case demonstrates that disseminated disease is a possible sequel to invasive fungal rhinosinusitis caused by A felis in cats.