Multi-centre assessment of mycotic rhinosinusitis in dogs: a retrospective study of initial treatment success (1998 to 2008)

Assessment of the nasal microbiota in dogs with fungal rhinitis before and after cure and in dogs with chronic idiopathic rhinitis

BACKGROUND

Pathogenesis of canine fungal rhinitis is still not fully understood. Treatment remains challenging, after cure turbinate destruction may be associated with persistent clinical signs and recurrence of fungal rhinitis can occur. Alterations of the nasal microbiota have been demonstrated in dogs with chronic idiopathic rhinitis and nasal neoplasia, although whether they play a role in the pathogenesis or are a consequence of the disease is still unknown. The objectives of the present study were (1) to describe nasal microbiota alterations associated with fungal rhinitis in dogs, compared with chronic idiopathic rhinitis and controls, (2) to characterize the nasal microbiota modifications associated with successful treatment of fungal rhinitis. Forty dogs diagnosed with fungal rhinitis, 14 dogs with chronic idiopathic rhinitis and 29 healthy control dogs were included. Nine of the fungal rhinitis dogs were resampled after successful treatment with enilconazole infusion.

RESULTS

Only disease status contributed significantly to the variability of the microbiota. The relative abundance of the genus Moraxella was decreased in the fungal rhinitis (5.4 ± 18%) and chronic idiopathic rhinitis (4.6 ± 8.7%) groups compared to controls (51.8 ± 39.7%). Fungal rhinitis and chronic idiopathic rhinitis groups also showed an increased richness and α-diversity at species level compared with controls. Increase in unique families were associated with fungal rhinitis (Staphyloccaceae, Porphyromonadaceae, Enterobacteriaceae and Neisseriaceae) and chronic idiopathic rhinitis (Pasteurellaceae and Lactobacillaceae). In dogs with fungal rhinitis at cure, only 1 dog recovered a high relative abundance of Moraxellaceae.

CONCLUSIONS

Results confirm major alterations of the nasal microbiota in dogs affected with fungal rhinitis and chronic idiopathic rhinitis, consisting mainly in a decrease of Moraxella. Besides, a specific dysbiotic profile further differentiated fungal rhinitis from chronic idiopathic rhinitis. In dogs with fungal rhinitis, whether the NM returns to its pre-infection state or progresses toward chronic idiopathic rhinitis or fungal rhinitis recurrence warrants further investigation.

Comparison of two minimally invasive enilconazole perendoscopic infusion protocols for the treatment of canine sinonasal aspergillosis

OBJECTIVES

To compare two minimally invasive enilconazole infusion protocols for the treatment of canine sinonasal aspergillosis and evaluate the importance of complete endoscopic debridement in determining first treatment success rate.

MATERIALS AND METHODS

Data for 48 dogs with confirmed sinonasal aspergillosis treated with endoscopic debridement followed by per-endoscopic enilconazole infusion were collected. Twenty-four dogs were treated according to the previously published 1-hour infusion protocol and 24 dogs underwent a simplified 15-minute infusion protocol. Completeness of debridement, evaluated as partial or complete at the end of the procedure and outcome after one or several treatments were assessed in all dogs. Multi-variable analysis was performed to derive odds ratios and 95% confidence intervals.

RESULTS

The median duration of the simplified protocol - 92∙3 minutes (range 40 to 140) - was substantially shorter than the duration of the previous protocol - 201∙3 minutes (range 120 to 265). First treatment success rates were 58 and 62∙5% for the previous and simplified protocol, respectively. Overall treatment success rate was similar in both groups (96%). Complete debridement was associated with an improved first treatment success rate compared to partial debridement.

CLINICAL SIGNIFICANCE

The simplified protocol is a valid alternative approach to the treatment of sinonasal aspergillosis. Completeness of endoscopic debridement before infusion is an important step for the success of treatment in canine sinonasal aspergillosis.

Canine rhinitis caused by an uncommonly-diagnosed fungus, Scedosporium apiospermum

A Golden Retriever cross was presented with a four week history of violent sneezing and licking at the nasal planum. Nasal mycosis was diagnosed and Aspergillus sp. presumed the causative agent, until culture, PCR and DNA sequencing showed that Scedosporium apiospermum, an uncommonly diagnosed, yet emerging, fungal pathogen, was the agent responsible. Debridement of the fungal plaques and systemic itraconazole therapy resulted in complete resolution of clinical disease. We discuss the current literature on S. apiospermum, review its clinical significance and question the validity of its ‘complex’ taxonomy.

Sinonasal aspergillosis: Outcome after topical treatment in dogs with cribriform plate lysis

BACKGROUND

Cribriform lysis has been considered a contraindication for topical treatment of sinonasal aspergillosis (SNA) because of concerns about drug extravasation with resultant neurologic signs or death.

OBJECTIVE/HYPOTHESIS

To describe dogs with SNA and cribriform plate lysis treated with topical antifungal medications. Our hypothesis was that the conventional dogma that topical therapy should be avoided in these cases is incorrect.

ANIMALS

Nine client-owned dogs with SNA and lysis of the cribriform plate, lysis of the floor of a frontal sinus or both detected by computed tomography (CT).

METHODS

A retrospective review of medical records was performed. Dogs that met inclusion criteria (ie, SNA confirmed by at least 1 laboratory test, braincase affected on CT, and topical treatment applied) were included. Size of lesions, ancillary diagnostic test results, topical therapy, and adjuvant PO treatments were recorded. Outcome was determined by phone calls.

RESULTS

Four dogs were alive at the time of the manuscript submission with follow-up ranging from 188 to 684 days without neurological signs observed. All dogs were discharged without major complication 1-7 days postoperatively. One dog that had presented with a history of seizures experienced seizure activity 2 months after treatment.

CONCLUSIONS AND CLINICAL IMPORTANCE

Topical therapy did not result in complications in these dogs in which lytic regions as large as 16 × 22 mm2 were noted. Sinonasal aspergillosis associated lysis of the cribriform plate; lysis of the floor of a frontal sinus or both detected on CT is not necessarily a contraindication to topical therapy.

Treatment of canine sinonasal aspergillosis with clotrimazole infusion in patients with cribriform plate lysis

OBJECTIVE

To describe the treatment of sinonasal aspergillosis with topical 1% clotrimazole solution in dogs with cribriform plate lysis.

MATERIALS AND METHODS

This retrospective study includes data retrieval from medical records of dogs with sinonasal aspergillosis and cribriform plate lysis that underwent topical treatment with 1% clotrimazole solution.

RESULTS

Five dogs with sinonasal aspergillosis, cribriform plate lysis diagnosed on CT scans, and normal neurologic examinations were treated with a single (n=3) or multiple (n=2) infusions of clotrimazole solution. No dogs developed clinical neurologic disease after therapy.

CLINICAL SIGNIFICANCE

In this study, a topical clotrimazole solution was not associated with adverse neurologic effects in neurologically normal dogs with sinonasal aspergillosis and cribriform plate lysis.

Treatment of Sinonasal Aspergillosis by Debridement and Sinonasal Deposition Therapy with Clotrimazole Under Rhinoscopic Guidance

Rhinoscopy was performed on 10 dogs with sinonasal aspergillosis (SNA). Direct access to the sinus via the nasal ostium was possible with a flexible endoscope to allow sinuscopy. Debridement of fungal plaques in the frontal sinus and the nasal cavity was performed, and a sinus and nasal deposition therapy with clotrimazole (1%) cream was made under rhinoscopic guidance. No oral medication was administered following the procedure. A rhinoscopic follow-up was performed monthly until cure. Six of ten (60%) dogs presented fungal plaques in the nasal cavity and in the frontal sinus and 4/10 (40%) dogs presented fungal plaques only in the frontal sinus. Five of ten (50%) dogs were considered to be cured at the first follow-up rhinoscopy, 4/10 (40%) after the second follow-up, and 1/10 (10%) after the third. Two dogs had delayed recurrence of SNA rhinoscopically assessed 12 and 21 mo, respectively, after the last clotrimazole treatment. Endoscopic debridement of fungal plaques and clotrimazole (1%) cream deposition therapy seems to be a valuable minimally invasive technique for SNA treatment in dogs without the use of complementary oral medication. Delayed recurrence is a potential finding following treatment of SNA.

Aspergillus and aspergilloses in wild and domestic animals: a global health concern with parallels to human disease

The importance of aspergillosis in humans and various animal species has increased over the last decades. Aspergillus species are found worldwide in humans and in almost all domestic animals and birds as well as in many wild species, causing a wide range of diseases from localized infections to fatal disseminated diseases, as well as allergic responses to inhaled conidia. Some prevalent forms of animal aspergillosis are invasive fatal infections in sea fan corals, stonebrood mummification in honey bees, pulmonary and air sac infection in birds, mycotic abortion and mammary gland infections in cattle, guttural pouch mycoses in horses, sinonasal infections in dogs and cats, and invasive pulmonary and cerebral infections in marine mammals and nonhuman primates. This article represents a comprehensive overview of the most common infections reported by Aspergillus species and the corresponding diseases in various types of animals.

What causes canine sino-nasal aspergillosis? A molecular approach to species identification

On the basis of phenotypic identification methods, Aspergillus fumigatus is reported as the most commonly identified aetiological agent of canine sino-nasal aspergillosis (SNA). However, definitive identification of Aspergillus spp. using phenotypic features alone is unreliable. The aim of this study was to determine the molecular identities of fungal species causing SNA in dogs. Genomic DNA was extracted from 91 fungal isolates from 90 dogs diagnosed with SNA in Australia, the USA and Belgium, and the ITS1-5.8S-ITS2 ribosomal DNA and partial β-tubulin regions were sequenced. Eighty-eight of 91 (96.7%) isolates were identified as A. fumigatus and 3/91 (3.3%) belonged to Aspergillus section Nigri spp. (Aspergillus tubingensis: 2/91; Aspergillus uvarum: 1/91). These findings confirm that A. fumigatus is the most common aetiological agent of canine SNA. This is the first report to document a pathogenic role for A. tubingensis and A. uvarum in dogs.

Sinonasal aspergillosis in dogs: a review

Sinonasal aspergillosis is an uncommon, yet debilitating and often frustrating condition to treat in dogs despite years of research evaluating pathogenesis, diagnosis and treatment. The disease is most commonly caused by non-invasive fungal infection, thought to be secondary to altered innate and/or adaptive immune responses. Attempts to confirm this have however failed. A variety of conflicting opinions regarding the diagnosis and treatment of sinonasal aspergillosis exist. Often the use of a particular treatment protocol is based upon personal or regional preference. Evaluation of the veterinary literature demonstrates that the evidence base in support of individual treatment recommendations is weak. A number of recent publications have helped to expand the current knowledge base and therefore our understanding of important practicalities for both diagnostic options and treatment protocols. The following review examines the current evidence for the pathogenesis of sinonasal aspergillosis in dogs, as well as the various diagnostic options. The available evidence for frequently utilised -therapeutic options and their likely outcomes is also explored.

Clotrimazole and enilconazole distribution within the frontal sinuses and nasal cavity of nine dogs with sinonasal aspergillosis

OBJECTIVES

Multiple topical treatments are often required for clinical cure of mycotic rhinosinusitis in dogs. The objective of this study was to describe the distribution and retention of enilconazole and clotrimazole solutions using a temporary trephination protocol.

METHODS

Nine client-owned dogs diagnosed with mycotic rhinosinusitis between March 2008 and December 2009 were prospectively enrolled and were sequentially allocated to receive treatment with either clotrimazole (1% in polyethylene glycol) or enilconazole (10% solution), after imaging and rhinoscopic assessment. Both frontal sinuses were trephined, debrided and flushed with saline. Infusion was administered via frontal sinuses with dogs in sternal recumbency and computed tomography (CT) performed 5 minutes after completion. Distribution was scored 1 to 4 at the canine tooth, premolar 4, cribriform plate and frontal sinus on both sides, for a maximum score of 32.

RESULTS

Distribution of antifungal agents to all regions of the nasal cavity and frontal sinuses was achievable, but varied considerably. Retention was poor in 10 of 18 regions assessed.

CLINICAL SIGNIFICANCE

Distribution of antifungal agents within the frontal sinuses is achievable using temporary trephination; however, distribution is variable and retention is often poor.

Distribution and persistence of topical clotrimazole after sinus infusion in normal canine cadavers

OBJECTIVES

To determine the in vitro persistence of clotrimazole 1% cream in the canine frontal sinus and to evaluate the distribution of clotrimazole solution over the sino-nasal mucosa using a previously described surgical treatment protocol for canine nasal aspergillosis.

METHODS

Two canine skulls were used to monitor the persistence of clotrimazole cream in the lateral frontal sinus at 37°C. The distribution of irrigation solution around the frontal sinus compartments and nasal cavity was determined using six canine cadaver heads by trephining either the lateral or both the lateral and rostral compartments of the frontal sinus. Stain was added to the sinus irrigation solution before visually inspecting the sagittally sectioned heads.

RESULTS

Clotrimazole cream persisted in the frontal sinus for at least 96 hours. The nasal cavity mucosa was completely stained in 8 of 12 sides and almost completely stained in the remaining 4 of 12 sides. Flushing irrigation solution through the lateral compartment of the frontal sinus resulted in inadequate staining of the rostral compartment but medicating both the lateral and rostral compartments resulted in complete coating of all frontal sinus mucosa in eight of eight sides.

CLINICAL SIGNIFICANCE

Clotrimazole cream has the potential to be retained in the frontal sinus for several days and is distributed effectively in normal canine cadavers. Medicating both the rostral and lateral compartments of the frontal sinus may be indicated in some clinical cases.