Treatment of canine nasal aspergillosis/penicilliosis with fluconazole (UK-49,858)

Oral administration of voriconazole with surgical fungal plaque debridement for the treatment of sinonasal aspergillosis with cribriform plate lysis in three dogs

CASE DESCRIPTION

3 dogs with chronic sinonasal signs (sneezing, nasal discharge, or epistaxis [or a combination of signs]) were examined.

CLINICAL FINDINGS

For all 3 dogs, CT revealed variable degrees of nasal turbinate destruction and frontal sinus involvement with cribriform plate lysis. Fungal plaques were detected during rhinoscopy or sinusoscopy. Results of fungal culture (2 dogs) or cytologic examination of a plaque specimen (1 dog) supported a diagnosis of sinonasal aspergillosis.

TREATMENT AND OUTCOME

All dogs underwent surgical rhinotomy or sinusotomy (or both) for fungal plaque debridement followed by oral treatment with voriconazole and periodic physical examinations, clinicopathologic analyses, and assessments of serum drug concentrations for a period ≥ 22 weeks. All dogs had considerable to complete reduction of their clinical signs and tolerated voriconazole treatment with minimal adverse effects. Adverse effects included development of reversible neurotoxicosis (associated with high serum voriconazole concentration) and mildly high serum liver enzyme activities. The dosage of voriconazole administered to achieve therapeutic serum concentrations (2.5 to 3.3 mg/kg [1.1 to 1.5 mg/lb], PO, q 12 h) was substantially lower than dosages suggested by previously published studies in dogs. The 3 dogs remained clinically normal or had mild clinical signs after voriconazole discontinuation for follow-up times of 6 to 15 months.

CLINICAL RELEVANCE

Findings in these 3 dogs indicated that surgical fungal plaque debridement followed by oral treatment with voriconazole may be an effective treatment option for dogs with sinonasal aspergillosis and cribriform plate lysis. Further evaluation of this treatment regimen with repeated CT examinations and longer follow-up times is warranted.

Minimally invasive treatment of sino-nasal aspergillosis in dogs

Background: Sino‐nasal aspergillosis is a common nasal disease in dogs. Recommended treatment protocols typically involve trephination of the frontal sinuses or the use of an antifungal solution instilled into the frontal sinus under anesthesia, both of which have associated morbidity and complications.

Objectives: To assess a minimally‐invasive topical treatment protocol for sino‐nasal aspergillosis in dogs.

Animals: Twelve client‐owned dogs diagnosed with sino‐nasal aspergillosis that completed recommended treatment.

Methods: Medical records were retrospectively reviewed to identify dogs with sino‐nasal aspergillosis that received treatment. Fungal plaques were manually debrided and irrigated via frontal sinuscopy in 12 dogs that then were treated topically with 1% topical clotrimazole cream. Irrigation and topical medication application was achieved using a catheter placed retrograde directly into the frontal sinuses using the Seldinger technique over a guidewire, thereby avoiding the need for frontal sinus trephination. Invasion into the calvarium was recorded before treatment but was not considered a criterion for exclusion. Debridement and cream deposition was repeated every 2 weeks as needed until negative culture and histopathologic findings were obtained.

Results: All dogs were cured (negative results for Aspergillus on endoscopy, fungal culture, and histopathology) with a median of 2 treatments. Treatments were well tolerated, with minimal adverse effects reported. Three dogs had evidence of erosion into the calvarium on computed tomography imaging.

Conclusions and Clinical Importance: This protocol appears to be an effective and well‐tolerated minimally invasive treatment for sino‐nasal aspergillosis, including in dogs with erosion into the calvarium. Only mild adverse effects were noted.

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.

Spatial Patterns and Impacts of Environmental and Climatic Factors on Canine Sinonasal Aspergillosis in Northern California

Sinonasal aspergillosis (SNA) causes chronic nasal discharge in dogs and has a worldwide distribution, although most reports of SNA in North America originate from the western USA. SNA is mainly caused by Aspergillus fumigatus, a ubiquitous saprophytic filamentous fungus. Infection is thought to follow inhalation of spores. SNA is a disease of the nasal cavity and/or sinuses with variable degrees of local invasion and destruction. While some host factors appear to predispose to SNA (such as belonging to a dolichocephalic breed), environmental risk factors have been scarcely studied. Because A. fumigatus is also the main cause of invasive aspergillosis in humans, unraveling the distribution and the environmental and climatic risk factors for this agent in dogs would be of great benefit for public health studies, advancing understanding of both distribution and risk factors in humans. In this study, we reviewed electronic medical records of 250 dogs diagnosed with SNA between 1990 and 2014 at the University of California Davis Veterinary Medical Teaching Hospital (VMTH). A 145-mile radius catchment area around the VMTH was selected. Data were aggregated by zip code and incorporated into a multivariate logistic regression model. The logistic regression model was compared to an autologistic regression model to evaluate the effect of spatial autocorrelation. Traffic density, active composting sites, and environmental and climatic factors related with wind and temperature were significantly associated with increase in disease occurrence in dogs. Results provide valuable information about the risk factors and spatial distribution of SNA in dogs in Northern California. Our ultimate goal is to utilize the results to investigate risk-based interventions, promote awareness, and serve as a model for further studies of aspergillosis in humans.

Assessment of Toll-like receptor 2, 4 and 9 SNP genotypes in canine sino-nasal aspergillosis

Background

The exact aetiology of canine sino-nasal aspergillosis (SNA) is unknown. In man, dysfunction in innate immunity, particularly in the function of pattern recognition receptors, is implicated in the pathogenesis of inflammatory sino-nasal disease and in fungal diseases. Associations between single nucleotide polymorphisms (SNPs) in Toll-like receptors (TLRs) and these diseases have been identified. Similarly, in dogs SNPs in genes encoding TLRs may be important in the pathogenesis of SNA. The aims of the present study were (1) to identify the presence of non-synonymous SNPs in the coding regions of the TLR2, 4 and 9 genes in dogs suffering from SNA, and (2) to investigate the SNP genotypes in dogs with SNA compared with a control population.

Results

Direct sequencing of nine dogs of various breeds with SNA revealed two non-synonymous SNPs in the coding region of TLR2, eight in TLR4 and four in TLR9. These non-synonymous SNPs were further evaluated in a case-control study of affected Golden Retrievers, Labrador Retrievers, Rottweilers and Beaucerons. Genotyping was performed using a combination of allele-specific primers and hydrolysis probe assays in 31 dogs with SNA and 31controls. No significant difference in minor allele frequency was identified between these groups, for all studied SNPs, in any of the four breeds.

Conclusions

These findings do not support a role for non-synonymous SNPs in the TLR 2, 4 and 9 coding regions in the pathogenesis of canine SNA, but do not exclude a role for innate immunity in the pathogenesis of the disease.

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.

Clinical resolution of nasal aspergillosis following therapy with a homeopathic remedy in a dog

A 6 yr old, male, neutered Weimaraner was treated homeopathically for nasal aspergillosis after failing to respond to two treatments of topical (intranasal) clotrimazole and oral amoxicillin trihydrate/clavulanate potassium. Computed tomography, rhinoscopy, fungal culture, and cytology previously confirmed the diagnosis. At presentation for homeopathic treatment, the dog had aggressive left-sided sinusitis and rhinitis with destruction of nasal turbinates and severe bouts of epistaxis. Erosion and depigmentation of the nasal planum were evident. After two treatments with homeopathic aurum metallicum, resolution of clinical signs occurred and clearance of the aspergillosis organisms was documented by computed tomographic scan, rhinoscopy, and histopathology. Homeopathic aurum metallicum may be beneficial in treating cases of canine nasal aspergillosis.

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.

Frontal sinus depth at four landmarks in breeds of dog typically affected by sinonasal aspergillosis

The objective of this study was to assess whether the frontal sinuses in dogs with aspergillosis and of breeds typically affected by this condition were deeper at a more caudal location. CT scans of the head performed at the Small Animal Teaching Hospital, University of Liverpool, between April 2007 and March 2009 for dogs diagnosed with aspergillosis (group 1) and unaffected dogs of similar breeds (group 2) were selected for study. Sinus depth was measured at four standardised locations from reconstructed images of these CT scans. Data were compared for differences in sinus depth between groups and between landmarks. No significant difference was found between measurements within individual dogs or for each of the various landmarks between groups. Difference in depth of the sinuses between landmarks was significant (P<0.001). Sinus depth was significantly greater at the more caudal landmarks and was shallowest at the previously recommended landmark for sinus entry. In 54 per cent of dogs, the frontal sinus depth measured less than or equal to 2 cm at one or more of the landmarks. Sinus entry at the deepest point will reduce the risk of accidentally damaging underlying structures. This may be approximately 1 cm caudal, in breeds of dog that typically develop aspergillosis, to a previously suggested landmark.

Repeated rhinoscopic and serologic assessment of the effectiveness of intranasally administered clotrimazole for the treatment of nasal aspergillosis in dogs

OBJECTIVE

To determine the role of rhinoscopic evaluation and repeated serologic testing in assessing the success rate of intranasally administered clotrimazole for treatment of dogs with nasal aspergillosis.

DESIGN

Prospective case series.

ANIMALS

23 dogs with nasal aspergillosis.

PROCEDURES

Dogs with nasal aspergillosis were treated with an intranasal infusion of 1% clotrimazole solution. Response to treatment was assessed with repeated rhinoscopic evaluation, with histologic examination and fungal culture when available. Results of repeated serologic testing for aspergillosis were monitored throughout the treatment course.

RESULTS

11 of the 23 (48%) dogs had no rhinoscopic evidence of disease after the first treatment. Three of 7 dogs were free of disease after the second treatment, and 1 of 3 dogs was free after the third treatment. Presence or absence of nasal discharge and results of repeated serologic testing were not consistent with disease status. Overall, the efficacy of intranasally administered clotrimazole for treatment of nasal aspergillosis could be confirmed in 15 of 17 dogs. Delayed recurrence or reinfection was confirmed in 3 of 15 dogs. When recurrences were taken into account, the success rate was 67% (12/15 dogs).

CONCLUSIONS AND CLINICAL RELEVANCE

Clinical signs were not predictive of disease state, and follow-up rhinoscopy is recommended to assess response to treatment. The success rate of intranasally administered clotrimazole was similar to rates in previous reports; however, the number of dogs with recurrent disease was relatively high. Monitoring of the results of serologic testing is not recommended for use in determining response to treatment.

Update on canine sinonasal aspergillosis

Sinonasal aspergillosis is a frequent cause of nasal discharge that occurs in otherwise healthy, young to middle-aged dogs. A local immune dysfunction is suspected in affected animals, and the role of increased interleukin-10 mRNA expression in the nasal mucosa of affected dogs is currently under investigation. Despite recent advances in imaging techniques, the "gold standard" for diagnosing the disease is direct visualization of fungal plaques during endoscopy or observation of fungal elements on cytology or histopathologic examination. Treatment can be challenging; however, the use of topical enilconazole or clotrimazole through noninvasive techniques has increased the success of treatment and decreased the morbidity and duration of hospitalization.

Long-Term Outcomes in Dogs With Sinonasal Aspergillosis Treated With Intranasal Infusions of Enilconazole

Long-term outcomes (mean 38±17 months) were evaluated in 27 dogs with sinonasal aspergillosis after successful medical treatment using intranasal infusions of 1% or 2% enilconazole (1%, n=15; 2%, n=12). Long-term outcomes with both treatment protocols were good, with half of the dogs being asymptomatic throughout the follow-up period. The remaining dogs showed mild clinical signs compatible with chronic rhinitis/sinusitis. These clinical signs were interpreted as chronic lymphoplasmacytic rhinitis/sinusitis and episodes of bacterial rather than fungal infection. Three dogs had confirmed reinfection or relapse 2 to 36 months after clinical resolution.

Surgical treatment of canine nasal aspergillosis by rhinotomy combined with enilconazole infusion and oral itraconazole

OBJECTIVES

To evaluate the effectiveness of rhinotomy and surgical debridement associated with topical administration of 2 per cent enilconazole and oral itraconazole in dogs with severe or recurrent sinonasal aspergillosis.

METHODS

A standard rhinotomy was performed on seven dogs. In the initial study, the bone flap was left attached cranially and replaced at the end of the procedure. In the main study group, the bone flap was discarded. Nasal passages were debrided and irrigated with enilconazole solution for one hour. Oral itraconazole was administered to four dogs for one month postoperatively. Follow-up rhinoscopy was performed in all dogs.

RESULTS

All three dogs in the initial study had recurrence of the disease and two dogs had a second surgery to remove the flap. The main study group included four dogs in which the flap was initially removed, and the two dogs from the initial study that required a second surgery. At follow-up rhinoscopy, five dogs were free of aspergillus but had bacterial or inflammatory rhinitis and one dog had a small aspergilloma but was subsequently asymptomatic. Telephone follow-up revealed that four dogs were asymptomatic, one dog had intermittent sneezing and serous nasal discharge, and one dog had intermittent epistaxis.

CLINICAL SIGNIFICANCE

Rhinotomy with removal of the flap combined with one-hour infusion of 2 per cent enilconazole and oral itraconazole resulted in satisfactory outcome in dogs with severe or recurrent aspergillosis.

Canine nasal aspergillosis

Chronic nasal discharge is a common clinical sign of disease in dogs. Canine sinonasal aspergillosis is a relatively common disease in dogs. The three hallmarks of canine nasal aspergillosis are a profuse mucoid to hemorrhagic chronic nasal discharge that may alternate with periods of epistaxis, ulceration of the external nares with crusting, and pain or discomfort in the facial region. Diagnostic imaging (preferably computed tomography, CT) of the nasal cavity and paranasal sinuses is an important component of the evaluation of dogs with signs of nasal disease. Rhinoscopy is an important part of both the diagnosis and the therapy for nasal aspergillosis. Therapeutic recommendations for sinonasal aspergillosis have included surgery and the use of several systemic and topical antifungal drugs.

Results of rhinoscopy alone or in conjunction with sinuscopy in dogs with aspergillosis: 46 cases (2001-2004)

OBJECTIVE

To determine results of diagnostic testing, including detection of nasal or frontal sinus fungal plaques, in dogs with nasal aspergillosis.

DESIGN

Retrospective case series.

ANIMALS

46 dogs with nasal aspergillosis.

PROCEDURES

Medical records were reviewed for information on computed tomographic findings; rhinoscopic findings, including whether fungal plaques were seen in the nasal cavity; results of frontal sinus trephination and sinuscopy, including whether fungal plaques were seen in the frontal sinus; and results of histologic examination of biopsy specimens.

RESULTS

In 38 (83%) dogs, fungal plaques were seen in the nasal cavity during rhinoscopy, whereas in the remaining 8 (17%), fungal plaques were not seen in the nasal cavity but were seen in the frontal sinus. Duration of clinical signs, proportions of dogs in which the referring veterinarian had performed a nasal examination prior to referral, proportions of dogs with computed tomographic evidence of nasal cavity cavitation or sinus involvement, and proportions of dogs with rhinoscopic evidence of destructive rhinitis were not significantly different between dogs with nasal fungal plaques and dogs with fungal plaques only in the frontal sinus.

CONCLUSIONS AND CLINICAL RELEVANCE

Results confirm that frontal sinus involvement is common in dogs with nasal aspergillosis and suggest that frontal sinus trephination and sinuscopy may aid in the diagnosis of aspergillosis in dogs, particularly dogs with rhinoscopic evidence of destructive rhinitis and computed tomographic evidence of sinus involvement that lack detectable fungal plaques in the nasal cavity.

Use of topical povidone-iodine dressings in the management of mycotic rhinitis in three dogs

Three dogs with mycotic rhinitis were treated with a proprietary wound dressing product intended to produce a sustained release of povidone-iodine. All of the dogs had been refractory to other treatments. One dog had extensive soft tissue involvement, including extension into the orbital tissues, and another had evidence of involvement of the supporting bones of the nose. In all cases, the affected nasal cavity and/or frontal sinus was exposed via a dorsal approach and partial turbinectomy was performed. The wound dressing was applied and retained with a 'tie-over' dressing. The dressing was replaced every 48 to 72 hours until all exposed tissue was covered by healthy granulation tissue, at which time the rhinotomy was closed by soft tissue reconstruction. There was no evidence of recurrence of the fungal infection at follow-up times of up to 20 months postsurgery.

Antifungal agents of use in animal health--practical applications

The purpose of this paper is to provide an overview of antifungal agents currently in use in veterinary medicine. The practical applications and the therapeutic regimens that have proved successful in the treatment and prevention of fungal infections in dogs and cats, cattle and sheep, horse, pig, poultry and other birds, rodents, rabbits and fur animals are summarized.

Intranasal infusion of enilconazole for treatment of sinonasal aspergillosis in dogs

OBJECTIVE

To determine effectiveness of infusion of 1 and 2% enilconazole for treatment of nasal and sinusal aspergillosis, respectively, in dogs.

DESIGN

Case series.

ANIMALS

26 client-owned dogs with aspergillosis.

PROCEDURE

All dogs had typical clinical signs of aspergillosis and rhinoscopically visible intrasinusal or intranasal fungal plaques associated with turbinate destruction. During rhinoscopy, affected nasal cavities and frontal sinuses were debrided meticulously. Nineteen dogs (group A) were treated with 1% enilconazole by use of a modified noninvasive infusion procedure. Seven dogs (group B) were treated with 2% enilconazole via catheters that were placed via endoscopic guidance into the frontal sinuses. All dogs underwent follow-up rhinoscopy for determination of further treatment until cure was established.

RESULTS

Age, disease duration, clinical score, and rhinoscopic score were similar for both groups before treatment. In group A, 17 of 19 dogs were cured; 9, 6, and 2 dogs were cured after 1, 2, or 3 treatments, respectively. The remaining 2 dogs were euthanatized before the end of the treatment protocol. In group B, all dogs were cured; 6 dogs and 1 dog were cured after 1 or 2 treatments, respectively. Only minor adverse effects such as nasal discharge, epistaxis, and sneezing developed.

CONCLUSIONS AND CLINICAL RELEVANCE

After extensive rhinoscopic debridement, 1 and 2% enilconazole infused into the nasal cavities and the frontal sinuses, respectively, were effective for treatment of aspergillosis in dogs. Intrasinusal administration via endoscopically placed catheters appeared to require fewer infusions for success. Follow-up rhinoscopy is strongly advised.

Computed tomographic assessment of noninvasive intranasal infusions in dogs with fungal rhinitis

The distribution of infusate administered to 12 dogs with fungal rhinitis, using a noninvasive, intranasal technique, was evaluated by computed tomography (CT). In every dog, contrast medium was identified on the postinfusion CT images, within the frontal sinuses, and throughout all areas of the nasal cavity. Adverse effects were transient and mild. The results of this study indicate that intranasal infusion may be a viable alternative to trephination of the frontal sinuses to administer antifungal medications in dogs with fungal rhinitis.

Pathogenesis and treatment of canine rhinitis

Unless a systematic approach is used, evaluation of a patient with rhinitis can be frustrating to the veterinary practitioner. A complete differential list for canine rhinitis should include infectious, inflammatory, neoplastic, and traumatic causes. Other causes of rhinitis include dental disease, parasitic infestation, and ciliary dyskinesia. Diagnostic techniques that should be considered when evaluating a patient with rhinitis include obtaining a complete history, performing a thorough physical and oral examination, evaluating the patient's coagulation abilities, cytology and culture of exudate, nasal radiographs, and rhinoscopy. This article describes the pathogenesis and treatment of the various causes of canine rhinitis.

Treatment of canine nasal aspergillosis with enilconazole

Twenty-four dogs with nasal aspergillosis were treated with enilconazole (10 mg/kg bid for 7-14 days) administered topically through tubes surgically implanted into the nasal chambers. Aspergillosis was eliminated in 19 dogs over a median follow-up period of 18 months. Another dog died, but at necropsy there was no evidence of causative fungus. Two of the four dogs that were not cured had infection of periorbital soft tissues. An additional seven dogs received 6 weeks ketoconazole (5 mg/kg bid PO) and enilconazole therapy topically. Six of these dogs were disease-free over a median follow-up period of 35 months. The seventh dog responded to repeated treatment with enilconazole. Twenty-six of the 29 dogs (90%) without extranasal aspergillosis were cured.