I’m pleased to say sinonasal aspergillosis is not a condition I see very often in either cats or dogs as I know it can be challenging to diagnose and manage. However, after watching Simon Tappin’s webinar on this very topic I now know when confronted with patients suffering from sinonasal aspergillosis, I will be much better equipped to steer these case in the right direction.
Simon firstly explained that aspergillus fumigatus is an opportunistic organism found in the soil and does not necessarily always cause disease. Aspergillosis may develop secondary to other issues such as the presence of a nasal foreign body, neoplasia or trauma. There are also certain breeds, such as the GSD and Rottweiler, that have issues with their cell mediated immunity making them more prone to developing Aspergillosis. For this reason it is always important to remember that if aspergillus is found on cytology ( usually after performing a nasal flush), it’s presence must always be interpreted in context to the clinical picture of the patient.
Diagnostics of Sinonasal Aspergillosis
A negative serology result for aspergillus must also be interpreted with caution. Antibody testing for aspergillus is highly specific meaning if you get a positive result then a false positive is highly unlikely to occur. However it only has moderately sensitive meaning false negative results are more likely. So if Aspergillus serology is negative for your patient but the clinical picture fits for aspergillosis then further diagnostics should be performed to rule out or rule in this diagnosis.
These further diagnostics include imaging of the nasal cavity using x-rays, CT, MRI and nasal rhinoscopy. Simon explained the pros and cons of each technique and also explained how to perform a nasal rhinoscopy. Nasal biopsies are however the key to making a diagnosis and again this technique was explained within the webinar. After nasal biopsies Simon explained that these patients do tend to bleed a lot post biopsy and may need to have their nose packed and/or have their nasal area flushed with iced saline. Simon also sometimes uses acepromazime as a sedative on recovery which also helps to reduce blood pressure slightly. He would also always recommend keeping these patients hospitalised overnight.
Treatment of Sinonasal Aspergillosis
Once cases of Aspergillosis are confirmed with nasal biopsies, treatment can be instigated either orally or topically. Simon explained that oral treatments are not as effective as topical treatments. Prolonged treatments with oral drugs such as fluconazole or itraconazole are necessary for 6-8 weeks. Vomiting, anorexia and hepatotoxicity are common side effects associated with these treatments and unfortunately only offer between 40-60% efficacy.
Topical treatment, however is a lot more effective, but a key part to this treatment’s success is to ensure that as much fungal material as possible has been debrided endoscopically first. Simon then talked us through how to perform sinus trephination to allow flushing of the nasal cavities. Once this has been performed Simon explained he then flushes with saline to aid in the debridement process followed by a further five minute flush with a 1% solution of clotrimazole. Finally a depo of clotrimazole cream is then administered.
For those of us who are less keen on the surgical process of sinus trephination, Simon also described how to perform a nasal soak where the nasal cavities are soaked with. 1% clotrimazole solution for 60 minutes. If these cases do recur then it will be necessary to resort to rescue therapies which usually involves the placement of an indwelling catheter allowing for the daily installation of an antifungal such as imaverol, or if we are really struggling to resolve the problem, it may be necessary to perform a rhinotomy as a last resort.
What do I think?
This was a highly informative webinar packed with advice on how to manage these challenging cases and will act as an excellent reference point for when a case of sinonasal aspergillosis is presented to us in practice.