Aspergillosis, a fungal infection, develops in the nasal cavities and frontal sinuses of dogs. Containing the fungus to the nasal cavities is critical to successful treatment. Disseminated aspergillosis usually results in death. No preventative measures or vaccines are available. Early detection and treatment are crucial.
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Description
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As the fungus grows it destroys the nasal turbinates, fine bone structures within the nostrils, causing discharge and bleeding. The fungus spreads to the sinus cavities and lungs, then enters the bloodstream. Once the fungus disseminates into the bloodstream, it affects the spine, organs and bones throughout the body. If left untreated, it could cause death.
Risk Factors
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Dogs with long- to moderate-length noses are more susceptible to aspergillosis. German Shepherds are the breed with the highest rate of infection. Short-nosed dogs such as pugs and Boston terriers rarely become infected. Dogs younger than seven years old appear to be at a much higher risk as well. Dogs with poor immune systems, pre-existing diseases, prolonged antibiotic therapy or prior sinus infections are more likely to become infected.
Symptoms
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Early recognition of aspergillosis increases the cure rate of this fungal infection. Watch for open sores around the nostrils; clear or cloudy nasal discharge, which can alternate with nasal bleeding; and pain in the facial region. One or all three of these symptoms may appear. Once aspergillosis has disseminated, the warning signs become much more life threatening: weight loss, fever, weakness, vomiting, lethargy, inflammation of the eyes and eventually paralysis.
Diagnosis
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A nasal tumor presents the same initial symptoms as aspergillosis, so a variety of diagnostic tests are extremely important. Nasal cavity cultures examined with a microscope are one option. X-rays of the frontal sinus cavities is a concrete way to diagnose aspergillosis. They show where the fungus has destroyed the sinus bones. Another diagnostic test is a nasal biopsy. Using a rhinoscope, veterinarians examine the inside of the nasal cavity and obtain a biopsy of the infected tissue. A final diagnostic option are the AGID and ELISA blood tests, which give fairly accurate results.
Treatment
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Systemic treatments consist of oral antifungal drugs, itraconazole or fluconazole, administered for approximately 10 weeks. The cure rate is usually 60 percent to 70 percent. The possibility of liver damage is a side effect. Topical treatments include periodic nasal infusions of enilconazole, an antifungal drug. Tubes surgically implanted into nasal and sinus cavities allow the drug to be distributed throughout the infected area. The cure rate for this treatment is 90 percent. Veterinarians can also anesthetize the dog and inject clotrimazole into the sinus cavities. This has a cure rate of 94 percent. Once aspergillosis has disseminated, cure rates drop considerably. Amphotericin B, an antifungal drug, must be given intravenously, which requires hospitalization. The side effect of this is possible kidney damage.
Follow-Up
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Follow-up with a veterinarian is critical. If the dog does not seem to be responding to treatment, seek immediate veterinarian care. Complete the full medication cycle even if the dog seems to be feeling better. Veterinarians often repeat X-rays and blood tests to ensure the fungus has been eliminated.
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