Interesting avian and exotic cases (Proceedings)
A 4 year old neutered male rabbit weighing 1.98 kg presented in December of 2002 for a 1 year history of nasal discharge and violent sneezing. The rabbit's condition was unresponsive to antibiotics. Due to the violent nature of the sneezing and the unresponsiveness to antibiotics, a nasal foreign body was suspected. Endoscopy of the nasal passageways revealed a large mass. Initial biopsies of the mass revealed pyogranulomatous inflammation and possible intralesional foreign bodies. Special stains revealed no acid fast staining organisms. A culture revealed normal respiratory flora.
The rabbit was referred to The University of Georgia Veterinary Teaching Hospital for a CT scan to determine the full extent of the mass. After the CT scan, the mass was debrided aggressively via endoscopy. At this point in time nearly complete destruction of the nasal septum was noted. A preliminary culture revealed Acinetobacter and an unidentified gram negative bacillus. The preliminary histopathology report showed granulomatous inflammation that was consistent with a possible foreign body reaction or fungal infection. While culture and sensitivity were pending, the rabbit was started on ciprofloxacin at 10mg/kg PO q 12 hrs, itraconazole at 10mg/kg PO q 12 hrs and carprofen at 2.5mg PO q 12 hrs.
The rabbit experienced complete cessation of the violent sneezing within 3 days of the aggressive debridement. The final histopathology report showed the presence of acid fast staining organisms. Approximately 3 weeks later culture results verified the presence of a Mycobacterium spp, however the Mycobacterium unable to be isolated and further typed.Within 2 months, the rabbit had begun to sneeze excessively and violently again. He presented again at the author's clinic. Endoscopy was performed and an excessive amount of crusty, scab-like material was debrided from the nasal passageway. Pieces of tissue were once again submitted for culture to identify the Mycobacterium species and to determine its sensitivities. After 7 weeks, the bacteria was identified as Mycobacterium avium complex. Sensitivity took an additional 4 months. The rabbit was started on a combination of rifampin at 75mg/kg PO q 12 hrs, azithromycin at 50mg/kg PO q 24 hrs and ciprofloxacin at 10mg/kg PO q 12 hrs.
The rabbit did well on this protocol for 8 months. He came in after 8 months for a recheck because there was an increase in sneezing again. Endoscopy showed a recurrence of the crusty dried exudates and excessive granulation tissue. The nasal passageway was debrided again and the rabbit improved. The rabbit was brought back in every 3-7 months for rechecks. Periodically the nasal passageways needed to be debrided again. Fourteen months later in January of 2005, the rabbit was doing well clinically and the medications were discontinued. After 2 weeks the rabbit stated having increased episodes of sneezing and appeared to be lethargic. Medications were resumed.
The rabbit was presented again 5 months later in June of 2005 for endoscopic debridement. The nasal conchi were improved. More defined conchi were observed. At this time, significant serum chemistry findings were an elevated ALKP 177 IU/L (ref 10-70IU/L) (1) and an elevated total bilirubin 15.3umol/L (ref 3.4-8.5umol/L) (1). The results of a complete blood count were a WBC of 4,100/uL (ref 5,000-12,000/uL)(1) consisting of 58% segmented neutrophils, 41% heterophils and1% monocytes. The RBC was 5.5 x 106 and the hematocrit was 28% (ref. 33-38%) (1). Another endoscopic debridement 5 months later in November of 2005 was peformed. A culture at that time grew a light growth of Bordetella bronchiseptica, Staphlococcus coagulase negative and no Mycobacterium species were noted.
In January of 2006 the medication regimen was changed to rifampin 6 times per week, azithromycin 3 times per week and ciprofloxacin twice daily. Meloxicam was also given at a dose of 0.2mg/kg PO q 12 hrs. Four months later in May of 2006 the rabbit presented again for endoscopic debridement. There was very little exudate and there was dramatic improvement in the appearance of the nasal conchi. Medications were discontinued at that time.