Diagnosis and Treatment of a Swainson's Toucan (Ramphastos ambiguus swainsonii) With Rhinosinusitis.
Key words: sinus, endoscopy, trephination, sinoscopy, rhinosinusitis, avian, Swainson's toucan, Ramphastos ambiguus swainsonii
A 6-year-old, female Swainson's toucan (Ramphastos ambiguus swainsonii) presented to the Veterinary Medical Teaching Hospital of the University of California, Davis School of Veterinary Medicine (Davis, CA, USA), with a complaint of a bill deformity since it was obtained at less than a year of age and nasal discharge for 2 years. The diet consisted of a low-iron softbill diet (Mazuri ZuLiFE Soft-Bill Diet for Iron-Sensitive Birds, Mazuri Exotic Animal Nutrition, PMI Nutrition International, St Louis, MO, USA). On initial presentation, the lateral aspects of the rhinotheca displayed lamellar striations, and a steplike abnormality was present midway along the rhinotheca in a rostral-caudal direction, causing the caudal half of the rhinotheca to be about 3 mm thicker than the rostral half (Fig 1). The left naris was completely occluded by a flat, tan plug of crustlike material. Radiographs revealed excess buildup of keratinized layers of the caudal maxillary bill, with multifocal opacities in the caudal maxillary sinus cavity and lobular opacities within the caudal mandibular diverticula of the infraorbital sinus (Fig 2). The toucan was discharged for at-home nebulization with sterile saline for 20 minutes, q8-12h.
The toucan presented for its first recheck 3 months later. The bird was placed under general anesthesia, and rhinoscopy was performed. Large amounts of yellow, caseous debris were observed in both nares and the nasal diverticulum, and debris was removed via a combination of curettage and lavage with sterile saline. Endoscopic biopsy samples were taken for cytologic examination and bacterial and fungal culture. The toucan then recovered from anesthesia and was discharged on meloxicam once fully awake (0.5 mg/kg PO q12h for 3 days). Results of cytologic examination showed massive numbers of anucleate keratinized squamous cells and low numbers of adherent heterogeneous bacteria. Results of fungal culture showed no growth, whereas bacterial culture grew small numbers of both aerobic and anaerobic species.
The toucan returned approximately 3 weeks later for a second recheck examination. Rhinoscopy was again performed, and nasal debris appeared reduced by approximately 75%. Both nares were flushed with gentamicin (0.03 mg/mL) and amphotericin B (0.03 mg/mL) diluted in sterile saline, and yellow, mucoid material was recovered through the choana. The toucan was discharged to its owners with recommendations for continued nebulization at home. During the next week, the toucan presented 3 times for planned nasal flushing procedures under sedation. Each time, the bird was sedated, and the nares were flushed with the gentamicin and amphotericin B solution as described above.
The bird presented 2 days after its last nasal flushing for a computed tomography (CT) scan and repeat rhinoscopy. Results of the CT scan showed mild enlargement of the nasal diverticulum and deviation of the septum with multiple soft tissue opacities and fluid accumulation within the maxillary sinus, consistent with chronic rhinosinusitis. Fluid was observed within the mandibular diverticula of the infraorbital sinus (Fig 3). On repeat rhinoscopy, the nasal cavity was mostly clear. Endoscopic biopsy samples were collected again for histopathologic examination, and both nares were flushed with gentamicin and amphotericin B in sterile saline. The bird was discharged with recommendations to continue nebulization and with meloxicam at the previous dosage for the next 5 days. Results of histopathologic examination of the nasal epithelium sample showed moderate, multifocal histiocytic, heterophilic, and eosinophilic rhinitis with mixed intralesional bacteria.
One month later, the toucan presented again for a recheck examination. Both nares were flushed with a small amount of sterile saline. Owners were sent home with ciprofloxacin (20 mg/kg PO q24h for 4 weeks, compounded suspension from a single 750-mg ciprofloxacin tablet in 7.5 mL Ora-Blend [Perrigo, Minneapolis, MN, USA], and 7.5 mL Ora-Plus [Perrigo]) and a dilute tobramycin solution (0.01% in sterile saline) to be used for nebulization q8-12h. The toucan was presented for a recheck 1.5 months later, and no nasal discharge or oral lesions were observed at that time. One year later, the toucan presented for recurrence of nasal discharge. A copious amount of orange nasal discharge was noted from both nares, and repeat rhinoscopy, debridement, lavage, and culture under anesthesia were recommended.
Approximately 2 years after the toucan's last visit to UC Davis, it presented to the Medical Center for Birds (Oakley, CA, USA) for a reevaluation of chronic, recurrent nasal discharge. On physical examination, a mild amount of crusting around the nares bilaterally was observed. Excessive keratin buildup was present along the caudal half to two-thirds of both rhinotheca and gnathotheca although more pronounced on the upper bill. At that time, repeat imaging was discussed with the owners.
On the subsequent visit, 1 month later, the toucan had no apparent crusting or discharge around the nares. Approximately 2 mL of sterile saline was flushed through both nares, which dislodged no debris, and a rostral choanal culture sample was obtained. A rotary/grinder tool (Dremel, Racine, WI, USA) was used to remove excess keratin. Results of radiographs showed 4 large areas of opacity presumed to be granulomas within the maxillary sinus cavity, ranging in size from 0.5 x 0.5 cm to 1.1 x 0.8 cm (Fig 4). Results of the choanal culture revealed large numbers of Pseudomonas aeruginosa and Proteus species. No treatment was pursued at that time, pending a planned sinus trephination and sinoscopy.
Approximately 6 months later, the toucan was presented for the recommended sinus trephination and sinoscopy procedure. Some regrowth of the excess keratin was noted on the caudal portions of the rhamphotheca. The bird was placed under general anesthesia. Any remaining excess keratin was removed with a Dremel tool, and the bill was then aseptically prepared. Two holes were made with a 4-mm inner diameter, 6-mm outer diameter bone trephine into the right nasal diverticulum of the infraorbital sinus of the maxillary bill, and a 1.8-mm, 12-cm 0[degrees]-angle telescope (Richard Wolf GmbH, Knittlingen, Germany) was used to visualize inside the sinus (Fig 5). Three 6- to 8mm-diameter, well-encapsulated granulomas were removed through the second trephination site as a portal of access; one of which appeared to contain necrotic bone. Samples were collected for histo pathologic examination and aerobic bacterial culture from the extracted granulomas. The remainder of the sinus appeared clear. A compounded water-soluble polymer with 4 mg/mL amikacin (Roadrunner Pharmacy, Phoenix, AZ, USA) was instilled in the sites of the granulomas, and a tape patch was applied over each trephination hole. The bird recovered uneventfully from anesthesia.
The next day, the trephination holes appeared clean. The tape was replaced with human adhesive bandages (Band-Aid; Johnson and Johnson, New Brunswick, NJ, USA), and the bird was discharged to its owners that afternoon with meloxicam (1.6 mg/kg PO ql2-24h) as needed. No growth was observed upon culturing of samples taken during trephination. Histopathologic results reported that the granulomas were characterized by variable, concentric laminations of dense, compacted keratin, interpreted to be consistent with primarily keratin granulomas.
Five days after discharge, the toucan presented for a recheck examination. The surgical trephination sites were almost completely healed, and no crusting or discharge was observed around the nares. Given the absence of an infectious agent present in the accessed sinus samples, no further antimicrobial treatments were prescribed. The bird was discharged to continue recovery. Thirty-six months later, owners report that clinical signs were significantly improved since the surgery, with only 2 episodes of clear nasal discharge since then. The sites of surgical trephination remain visibly discernable but healed, and keratin overgrowth recurrence has been minimal.
This case describes the basic and advanced diagnostic procedures, as well as the medical and advanced surgical treatment, of chronic bacterial rhinosinusitis in a toucan.
Rhinitis and sinusitis are common presenting complaints in birds and can lead to accretions in the upper airways, particularly with chronicity. (1) Inflammation of the sinuses is frequently attributable to bacterial or fungal infection or both, but other factors, such as hypovitaminosis A, viral infection, choanal atresia, parasites, tumors, foreign bodies, and environmental pollutants, can be risk factors for rhinosinusitis as well. (1-8) Because the toucan was on an appropriate softbill diet and had no evidence of squamous metaplasia or other consequences of hypovitaminosis A, malnutrition was not considered likely to have a role in its condition. Other causes, such as choanal atresia, neoplasia, and foreign body, were ruled out by results of rhinoscopy and cytologic and histopathologic examination.
Various different organisms have been reported to cause bacterial rhinitis or sinusitis in birds, such as Aeromonas, Proteus, Klebsiella, Salmonella, Staphylococcus, Streptococcus species, Pasteurella multocida, and Escherichia coli. (7-11) Atypical organisms, such as Mycobacterium and Mycoplasma species, have also been shown to cause rhinitis, although both organisms more commonly cause other clinical signs. (5,12) However, there have been no previous, published case reports, to our knowledge, of bacterial rhinitis in a toucan. In this case, bacterial infection was undoubtedly a perpetuating component and possibly the inciting cause, given the repeated culture of Pseudomonas and Proteus species from the nares and nasal passages. Neither Pseudomonas nor Proteus species have previously been reported, to our knowledge, in toucan rhinosinusitis cases, although P aeruginosa is a frequent isolate from upper respiratory infections in psittacine birds. (13) Results of cytologic and histopathologic examinations were important factors in this case in ruling out other bacterial organisms and other underlying causes of rhinosinusitis, particularly hypovitaminosis A and fungal disease.
In cases of diffuse rhinosinusitis, initial medical management is an appropriate therapy to control inflammation and reduce the load of infectious organisms. (6) Medical treatment typically consists of local therapy, such as nasal flushes, and systemic therapies, such as antibiotics and anti-inflammatory drugs, depending on severity. (9-11) Based on the clinical signs observed on first presentation and the diffuse changes seen on radiographs, this toucan was initially a good candidate for medical management. The abnormalities of the maxillary diverticula of the infraorbital sinus were diffuse in nature rather than showing a nidus of infection and inflammation. Thus, targeted local therapy consisting of flushing, manual removal of debris, and intranasal antimicrobials, together with systemic antibiotic therapy, was used until a more-localized surgical target became apparent.
The sinus anatomy of the toucan is complex. The infraorbital sinuses bilaterally connect to the nasal passages and surround each orbit with multiple diverticula. The maxillary and mandibular diverticula extend into the cavities of the maxillary and mandibular bill, respectively. In this toucan, initial infection likely occurred inside the nasal passages, producing a rhinitis. This potentially spread from there into the maxillary and mandibular diverticula of the infraorbital sinus.
Rhinoscopy has not previously been reported, to our knowledge, in a toucan, although it is considered a standard component of a diagnostic workup for rhinitis in psittacine birds. (12) In this case, rhinoscopy allowed initial understanding of the diffuse nature of the rhinitis and also provided a method of documenting and monitoring resolution of the disease. Rhinoscopy also permitted cytologic and histopathologic samples to be taken directly from the areas most affected so that microbiological results were most accurate and representative.
Both conventional digital radiographs and CT were instrumental in characterizing the extent of disease, as well as in identifying a surgical target later in the course of treatment. Typically, radiography is not considered a very sensitive imaging modality for alterations in soft tissue structures, such as mild rhinosinusitis, but can become effective in more severe or chronic cases with excessive amounts of exudate or bony changes. (13) The extent of the buildup of keratin on the rhamphotheca and the increased opacity in the sinuses of this toucan were apparent on radiographs and CT imaging because of the advanced nature of the disease process. (14)
Computed tomography has been shown to be a more-sensitive method to diagnose mild or subtle cases of rhinosinusitis than conventional radiography and allows for more-accurate and -detailed imaging of the pneumatized spaces of the avian skull. (13) It has also been used in cases of rhinosinusitis that were refractory to medical treatment to identify a nidus of ongoing infection not obvious on radiographs. (10) Results of skull CT of this toucan were consistent with changes from chronic rhinosinusitis and confirmed that further treatment and follow-up were needed.
Sinus trephination is a procedure that has been described in birds for several years as a method to introduce antimicrobial therapy directly into the local area of infection by accessing regions of the upper respiratory tract that are not reachable with simple flushing, such as the dorsal and caudal portions of the infraorbital sinus or the maxillary diverticulum. (15-18) In this case, trephination into the maxillary diverticulum of the infraorbital sinus allowed the removal of several granulomas and permitted direct flushing of the region and instillation of antibiotics directly into the affected area.
The bill and nasal passages of the toucan in this case were affected by chronic rhinosinusitis, which caused recurrent mucoid nasal discharge and may have had a role in the development of the observed keratin abnormalities. The nature and extent of the disease were evaluated and monitored with basic and advanced imaging, including rhinoscopy and CT. Medical management with systemic antibiotics and repeated sinus flushing with antibiotics was successful in eliminating the bacterial infection. Sterile granulomas were removed via trephination into the maxillary diverticulum of the infraorbital sinus and allowed resolution of the clear nasal discharge.
(1.) Bennett RA, Harrison GJ. Soft tissue surgery. In: Ritchie BW. Harrison GJ. Harrison LR, eds. Avian Medicine and Surgery: Principles and Application. Lake Worth, FL: Wingers Publishing; 1994:1096-1136.
(2.) Raidal SR. Butler R. Chronic rhinosinusitis and rhamphothecal destruction in a Major Mitchell's cockatoo (Cacatua leadbeateri) due to Cryptococcus neoformans var gattii. J Avian Med Surg. 2001; 15(2): 121-125.
(3.) Songserm T, Viriyarampa AS, Sae-Heng N, et al. Pasteurella multocida-associaled sinusitis in khaki Campbell ducks (Anas platyrhynchos). Avian Dis. 2003;47(3):649-655.
(4.) Murakami S, Miyama M, Ogawa A, et al. Occurrence of conjunctivitis, sinusitis and upper region tracheitis in Japanese quail (Coturnix coturnix japonica), possibly caused by Mycoplasma gallisepticum accompanied by Cryptosporidium sp. infection. Avian Pathol. 2002;31(4):363-370.
(5.) Ley DH, Moresco A, Frasca S Jr. Conjunctivitis, rhinitis, and sinusitis in cliff swallows (Petrochelidon pyrrhonota) found in association with Mycoplasma sturni infection and cryptosporidiosis. Avian Pathol. 2012;41 (4):395-401.
(6.) Bezjian M, Kollias G. Americal kestrel (Falco spaverius [s/c]) fledgling with severe bilateral periorbital swelling and infection with Mycoplasma buteonis, Avibacterium (Pasteurella) gallinarum, and Staphylococcus pasteuri. J Avian Med Surg. 2014:28(2): 127-131.
(7.) Tully TN Jr. Avian respiratory diseases: clinical overview. J Avian Med Surg. 1995:9(3): 162-174.
(8.) Morrisey JK. Diseases of the upper respiratory tract of companion birds. Semin Avian Exot Pet Med. 1997:6(4): 195-200.
(9.) Noonan BP, de Matos R, Butler BP, et al. Nasal adenocarcinoma and secondary chronic sinusitis in a hyacinth macaw (Anodorhynchus hyacintliinus). J Avian Med Surg. 2014;28(2): 143-150.
(10.) Meyer AM, Phair K, West G. Use of computed tomography for investigation of rhinitis and sinusitis in a greater rhea (Rhea americana). J Zoo Wildl Med. 2016:47(4): 1069-1072.
(11.) Gartrell BD. Alley MR. Kelly T. Bacterial sinusitis as a cause of beak deformity in an Antipodes Island parakeet (Cyanoramphus unicolor). N Z Vet J. 2003; 51(4): 196-198.
(12.) Tully TN Jr, Harrison GJ. Pneumonology. In: Ritchie BW, Harrison GJ. Harrison LR, eds. Avian Medicine and Surgery: Principles and Application. Lake Worth, FL: Wingers Publishing; 1994:556-581.
(13.) Krautwald-Junghanns ME. Kostka VM, Dorsch B. Comparative studies on the diagnostic value of conventional radiography and computed tomography in evaluating the heads of psittacine and raptorial birds. J Avian Med Surg. 1998;12(3):149-157.
(14.) Speer BL. Beak deformities: form, function, and treatment methods. Proc Annu Conf Assoc Avian Vet. 2014:213-219.
(15.) Rosskopf WJ Jr, Woerpel RW. Sinus trephination of the supra-orbital sinuses in psittacine birds: an aid in the treatment of chronic sinus infections. Proc Annu Conf Mid Atl Assoc Avian Vet. 1991:170-176.
(16.) Speer BL, Echols MS. Surgical procedures of the psittacine skull. Proc Annu Conf Assoc Avian Vet. 2013:99-109.
(17.) Bowles HL, Odberg E, Harrison GJ, Kottwitz JJ. Soft tissue surgery. In: Harrison GJ and Lightfoot T. Clinical Avian Medicine. Vol 2. Palm Beach. FL: Spix Publishing; 2005:775-830.
(18.) Pye GW. Surgery of the avian respiratory system. Vet Clin North Am Exot Anim Pract. 2000;3(3):693-713.
Rachel M. Baden, DVM, David Sanchez-Migallon Guzman, LV, MS, Dipl ECZM (Avian, Small Mammal), Dipl ACZM, Brian L. Speer, DVM, Dipl ABVP (Avian), Dipl ECZM (Avian), Amberly M. Sokoloff, VMD, and Michelle G. Hawkins, VMD, Dipl ABVP (Avian)
From the William R. Pritchard Veterinary Medical Teaching Hospital (Baden, Sokoloff) and the Department of Medicine and Epidemiology (Guzman. Hawkins). School of Veterinary Medicine, University of California. Davis, One Shields Avenue, Davis. CA 95616, USA; the Medical Center for Birds. 3805 Main Street, Oakley, CA 94561, USA (Speer); and the Airport Animal Hospital, 6209 N 9th Avenue, Pensacola, FL 32504. USA (Sokoloff).
Caption: Figure 1. Appearance on initial presentation of an adult, female Swainson's toucan with a 2-year history of chronic nasal discharge and bill asymmetry. The bird had excess keratin on the proximal half of the bill (A) and mucoid nasal discharge (B). (A) The arrow denotes the excess keratin buildup. (B) The arrowhead illustrates the nasal discharge.
Caption: Figure 2. Lateral (A) and ventrodorsal (B) skull radiographs of the Swainson's toucan described in Figure 1 on the day of initial presentation for chronic mucoid nasal discharge, showing excess keratin buildup proximally, diffuse patchy opacities within the maxillary diverticulum of the infraorbital sinus (arrows), and lucencies within the mandibular diverticulum proximally (arrowheads).
Caption: Figure 3. Computed tomography scan of the skull of the Swainson's toucan described in Figure 1 at 4 months after initial presentation. The scout image (upper left) shows the locations of the other images, which illustrate the extent of rhinosinusitis (arrows) within the maxillary diverticulum and infraorbital sinus.
Caption: Figure 4. Lateral (A) and ventrodorsal (B) skull radiographs of the Swainson's toucan described in Figure 1 at 3.5 years after initial presentation, showing several masslike opacities in the maxillary diverticulum of the infraorbital sinus (arrows). These were considered likely potentiating factors in the chronic rhinosinusitis of this bird and were targeted for surgical removal.
Caption: Figure 5. Trephination, sinoscopy, and mass removal performed on the Swainson's toucan described in described in Figure 1. The masses were revealed to be keratin granulomas on histopathologic examination.
|Printer friendly Cite/link Email Feedback|
|Title Annotation:||Clinical Report|
|Author:||Baden, Rachel M.; Guzman, David Sanchez-Migallon; Speer, Brian L.; Sokoloff, Amberly M.; Hawkins, Mi|
|Publication:||Journal of Avian Medicine and Surgery|
|Date:||Jun 1, 2019|
|Previous Article:||Infraorbital Keratin Cyst in an Umbrella Cockatoo (Cacatua alba).|
|Next Article:||Key Ring Fixator: A Novel External Fixation Technique for Avian Long Bone Stabilization.|