J . small Anim. Pract. (1987) 28, 839-844

Rhinoscopy : a diagnostic aid? M A R T I N S U L L I V A N

Department of Veterinary Surgery, Glasgow University Veterinary School, Bearsden Road, Bearsden, Glasgow G61 IQH

A B S T R A C T

Sixty dogs with confirmed chronic nasal disease were examined rhinoscopi- cally. The relative merits of the otoscope, an arthroscope and a flexible bronchoscope as instruments are discussed. Rhinoscopy has a limited place in the investigation of chronic nasal discharge in the dog due to the volume of discharge present and induced haemorrhage. It is most useful in cases of destructive rhinitis (including aspergillosis) and foreign body obstruction.

I N T R O D U C T I O N

The use of endoscopy in the investigation and treatment of nasal disease has become well established in man (Stammberger, 1986), and in the horse since the introduction of the flexible fibreoptic endoscope (Cook, 1974). In the equine the procedure can be carried out on the conscious animal, and the nasal cavity can be examined from external to caudal nares.

The use of endoscopy in the examination of the canine nasal cavity has not been advocated widely, because excess discharge, which is invariably present in the dog with a nasal problem, is considered to obscure and therefore reduce meaningful interpretation (Gibbs, Lane and Denny, 1979). This problem has been reported as being surmountable by the deployment of a suction cannula or a continuous irrigation system (Venker-van Hagen, 1985 ; McCarthy, 1986).

Cook (1964) divided endoscopy of the nasal cavity into two components. Rostra1 rhinoscopy, where a dilatable nasal speculum and head mirror were used; and caudal rhinoscopy, where the caudal nares were investigated per os, using a laryngeal or dental mirror. Since then there have been a number of papers reporting the use of the otoscope and appropriate speculum in the investigation of nasal disease. Bright and Bojrab (1976) considered that rostra1 rhinoscopy could, at most, eliminate a foreign body as a potential diagnosis. Sande and Alexander (1970) and Delmage (1973), commenting on single cases, found the results inconclusive. However,

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840 M. S U L L I V A N

Legendre, Spaulding and Krahwinkel(l983) were more optimistic that rhinoscopy could be definitive in the diagnosis of nasal tumours. To overcome the disadvantage that the otoscope limits examination to the rostral nasal cavity, Norris and Laing (1985) employed a rigid 1.7 mm endoscope and were able to examine the entire nasal cavity. Lane (1982) stated that the nasal disorder might be identified occasionally, using an otoscope or 5 mm fibrescope.

In order to support or refute these discouraging results and opinions, 60 dogs with chronic nasal discharge were investigated using rostral rhinoscopy.

MATERIALS A N D METHODS

Sixty dogs referred to the Department of Surgery with a history of chronic nasal discharge were investigated endoscopically. The majority were medium-sized weighing more than 10 kilograms, and all were dolichocephalic or mesaticephalic. Premedication with acepromazine maleate was followed by induction with a short acting barbituate. The animals were then maintained on an oxygen/halothane mixture. The instruments used were (a) an otoscope with speculum, (b) a 1.7 mm arthroscope (Olympus SES-171 lK), (c) a 4.8 mm flexible fibreoptic forward-viewing bronchoscope, with bending angles 180" up and 100" down (Olympus BF-10). Ninety-two rostral rhinoscopic examinations were carried out on the 60 dogs; 15 dogs with both otoscope and arthroscope, 17 with otoscope and flexible bronchoscope, and 28 with the bronchoscope alone. Discharge which had accumulated at the external nares was swabbed clear, so that the instrument tips were not soiled on insertion. Initially, attempts were made to flush obstructing discharge with isotonic saline but were abandoned. The nasal cavities of all the dogs were radiographed, and where appropriate, biopsies and/or samples for mycological examination were obtained to enable a definitive diagnosis to be reached, thus confirming the endoscopic findings.

RESULTS

Instrumentation The three instruments used to examine the 60 cases are compared in Table 1, and the lesions and combinations of instruments are listed in Table 2.

Rhinoscopic appearance Neoplasia (19 dogs). Tumours were positively identified in only six cases. The

turbinate scrolls were absent and the neoplastic tissue appeared as a large mass with an irregular granular surface, which gave multiple light reflections when the arthroscope or bronchoscope were used. In three cases, there were rostral remnants of turbinate and the tumour occupied the meatii pushing the scrolls apart. Failure to identify tumours in the other 13 cases was attributable to the otoscope and bronchoscope being unable to penetrate deeply enough to reach the ethmoturbinate

R H I N O S C O P Y : A D I A G N O S T I C A I D 84 1

TABLE 1. Comparison of endoscopes used for rhinoscopy

Otoscope Arthroscope Bronchoscope ~~

cost Penetration Field of vision Orientation Object-eye distance Biopsy capability Foreign body retrieval Ease with which clouding of

is cleared

Induced epistaxis

tip

El20 + +++ easy long + + + + + + + +++ (insufflation &

cotton bud) unlikely

51,500 ++++ + difficult short + + + (withdrawal &

re-insertion) inevitable

S8,OOO + + + + + easy short +++ +++ ++ (insufflation or

withdrawal) occasional

(+) = poor, (+ +) = reasonable, (+ + +) = good, (+ + + +) = excellent

TABLE 2. Diagnosis of cases examined and instruments used

Endoscope

Lesion .-

Neoplasia (19) Aspergillosis (13) Hyperplastic rhinitis (9) Rhinarial ulceration (9)

Destructive rhinitis (3)

Number of dogs 60

Foreign body ( 5 )

Oro-nasal fistula (2)

oto-/arthroscope

4 5 4

1 1

15

oto-/ bronchoscope bronchoscope

3 12 4 4 1 4 5 4 2

2 17

- 2 2

28

region, the volume of exudate blocking the view, or the exudate preventing differentiation of turbinate scrolls from neoplastic tissue. Although the arthroscope could reach the caudal nares no tumours were identified using this instrument due to difficulty in orientation, the poor field of vision and the easily induced haemorrhage.

Aspergiflosis (13 dogs). Fungal plaques were visible in all cases with the three instruments used. The first impression was of a large, empty, rather dark cavity caused by the loss of turbinates. The turbinate loss was variable, and in six cases the root of the ventral concha was present resembling a red walnut. The lining of the cavity was much redder than normal turbinate mucosa. The fungal plaques were yellow/white, some having small black dots on the surface. The plaques were situated on the residual truncated ventral concha, the main ethmoturbinates, or dorsally on the turbinates leading to the frontal sinus. In five cases, one or two fungal

842 M. SULLIVAN

masses lay free in the nasal cavity and were easily dislodged. These were greyer than the sessile plaques.

Chronic hyperplustic rhinitis (10 dogs). Turbinate scrolls could be identified in five cases, but excess discharge in the remaining five prevented examination of the nasal cavity. No positive interpretation could be made in any of the cases.

Rhinuriul ulceration (8 dogs). Once past the inflamed ulcerated mucosa of the external nares the turbinate scrolls were normal and covered with a fine film of mucus.

Foreign body (5 dogs). Four cases had twigs or plant stems 5-8 cm long removed easily with the otoscope or bronchoscope. The twigs were surrounded by a white muco-purulent discharge and the twig could be identified end-on as a hard yellow mass lying in this exudate. In the fifth case, a pine needle was not located but sneezed out by the dog subsequent to examination.

Destructive rhinitis (3 dogs). The absence of turbinates and reddened residual turbinates were similar to the findings in those cases of aspergillosis. No plaques were visible, although it was not possible to examine the frontal sinus via the external nares.

Oro-nusalJtstulu (2 dogs). A tenacious muco-purulent discharge was found focally on the lateral aspect of the rostra1 nasal cavity. Normal concha were visible caudally.

DISCUSSION

The results demonstrate that the nasal cavity can be examined endoscopically. The potential of rhinoscopy to detect significant abnormalities depends on the instrument used and, paradoxically, on the pathological state of the cavity which often limits the usefulness of this diagnostic aid. None of the three instruments employed was considered at the outset, or found to be, ideal. The least satisfactory performance was given by the arthroscope because of the poor field and depth of vision. This was due to the very narrow and angled tip of the instrument. The poor .

performance was compounded by the ease with which the sharp and relatively pointed tip induced haemorrhage. This drawback was most pronounced in those cases of neoplasia, where the tumour tissue was very friable. The bronchoscope was superior to the arthroscope because of the excellent illumination, flexible construction and good field of vision but the penetration achieved was no better than that of the otoscope, except in cases of destructive rhinitis. The otoscope in terms of cost and results was the most effective instrument. Two techniques, which prolong the duration of the examination, have been suggested to improve the information obtained from rhinoscopy. Venker-van Haagen (1985) used a fine suction cannula to remove much of the discharge, but requires additional equipment to achieve adequate aspiration. Secondly, MacCarthy (1986) used irrigation to remove discharge, but this tends in our experience to stir up as much debris as it removes and it is very difficult to achieve a clean nasal cavity.

As far as specific conditions are concerned, rhinoscopy is unlikely to identify a

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neoplasm unless the rostra1 compartment is involved and discharge is minimal. Discharge was one major handicap, because although tissue could be seen it was frequently impossible to distinguish turbinate scrolls from neoplastic tissue. Therefore endoscopic differentiation of tumour from chronic hyperplastic rhinitis was unreliable. Another problem was that haemorrhage was easily induced. Although initially use was made of flushing isotonic saline in attempt to clear the discharge, this was quickly abandoned as it was counterproductive because debris merely clouded the flushing fluid.

Rhinoscopy proved invaluable in evaluating cases of aspergillosis, idiopathic destructive rhinitis and foreign body. Cases of aspergillosis had plaques identified in all cases and allowed differentiation from idiopathic destructive rhinitis where the radiological findings were essentially similar. Consequently rhinoscopy should be used in all suspected cases of destructive rhinitis.

In summary, rhinoscopy should not be dismissed because many of the examinations may be fruitless. It should be a rapid procedure and ought to be considered as a supplement to other investigations such as radiology.

A C K N O W L E D G E M E N T S

The bronchoscope used in this study was a gift to the Department of Veterinary Surgery by the RCVS Spencer-Hill Trust.

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