feline-upper airway obstruction in cats

8/14/2019 FELINE-Upper Airway Obstruction in Cats

1/11

Vol. 22, No. 10 October 2000

Refereed Peer Review

FOCAL POINT

KEY FACTS

5A thorough understanding offeline upper airway obstructive

diseases and possible therapeutic

alternatives allows diagnosis and

treatment under the sameanesthetic episode, thereby

improving outcome.

Upper AirwayObstruction in Cats:Diagnosis and

Treatment*University of Edinburgh

Dominique J. Griffon, DVM, MS, MRCVS

ABSTRACT: Clinical signs of upper airway obstruction provide valuable information regarding

the degree of airway compromise and the anatomic compartment involved but are not specific

to any disease process. The purpose of the diagnostic workup is to determine the extent and

nature of the condition. The extent of the physical examination depends on the degree of up-

per airway obstruction, and complete evaluation may need to be postponed until the patient is

anesthetized. However, rapid assessment of respiratory impairment is crucial because it al-

lows appropriate triage of patients. In cats with mild upper airway obstruction, radiographs of

the thoracic and cervical areas may be obtained with the patient either awake or under seda-

tion. A complete oral and laryngeal examination should be performed with the patient under

anesthesia. Additional tests may also be indicated. Manipulation of the upper airway in a com-

promised patient is likely to exacerbate signs; therefore, diagnostic tests and corrective

surgery should be scheduled under the same anesthetic episode. This article describes the

corrective surgical techniques for obstructive airway diseases. Although these techniques may

be technically demanding, they do not require specialized equipment and, depending on the

nature of the disease, often provide good results.

Clinical signs of upper airway obstruction are variable and not specific toany disease process. Signs may help to localize disease, but a thorough di-agnostic approach is needed to diagnose the condition. The severity of

signs will depend on the degree of functional obstruction and will dictate theinitial therapeutic approach. On presentation, triage should be conducted im-mediately so that patient care can be prioritized accordingly. Cats with severeupper airway obstruction should be anesthetized and intubated as quickly aspossible.1 Placement of a cricothyrotomy tube or emergency tracheostomyshould be limited to patients that cannot be intubated and that require bypass ofthe larynx.

Diagnostic evaluation should be performed after respiratory function has im-

CE

s Flexible endoscopy is valuable

for evaluating the choanae,

nasopharynx, and subepiglottic

areas.

s Middle-ear evaluation is part ofthe diagnostic approach for

nasopharyngeal polyps.

s Nasopharyngeal stenosis is easy

to diagnose and carries a good

prognosis after surgery.

s Treatment of granulomatous

laryngitis consists of surgery and

long-term antiinflammatory

therapy.

s Unilateral arytenoid lateralization

provides excellent results in cats

with permanent laryngeal

paralysis.

*A companion article entitled Upper Airway Obstruction in Cats: Pathogenesis andClinical Signs appeared in the September 2000 (Vol. 22 No. 9) issue ofCompendium.


2/11

proved. The physiologic re-sponse to a stress-induced in-crease in oxygen requirementsinvolves an acceleration of therespiratory rate. This will exac-

erbate any preexisting compro-mise of the upper airway andmay quickly result in a life-threatening situation. For thatreason, handling of patients

with compromised airwaysshould be minimized, and mostdiagnostic tests should be per-formed while the patient is un-der anesthesia. Routine hema-tology and blood chemistryshould be performed before

anesthesia if the patient cansafely tolerate blood sampling.Alternatively, analyses may bepostponed until the cat hasbeen sedated or anesthetized.Because examination and intu-bation of the upper airway mayexacerbate the obstruction andcomplicate recovery, diagnosticevaluation should be scheduled

when treatment of the condi-tion may be achieved under the

same anesthetic episode. If thisis not possible, clinicians shouldbe prepared to place a tempo-rary tracheostomy tube.

DIAGNOSISPhysical Examination

The purpose of the initial ex-amination is to assess the degreeof airway compromise. This canbe done from a distance by ob-serving the attitude, posture,

breathing pattern, respiratoryrate, and color of mucous mem-branes. A gentle physical exami-nation and auscultation maythen be performed. Oxygentherapy should be provided dur-ing examination, if required.

Any step of the examinationthat causes stress should bepostponed until the cat is anes-thetized and intubated.

Various tube types and sizes

(including urinary catheters)should be prepared to allow in-tubation of a narrowed airway.

At this point, intravenous ad-ministration of an ultrashort-

acting corticosteroid (e.g., 0.25mg/kg of dexamethasone sodi-um phosphate) is recommendedto minimize edema. Ideally, la-ryngeal anatomy and functionshould be evaluated before intu-bation. This examination can beperformed with the patient un-der light anesthesia, with simul-taneous observation of the respi-ratory cycle. After intubation,the soft palate should be evaluat-

ed for any ventral deviation thatmay be associated with nasopha-ryngeal masses. Nasopharyngealpolyps present as unilateral orbilateral gray or pink masses

with a smooth or nodular sur-face (Figure 1). Although theyoften measure 1 to 2 cm in di-ameter when diagnosed, polypsmay reach up to 5 2 cm. Alaryngoscope placed at the baseof the tongue facilitates inspec-

tion of the pharynx and larynxfor any mass, inflammation, orforeign body. Gentle retractionof the soft palate with a spayhook or stay sutures provides ex-posure of the caudal nasophar-ynx. Otoscopic examination isimportant in cats with nasopha-ryngeal diseases and/or signsof auricular disease. Auriculardischarge and rupture of thetympanic membrane may be as-

sociated with otitis media. Oto-pharyngeal polyps are some-times seen through a bulgingtympanic membrane (Figure 2).

Cannulation of the nose witha 6-Fr nasogastric tube shouldbe attempted in cats with sus-pected nasal or nasopharyngealobstruction. In cats with na-sopharyngeal stenosis, a cannu-la can be advanced through thenasal passages but stops before

Small Animal/Exotics Compendium October 2000

H E M A T O L O G Y s A I R W A Y C O M P R O M I S E s N A S O P H A R Y N G E A L P O L Y P S s O T I T I S M E D I A

Figure 1Intraoperative view of the nasopharynx of an8-year-old cat with bilateral nasopharyngeal polypsand nasopharyngeal foreign body. A ventral midlineapproach through the soft palate was used.

Figure 2B

Figure 2Otoscopic examination of a cat. (A) Normaltransparent appearance of the tympanic membrane.(B) A nasopharyngeal polyp in the middle ear. Themass can be seen behind the tympanic membrane.

Figure 2A


3/11

reaching the laryngopharynxon both sides. Cannulation ofthe nasal passages allows cau-dal displacement of nasopha-ryngeal masses and, used in

combination with cranial re-traction of the soft palate, im-proves their visualization. Ifno abnormality is found onclinical and radiographic ex-amination, further diagnostictests (e.g., endoscopic exami-nation of the subepiglotticarea and nasopharynx) shouldbe considered.

Radiography

Thoracic radiographs arepart of the routine evaluationof patients with respiratorydisease. Indeed, localization ofrespiratory signs is not alwaysaccurate. Symptoms of prima-ry lower respiratory tract dis-ease may be masked if pa-tients suffer concurrent upperairway obstruction. One ven-trodorsal and two lateral pro-

jections should be evaluated

for metastases in cats suspect-ed of having laryngeal neopla-sia. Evaluation of the entirerespiratory tract is warrantedto establish a treatment planand prognosis.

Cervical radiographs are also indicated. Radiodenseforeign bodies (e.g., needles, pellets) are occasionallyfound in cats. Radiographic signs of laryngeal neoplasiaare variable. Feline laryngeal tumors may appear as ageneralized thickening of the larynx rather than a dis-tinct mass lesion.2 Tumors are best visualized by laryn-

goscopy. Conversely, radiographs are useful in localizingmass lesions causing extramural compression of the lar-ynx. Soft tissue radiopacities are suggestive of tumors orabscesses of the larynx and adjacent structures. Soft tissueswelling, subcutaneous emphysema, and displacement ofthe tracheolaryngeal cartilages may be found in animals

with laryngeal trauma.1 In these cases, radiographs arealso helpful in assessing the status of the spine.

Whereas cervical and thoracic radiographs may be ob-tained using sedation in some patients, skull radiographyis always performed while the patient is anesthetized inorder to ensure proper positioning. Skull radiography is

warranted in cats with nasal ornasopharyngeal disease, withor without auricular signs. Na-sopharyngeal polyps are bestvisualized on the lateral projec-

tion as a soft tissue density inthe nasopharynx, displacingthe soft palate ventrally (Figure3). The best radiographic viewto evaluate middle-ear diseaseis the open-mouth view.3 Ad-ditional views include obliqueviews of the bullae and a ven-trodorsal projection to assessthe external canal and petroustemporal bone. Soft tissueopacity within the bulla and

thickening of the wall suggestmiddle-ear involvement. How-ever, radiographic changes areinconsistent, especially early inthe disease course, and false-negative radiographic diagnosisof otitis media has been report-ed in up to 25% of the cases.3

Computed tomography of theskull may be considered in theabsence of radiographic signsof middle-ear disease.4,5 Radio-

graphic signs of nasopharyn-geal stenosis are inconsistent.6,7

A dorsal deviation of the softpalate may occasionally be seen8

(Figure 4).

EndoscopyEndoscopic examination of the nasopharynx requires

retroflexion of a flexible endoscope over the soft palate,thereby allowing visualization of the entire nasopharynxand choanae as well as the most caudal portion of thenasal cavities. By the time of presentation, nasopharyn-

geal polyps tend to have reached such a significant sizethat endoscopic evaluation is rarely needed for diagno-sis. However, endoscopy is crucial for the diagnosis ofnasopharyngeal stenosis, radiolucent foreign bodies, ab-scesses, and neoplasia. In nasopharyngeal stenosis, adhe-sions are occasionally located at the junction of the na-sopharynx and laryngopharynx, preventing retroflexionof an endoscope over the soft palate. Cranial retractionof the soft palate allows direct visualization of the area.

The same flexible endoscope may be used to evaluatesubepiglottic disorders. Foreign bodies are occasionallyfound caudal to the larynx and may be retrieved endo-

Compendium October 2000 Small Animal/Exotics

C A N N U L A T I O N s L A R Y N G O S C O P Y s O P E N - M O U T H V I E W s S O F T P A L A T E

Figure 3Lateral radiograph of the skull of a cat with anasopharyngeal polyp. Note the soft tissue opacity overthe nasopharyngeal area and the ventral deviation of thesoft palate.

Figure 4Lateral radiograph of the skull of a cat with na-sopharyngeal stenosis. Note the dorsal deviation of thecaudal edge of the soft palate.


4/11

scopically. Tracheoscopy will also improve visualizationof subepiglottic tumors and facilitate biopsy.

HistopathologyHistologically, nasopharyngeal polyps consist of a

core of well-vascularized fibrous connective tissue cov-ered by stratified squamous or columnar epithelium.9

Inflammatory cells are especially prominent in the sub-mucosa.10 However, a presumptive diagnosis of na-sopharyngeal polyp can usually be made on the basis ofsignalment, history, and the appearance of the mass.Preoperative biopsy is, therefore, not essential. Instead,I recommend immediate surgical treatment and histo-pathology of the excised tissue. Similarly, the gross ap-pearance of nasopharyngeal stenosis and abscesses is char-acteristic.

Making a diagnosis of laryngeal masses requires

histopathology. Granulomatous laryngitis must be dif-ferentiated from neoplasia because the prognoses differsignificantly. The inflammatory disorder clinically re-sembles neoplasia but histopathologic findings consistof a mixed inflammatory cell infiltrate involving mac-rophages, lymphocytes, and plasma cells. Ulceration ofthe epithelium is a common finding in humans and hasalso been described in cats.11

Histopathologic examination of frozen sections is help-ful in the management of laryngeal masses. The tests ac-curacy was 93% in a study comparing the diagnosesbased on evaluation of frozen sections compared with tis-

sue prepared using conventional methods.

12

Establishingan intraoperative diagnosis provides a rational basis fordecisions regarding therapeutic options or euthanasia.

Other TestsCytologic examination of laryngeal masses may be at-

tempted if frozen sections are not available. Inflammationmay, however, be difficult to differentiate from neopla-sia.13 Before recovery from anesthesia, a temporary tra-cheostomy should be considered to palliate the obstruc-tion until a definitive diagnosis can be made. Cytology ismore useful in the diagnosis of fungal infections, where

organisms may be seen in the specimen.Results of bacterial cultures should be interpreted incombination with other diagnostic tests. Although bacte-rial infections may be clinically significant, they often aresecondary to upper airway obstruction.

Ultrasonography is often used to evaluate patients thatpresent with cervical masses, to define the character ofthe mass as well as the organ involved.14 Ultrasonographymay be easier than is radiography to perform on sedatedpatients and may provide useful preoperative informa-tion. Assessing the degree of vascularization and invasive-ness of cervical masses will help in planning surgical


M A C R O P H A G E S s T R A C H E O S T O M Y

COMPENDIUMON CONTINUING EDUCATION

F O R T H E P R A C T I C I N G V E T E R I N A R I A N

Veterinary Technician reprints also available

2001 PRICE SCHEDULE*

2 4 8 12 16Quantity pages pages pages pages pages

Black & White

100 $ 108 $ 204 $ 416 $ 604 $ 784500 152 296 616 896 1,156

1000 208 412 868 1,260 1,6285000 636 1,264 2,828 4,076 5,160

10,000 1,172 2,332 5,280 7,596 9,572

Color

100 $ 972 $1,408 $2,856 $4,180 $5,380500 1,152 1,612 3,112 4,704 6,040

1000 1,264 1,840 3,428 5,260 6,8525000 2,328 3,600 7,140 10,672 12,168

10,000 3,280 5,792 10,640 16,704 18,812

*Price includes UPS Ground Shipping to one location.

ORDER FORMQuantity _____________ Black & White Color

With Review Questions Without Review Questions

Author _________________________________________

Title of Article ___________________________________

______________________________________________

From Vol. _________________ No. ______________

Compendium Veterinary Technician

Payment Enclosed (All payments must be in US funds drawnon a US branch of a US bank.)

Purchase Order Attached

Contact Person ___________________________________

Phone __________________________________________

SHIP TO:

NAME

COMPANY OR PRACTICE

ADDRESS

CITY STATE ZIP

BILL TO:NAME

COMPANY OR PRACTICE

ADDRESS

CITY STATE ZIP

Detach and Mail to: Reprints DepartmentVeterinary Learning Systems275 Phillips BoulevardTrenton, NJ 08618No telephone calls accepted.


5/11

treatment and in anticipating complications. The ultra-sonographic appearance of a laryngeal cyst has recentlybeen reported in a cat.15 Ultrasonographic evaluationperformed without sedation provided a preoperativediagnosis. Alternatively, cysts may be diagnosed by fine-

needle aspiration during laryngoscopic examination. Sur-gical treatment may be performed under the same anes-thetic episode.

Computed tomography helps delineate the extent ofnasal and nasopharyngeal tumors and may be used toevaluate middle-ear disease in cats with nasopharyngealpolyps.4,5 Electromyography and muscle biopsies are notneeded to diagnose laryngeal paralysis. They may, how-ever, be indicated to evaluate other muscle groups incats with suspected generalized neuropathy.

TREATMENT

Nasopharyngeal PolypsThe timing of surgery and the techniques used willdepend on clinical presentation and the extent of dis-ease. A ventral bulla osteotomy is indicated when evi-dence of middle-ear disease is found. This may be per-formed first to remove all attachments of the polyp.The septum dividing the bulla into a small ventromedi-al and a large dorsolateral compartment must be re-moved.16 Care should be taken when curetting thepromontory to avoid damage to sympathetic fibers andsubsequent postoperative Horners syndrome.17 Cul-tures can be obtained from the bulla during surgery,

and excised tissue can be submitted for histopathology.Secondary bacterial infection should be anticipated anda broad-spectrum antibiotic administered intravenously(e.g., cephazolin, 20 mg/kg). When a bacterium is iso-lated, postoperative antibiotherapy should be adjustedaccording to sensitivity and continued for 3 weeks. APenrose drain or a modified butterfly catheter connect-ed to a vacutainer tube18 may be placed before closureof the surgical site to provide drainage and minimizepostoperative swelling. Primary closure has been foundto be as successful as is passive drainage after total earcanal ablation and lateral bulla osteotomy in dogs.19Al-

though no similar study has been performed in catswith ventral bulla osteotomy, primary closure is an ac-ceptable option.

If a bulla osteotomy is not indicated, traction avul-sion is used to remove polyps from the ear canal and/ornasopharynx. A ventral midline approach through thesoft palate may be required if the nasopharyngeal polypcannot be retracted caudally (Figure 1).

Nasopharyngeal StenosisNasopharyngeal stenosis can be treated by resecting

the membrane covering the internal nares; however, web-


LARYNGEAL PARALYSIS s VENTRAL BULLA OSTEOTOMY

Produce the ultimatein dental x-rays

CALL OR FAX TODAY TO ORDER800-426-9119 Fax: 800-556-3288

BOOKSVLSV E T E R I N A R Y L E A R N I N G S Y S T E M S

Price valid only in the US, Canada, Mexico, and

the Caribbean. Request international pricing.

Email: [email protected]

s Practical tips throughouts More than 840 real-case images with indicative

arrowss State-of-the-art techniques for the beginning

practitioner, technician, and specialists Precise information on positioning, supplies

and equipment, processing, safety, film

handling, and more

$89

$80

Atlas of Canine & FelineDENTAL RADIOGRAPHYThomas W. Mulligan Mary Suzanne Aller Charles A. Williams

Mary Suzanne Aller, Editor248 pages, 846 radiographs with arrowoverlays to indicate notable features

RATED5 5 5 5 55 5 5 5 5

First in the field

846 reference radiographs10%of

f!


6/11

bing may recur, especially if pri-mary closure cannot be achievedand a mucosal defect is left toheal by second intention.20,21 Re-currence after bougienage has

also been described.

21

In humans,various techniques have been de-signed to try to prevent this com-mon complication after resectionof stenotic webs; surgical laser,mucosal flaps, and airway stentshave been used with variable suc-cess.22 The use of a braided stain-less-steel stent did not resolveclinical signs in a cat with recur-rent nasopharyngeal stenosis.21

This complication should be pre-

vented by reconstructing the mu-cosal surface of the nasopharynxfollowing excision of the stenosis.If primary closure cannot be ac-complished, a nasopharyngeal ad-vancement flap can be used.8 Themucosa and submucosa of thedorsal laryngopharynx should begently elevated (Figure 5). Theflap should be advanced and su-tured to the cranial edge of thedorsal nasopharyngeal defect

(Figure 6). Primary closure of thesoft palate can then be achievedin a routine manner.

Granulomatous LaryngitisFrom the limited data avail-

able, combined medical and sur-gical treatment may be warrantedto treat obstructive inflammatorylaryngeal disease in dogs andcats.23,24 Because no evidence forbacterial infection has been found,

the need for antibiotic treatmentin granulomatous laryngitis isquestionable.11 Antibiotic and corticosteroid treatmentalone provide only slight and temporary improvement.11

Surgical excision of the proliferative laryngeal tissue bypartial laryngectomy has been reported, but intermittentor long-term administration of prednisolone may be re-quired to control clinical signs after surgery.23 Permanenttracheostomy may be considered as a last resort. In con-trast to laryngeal neoplasia, the long-term prognosis fol-lowing treatment of proliferative inflammatory laryngitisis good.11,23,24

Laryngeal NeoplasiaBecause laryngeal tumors in

cats are rare and may not be re-sectable by the time of presenta-tion, information regarding surgi-

cal treatment is often scarce. Totallaryngectomy and permanent tra-cheostomy are techniques used inhumans that have had limited usein veterinary medicine.25,26 Laryn-geal lymphoma may have a betterprognosis than squamous cell car-cinoma and adenocarcinoma be-cause it may respond to chemo-therapy and radiation therapy.2729

However, I am not aware of anystudy reporting treatment proto-

cols and survival times in cats withlaryngeal neoplasms.Even if the laryngeal neo-

plasm cannot be resected, a per-manent tracheostomy with or

without adjunctive treatmentmay be considered as palliativetherapy for upper airway obstruc-tion. The technique for perma-nent tracheostomy in cats is simi-lar to that in dogs.30,31 However, I

would recommend the use of a

rectangle rather than an oval tra-cheostomy because the mucosa incats is more delicate and difficultto elevate from the tracheal ringsthan that in dogs. Because laryn-geal tumors may extend into thetrachea, the tracheostomy siteshould be positioned as distal aspossible. An H-shaped incisionshould be made over four tra-cheal rings to create two full-thickness tracheal flaps at both

the cranial and caudal ends of theincision (Figure 7). The trachealflaps should be raised, and a rectangle of skin and subcu-taneous tissue can be excised. The amount of tissue re-sected must be determined on an individual basis to allowtension-free closure without obstruction by redundantskin. Two longitudinal skin flaps should be elevated lat-erally to the tracheostomy site. The width of these flapsshould approximate the thickness of the subcutaneoustissue and trachea. The tracheal flaps are sutured to theskin to seal the cranial and caudal borders of the tra-cheostomy. Finally, the longitudinal skin flaps should be


S T E N O T I C W E B S s P R E D N I S O L O N E s L A R Y N G E C T O M Y s T R A C H E A L R I N G S

Figure 5B

Figure 5(Aand B) Surgical treatment of nasopha-ryngeal stenosis. After excision of the membrane, amucosal flap is elevated caudal to the dorsal na-sopharyngeal defect. (From Griffon DJ, Tasker S:Use of a mucosal advancement flap for the treat-ment of nasopharyngeal stenosis in a cat. J Small

Anim Pract41:7173, 2000; with permission.)

Figure 5A


7/11

brought in apposition with the incised mucosa at the lev-el of the tracheal lumen.

Laryngeal ParalysisCats with cervical swelling resulting from trauma,

surgery, or neoplasia of adjacent structures may presentwith neurapraxia of the recurrent laryngeal nerve. Inthese cases, laryngeal paralysis can be temporary and sup-portive treatment may be considered.32,33 Oxygen therapyand temporary tracheostomy in combination with an an-tiinflammatory dose of short-acting corticosteroids (e.g.,dexamethasone sodium phosphate, 0.25 mg/kg twice/day) are often required. This treatment should be discon-tinued (within a week) after the swelling has decreased orif the tracheostomy tube becomes nonfunctional. Catstend to produce more mucus than do dogs31 and I havefound maintenance of tracheostomy tubes beyond 3 days

difficult. If palliative treatment becomes impractical be-fore laryngeal function is recovered, definitive repair isrecommended.

The three surgical procedures most commonly de-scribed for the treatment of laryngeal paralysis in dogsinclude castellated laryngofissure, ventriculocordectomyand partial arytenoidectomy, and unilateral or bilateralarytenoid lateralization.3436 Castellated laryngofissure istechnically demanding in dogs, and would be even moreso in cats, in which the thyroid cartilage may be toosmall to create an adequate central cartilaginous flap.Partial laryngectomy and vocal fold removal by an oral

approach has been used successfully in a few cats with la-ryngeal paralysis.3739 Although relatively simple, thistechnique requires placement of a temporary tracheosto-my tube37; complications, including postoperative ede-ma, aspiration, and laryngeal stenosis, are well recog-nized in dogs.26,35,37

Although unilateral arytenoid lateralization is techni-cally more demanding, I prefer the procedure describedby Lahue34 for treating cats with permanent laryngealparalysis. Unilateral arytenoid lateralization has previ-ously been described in cats.40,41 Mobilization of thearytenoid cartilages seems subjectively easier in cats

than in dogs, possibly because cats lack an interary-tenoid cartilage. Transection of the interarytenoid liga-ment is not warranted. Two 3-0 polypropylene suturesshould be placed through the dorsocaudal edge of thecricoid. Alternatively, sutures may be placed throughthe caudal cornu of the thyroid cartilage. In canine ca-daver larynges, however, cricoarytenoid lateralizationtechniques provided a greater increase in the size of theglottic opening than did thyroid lateralization tech-niques.40 Each suture passes under the caudal laryngealnerve and through the cricoarytenoid articular surfaceor the muscular process of the arytenoid cartilage. The


O X Y G E N T H E R A P Y s T H Y R O I D C A R T I L A G E

Robert E. Cartee, Editor400 pages, hard cover

1597 illustrations

s Sonographic diagnosis in dogs and cats,including ultrasound, M-mode, pulsedand color Doppler echography

s Echocardiography, abdominal and pelvicsonography, and fetal ultrasonography

s Case illustrations using conventionalradiography, computed microfocal

tomography, specimen photography,and line drawings

s Recognition of the disease process andcourses of treatment

New

$149

Your comprehensiveguide to diagnosticultrasonographyNautrup and Tobias

CALL OR FAX TODAY TO ORDER800-426-9119 Fax: 800-556-3288

Price valid only in the US, Canada, Mexico, and

the Caribbean. Request international pricing.

Email: [email protected]


8/11

sutures are tied, moving the arytenoid cartilage caudallyand laterally. Based on the few reported cases as well asmy own experience, results have been excellent.40,41

Other DiseasesNasopharyngeal foreign bodies can be removed using

cranial retraction of the soft palate or endoscopy. If anasopharyngeal abscess is present, a ventral midline ap-proach through the soft palate is required to allow re-moval of any foreign body, debridement, and lavage. A

ventral bulla osteotomy is indicated if the abscess is anextension of otitis media. Excised tissue is submittedfor histopathology and bacteriology. Postoperative an-tibiotherapy is prescribed for 3 weeks after surgery,based on the sensitivity of the organism isolated.

Treatment of nasopharyngeal cryptococcosis includes


Figure 6B

Figure 6(Aand B) Surgical treatment of nasopharyn-geal stenosis. The mucosal flap is advanced cranially toallow primary closure of the defect. (From Griffon DJ,Tasker S: Use of a mucosal advancement flap for thetreatment of nasopharyngeal stenosis in a cat. J Small

Anim Pract41:7173, 2000; with permission.)

Figure 6A

Figure 7Permanent tracheostomy. (A) Two incisionsare made perpendicular to the midline skin incision(1) to create two skin flaps (2,3). (B) The trachea isstabilized in a ventral position by suturing the ster-nohyoid muscle to its lateral and dorsal wall. An H-shaped incision is made through the ventral trachealrings to create two full-thickness tracheal flaps (1,2)perpendicular to the skin flaps. (C) An open tra-cheostomy. (D) The tracheal flaps (1,2) are externallyreflected and sutured to the skin. The free edges of theskin flaps (3,4) are sutured to the incised mucosa at

the level of the tracheal lumen. (From Nelson AW:Lower respiratory system, in Slatter D [ed]: Textbookof Small Animal Surgery, ed 2. Philadelphia, WB Saun-ders Co, 1993, p 793; with permission.)

A R Y T E N O I D C A R T I L A G E s N A S O P H A R Y N G E A L A B S C E S S s B A C T E R I O L O G Y


9/11


10/11

After the nature, location, and extent of the diseasehave been identified, treatment options and prognosiscan be discussed. When possible, diagnostic tests andcorrective surgery should be performed during the sameanesthetic episode to facilitate recovery. Some diseases

(i.e., nasopharyngeal stenosis, abscesses and cryptococ-cosis, laryngeal cysts, granulomatous laryngitis) are un-usual but carry a good to excellent prognosis if recog-nized early and treated appropriately. When surgery isindicated, successful outcome will depend on appropri-ate surgical technique as well as anticipation of potentialcomplications and postoperative monitoring.

REFERENCES1. Aron DN, Crowe DT: Upper airway obstruction. General

principles and selected conditions in the dog and cat. VetClin North Am Small Anim Pract15(5):891917, 1985.

2. Carlisle CH, Biery DN, Thrall DE: Tracheal and laryngeal

tumors in the dog and cat: Literature review and 13 addi-tional patients. Vet Radiol32(5):229235, 1991.3. Remedios AM, Fowler JD, Pharr JW: A comparison of ra-

diographic versus surgical diagnosis of otitis media. JAAHA27:183188, 1991.

4. Seitz SE, Losonsky JM, Marretta SM: Computed tomo-graphic appearance of inflammatory polyps in three cats. VetRadiol Ultrasound37(2):99104, 1996.

5. Libermann S, Begon D: Un cas particulier de polype naso-pharynge chez un chat. Prat Med Chir Anim Comp32:507514, 1997.

6. Greenfield CL: Upper airway obstruction in cats. ACVSSymp Proc, Orlando, pp 453455, October 1619, 1997.

7. Mitten RW: Acquired nasopharyngeal stenosis in cats. JSmall Anim Pract29:341345, 1988.

8. Griffon DJ, Tasker S: Use of a mucosal advancement flapfor the treatment of nasopharyngeal stenosis in a cat.J Small

Anim Pract41:7173, 2000.9. Pope ER: Feline inflammatory polyps. Semin Vet Med Surg

(Small Anim)10(2):8793, 1995.10. Davidson JR: Otopharyngeal polyps, in Bojrab MJ (ed):

Current Techniques in Small Animal Surgery, ed 4. Baltimore,Williams & Wilkins, 1998, pp 147151.

11. Tasker S, Foster DJ, Corcoran BM, et al: Obstructive inflam-matory laryngeal disease in three cats. J Feline Med Surg1:5359, 1999.

12. Whitehair JG, Griffey SM, Olander HJ, et al: The accuracyof intraoperative diagnoses based on examination of frozensections. A prospective comparison with paraffin-embeddedsections. Vet Surg22(4):255259, 1993.

13. Rogers KS, Barton CL, Habron JM: Cytology duringsurgery. Compend Contin Educ Pract Vet18(2):153163, 1996.

14. Rudorf H, Brown P: Ultrasonography of laryngeal masses insix cats and one dog. Vet Radiol Ultrasound39(5):430434,1998.

15. Rudorf H, Lane JG, Brown PJ, et al: Ultrasonographic diag-nosis of a laryngeal cyst in a cat.J Small Anim Pract40:275277, 1999.

16. Ader PL, Boothe HW: Ventral bulla osteotomy in the cat.JAAHA15:757762, 1979.

17. Little CJL, Lane JG: The surgical anatomy of the feline bullatympanica. J Small Anim Pract27:371378, 1986.

18. Swaim SF, Lee AH: Wound drainage techniques, in BojrabMJ (ed): Current Techniques in Small Animal Surgery, ed 3.Philadelphia, Lea & Febiger, 1990, pp 3133.

19. Devitt CM, Seim HB, Willer R, et al: Passive drainage ver-sus primary closure after total ear canal ablation-lateral bullaosteotomy in dogs: 59 dogs (19851995). Vet Surg26(3):210216.

20. Coolman BR, Marretta SM, McKiernan BC, et al: Choanalatresia and secondary nasopharyngeal stenosis in a dog.JAAHA34(16):497501, 1998.

21. Novo RE, Kramek B: Surgical repair of nasopharyngealstenosis in a cat using a stent.JAAHA35:251256, 1999.

22. Brown OE, Pownell P, Manning SC: Choanal atresia: Anew anatomic classification and clinical management appli-cations. Laryngoscope106:97101, 1996.

23. Harvey CE, OBrien JA: Surgical treatment of miscellaneouslaryngeal conditions in dogs and cats. JAAHA18:557562,1982.

24. Oakes MG, McCarthy RJ: What is your diagnosis? Granulo-matous laryngitis in a dog.JAVMA204:18911892, 1994.

25. Block G, Clarke K, Salisbury SK, et al: Total laryngectomyand permanent tracheostomy for treatment of laryngealrhabdomyosarcoma in a dog.JAAHA31(6):510513, 1995.

26. Nelson AW: Upper respiratory system, in Slatter D (ed):Textbook of Small Animal Surgery, ed 2. Philadelphia, WB

Saunders Co, 1993, pp 733777.27. Willoughby K, Kelly DF: Chronic upper airway obstruction

caused by laryngeal adenocarcinoma in a cat. J Small AnimPract34:293295, 1993.

28. White RAS: The respiratory system, in White RAS (ed):Manual of Small Animal Oncology. Cheltenham, UnitedKingdom, BSAVA Publications, 1991, pp 281296.

29. Withrow SJ: Tumors of the respiratory system, in WithrowSJ, McEwen EG (eds): Small Animal Clinical Oncology, ed 2.Philadelphia, WB Saunders Co, 1996, pp 271274.

30. Nelson AW: Lower respiratory system, in Slatter D (ed):Textbook of Small Animal Surgery, ed 2. Philadelphia, WBSaunders Co, 1993, pp 777804.

31. Colley P, Huber M, Henderson H: Tracheostomy tech-niques and management. Compend Contin Educ Pract Vet21(1):4453, 1999.

32. Taboada J, Goldston RT, Hoskins JD: The respiratory sys-tem, in Goldston RT, Hoskins JD (eds): Geriatrics andGerontology of the Dog and the Cat. Philadelphia, WB Saun-ders Co, 1995, pp 74134.

33. Holland CT: Horners syndrome and ipsilateral laryngealhemiplegia in three cats. J Small Anim Pract37:442446,1996.

34. Lahue TR: Treatment of laryngeal paralysis in dogs by uni-lateral cricoarytenoid laryngoplasty. JAAHA 25:318324,1989.

35. Trout NJ, Harpster NK, Berg J: Long-term results of unilat-eral ventriculocordectomy and partial arytenoidectomy forthe treatment of laryngeal paralysis in 60 dogs. JAAHA30:401407, 1994.

36. Smith MM, Gourley IM, Kurpershoek CJ, et al: Evaluationof a modified castellated laryngofissure for alleviation of up-per airway obstruction in dogs with laryngeal paralysis.JAVMA188(11):12791283, 1986.

37. Birchard SJ, Bradley RL: Surgery of the respiratory tract andthorax, in Sherding RG (ed): The Cat. Diseases and ClinicalManagement, ed 2. New York, Churchill Livingstone, 1994,pp 10931117.

38. Hardie EM, Kolata RJ, Stone EA, et al: Laryngeal paralysisin three cats.JAAHA179:879882, 1981.

39. Rozanski EA, Stobie D: Laryngeal paralysis secondary to acystic thyroid adenoma in a cat. Feline Pract 23(6):67,1995.

40. White RN: Unilateral arytenoid lateralisation for the treat-



11/11

ment of laryngeal paralysis in four cats. J Small Anim Pract35:455458, 1994.

41. Payne JT, Martin RA, Rigg DL: Abductor muscle prosthesisfor correction of laryngeal paralysis in 10 dogs and one cat.

JAAHA26:599604, 1990.42. Lussier B, Flanders JA, Erb HN: The effect of unilateral ary-

tenoid lateralisation on rima glottidis area in canine cadaver

larynges. Vet Surg25:121126, 1996.43. Malik R, Martin P, Church DB, et al: Nasopharyngeal cryp-

tococcosis.Aust Vet J75(7):483488, 1997.44. Levy JK, Ford RB: Diseases of the upper respiratory tract, in

Sherding RG (ed): The Cat. Diseases and Clinical Manage-ment, ed 2. New York, Churchill Livingstone, 1994, pp947978.

45. Caywood D, Wallace LJ, Alsaker RD, et al: A laryngeal cystin a dog: A case report.JAAHA13(1):8791, 1977.

46. Joffe DJ: Branchial cyst in a cat. Can Vet J31:525526.47. Welsh EM, Griffon DJ, Whitbread TJ: Plexiform vasculari-

sation of a retropharyngeal lymph node in a cat. J SmallAnim Pract40(6):291293, 1999.

About the AuthorDr. Griffon is affiliated with the Department of Small Ani-

mal Surgery, Hospital for Small Animals, University of Ed-

inburgh, United Kingdom. She is a Diplomate of the Amer-

ican College of Veterinary Surgeons and the European

College of Veterinary Surgeons.


feline-upper airway obstruction in cats

Documents