Nasopharyngeal and otic polyps in the cat (Proceedings)

There are many causes of upper airway disease in the cat. Veterinarians are well acquainted with nasal and frontal sinus disease secondary to viral infections. Neoplastic and fungal diseases also may affect the upper airways of cats. Less common pathology such as laryngeal paralysis and tracheal disease has also been described in the cat. In this lecture, we'll characterize and discuss nasopharyngeal and otic polyps which tend to affect young cats but have been seen in mature middle aged animals as well (especially otic polyps).

I. Nasopharyngeal and Otic Polyps (Inflammatory Polyps)

A. Clinical Signs

May be a history of chronic respiratory or otic disease. No relationship to FELV/FIV status. Clinical signs are related to the location of the primary mass, either respiratory or otic. These polyps arise from the medial aspect of the middle ear chamber (dorsolateral compartment of the bulla). These are slow growing BENIGN masses that may extend out the external ear canal OR through the auditory tube into the nasopharynx. It is generally thought that these polyps arise secondary to chronic inflammation caused by virus or bacteria. Congenital origins have also been suspected.

                   Nasopharyngeal Polyps                    Otic Polyps

                   Open-mouthed breathing                  Head-shaking

                   Stertorous respiration                       Pawing at ear

                   Nasal discharge                               Otitis externa, media

                   Sneezing/gagging                              Head tilt/Ataxia

                   Dysphagia                                        Horner's Syndrome ±

                   Otitis ±                                             (Miosis, Ptosis, 3rd eyelid prolapse)

B. Diagnosis/Treatment

     1. Sedation or Anesthesia to carefully examine the ear canal and/or the nasopharynx. A spay hook is a handy way to retract the soft palate cranially to examine for masses in the dorsal nasopharynx.

     2. Otic polyps have a variable appearance but are usually smooth, pink, and cigar shaped.

     3. Lateral skull radiographs may show a large soft tissue dense mass in the nasopharynx displacing the soft palate ventrally however radiographs are primarily taken to look at the bullae and not for polyp diagnosis per se. "Open-mouthed" radiographic views may show increased density within one (most common) bulla. Absence of radiographic signs does not rule out otitis media or the bulla as a source of the polyp.

     4. Large nasopharyngeal polyps are easily diagnosed with the animal under anesthesia; the polyp may be palpated dorsal to the soft palate and visualized by retracting the soft palate rostrally with a Snook OVH hook. Stay sutures" can also be used especially if you anticipate incising the soft palate to remove the polyp although this is rarely necessary. In either case, you'll find that the animal needs to be in a relatively deep plane of anesthesia otherwise gagging will result from pharyngeal stimulation. Nasal polyps can be removed by steady traction and twisting of the polyp. The polyp should be removed along with its "stalk" which tapers at one end.

     5. Local removal (avulsion) of a nasopharyngeal polyp will result in alleviation of clinical respiratory signs however recurrence rates of 15-50% have been reported if a bulla osteotomy is NOT performed. The recurrence rates tend to be lower for nasopharyngeal polyps and HIGHER for otic polyps.

Polyps that do recur usually do so within a year however I recently removed a polyp and performed bulla osteotomy in an animal that had a polyp avulsed 5 years previously by another surgeon (same polyp or new growth?). Is there harm/contraindication in avulsing the polyp and waiting to see if it regrows?? Not that I can ascertain or find reported but AGAIN if definitive treatment is desired perform a bulla osteotomy is strongly recommended. Because of their inflammatory nature some surgeons have recommended a declining dose of prednisone in conjunction with polyp removal.

     6. Otic polyps usually appear as pink "cigars" growing in the horizontal canal. Cleaning the canal is often necessary to adequately visualize the polyp. Avulsion of the polyp MAY be performed with Alligator forceps however incomplete removal is likely. It has been suggested that recurrence rates following Otic polyp avulsion are higher than for nasopharyngeal polyps. I perform ventral bulla osteotomy followed by avulsion of the ear polyp in all animals with the condition. Following bulla osteotomy, the polyp is easily removed via traction with an Alligator forceps. Some surgeons might perform a lateral ear resection to excise the polyp but this is usually not necessary. Practicing veterinarians have reported to me that lateral ear resection and polyp excision has resulted in "cure" in some of the cases they've operated on.

C. Ventral Bulla Osteotomy

Performance of bulla osteotomy in the cat is quite straightforward as compared to the canine as the bullae can usually be palpated relatively easily.

      1. Place the animal in dorsal recumbency with the cervical and ventral facial area prepped for aseptic surgery. Tape the head with 1 inch adhesive tape over the rostral mandibular rami.

      2. Make a paramedian 4-6 cm skin incision from the bifurcation of the jugular vein extending rostrally. The incision is centered about the level of the vertical mandibular rami. PALPATE the bulla if possible to center the paramedian incision.

      3. Continue the incision through the platysma muscle and use a mosquito hemostat and baby metzenbaums to bluntly and sharply expose the bulla medial to the digastricus muscle. Very small Gelpi retractors are a nice aid in maintaining exposure. Avoid trauma to the hypoglossal nerve and lingual artery medially.

      4. Bluntly elevate muscle from the bulla and use an 1/8th inch Steinman pin to open the ventromedial compartment of the bulla. Extend the bulla osteotomy into the dorsolateral compartment of the bulla by removing the ventral septum between the two compartments. The spetum between the two compartments is actually incomplete dorsally so there is communication between the two compartments. Culture bulla contents and use a small currette to remove any tissue within both compartments

      5. of the bulla. Some authors recommend culturing for Mycoplasma. Culture results have been variable in different retrospective studies of bulla disease in cats.

      6. Lavage the bulla with saline solution. I DO NOT routinely drain these patients at this time and have not encountered problems (to my knowledge) with this.

      7. Close the deep musculature with 4/0 absorbable suture and the subcutaneous tissue and skin.

      8. EXPECT Horner's syndrome postoperatively which usually resolves within 30 days. I would typically have these animals on Clavamox in the perioperative time period until culture results return.

References

Kapatkin AS, Matthiesen DT, et al : Results of surgery and long term follow-up in 31 cats with nasopharyngeal polyps. J Am Anim Hosp Assoc 26:387-392, 1990.

Faulkner JE, Budsberg SC: Results of ventral bulla osteotomy for treatment of Middle ear polyps in cats. J AM Anim Hosp Assoc 26:496-499, 1990.

Smeak D: Ventral bulla osteotomy in cats. In Proceedings of the 12th ACVS Veterinary Symposium, San Diego, 2002, 122-125.