Page 292 - Small Animal Internal Medicine, 6th Edition

264 PART II Respiratory System Disorders

are swallowed and pass in the feces. Clinical signs include to mucopurulent nasal discharge. Signs of otitis externa or
sneezing and mucopurulent nasal discharge, with or without otitis media/interna, such as head tilt, nystagmus, or Horner
VetBooks.ir hemorrhage. The diagnosis is made by identifying double syndrome, can also occur.
operculated Capillaria (Eucoleus) eggs on routine fecal flota-
Diagnosis
tion (similar to the eggs of Capillaria [Eucoleus] aerophila;
see Fig. 20.12, C) or by visualizing adult worms during rhi- Identification of a soft tissue opacity above the soft palate
noscopy. Treatments include ivermectin (0.2 mg/kg, orally, radiographically and gross visualization of a mass in the
once) or fenbendazole (25-50 mg/kg, orally, q12h for 10-14 nasopharynx, nasal cavity, or external ear canal support a
days). Ivermectin is not safe for certain breeds. Success of tentative diagnosis of nasopharyngeal polyp. Complete eval-
treatment should be confirmed with repeated fecal examina- uation of cats with polyps also includes a deep otoscopic
tions, in addition to resolution of clinical signs. Repeated examination and radiographs or CT scans of the osseous
treatments may be necessary, and reinfection is possible if bullae to determine the extent of involvement. Most cats
exposure to contaminated soil continues. with polyps have otitis media, detectable radiographically
as thickened bone or increased soft tissue opacity of the
bulla (see Fig. 14.6). The definitive diagnosis is made by
FELINE NASOPHARYNGEAL POLYPS histopathologic analysis of tissue that is usually obtained
during surgical excision. Nasopharyngeal polyps are com-
Nasopharyngeal polyps are benign growths that occur most posed of inflammatory tissue, fibrous connective tissue, and
often in kittens and young adult cats, although they are occa- epithelium.
sionally found in older animals. Their origin is unknown, but
they are often attached to the base of the eustachian tube. Treatment
They can extend into the external ear canal, middle ear, The primary treatment of nasopharyngeal polyps is surgical
pharynx, and nasal cavity. Grossly, they are pink, polypoid excision by way of traction via the oral cavity. Recurrence is
growths, often arising from a stalk (Fig. 15.6). Because of possible as a result of tissue being left behind. Cats with
their gross appearance, they are sometimes mistaken for radiographic or CT evidence of involvement of the osseous
neoplasia. bullae are at increased risk of recurrence, and bulla osteot-
omy for complete removal has been recommended for such
Clinical Features cats. However, Anderson et al. (2000) reported successful
Respiratory signs caused by nasopharyngeal polyps include treatment with traction alone, particularly when followed by
stertorous breathing, upper airway obstruction, and serous a course of prednisolone. Prednisolone was administered
orally at 1 to 2 mg/kg q24h for 2 weeks, then at half the
original dose for 1 week, then every other day for 7 to 10
more days. A course of antibiotics (e.g., amoxicillin) was also
administered. Therefore removal of the polyp by traction
followed by a course of corticosteroids and antibiotics is
generally recommended before exploration of the middle ear
via bulla osteotomy. Rarely, rhinotomy is required for com-
plete removal of a nasal polyp.
Prognosis
The prognosis is excellent, but treatment of recurrent disease
may be necessary. Regrowth of a polyp can occur at the
original site if abnormal tissue remains, with signs of recur-
rence typically appearing within 1 year. Bulla osteotomy, if
not performed with initial treatment, should be considered
in cats with recurrence and signs of otitis media.

CANINE NASAL POLYPS

Dogs rarely develop nasal polyps. These masses can result in
chronic nasal discharge, with or without hemorrhage. They
are often locally destructive to turbinates and bone, and as a
FIG 15.6
A nasopharyngeal polyp was visualized during rhinoscopy result can be misdiagnosed as neoplasia. The diagnosis is
through the exterior naris of a cat with chronic nasal made by histologic evaluation of biopsy specimens. Aggres-
discharge. The polyp was excised by traction and has an sive surgical removal is recommended. Complete excision
obvious stalk. may be impossible and signs may recur.