Page 2076 - Cote clinical veterinary advisor dogs and cats 4th

Voice Change 1039

In some dogs, glucocorticoids eventually can • Additional information can be found in strapping the patient to a backboard for severe
be discontinued. chapters on head tilt (p. 403), nystagmus flailing or rolling. Use sling support until
VetBooks.ir • Metronidazole toxicosis: excellent Prevention Client Education Diseases and Disorders
(p. 698), and ataxia (p. 86).
balance improves.
• Neoplasia: generally poor long-term prognosis
PEARLS & CONSIDERATIONS
• Thyroid supplementation in dogs with
hypothyroidism Head tilt may persist.
Comments • Avoid high doses and/or prolonged courses of SUGGESTED READING
• Compensation for vestibular diseases will metronidazole treatment. The recommenda- Sanders SG: Disorders of hearing and balance: the
occur in many animals regardless of lesion tion is to limit the maximum daily dose vestibulocochlear nerve (CN VIII) and associated
location, and clinical signs may improve to 15 mg/kg PO q 12h or less if hepatic structures. In Dewey CW, et al, editors: A practical
slightly even if the lesion is slow growing. function is compromised. guide to canine and feline neurology, ed 3, Ames,
• The long-term prognosis for animals with IA, 2015, Wiley-Blackwell, pp 277-298.
CVD is variable depending upon the Technician Tips AUTHOR: Mark T. Troxel, DVM, DACVIM
specific cause; however, treatment should The patient should be provided with thick EDITOR: Karen R. Muñana, DVM, MS, DACVIM
be attempted to alleviate clinical signs. bedding in a well-padded cage. Consider

Voice Change

BASIC INFORMATION • Variable voice changes, depending on • Eversion of the laryngeal saccules
condition • Laryngeal/pharyngeal foreign body
Definition ○ Peracute if traumatic • Laryngeal inflammation; laryngitis (traumatic,
Condition is characterized by reduced vocaliza- ○ Acute if infectious infectious [viral, bacterial], granulomatous,
tion and/or change in pitch of vocalization. ○ Subclinical and subtle if associated with immune mediated, oral irritant exposure,
neoplasia or with laryngeal paralysis polyp)
Epidemiology • May be associated with • Laryngeal neoplasia (mast cell tumor, SCC,
SPECIES, AGE, SEX ○ Exercise intolerance if mild upper airway leiomyoma/sarcoma, rhabdomyoma/sarcoma,
• Canine and feline obstruction (structural or functional) fibroma/fibrosarcoma, lymphoma)
• Apparent male predisposition (3 : 1) for ○ Inspiratory stridor and respiratory distress Functional causes:
idiopathic laryngeal paralysis (dyspnea, cyanosis, syncope) if substantial • Dysfunction of the recurrent laryngeal nerve
upper airway obstruction (structural or ○ Congenital/idiopathic laryngeal paralysis
GENETICS, BREED PREDISPOSITION functional) ○ Trauma to the nerve (direct or indirect):
• Hereditary laryngeal paralysis (Bouvier des ■ Can occur after thyroidectomy or patent
Flandres, Siberian Husky, pit bull terrier) PHYSICAL EXAM FINDINGS ductus arteriosus correction in cats.
• Generalized polyneuropathy (Dalmatian) Variable: depends on primary cause ○ Nerve compression (hematoma, abscess,
• Acquired laryngeal paralysis (giant and large tumor [thyroid carcinoma, lymphosarcoma])
breeds are overrepresented) Etiology and Pathophysiology ○ Neuropathy, polyneuritis
• Laryngeal edema/eversion of laryngeal sac- • Anatomic cause: structure of the larynx • Myopathy (including cricoarytenoid dorsalis
cules (brachycephalic breeds) affected muscle)
• Functional cause: innervation of the larynx • Neuromuscular disease (myasthenia gravis)
CONTAGION AND ZOONOSIS affected
If secondary to infectious diseases (e.g., infectious Initial Database
tracheobronchitis [kennel cough]), potential DIAGNOSIS • CBC, serum biochemistry panel, and
but rare zoonosis (e.g., immunocompromised urinalysis: often unremarkable
persons) with Bordetella bronchiseptica Diagnostic Overview • Cervical/thoracic imaging
Although most causes of voice change originate ○ Radiographs: the normal larynx, especially
ASSOCIATED DISORDERS from a laryngeal/pharyngeal lesion (warranting if mineralized, should not be mistaken
Dogs: a sedated laryngeal exam), systemic disturbances for a foreign body. Laryngeal osseous
• Infectious tracheobronchitis (kennel cough) such as myasthenia gravis should be ruled out metaplasia has been reported (rare).
• Laryngeal paralysis first, particularly if the history and physical ○ Ultrasound (mass lesions, laryngeal
• Brachycephalic airway syndrome exam are consistent with such disorders. paralysis)
Cats: • Oral/laryngeal/pharyngeal exam (visual ±
• Lymphoma Differential Diagnosis endoscopy) (p. 1125); requires sedation
• Squamous cell carcinoma (SCC) Anatomic causes: depending on whether severe inspiratory
• Secondary to thyroidectomy • Laryngeal distortion dyspnea is present. With severe dyspnea, the
• Laryngeal paralysis ○ Blunt trauma (e.g., choke chain, hit by laryngeal exam may be performed while the
car, kicked by horse) patient is awake because the patient is breath-
Clinical Presentation ○ Penetrating trauma (e.g., stick, gunshot, ing with mouth and oropharynx is maximally
HISTORY, CHIEF COMPLAINT dog/snake bite) opened. Direct per os laryngoscopy combined
Voice change may be described as a change in ○ Osseous metaplasia with the knowledge of the clinical history
pitch of bark or meow (dog/cat, respectively) • Laryngeal edema (elongated soft palate, insect and physical exam is preferred to alternative
or a persistent hoarseness. bite, chronic barking) techniques.

www.ExpertConsult.com