Page 317 - Cote clinical veterinary advisor dogs and cats 4th

Bronchitis, Chronic 137

heart failure [p. 408]). Thoracic radiographs • Computed tomography: more sensitive than Behavior/Exercise
and cytology of airway secretions (nonseptic, radiographs, with far greater airway/ Encourage moderate exercise for weight control,
VetBooks.ir the diagnosis. Attempts should be made to TREATMENT and humidity. Diseases and Disorders
but avoid outdoor exercise during high heat
pulmonary detail; not routinely indicated
degenerative neutrophilic inflammation) support
exclude pathogenic bacteria, fungi, parasites,
Drug Interactions
or other relevant causes of cough (e.g., heart
failure if murmur is recognized). Treatment Overview • Theophylline or aminophylline levels may
Treatment is directed at limiting airway inflam- be increased by the concurrent administration
Differential Diagnosis mation, controlling cough, and treating any of fluoroquinolone antibiotics.
• Cough (p. 217) comorbid condition (including secondary • Prednisone can contribute to weight gain,
• Key differential diagnoses include tracheal infection). Weight loss is crucial in overweight which can worsen clinical signs.
collapse (dogs), congestive heart failure or obese dogs. Cats and rarely dogs may benefit
(dogs), pneumonia, interstitial lung disease/ from bronchodilator therapy. Possible Complications
pulmonary fibrosis, lung tumor, and asthma • Pulmonary hypertension
(cat). Acute General Treatment • Secondary pneumonia
Animals with CB are managed as outpatients • Bronchomalacia: airway collapse secondary
Initial Database and seldom require acute or emergent care. to chronic inflammation
• CBC/chemistry profile/urinalysis: typically Disease exacerbations can occur from secondary • Although rare, spontaneous pneumothorax
unremarkable infection or comorbid disease, and re-evaluation may develop associated with chronic
• Heartworm testing: antigen (dog), antigen is appropriate. Importantly, because mitral valve cough.
and antibody (cats). In Europe or Newfound- disease is a common finding in dogs with CB,
land, Canada, consider testing for Angio- some patients eventually develop concurrent Recommended Monitoring
strongylus vasorum. congestive heart failure. • Body condition, weight gain, cough
• Fecal examination (Baermann fecal floata- frequency/severity
tion); insensitive due to intermittent fecal Chronic Treatment • Physical examination and thoracic radio-
shedding • Glucocorticoids (oral or inhaled): mainstay graphs if clinical signs worsen or q 6-12
• Thoracic radiographs of therapy for CB months
○ Bronchiolar pattern characteristic (e.g., ○ Prednisone or prednisolone (preferred for • ± Pulmonary hypertension check (echocar-
“donuts and tramlines”) cats): starting dose 1-2 mg/kg PO q 24h. diogram)
○ Bronchiectasis may be present in chronic If cough improves, taper by ≈25% q 3
disease. weeks to the lowest possible dose to PROGNOSIS & OUTCOME
○ Hyperinflation may be seen in cats with control cough.
concurrent asthma. ○ Fluticasone 110-222 mcg/puff, one puff • CB is managed rather than cured.
○ Examine for evidence of comorbid disease q 12h by face mask (e.g., AeroDawg, • Mild to moderately affected dogs: good
(e.g., left atrial enlargement) or alternative AeroKat). Inhaled steroids have a delayed prognosis for disease control
diagnosis (e.g., lung tumors). onset of efficacy, and are not more effective • Severely affected: severity of cough, exercise
than oral steroids. However, they minimize intolerance, secondary complications (e.g.,
Advanced or Confirmatory Testing systemic effects. Recommended starting bronchomalacia, secondary pneumonia)
• Echocardiography (p. 1094): indicated if with oral steroids before transitioning to sometimes result in euthanasia (quality of
cardiac examination is abnormal (e.g., inhaled. life considerations).
murmur) or if radiographs identify abnor- • Cough suppressants (e.g., hydrocodone, butor-
malities of the cardiac silhouette or blood phanol, diphenoxylate): antitussive therapy is PEARLS & CONSIDERATIONS
vessels. Can also be used to identify pulmo- controversial because it may mask poor disease
nary hypertension (p. 838) in animals with control, allowing airway inflammation and Comments
evidence of airway remodeling. remodeling to progress. Antitussives may be • If apparent exacerbation of cough is recog-
• Bronchoscopy (p. 1074): irregular mucosal recommended in patients with concurrent col- nized in dogs, especially if animal is
surface, often thick, rough, or granular in lapsing trachea contributing to chronic cough tachycardic, rule out heart failure (p. 408).
appearance. Hyperemia and excessive mucus (p. 194) or if quality of life is compromised • Inflammatory airway disease is usually rec-
accumulation often appreciated. Bronchiec- by cough despite appropriate medical therapy. ognized in younger cats. Maintain suspicion
tasis is sometimes recognized. • Antibiotics: as needed for secondary pneu- of an alternate diagnosis in cats > 12 years.
• Airway lavage (cytology and culture) monia (ideally based on culture and suscep-
○ Bronchoscopic airway lavage: advantage tibility) or during acute exacerbation of Prevention
of airway visualization, as above (figure cough (e.g., doxycycline, azithromycin) It seems prudent to avoid exposure to tobacco
at www.ExpertConsult.com) • Bronchodilators: very little evidence of smoke and pollution.
○ Blind bronchoalveolar lavage (p. 1073) efficacy for dogs with CB but likely more
○ Transtracheal wash useful for cats (p. 84) Technician Tips
○ > 10% nondegenerative neutrophils on • Additional proposed therapies (limited Technicians should work closely with owners
cytology experience) to ensure treatment compliance and to teach
○ Eosinophilic inflammation suggests an ○ Maropitant: small clinical trial supported them how to use inhalers. Supporting pet
alternative diagnosis (e.g., parasites, efficacy owners who deal with this frustrating condition
allergic asthma). ○ Gabapentin is vital.
○ Diagnosis of CB cannot be confirmed ○ Fish oil supplementation
if there are degenerative neutrophils • Eliminate environmental irritants Client Education
with a positive bacterial culture (must • Address pulmonary hypertension, if present • Canine CB is a progressive, incurable disease,
rule out infection before diagnosis (p. 838). and exacerbations occur periodically. The
of CB). goal of therapy is to minimize cough to
○ Consider polymerase chain reaction (PCR) Nutrition/Diet improve the quality of life for pet and owner.
assay for Mycoplasma spp. Maintain a lean body weight (p. 1077). Cough may not resolve completely.

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