Page 207 - Cote clinical veterinary advisor dogs and cats 4th

Asthma, Feline 85

minimizing exposure to environmental allergens • Aminophylline 4-5 mg/kg PO q 8h Behavior/Exercise
and irritants, suppressing inflammation, and • For cats requiring only occasional broncho- • Ideally, remove the allergen triggering clinical
VetBooks.ir recommended treatment approach and protocol • Chronic use of racemic aerosolized albuterol ○ In practice, this is difficult or impossible Diseases and Disorders
signs.
dilator use, albuterol MDI (as for acute
alleviating bronchoconstriction as needed. A
treatment) is acceptable.
to do.
are provided on p. 1403.
Acute General Treatment exacerbates airway eosinophilia; levalbuterol ○ Serum allergen-specific IgE testing and
intradermal skin testing are options for
(R-albuterol) is a better alternative for inhal-
Cats may be well at the time of presentation ant albuterol if administered more than 2-3 determining specific allergens to minimize/
or in crisis. When in crisis, times weekly. avoid.
• Minimize handling and stress. • Owners can be taught to give terbutaline • Minimize exposure to airborne irritants (e.g.,
• Administer oxygen (p. 1146). 0.01-0.04 mg/kg SQ to cats that develop dusts, smoke, aerosols).
• Bronchodilators, parenteral status asthmaticus at home. • HEPA-type air filters for cats spending a
○ Terbutaline 0.01-0.04 mg/kg SQ or IM Antibiotics: considerable amount of time indoors,
q 4-8h prn • If secondary bacterial infection (uncommon) especially if IgE reactivity to indoor allergens
○ In severe cases, epinephrine 0.1 mg/CAT is documented based on cytologic evidence can be documented
SQ, IM, or IV may be beneficial. and culture and susceptibility, an appropriate
Hypoxemia can cause epinephrine to antibiotic can be administered. Drug Interactions
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be arrhythmogenic, and oxygen should • Alternatively, if response to glucocorticoids Do not give propranolol or other nonspecific
be administered concurrently. is suboptimal, a short course of a broad- beta-adrenergic blockers to asthmatics; these
Contraindicated in cats with heart spectrum antibiotic that penetrates into drugs can exacerbate bronchoconstriction.
■
disease or systemic hypertension bronchial secretions and bronchial epithelium
• Bronchodilators by nebulization or metered- may be tried (e.g., doxycycline 5 mg/kg Possible Complications
dose inhalers (p. 1134): PO q 12h; azithromycin 10 mg/kg PO • Long-term oral glucocorticoids can predis-
○ Albuterol 0.5% solution for nebulization: q 24h). pose to development of diabetes mellitus
give 0.1-0.25 mL diluted in 2 mL sterile Cyclosporine (5 mg/kg PO q 12h to start): and exacerbation of heart disease in some
saline through a nebulizer q 4h. • May be considered in cats refractory to other cats.
○ Metered-dose inhalants (MDI) are medications, or cats with concurrent diseases • Theophyllines have a low therapeutic index,
delivered by using a spacer with a face that prevent treatment with glucocorticoids and dosages should be based on lean body
mask designed for cats. Albuterol 17-g (e.g., diabetes mellitus, heart disease) weight. They are relatively contraindicated in
inhalant: 1-2 actuations (puffs) into the • Therapeutic blood monitoring is strongly patients with hypertension, hyperthyroidism,
spacer while the cat takes ≈10 breaths can recommended (p. 1333). and cardiac disease. The sustained-release
be repeated q 30 minutes if necessary for • Cyclosporine has been evaluated only in an oral formulations of theophylline (currently
1-4 hours. experimental model of asthma. unavailable) are not designed for absorp-
• Glucocorticoids, parenteral: Tyrosine kinase inhibitors (masitinib 50 mg/CAT tion by the gastrointestinal tracts of small
○ Prednisolone sodium succinate (1-2 mg/ PO q 24h): currently unavailable animals, and variable assimilation of the
kg slowly IV) or dexamethasone • May reduce airflow limitation and airway drug (underabsorption or overabsorption)
(0.2-0.3 mg/kg IV or IM) eosinophilia is possible. Manifestations of toxicosis include
○ Inhaled glucocorticoids do not work fast • Consider only in severe refractory cases or tachycardia and behavior changes such as
enough to be of benefit in acute treatment. if concurrent diseases prevent treatment with agitation and anxiety (similar to theobromine
glucocorticoids. toxicosis).
Chronic Treatment • Masitinib has been evaluated in an experi- • Masitinib (and other tyrosine kinase inhibi-
Glucocorticoids: mental model of asthma; severe proteinuria tors) can cause marked proteinuria in cats,
• Critical to reduce airway inflammation that is common and dose limiting. Toceranib which may be reversible with early detection
leads to airway hyper-responsiveness and may have similar effects but has not been and discontinuation of the drug.
remodeling evaluated.
• Oral glucocorticoids preferred initially: Mesenchymal stem cell therapy (adipose Recommended Monitoring
prednisolone 2 mg/kg PO q 24h derived): • Clinical signs at home
• Metered-dose inhaled glucocorticoids ideal • Intravenous stem cell therapy was found to ○ Persistence or exacerbation of clinical signs
for long-term maintenance because systemic have a delayed treatment effect in cats with implies poor control.
glucocorticoid effects are reduced: fluticasone experimentally induced asthma, reducing ○ Absence of clinical signs does not imply
110-220 mcg q 12h administered into spacer inflammation 9 months after treatment. resolution of airway inflammation
while the cat takes ≈10 breaths (p. 1134) • Early intervention reduced airway remodeling and cannot be assumed to reflect good
○ Train owners to count breaths, not in experimentally induced asthma. control.
seconds, as cats may breath hold when No benefit has been demonstrated in • Physical examination and thoracic radio-
the mask is initially placed over the experimental models of feline asthma for graphs if initially abnormal.
muzzle. cysteinyl leukotriene antagonists (e.g., zafirlu- • If response is poor, BAL fluid cytologic
○ Overlap oral and inhaled steroids because it kast), antiserotonergic agents, (cyproheptadine), re-evaluation to recognize subclinical airway
can take up to 2 weeks for inhaled steroids neurokinin-1 receptor antagonists (e.g., inflammation and check for secondary
to effectively blunt airway inflammation. maropitant), or second-generation H1-receptor infection
○ Other inhalant steroids (e.g., flunisolide, antagonists (e.g., cetirizine to control eosino-
budesonide) may have efficacy. philic airway inflammation). PROGNOSIS & OUTCOME
• Repositol injectable glucocorticoids often
appear to lose efficacy over time and must Nutrition/Diet • Prognosis can range from grave to good,
be given more and more frequently. Omega-3 polyunsaturated fatty acids and depending on the number and severity of
Bronchodilators: oral route ideal for routine luteolin as adjunctive treatment may improve status asthmaticus episodes and response to
chronic therapy (if required) airflow limitation but are not suitable as acute and chronic management. Prognosis
• Terbutaline 0.625 mg/CAT PO q 12h, or monotherapy because they do not blunt airway also depends on the magnitude of irreversible
• Theophylline 25 mg/kg PO q 24h, or inflammation. structural changes in the lung.

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