Answers and Discussion
Case #12 -- Feline Asthma
Answers and Discussions to the Questions:
- What criteria are used to make the diagnosis of asthma?
A presumptive diagnosis of asthma can be made based on physical exam and history (i.e. a
cat with increased expiratory effort and wheezing). Radiographs can be helpful but
are often normal. CBC may or may not show eosinophilia. Transtracheal wash may
show eosinophils, but this is also not pathognomonic for asthma. Bronchoscopy
usually reveals mucosal erythema and edema and significant circumferential reduction in
airway lumens.
- What radiographic changes can you see with asthma?
Peribronchial cuffing is usually found. The diaphragm may be flattened and the lung
fields may appear hyperlucent, both indicating air trapping.
- What emergency treatments are instituted in cats with acute respiratory distress
secondary to asthma?
These cats should be handled with minimal restraint! Have an oxygen cage ready and
supply oxygen by mask while handling, if possible. A rapidly acting corticosteroid
should be given IV if possible (prednisone sodium succinate 50-100mg/cat; dexamethasone
1mg/kg IV or IM). If needed, a bronchodilator can be given (terbutaline 0.01 mg/kg
SC).
- With respect to medication and the household environment, how do you manage the
asthmatic patient for the long term?
Corticosteroids are the mainstay of therapy: prednisone 1-2 mg/kg BID initially,
then taper over 2-3 months to the lowest every-other-day dose possible.
Bronchodilators: terbutaline 0.625 mg/cat BID orally; theophylline 50-100 mg/cat
every 24 hours at night. Cyproheptadine can also be used (and will stimulate
appetite): 1-2 mg/cat BID. As for the environment, attempt to identify and avoid
situations or substances that provoke an attack. Since dust usually irritates asthma
symptoms, changing kitty litter to a low-dust form is helpful. Also, if the client
smokes, recommend not smoking inside the house.
Follow-Up: "Duncan" deteriorated rapidly over the next
few days. He was not responding to therapy. He arrested late one night and
efforts to revive him were unsuccessful.
Asthma Pearls
- Most diagnoses of asthma can be made on history and physical exam alone (ie. a cat with
increased expiratory effort and wheezes)
- Emergency treatment for asthmatic respiratory distress includes oxygen, steroids and a
bronchodilator
- Long-term care includes corticosteroids, bronchodilators and providing a dust/smoke-free
environment
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Copyright 1999, Wayne E. Wingfield,
DVM and Brenda McClelland, DVM, Colorado State University
This page was last edited: 12/14/99