Page 61 - Problem-Based Feline Medicine

5 – THE DYSPNEIC OR TACHYPNEIC CAT 53

significant pneumothorax requires that air be removed ● Transtracheal wash may be perfomed in the awake
more than three times within 24 h. cat.
● Bronchoscopy for bronchoalveolar lavage (BAL) or
Positive-pressure ventilation must be used with
unguided catheter BAL are performed in the anes-
extreme caution due to the fragility of the traumatized
thetized cat and are preferred by most clinicains over
lung and susceptibility to additional barotrauma.
a transtracheal wash.
Cytology reveals highly cellular samples with intact
FELINE ASTHMA/BRONCHITIS COMPLEX*** non-degenerative neutrophils as the primary cells.
● Eosinophils are not a reliable marker of inflamma-
Classical signs tion in the cat due to the increased prevalence (up to
● Expiratory dyspnea with wheezing. 24%) in normal airways.
● Cough is a prominent sign. Pulmonary function testing for increased airway resist-
● Status asthmaticus – severe acute ance includes spirometry, whole-body plethysmogra-
respiratory distress. phy, and tidal breathing flow–volume loops (TBFVL).
● Cyanosis, open-mouth breathing. These are rarely available outside of teaching institu-
tions.
See main reference on page 92 for details (The Coughing
Cat ).
Differential diagnosis
Main differential for status asthmaticus is acute con-
Clinical signs gestive heart failure of cardiomyopathy.
Signs can occur at any age, although average is 2–8 Other respiratory diseases, such as parasitic pneumo-
years. nia, aspiration pneumonia, bronchopulmonary neopla-
Signs may be episodic (with asthma) or chronic (with sia and pleural space diseases may present with
bronchitis). dyspnea.
There may or may not be a history of coughing for
weeks or months preceding an episode of mild to Treatment
severe, life-threatening respiratory distress from bron-
● The cornerstone of therapy for cats with status
choconstriction. Cats may present severely air-starved,
asthmaticus is to minimize handling until signs
with cyanosis, open-mouth breathing and a significant
abate, and administer oxygen, bronchodilators and
expiratory push.
glucocorticoids.
● Oxygen supplementation is required during respi-
ratory distress and an oxygen chamber or tent
Diagnosis
seems to be best tolerated by air-starved patients.
Adventitial lung sounds such as wheezing and crackles Oxygen hoods made with an Elizabethan collar and
are very common. cellophane, or oxygen delivery via a nasal canula
have proven useful in some cats, but may stress
Thoracic radiographs may be normal or have the fol-
other cats and exacerbate signs.
lowing changes:
● Minimal handling and restraint of acutely dysp-
● Hyperlucency, hyperinflation, and flattening of
neic patients is essential.
the diaphragm due to air trapping may be seen with
● For severe signs (dyspnea, open mouth breathing
asthma.
+/- cyanosis) which are a life-threatening emer-
● Diffuse prominent peribronchiolar pattern is the
gency, it is important not to stress the cat as this
hallmark of chronic bronchitis.
may precipitate death. Administer oxygen via oxygen
● Right heart enlargement may be present.
cage or nasal canula, methylprednisolone sodium
Lung wash for cytology and culture. succinate (100 mg/cat IV) or dexamethasone