Page 56 - Problem-Based Feline Medicine

48 PART 2 CAT WITH LOWER RESPIRATORY TRACT OR CARDIAC SIGNS

QUICK REFERENCE SUMMARY
Diseases causing a dyspneic or tachypneic cat
DEGENERATIVE

● Cardiomyopathy** (p 54)
Dilated cardiomyopathy (DCM), hypertrophic (HCM), intermediate (ICM) or restrictive (RCM)
often present as acute dyspnea. Abnormal heart sounds are often audible as mumurs, gallops and
arrhythmias. Advential lung sounds, such as crackles may be audible with pulmonary edema.
Occasionally, marked pleural effusion is present and heart and lung sounds are muffled ventrally.
Coughing is an uncommon presenting sign in the cat.
● Tracheobronchial collapse (p 69)
Very rare in cats. Degeneration of the cartilage support of the large airway walls results in tracheo-
bronchial collapse. Cervical collapse causes inspiratory dyspnea, while intrathoracic collapse
causes expiratory dyspnea. Harsh honking cough and stridor may be evident.
● Laryngeal paralysis (p 67)
Idiopathic laryngeal paralysis is reported in cats. Iatrogenic paralysis may occur after cervical sur-
gery or trauma. Inspiratory dyspnea, stridor and stertor are common signs.
ANOMALIES

● Congenital heart defects (p 67)
Atrioventricular valve dysplasia, septal defects, aortic and pulmonic stenosis (rare) and patent duc-
tus arteriosus all lead to pressure and/or volume overload on the heart and potentially result in con-
gestive heart failure. Dyspnea, open-mouth breathing, cyanosis, exaggerated chest excursions with
minimal airflow all may occur. Abnormal heart sounds are common.
● Congenital anomalies of the upper respiratory tract (p 68)
Stenotic nares, elongated soft palate, hypoplastic trachea (i.e., brachycephalic syndrome) create
variable upper airway resistance. Stertor and inspiratory dyspnea are common signs.
● Acquired or congenital diaphragmatic defects* (p 57)
Abdominal contents lie within the pleural or pericardial cavities, creating variable degrees of dysp-
nea. Signs include increased chest excursions with decreased airflow, muffled heart and lung
sounds, and reluctance to lie in lateral recumbency. Palpation of the abdomen has an empty feel.
MECHANICAL
● Grass awns, foreign bodies (p 65)
Foreign bodies may be inhaled into the nasal cavity, upper respiratory tract or lower airways. The
character of the dyspnea is dependent on location.
● Pleural effusion** (p 54)
Dyspnea characterized by excessive chest excursions with poor airflow, orthopnea, muffled heart
and lung sounds. Signs of chronic illness may be present such as weight loss.
METABOLIC
● Myopathy/neuropathy (p 61)
Hypokalemia, myasthenia gravis, polyradiculoneuritis (rare in cats), botulism, polymyositis and
other causes of weakness of the respiratory muscles cause poor ventilatory muscle excursions.