Page 57 - Problem-Based Feline Medicine

5 – THE DYSPNEIC OR TACHYPNEIC CAT 49

● Anemia/hypoxemia* (p 57)
Reduced oxygen-carrying capacity of the blood results from anemia (blood loss, hemolysis,
myelodysplastic disease) or altered hemoglobin (methoxyhemoglobinemia from acetaminophen
toxicity, carboxyhemoglobinemia from CO toxicity). Tachypnea, pallor, cyanosis or brick-red
mucous membranes may be seen.
● Pulmonary thromboembolism*
Secondary to hypercoagulable states, blood flow stasis, vascular injuries and heartworm disease.
Creates significant ventilation/perfusion mismatch, with sudden onset of severe dyspnea and
tachypnea. Cyanosis and collapse may occur. Lung parenchyma may appear normal radiographi-
cally.
● Aortic thromboembolism* (p 58)
Acute single-limb paresis or, with “saddle” thrombus, bilateral hindlimb paralysis. The affected
limb is cold, painful and the foot pads are cyanotic. Signs of congestive heart failure may be
severe, with marked worsening of dyspnea.
NEOPLASTIC
● Pleural/mediastinal masses*
Signs relate to the space-occupying nature of the mass. Dyspnea with muffled heart and lung
sounds or pleural effusion. Heart sounds are typically asymmetric because of displacement of the
heart by the mass. Compression of the chest wall may reveal decreased compliance.
● Airway tumors
Nasal, laryngeal and cervical tracheal masses create stertor, stridor and inspiratory dyspnea.
Thoracic tracheal and bronchial masses create expiratory dyspnea. Coughing may occur with tra-
cheal masses.
● Pulmonary neoplasia
Dyspnea may be subtle. Systemic signs such as weight loss and possibly coughing may be evident.
Inappetence, weight loss, fetid breath and reluctance to play may also be noted.
● Cardiac tumors
Extremely rare in cats. Space-occupying effect in chest or signs of congestive heart failure from
obstruction of blood flow may produce dyspnea.
INFLAMMATORY

INFECTIOUS
● Acute and chronic infectious upper respiratory tract disease**
Sneezing, acute or chronic oculonasal discharge, and sometimes conjunctivitis are present.
Inspiratory dyspnea occurs if there is marked nasal obstruction. Nasal distortion may be present
with cryptococcosis, neoplasia or rarely with secondary bacterial rhinitis.

Bacterial:
● Pyothorax**
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. Signs of sepsis
such as hypothermia and hypoglycemia are occasionally present. Often signs of chronic illness
such as weight loss and inappetence were evident before presentation for dyspnea.

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