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 25-28 September, 2018 | Singapore
space disease and diaphragmatic rupture. Respiratory fatigue is a concern, because further decompensation may be associated with respiratory failure. When clinical signs of respiratory distress in cats are accompanied
by postural adaptations (for example, orthopnoea, represented by a sternal recumbency with an extended neck and abducted elbows to reduce the resistance to airflow) or persistent open mouth breathing, the situation should be considered grave and the patient highly unstable. Owners and other staff handling the patient should be cautioned, and equipment for endotracheal intubation and cardiopulmonary resuscitation should be prepared.
Once the cat is settled in a calm, oxygen rich environment, a full history can be obtained from the owner. Alternatively, this may be carried out by another veterinarian or experienced veterinary nurse whilst the primary clinician is overseeing initial stabilisation. In most cases it is appropriate for owners to be provided with reassurance that their cat is being cared for appropriately whilst they wait. In the event that an owner has left the premises, a telephone call to update them and take a history should suffice, provided that signed consent was previously obtained.
Table 1: The observation of respiratory pattern can be used to help localise the disease and narrow the list of differential diagnoses.
CHF, congestive heart failure
be interrogated thoroughly, as should any concurrent clinical signs. Historical reports of a persistent or chronic cough should assist in identifying lower airway disease, but may also be attributable to respiratory tract neoplasia. Coughing is rare in cats with congestive heart failure (CHF), which tend to present primarily with tachypnoea. Retching or gagging is highly suggestive of nasopharyngeal or laryngeal disease, but the sounds are easily confused with a cough by owners. For this reason, we would encourage clinicians not to be shy
in performing impressions of the different respiratory noises, to aid in owner differentiation and thus assist
in appropriately narrowing your list of differential diagnoses. An alternative would be to record a series of videos to demonstrate the different clinical signs to owners. Syncope, collapse, episodic weakness or even evidence of partial seizures (such as facial motor activity or periods of absence) in the history of a cat presenting with respiratory distress hint at cardiac arrhythmias, and may lead the clinician to prioritise the investigation of possible heart disease if other clinical findings support this diagnosis.
Physical examination
Once a cat has stabilised and calmed somewhat, physical examination is likely to be permitted. Again, this should be performed so that stress is minimised, potentially in the kennel or ward where the patient has acclimatised (preferably a cat only area). A quiet environment is essential for accurate auscultation and temporary cessation of oxygen therapy may be necessary to facilitate this.
The minimum physical examination of a cat presenting with respiratory distress should consist of noting the respiratory rate and pattern exhibited, assessment of mucus membrane colour and capillary refill time, noting heart rate and rhythm, auscultating heart and lung sounds, performing thoracic compression and thoracic percussion, and assessment of bilateral femoral pulses. Abdominal palpation may be useful if a diaphragmatic rupture is suspected (subjective absence of a normal volume of abdominal contents is uncommon but supportive), but should be performed with care in such patients. Also, the presence of a fluid thrill on abdominal ballottement may indicate ascites, which may occur concurrently with a pleural effusion in patients with severe heart disease, neoplasia or feline infectious peritonitis (FIP).
The presence of a heart murmur in a cat is a non-specific finding. Studies performed in a non-selected population of cats in rehoming centres suggest that only 1 in 3 cats with murmurs have any identifiable echocardiographic abnormalities. However, the specificity of murmur to identify heart disease is greater if the murmur is louder (grade III-IV/VI or above) or if the cat is older (Wagner
et al. 2010). In the authors’ experience, some cats with
  Common differentials
  Diagnostic tests to consider
 Long, slow inspira- tory phase, often accompanied by stridor
   Upper respirato- ry tract
 Nasopharyngeal ob- struction (polyp, for- eign body) Laryngeal obstruction (mass lesion, paralysis)
   Upper respiratory tract visual- isation and imaging
 Rapid, shallow pattern with even effort on inspiration and expiration
   Pleural space, al- veoli, pulmonary interstitium
 Pleural fluid (effusion, haemothorax, pyothorax) Pneumo- thorax Pulmonary oedema (CHF)
   Thoracic ultrasonog- raphy
Near-normal rate with disproportion- ate expiratory effort, often involving an expiratory abdomi- nal push
  Lower airway disease
Lower airway obstruction (chronic bronchitis, asthma)
  Thoracic radiog- raphy or computed tomogra- phy
  Caudal thorax and cranial abdomen move in opposite directions during both phases, often fast rate
  Non-specific; represents respiratory fatigue Common in pleural space disease
  Pleural space disease, Pulmonary oedema (CHF), Low- er respiratory tract disease Diaphrag- matic rupture
  Thoracic ultrasonog- raphy
 Paroxysmal: open mouth, rapid, short, shallow breaths
ic; may not represent true respiratory distress if respi- ratory pattern normal between episodes
 Stress Hyperthy- roidism Right-to-left shunting cardiovas- cular disease
   Dependent on other clinical findings
 As always, a thorough history and establishing a timeline of events is vital in achieving a diagnosis and formulating an appropriate treatment plan. The duration, intensity and progression of respiratory signs should

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