Lower airway disease in cats

• Most likely LRT differentials for older cats

  Hyperthyroidism

  Neoplasia

  Cardiac disease
• Most likely LRT differentials in younger cats and kittens

  Infectious disease

  Viral

  Parasitic

  Mycoplasma

  Bacterial

  Toxoplasma
• Clinical history of LRT

  Usually low grade chronic disease - coughing, audible wheezing, exercise intolerance.

  Sometimes a very acute presentation - brought in as an emergency, respiratory distress, mouth breathing, tachypnoea.
• Laryngeal disease

  Laboured inspiration - stridor, increased effort, slow inspiratory phase.

  +/- change in; purr, vocalisation.
• Upper airway disease

  Check the clinical history for signs of; dysphagia +/- salivation, coughing/ gagging (might be triggered by eating/drinking), ‘head shaking‘ behaviour - may indicate nasal disease.
• Lower airway disease

  Laboured expiration - prolonged expiratory phase, additional expiratory push, audible expiratory wheeze.

  Airway resistance due to - bronchospasm, mucous, bronchial wall thickening.

  +/- occasional paroxysmal cough.
• Feline asthma

  Reversible

  Inhaled allergen

  Airway hyper reactivity

  Bronchoconstriction

  Eosinophillic airway inflammation

  Signs; episodic respiratory distress and dyspnoea, coughing
• Chronic bronchitis

  Response to infection or inhaled irritants

  Airway damage

  Excess mucus

  Neutrophilic airway inflammation

  Signs; coughing is a key feature.
• Differential diagnosis for coughing in cats

  Upper respiratory tract disease

  Inflammatory lower airway disease

  Infectious - bacterial, viral, parasitic.

  Foreign body.

  Neoplasia.
• Differential diagnosis for hyperpnoea/ tachypnoea in cats

  Stress/ pain/ fear response - mouth breathing. CNS disease. Anaemia/ hypovolaemia. Heart stroke/ cardiac disease. Pleural space disease. Mediastinal disease. Ruptured diaphragm. PPDH (peritoneo pericardial diaphragmatic hernia).
• Diagnostic plan for LRT in cats

  Heamotolgy and biochemistry

  Diagnostic imaging - radiography, ultrasound, advanced imaging (CT)

  Faecal analysis for parasites

  Bronchoscopy - +/- BAL

  Endotracheal wash.
• Management for LRT in cats

  Ruse out other clauses of coughing and dyspnoea.

  Preoxygenate.

  GA but not if stable

  Thoracic radiographs.

  Bronchoscopy - hyperaemia, oedema, excess mucus, decrease in airway diameter.
• Feline lungworm

  Aelurostrongylus abstrusus.

  Paratenic hosts required.

  Pre-patent period 1-2 months.

  Most infected cats are asymptomatic.

  Clinical presentation - usually young cats, mild coughing but could get to dyspnoea, on radiography similar to IAD.

  Diagnose by identifying L1 larvae but false -ves occur, consider faecal flotation.

  Treat with fenbendazole trial.
• Mycoplasma pneumonia

  M. felis associated with LRD in cats, but may also cause URT signs.

  Not all infections are significant - might be a contributing factor to feline inflammatory airway disease.

  Clinical signs; fever, cough, tachypnoea, lethargy.

  Diagnosis: PCR on tracheal wash.

  Treat with doxycycline.
• Mycobacterial pneumonia

  M. bovis, M. microti.

  Pneumonia represents late stage systemic spread of infection.

  Early cutaneous signs - after bite from an infected vole or rodent, non-healing sores or nodules.

  Early GI signs; after ingestion (e.g. contaminated milk), vomiting, diarrhoea, weight loss, poor appetite, lesion (inflammatory granulomas)

  Diagnosis: histopath and PCR - seek advice because we need to consider zoonotic aspects.