Coughing in dogs Flashcards
What are the main canine URT diseases?
Common: Post nasal drip (purulent rhinitis)
BOAS with retching of saliva, aspiration pneumonia
Laryngeal paralysis
Tracheal collapse
Kennel cough
Less common Laryngeal neoplasia Inflammatory laryngitis Tracheal polyp Oropharyngeal penetrating stick injuries Primary ciliary dyskinesia
What are the common lower airway and pulmonary parenchymal diseases causing cough in the dog?
inhaled airway FB Chronic bronchitis Eosinophilic bronchopneumopathy Bronchomalacia Lungworm disease Idiopathic pulmonary fibrosis Aspiration pneumonia Pulmonary neoplasia (primary or metastatic)
What are the uncommon lower airway and pulmonary parenchymal diseases causing cough in the dog?
Non-cardiogenic oedema Bronchiectasis Lung lobe torsion Pneumocystis pneumonia Viral pneumonia Pulmonary granuloma (eg, eosinophilic) Pulmonary abscess Pulmonary haemorrhage (warfarin poisoning) Irritant gas inhalation Trauma Fungal pneumonia (rare in the British Isles)
What cardiac diseases can cause a cough
Left atrial dilation causing compression of the left mainstem bronchus
Pulmonary oedema
Pericardial effusion
Heart base tumour
What pleural space diseases cause a cough?
Large mediastinal mass compressing airways
Large hilar lymph nodes compressing airways
Pleural effusions
Pleuritis
What oesophageal disorders can cause cough?
Megaoesophagus causing retching or aspiration pneumonia
Gastro-oesophageal intussusception causing
retching or leading to aspiration
What may a cough on excitement suggest?
might be suggestive of dynamic large airway collapse.
Why can nasal discharge lead to a cough and what can you infer from this?
discharge trickling to the pharynx and triggering a cough, sometimes referred to as a ‘post-nasal drip’. In the majority of these cases the nasal discharge is also evident at the nares along with other nasal signs and nasal disease can reasonably be assumed to be the cause of the cough. However, it would be prudent to obtain chest radiographs and perform bronchoscopy to screen for lower airway disease.
Outline BOAS syndrome
typically narrowed nares, overlong and/or fat soft palate, hypoplastic trachea and possibly swollen
or prolapsed laryngeal saccules. BOAS predominately
results in inspiratory stertor and inspiratory dyspnoea.
However, many dogs also tend to regurgitate or retch
dogs may have concurrent gastric irritation or even
a hiatal hernia that contributes to the saliva accumulation. In some, the saliva, or even food, can be aspirated leading to a ventral pneumonia or airway irritation, triggering coughing
Non-cardiogenic pulmonary oedema can also be triggered by acute and severe episodes of dyspnoea from the upper airway obstruction.
How does laryngeal paralysis present?
usually affects older dogs of large breeds (labrador, setter, etc) and may also present with a history of decreased exercise tolerance and coughing
What are the signs of laryngeal paralysis?
usually a change in tone of the bark (if the dog barks) and they usually have a degree of inspiratory dyspnoea with an increased and prolonged airway noise (stridor) on auscultation over the larynx/trachea. The clinical signs can be exacerbated by heat or exercising on warm days,
How do you diagnose laryngeal paralysis?
The diagnosis requires laryngoscopy (in sternal recumbency) under a very light plane of anaesthesia, such that the swallowing reflex is still present. Timing with breathing is critical to the diagnosis. In the normal dog, there should be active abduction of the arytenoids (opening of the glottis) during inspiration; failure to do so is indicative of paralysis You can get paradoxical movement - inspiration pulses the arytenoids in due to pressure
How do you treat laryngeal paralysis?
surgically managed with a tie-back procedure for those in which there is a significant inspiratory dyspnoea or stridor.
Only do this in very affected dogs as there are lots of risks.
Approx 5-10% already have aspiration pneumonia at time of dx, 10-30% will get it after sx, there is always a lifelong risk of getting it
How does tracheal collapse present?
affects small breed dogs (eg, Yorkshire terrier), which present with chronic, ‘honking’ coughing exacerbated by excitement.
Caused by a dorsoventral flattening of the trachea, 4 stages progressive
25% of toy breeds have it by 1 year old
Once symptomatic there is a cough - inflammation cycle
How do you diagnose tracheal collapse?
Has 4 levels and severity and is progressive!
A radiographic diagnosis alone is often insufficient, requiring an element of luck in recording the movement of the trachea, with both inspiratory and expiratory views required. Bronchoscopy (Fig 2) and/or fluoroscopy (Fig 3) are much more useful in assessment of a moving structure such as tracheal collapse
How do you treat tracheal collapse?
Weight loss and avoidance of collars are an important
part of the medical management of the condition.
Antitiissives - codeine, atropine, butorphanol
As a salvage procedure a tracheal stent can be implanted in patients with severe
obstructive airway disease that is causing life threatening dyspnoea (this requires fluoroscopic image intensification). However, dogs will continue to cough and so cough alone is not an indication for this
What is bronchomalacia?
refers to narrowing or collapse (usually dynamic) of the principal bronchi and/or lobar bronchi associated with weakness in the airway walls. Many dogs with tracheal collapse (see above) also have bronchomalacia and this is referred to as tracheobronchomalacia (TBM).
There is a high prevalence of airway collapse
in brachycephalic breeds. TBM is often concurrently
present with lower airway diseases (described later)
and has similar clinical signs
How do you treat bronchomalacia?
The airway collapse triggers chronic and often severe coughing, which in itself triggers airway inflammation. Breaking the cycle is key to easing clinical signs by decreasing inhaled environmental irritants, providing bronchodilators and reducing inflammation with corticosteroids. Additionally, concurrent respiratory disease and obesity needs to be addressed. Cough suppressants can also be helpful in some cases to break the cough-inflammation cycle.
