Coughing in Small Animals Flashcards
Presenting signs seen in patients with respiratory tract disease?
- Change in the rate or character of respiration e.g. dyspnoea, tachypnoea, hyperpnoea, orthopnoea.
- Coughing
- Sneezing/nasal discharge
- Resp. noise esp. with URT
- Cyanosis
- Others incl. change in voice (layngeal lesion), weight loss, exercise intolerance, facial deformities.
What is a cough?
Receptors in the airway that detect physical or chemical irritants.
Receptors are everywhere except the alveoli. Unlikely to be deeper than the terminal bronchus.
Most patients that cough have some form of airway irritation or disease.
Causes of acute coughing?
Tracheobronchitis - “kennel cough”
Irritation by smoke/dust/chemicals/medicines!
Airway FB - may have been in there some time.
Continuous cough often.
Pulmonary haemorrhage - often + dyspnoea
Acute pneumonia, e.g. inhalation - often + dyspnoea
Acute oedema - often + dyspnea
cardiogenic/non/cardiogenic
Airway trauma - choke chains/bites etc.
Explain Kennel cough aka infectious tracheobronchitis
Infectious disease of canine URT
ANY contact – not just kennels!
Causes include: Canine parainfluenzavirus, Canine adenovirus (2), Bordetella bronchiseptica
Vaccines available: Bordetella bronchiseptica – live by intranasal, Canine parainfluenzavirus – live by injection, Canine adenovirus (2) – live by injection
Can close a practice/wards!
Spontaneous recovery – 7–10 days
Systemic antibacterial agents often dispensed: If pyrexic, If systemically ill, Muco-purulent nasal discharge
Not usually antimicrobial response, however, if have the above, it increases your suspicion of secondary bacterial infections and will suggest the requirement for antibiotics.
See unproductive retching.
Common LRT conditions in dogs (and cats)?
Canine chronic bronchitis - Most common cause of coughing in dog’s.
(Feline chronic bronchitis)
Respiratory foreign bodies
Bacterial bronchopneumonia
Idiopathic pulmonary fibrosis (may cough, but usually present with resp. difficulty instead).
Many more occur and are part of the SDLs e.g. eosinophilic lung disease Ensure awareness of additional common pathologies including
Lung lobe torsions
Congenital airway diseases
Bullous pulmonary diseases
Lipid pneumonias
Smoke inhalation
Causes of chronic coughing in the dog?
Chronic bronchitis/bronchiectasis - Degenerative
L. heart failure - Degenerative
Oslerus /Aelurostrongylus infestation
Tracheal collapse - Degenerative
Airway F.B.- Traumatic
Bronchopneumonia - Infectious
Pulmonary neoplasia - primary or secondary
Extra-luminal mass lesions - thyroid, abscess, lymphoma
Eosinophilic disease – EBP/PIE/allergic airway disease
(Pulmonary “fibrosis”)
(Pleural irritation)
Explain Canine Chronic Bronchitis
- Daily coughing for greater than 2months
- Characterised by: structural change in lining of airways, eventually leading to fibrosis, leading to loss of structural integrity, meaning normal mucous isn’t produced or moved as it should be.
- Increased goblet and glandualr cell size and number.
- Loss of ciliated epithelial cells and failure of mucociliary clearance and debris.
- Once this process has begun, the airway lining is structurally damaged for doog and they will have this problem for the rest of their lives.
- Combination of these events leads to thickening of bronchial tissue, overproduction of airway mucus and narrowing of the airways esp. terminal bronchi. this leads to the clinical signs of wheezing and a productive cough.
What breeds is canine chronic broncitis common in?
Small, toy breeds
Cough characterisitics for canine chronic bronchitis?
Harsh cough with attempts at production.
Usually externally well, often obese.
Tracheal pinch positive
Crackles and expiratory wheeze on auscultation if really severe.
Diagnosis of CCB?
- Typical histroy and physical findings: often has an exaggerated sinus arrhythmia due to difficulty getting air out of the lungs.
- Thoracic radiographs will show increased bronchial lung pattern.
- Bronchoscopy and BAL.
CCB BAL results
Increased mucus
Non-degenerate neutrophils, eosinophils and macrophages
Cushmann’s spirals (airway mucus casts)
Presence of bacteria / particulate matter are less common (rare) and if present would suggest underlying cause present
Usually just evidence of chronic inflammatory change.
Management of CCB?
Explain to O it is very unlikely that the dog will stop coughing.
General management: Weight control (lose weight), Harness rather than collar / lead, Avoid irritants / smoking environment
Mucous is easier to shift if hydrated: Avoid very dry environments, Nebuliser (rare) , Steam in the bathroom – will help thin mucous out and help animal to get rid of it – expect animal to cough more after this, but this is a good thing.
Glucocorticoids: Oral and inhaled approaches, Anti-inflammatory. Inhaled reduces side effects associated with steroid use.
Bronchodilator therapy (Malcom doesn’t think these make a difference) – will only work if bronchoconstriction is an element to the disease: Theophylline, Beta-agonists – terbutaline, salbutamol, salmeterol
Inhaled medications – long term goal to reduce side effects
Coupage (using cupped hands to slap the chest – owners can do this)
Don’t use cough suppressants unless absolutely necessary – as coughing IS protective in most cases: Value particularly in anatomical airway disease, Intractable non-productive pathological cough
Antimicrobials based on evidence of need
Oxygen as necessary but needs to be humidified
By assuming bronchodilators will work assuming that there is still the capacity for the airways to dilate ie bronchoconstriction is occuring
Beta agonists can increase exp airflow, reduce wheezing, increase exercise intolerance and reduce cough
Theophylline act synergistically with steroids to control airway inflam – antecdotal reports
Relax bronchial smooth muscle, increase mucocilary transport rates, stabilise mast cell membanes, decrease bronchovascular leak, increase contractility of tired diaphagmatic muscles
SE adenosine antagonism – GIT SE, restlessness tachycardia etc
Prognosis for CCB?
Long term control possible, not cure - Your dog will always cough
Most patients continue with periodically productive cough
Major goal is to prevent long term sequelae which include:
- Secondary pneumonia
- Bronchiectasis/bronchomalacia - Dilation of the airways where they become so weak they become dilated and full of mucous/ weaking of bronchial walls – they start to collapse. They are a consequence of CCB – don’t want this to occur.
- Emphysema
- Pneumothorax / Pneumomediastinum
Feline bronchial disease?
AKA Feline asthma, feline allergic airway disease.
General considered to be a type I hypersensitivity condition to inhaled allergens
Suspected genetic predisposition
Bronchial foreign bodies - how would they present?
- Sudden onset coughing and gagging
- Very common.
- High frequency in working dogs or those living in rural environments
- Often have history of signs after exercising in agricultural fields and came back with acute onset coughing and retching. Typically go into the right diagrammatic lung lobe.
- Often see good initial response to antibiotics
- Halitosis may be present and progressive
- May see weight loss if infection associated with FB becomes significant
- More substantial respiratory signs may suggest progression to pleural disease
- Laboratory testing
- Fully CBC and biochemistry
- If have dog with acute onset cough after running through fields, most useful thing for you to do would be endoscopy – have a look for something! You may not see on radiograph depending on its opacity.
- Thoracic radiographs
- Fully evaluate for signs of pleural involvement
- Determine if there is suggestion of lobar involvement or disease seems more diffuse
- Bronchoscopy
- BAL and culture for specific antibiotic therapy
- Enables visualisation and retrieval of object
