Respiratory Flashcards
what is the function of a cough?
permit removal of material from airways (assist mucociliary clearance, expel inhaled particulate, protect against irritants)
what are the two types of cough receptors?
mechanoreceptor
chemoreceptor
where are cough mechanoreceptors found?
larger airways
where are cough chemoreceptors found?
medium airways
where are cough receptors most numerous in the airways?
larynx then trachea then bronchi
what parts of the airway have no cough receptors in?
bronchioles and alveoli
what are the three general differentials for coughing?
compression of mainstream lobar bronchi
stimulation of cough receptors
excessive mucus/fluid/inflammation
what can cause compression of mainstem lobar bronchi?
left atrial enlargement
lymph node enlargement
neoplasia
how will heart rate change in dogs coughing due to cardiac disease?
normal or increased
how will heart rate change in dogs coughing due to respiratory disease?
normal or decreased
what will the heart rhythm be of a dog coughing due to cardiac disease?
regular sinus rhythm or sinus tachycardia/arrhythmia
what will the heart rhythm be of a dog coughing due to cardiac disease?
sinus arrhythmia
when will a dog cough if the cough is due to cardiac disease?
at night or when sleeping/resting
when will a dog cough if the cough is due to respiratory disease?
when excited or on exertion
what sort of information would you like to find out in a history about a coughing patient?
environment
worming history
travel history
recent events/illness
other clinical signs
regarding the cough itself, what would you like to find out?
onset
character - productive??
description - when’s it worst??
length of cough
changes to bark
how will inflamed bronchioles look on radiographs?
doughnuts - side on
tramlines - longitudinal
what are the characteristics of the airways in chronic bronchitis?
excessive mucus production due to increased goblet cells and submucosal hyperplasia
damage and loss of cilia often with secondary infections
what dogs is chronic bronchitis most commonly seen in?
small/toy breed dogs
what is the prognosis of dogs with chronic bronchitis?
often guarded because mucosal changes or normally non-reversible
(aim to manage condition)
what is the diagnostic tool of choice for chronic bronchitis cases?
bronchoscopy and broncheoalveolar lavage (cytology, bacteriology…)
what should be visible on a successful BAL?
froth/foam on top (surfactant)
what is bronchial collapse?
regional to diffuse airway collapse of segmental/subsegmental bronchi with associated clinical signs due to airflow limitations
what is bronchial collapse also known as?
bronchomalacia
what type of cough is seen with bronchial collapse?
wheezy cough
what respiratory parasites can be found in cats/dogs?
Oslerus osleri
Crenosoma vulpis
Aelurostrongylus abstrusus (cats)
what is the typical finding on bronchoscopy of an animal with Oslerus osleri?
nodules at the bifurcation
what is the typical finding on bronchoscopy of an animal with Crenosoma vulpis?
worms readily seen on airway (large worms)
what volume is used for BAL?
0.5-1ml/kg
how much fluid should be aspirated on BAL?
half of what you put in
how many washes should be carried out in BAL?
2-3 sites/washes
what are normal cell to see on BALF cytology?
ciliated columnar epithelial cells
goblets cells
macrophages, neutrophils, lymphocytes, eosinophils
how will you know if you BAL sample is contaminated with oral fluids (using cytology)?
presence of certain bacteria (Simonsiella)
what will be found on cytology of BALF in chronic bronchitis cases?
increased mucus
increased neutrophils and amacrophages
possible bacteria and particulate matter
possible squamous metaplasia of columnar epithelial cells
why should BALF be submitted for bacteriological culture in cases where chronic bronchitis is suspected?
to rule out bacteria or mycoplasma being the cause
what should be done in the general management of chronic bronchitis cases?
weight control
harness rather than collar/lead
avoid irritant/smoky environment
how can excess mucous be managed in chronic bronchitis cases?
avoid dry environment
nebuliser
(put in bathroom when owner shower/bathing)
what drugs are used as treatment for chronic bronchitis?
bronchodilators
anti-inflammatory (steroids)
what effects do the bronchodilators have on managing chronic bronchitis?
reduce lower airway spasm
reduce intra-thoracic pressure
reduce large airway collapse
improve diaphragmatic function
improve mucociliary clearance
inhibit mast cell degranulation (reduce bronchoconstriction mediators)
prevent microvascular leakage
what are the bronchodilators used for chronic bronchitis?
theophyline (dogs)
terbutaline (not licensed)
what are the desired effects of glucocorticoids in chronic bronchitis cases?
broncho-dilatory
anti-inflammatory
inhibit prostaglandin synthesis
potential beta-2 adrenergic activity
induce lymphopenia
inhibit fibroblast formation
modulate immune system
what is a mucolytic that can be used if chronic bronchitis cases?
bromhexine
what is bronchiectasis?
the entire bronchus is very dilated
should an antibiotic for respiratory infections be bactericidal or bacteriostatic?
bactericidal
how long should respiratory tract infections be treated with antibiotics?
2 weeks minimum
what are some common antibiotics used for respiratory infections?
potentiated amoxycillin
cephalexin
TMP sulphonamides
fluroquinolones
doxycycline (myocplasma)
what is eosinophilic lung disease?
spectrum of disease from chronic bronchitis to pulmonary granulomatous disease (usually with bronchial and interstitial involvement
what dogs is eosinophilic lung disease most commonly seen in?
young large breeds
what is the presumed cause of eosinophilic lung disease?
hypersensitivity to inhaled allergens
how will eosinophilic lung disease generally present on bronchoscopy?
copious amounts of green mucus and inflammation
how is eosinophilic lung disease treated?
immunosuppressive doses of prednisolone (2 mg/kg/day)
what is the most common cause of coughing cats?
inflammatory airway disease
does feline asthma usually cause an inspiratory or expiratory dyspnoea?
expiratory
what is used to treat feline asthma for dyspneic cats?
humidified oxygen
minimise stress
IV dexamethasone (steroid)
bronchodilator (terbutaline)
what drugs can be used in inhalers for feline asthma?
salbutamol
fluticasone (long term inflammation control)
what are the clinical signs of bronchial foreign body?
sudden onset cough
halitosis (if its been there a while)
history of field/woodland walking
what mismatch in ratio do pulmonary parenchymal diseases result in?
ventilation:perfusion mismatch
what partial pressure of oxygen will make a patient clearly cyanotic?
<60mmHg
is audible breathing noise associated with upper or lower airway disease?
upper
what is the main cause of inspiratory dyspnoea?
upper airway obstruction (laryngeal paralysis, mass/compression…)
what is the main cause of expiratory dyspnoea?
dynamic airway collapse of bronchial narrowing
what can cause both inspiratory and expiratory dyspnoea?
oedema or idiopathic fibrosis
what is the main sign of obstructive dyspnoea?
increased breathing effort
what is the main sign of restrictive dyspnoea?
fast shallow respirations
what can cause inspiratory obstructive dyspnoea?
upper airway obstruction
what causes expiratory obstructive dyspnoea?
bronchospasm (feline asthma…)
is restrictive dyspnoea usually inspiratory or expiratory?
usually both (pleural effusions…)
what percentage oxygen should be given to patients with dyspnoea?
<50% (avoid 100% as can cause toxicity)
what does a poor response to supplementing a cyanotic dyspnoeic animal with oxygen suggest?
animal may have congenital heart disease with a right to left shunt
what is inspiratory stirtur usually caused by?
upper airway obstruction
what breathing pattern is usually seen with pleural effusions?
restrictive (increased effort)
how does a radiograph of a pneumothorax look?
lungs partially collapsed
heart elevated from sternum
what are the physiological mechanisms that cause pleural effusion?
increased hydrostatic pressure
decreased plasma oncotic pressure
increased vascular/pleural permeability
increased fluid production
why are standing lateral radiographs discouraged?
dangerous - unless lead lined walls
why would a standing lateral radiograph be useful in pleural effusion cases? (discouraged)
will get a clear line of fluid and gas
what is used instead of a standing lateral radiograph to visualise pleural effusions?
ultrasound
how is thoracocentesis done?
clips and clean area
use 21G 1 inch butterfly catheter with and three way tap and syringe and insert into 7th/8th intercostal space at the costochondral junction
how does a pure transudate appear?
clear colourless fluid
how does a modified transudate appear?
slightly red/straw coloured
how much protein and cells do transudates have?
very low protein and cells (pretty much done)
how much protein and cells do modified transudates have?
high proteins but low cells
how much protein and cells do exudates have?
high proteins and cells
what are some examples of exudates?
haemothorax
pyothorax
chylothorax
what is the most common cause of pleural effusion in cats?
congestive heart failure
what should be done if you diagnose after thoracocentesis that the pleural effusion is due to a pericardial effusion
rapidly carry out pericardiocentesis
what should be done if purulent exudate is drained by thoracocentesis?
submit for aerobic/anaerobic culture and sensitivity
insert drain to lavage daily
what are some possible broad spectrum antibiotics that can be used while awaiting culture/sensitivity of prothorax fluid?
potentiated amoxycillin
metronidazole
fluroquinolone combination
what are some possible causes of chylothorax?
trauma/lesions disrupting thoracic duct or cranial vena cava
pericardial disease
congestive heart failure (especially cats)
lung lobe torsion
idiopathic
how can chylothorax be treated following thoracocentesis?
treat underlying disease
feed low fat diet
rutin (reduce chyle production)
most cases require surgery
what needs to be done in all pleural effusion cases after thoracocentesis?
radiograph to check for neoplasia (will get a clear view now there is no fluid)
