Presenting Signs: Cough and Dyspnoea Flashcards
- Define cough.
- Define Dyspnoea.
- Sudden expiratory effort against a closed glottis, results in noisy expulsion of air from lungs.
- Difficulty breathing w/ increased effort.
- Tachypnoea.
- Hyperpnoea.
- Orthopnoea.
- Cyanosis.
- Increased RR.
- Increased respiratory effort (deeper breaths) w/o dyspnoea.
- Difficulty breathing in while laying down. Cats often sit or stand to facilitate breathing w/ elbows abducted and neck extended.
- Blue MM colouration due to reduced oxygenation.
- Aim of cough.
- Cough receptors.
- Cough arc reflex.
- How does heart disease result in cough?
- Aim is protective reflex to clear excess secretions / foreign materials.
- Cough receptors in large airways and low density cough receptors in nose, sinuses, pharynx, pleura.
- mechanical receptors for mucus, FB etc.
- chemical receptors for acid, heat etc. - Cough arc reflex:
- afferent pathway: sensory nerves (vagus).
- cough centre: medulla oblongata.
- efferent pathway: via vagus, phrenic and spinal motor nerves to diaphragm, abdominal wall and muscles. - Enlarged LA.
Tachypnoea caused by pulmonary oedema.
Harmful effects of coughing.
Exacerbate airway inflammation and irritation.
Emphysema.
Pneumothorax.
Weakness and exhaustion.
Dissemination of infections.
Causes of dyspnoea and tachypnoea.
Respiratory:
- obstructive – fixed or dynamic obstruction.
- restrictive – decreased volume of air that the lungs can hold.
Cardiac.
Haematologic.
Metabolic.
Neurological.
Approach to the patient presenting w/ dyspnoea and cough.
Assess patient:
- O2.
- Reduce stress – consider sedation and environment.
Hx.
PE.
Problem list and differentials.
Dx investigations.
Interventions/management.
Considering the causes of the cough.
Cardiac or respiratory?
- what causes coughing in heart disease?
- any other signs of heart disease?
- any other signs of cardiac failure (i.e. dyspnoea and/or tachypnoea)?
– murmur?
- sinus arrhythmia?
– Y –> CHF v unlikely.
– N –> does not help.
- cats w/ heart disease rarely cough.
- Likely cause of dyspnoea and cough in young patients?
- Likely cause of dyspnoea and cough in older patients?
- Breed dispositions for diseases causes coughing and dyspnoea.
- Lungworm?
- Neoplasia? Chronic bronchitis?
- Brachycephalic or dolichocephalic.
Working/outdoor lifestyle - airway FB?
CKCS and others = MMVD.
Brachycephalic breeds - BOAS.
Toy breed dogs e.g. Yorkie - tracheal collapse.
Siamese cat - Feline asthma/chronic bronchitis.
Westie - idiopathic pulmonary fibrosis.
Taking a general history.
Vac status, contact w/ other animals.
Worming history (lungworm).
History of trauma.
Exercise tolerance.
Environmental influences: rural/urban/tobacco smoke.
Additional clinical signs: - vomiting or regurgitation?
Characterising the clinical signs.
Coughing vs panting.
Reverse sneezing, gagging, retching.
Onset and duration:
- acute versus chronic >2mths.
- progressive?
The cough:
- initiating factors.
- Productive vs non-productive.
- sound: moist, gurgling, dry, goose honk.
- Presence of terminal retch.
Change in sound of bark/purr/meow.
- Is a patient suffering from BOAS suffering from an obstructive dyspnoea or restrictive dyspnoea?
- Is a patient suffering from BOAS suffering from expiratory dyspnoea, inspiratory dyspnoea or both?
- Is a patient w/ pneumonia likely the present with an obstructive dyspnoea or restrictive dyspnoea?
- Is a patient w/ pneumonia likely to suffer inspiratory dyspnoea, expiratory dyspnoea or both?
- Obstructive.
- Inspiratory.
- Restrictive.
- Both.
Distant exam of the patient.
Assess patient first and stabilise if necessary (O2).
Observe patient’s posture.
Observe patient’s respiratory rate a rhythm.
- inspiratory vs expiratory effort.
- shallow vs laboured.
Listen for:
- URT noise.
– stertor (like snoring) vs stridor.
- wheezing (LRT).
Closer PE.
Once stable.
Palpate:
- cranial mediastinum compressibility in cats (gently!)
- thoracic cavity trauma/deformities.
- tracheal pinch.
Assess LNs.
Thoracic auscultation.
Auscultate:
- crackles.
- wheezes.
- HR and rhythm: respiratory sinus arrhythmia?
- heart murmur.
- muffled/lack of heart sounds.
Percuss:
- increased/decreases resonance.
Respiratory causes of dyspnoea and tachypnoea?
URT:
- obstructive disorders (e.g. laryngeal paralysis / tracheal collapse / BOAS).
LRT:
- obstructive disorders: luminal (e.g. mucus) vs mural (mass or bronchospasm e.g. feline asthma, chronic bronchitis).
Pulmonary parenchyma:
- restrictive disorder / reduced lung capacity e.g. pneumonia, haemorrhage, oedema.
Pleural space:
- restrictive disorder/reduced lung volume: e.g. pleural effusion.
- obstructive disorder e.g. mediastinal mass.
Non-respiratory causes of dyspnoea and tachypnoea.
Haematological disorders:
- decreased O2 carrying capacity (anaemia or methaemoglobinaemia).
Metabolic disorders:
- compensatory mechanism to acidosis (DKA).
- muscular weakness (hypokalaemia).
Neurological disorders:
- brain, spinal cord, peripheral nerves.
Diagnostic investigations of coughing and dyspnoeic patient.
Assess O2:
- SpO2.
- Arterial blood gas analysis.
Blood and faecal tests.
Diagnostic imaging:
- assess pleural space disease.
Laryngeal exam.
Advanced techniques e.g. bronchoscopy.
Clinical pathology investigations.
Haematology:
- Neutropenia?
- Eosinophilia?
- Thrombocytopenia?
Biochemistry.
Lungworm?
- Angiostrongylus Antigen ELISA (blood test: AngioDetect).
- Faecal smear or Baermann for lungworm.
- Can get false negatives.
- Consider empirical treatment trial w/ fenbendazole or moxidectin.
NT-pro BNP.
- Cardiac vs respiratory cause.
- in pleural effusion (cats).
– negatives reliable.
Investigations of cough/dyspnoea under GA.
ONCE STABILISED!
Laryngeal exam.
- structure: mass, collapse.
- function: paralysis.
Diagnostic imaging.
- Which lung pattern is best described as doughnuts and tram lines?
- Which lung pattern is best described as cloudy/fluffy/patchy?
- Which lung pattern is best described as looking through net curtains?
- Which lung pattern is best described by cannon balls.
- Bronchial.
- Alveolar.
- Interstitial diffuse.
- Interstitial nodular.
Diagnostic imaging in the coughing and dyspnoeic patient.
Ultrasound:
- thoracic mass?
- E.g. T-FAST techniques (look for thoracic fluid).
Radiography:
- pulmonary patterns (bronchial, alveolar, interstitial).
- heart and vessels.
- masses.
- pleural space.
CT:
- likely referral.
Sampling for further investigation.
BAL:
- blind or guided by bronchoscope.
- pre-treat cats with Terbutaline.
- cytology.
- bacterial culture.
- Bordetella bronchiseptica and Mycoplasma spp. PCR.
Tracheal wash?
Lung FNA:
- ultrasound-guided.
- peripherally located lesions.
Further investigations - bronchoscopy.
Method.
Pre-treat cats w/ terbutaline.
Pass through trachea in small patients.
Through ET tube in larger patients.
Look at tracheal mucosal surface.
Tracheal structure.
Facilitate collection of BAL samples.
Removal of FBs.
- can be difficult to retrieve seed head due to spike directions.
- lung lobectomy.
Oxygen supplementation options for patients with dyspnoea.
Flow-by.
Mask.
Nasal prongs.
Nasal catheter.
Oxygen hood.
Oxygen cage/incubator.
Intubation w/o mechanical ventilation.
- Advantages of flow-by O2 supplementation.
- Disadvantages of flow-by O2 supplementation.
- Advantages of mask.
- Disadvantages of mask.
- Useful during initial assessment.
Easy and well tolerated. - Needs someone to hold the tube.
Fraction of O2 inhaled by patient is quite low - 25-40%. - Easy.
Useful for recumbent patient. - Patient may not tolerate.
Fraction of O2 inhaled by patient not very high - 50-60%.
- Advantage of nasal prongs.
- Disadvantages of nasal prongs?
- Advantages of nasal catheters.
- Disadvantages of nasal catheters.
- Fraction of O2 inhaled by the patient w/ nasal catheters?
- Easy to place.
- Often dislodge - designed for humans.
- Can be used longer term.
Well tolerated.
Easy access to patient.
Easy to place. - More invasive / time consuming.
- Unilateral = 40%.
Bilateral = 80%.
- Disadvantages of O2 hood.
- Advantages of O2 cage / incubator.
- Disadvantages of O2 cage/incubator.
- Risk of hyperthermia.
CO2 build-up.
Humidity.
Low fraction of O2 inhaled by patient at 30-40%. - well-tolerated.
well suited for small patients. - Limited access for patient handling (but may have access via side).
Need to monitor humidity and temperature.
Fraction inhaled O2 60% and drops when open door.
- Indication for intubation w/o mechanical ventilation?
- FiO2 w/ intubation w/o mechanical ventilation?
- Additional O2 supplementation techniques.
- Upper airway obstruction.
- 100%.
- Positive and expiratory pressure.
Mechanical ventilation.
Referral.
