Respiratory: Pulmonary Diseases Flashcards
What does severe pulmonary disease frequently result in?
Dyspnoea
What happens when pulmonary parenchymal diseases result in a ventilation: perfusion mismatch?
Can be identified by arterial blood gas analysis
If PaO2 falls below 60mmHg the patient will be clearly cyanotic and emergency treatment required
If the animal is making an audible breathing noise (without a stethoscope) what is it associated with?
Associated with upper respiratory tract disease
Stertor, stridor
What may expiratory dyspnoea be associated with?
May be associated with dynamic airway collapse or bronchial narrowing
Expiration may be slow and associated with marked abdominal effort
What dyspnoea can pulmonary oedema and idiopathic pulmonary fibrosis result in?
May result in both inspiratory and expiratory dyspnoea and increased RR, respiratory depth is shallow.
Pleural effusions, pneumothorax also result in combined dyspnoea
What is the difference between an obstructive dyspnoea and restrictive?
Obstructive- increased effort
Restrictive- fast, shallow respirations
What can cause obstructive dyspnoea?
Can be inspiratory, due to upper airway obstruction (BOAS, laryngeal paralysis- normally upper resp noise)
Or expiratory due to bronchospasm- feline asthma
What does restrictive dyspnoea cause?
Is normally both inspiratory/expiratory dyspnoea
Can be due to pulmonary parenchymal disease or pleural effusions/pneumothroax
What is the initial treatment for a dyspnoeic animal?
Provide humidified oxyen (try and maintain <50% inspired O2)
100% should be avoided for all but can be given for a short time to avoid oxygen toxicity
How can oxygen be provided for a dysponeic animal?
- In an incubator
- In a temporary oxygen cage
- Into an elizabethan collar with cling film
- Via intranasal oxygen catheter
- Via a face mask
Patients reciveing O2 in a chamber can overheat rapidly
What can a poor response to oxygen in a dyspnoeic, cyanotic animal reflect?
More likely to suggest a congenital heart disease with right to left shunting
Pulmonary oedema or respiratory causes of dyspnoea should respond to O2 supplementation
As well as recording respiratory rate what else should be recorded?
Pattern of respiration
What is a normal respiration pattern?
Inspiration 30%
Expiration 60%
Pause 10%
What may an increased duration and effort of inspiration show?
Consistent with upper airway obstruction or pulmonary parenchymal lesions
What can increased depth of respiration be associated with?
Mass lesions or diaphragmatic rupture
What can rapid shallow respirations be associated with?
Pulmonary parenchymal disease- pulmonary oedema, idiopathic pulmonary fibrosis
What is paradoxical respiration?
Part of the ribs being ‘sucked in’ during inspiration
What can paradoxical respiration be associated with?
- May result from a flail chest (rib fractures, post trauma)
- Certain neurological lesions
- Any dyspnoeic animal (especially pleural disease)
On a cursory clinical examination of dyspnoeic dog, what can show heart failure rather then respiratory disease?
Dogs with heart failure usually have tachycardia or arrhythmias and heart murmurs or diastolic gallops
What clinical signs can show significant respiratory disease and cardiac disease to be less likely?
Presence of sinus arrythmia- may show increased vagal tone
- What disease is associated with dramatic crackles ‘cellophane’?
- What disease results in soft, inspiratory crackles
- Idiopathic pulmonary fibrosis
- Pulmonary oedema
What are expiratory wheezes usually associated with?
Bronchial narrowing
How can you ‘unmask’ respiratory sounds?
Sometimes adventitious respiratory sound can be unmasked by precipitating a paroxysm of coughing
After attempting to elicit a cough by tracheal pinch, the lung field should be re-auscultated
What is inspiratory stridor normally associated with?
Upper airway obstruction
On a cursory clinical exam what should be checked and asked?
- Ascultate lungs, elicit cough
- Trachea and larynx- collapse/paralysis
- Ask about bark/miaow- change laryngeal disease
- Percussion resonance- pleural effusions or masses
- Assessing thoracic compressability in cats (cranial thorax)- less with anterior mediastinal masses or pleural effusion
- Careful attention to position of the heart
- In diaphragmatic rupture with significant herniation of the abdominal contents into the thoracic cavity, improvements may be seen by holding the animal up by its front legs
How can pleural effusion be detected?
Often by reduced percussion resonance ventrally
Or by T-FAST ultrasound scan
Describe the process of thoracocentesis for a pleural effusion
- 21G 1 inch butterfly catheter
- Introduced cautiosly about the 7-8th intercostal space while maintaining suction
- Via a three wat tap with a syringe
- Sample can be retained for cytology/bacteriology
- Once confirmed the pleural effusion should be completely drained
What can the distribution of lesions radiographically suggest in bronchopneumonia/pneumonia?
Source of infection
* Ventral distribution suggests it may be secondary to airway disease or aspiration
* Caudodorsal distribution may indicate haematogenous spread
* Aspiration pnemonia secondary to megaoesophagus
What is pneumocystis carinii infection?
How is it diagnosed and treated?
Rare cause of pneumonia in an immunosuppressed individual
Dx- based on signalment, demonstration of the organisms on lung aspirated, immunoglobulins can support
Treatment- trimethroprine potentiated sulphonamides
Some breeds of dogs- young dogs, CKCS
What is the name of the french heart worm?
What clinical signs may dogs have?
Angiostrongylus vasorum
Dogs may be completely asymptomatic, typically cough or show respiratory signs
May also show coagulopathy, ocular or neurological manifestations
How can angiostrongylus vasorum infestations be diagnosed?
- Thoracic radiographs can show enlargment of pulmonary arteries
- Dx- identification of larvae in faeces or BALF, angio detect SNAP test
Occasionally causes pulmonary hypertension or atriovenous shunts bypass lung tissue- hypoxia, pulmonary thromboembolism
How is angiostrongylus treated?
- Fenbendazole- 50mg/kg SID 7-21 days, then possibly repeat
- Milbemycin oxime
- Moxidectin- topical single treatment, repeat after 30 days
What drugs can be used to prevent angiostrongylus infestations?
Moxidectin
Milbemycin
How are lung neoplasia usually ascertained?
Thoracic radiographs- all views allow attempt to localise
Conformation requires obtaining tissue- FNA
Most frequently affected site of metastatic disease
- What breed most commonly is affected by idiopathic pulmonary fibrosis?
- How do dogs present?
- How does it appear radiographically?
- How can dogs be treated?
- Mainly terrier breeds- highland white, cairn terriers
- Severly dyspnoeic at presentation and cyanotic, marked abdominal effort, palpable rectus abdominus muscle hypertrophy
- Generalised increase in interstitial markings may be present
- Treatment non-specific- rested and unstressed, O2, bronchiodilators for airway collapse, steroids and colchicine anti-fibrotic
Prognosis very guarded- survival usually only a few weeks
What happens with paraquat intoxication?
Pneumotoxicity
Severe dysponea, minimal radiographic change initially
Later increased interstitial markings- prognosis hopeless, euthanised
What does pulmonary thrombo-embolism result in?
Severe ventrilation: perfusion mismatch
Ventilated areas of lungs recieve no blood flow
PTE usually results from systemic conditions such as IMHA, DIC
What can cause pulmonary thrombo-embolism?
- IMHA
- Hyperadrenocorticism
- Nephrotic syndrome
- Sepsis
- Pancreatitis
- Neoplasia
- DIC
- Dirofilariasis
How can PTE be confirmed?
pulmonary thromboembolism
Evidence of pulmonaty hypertension
Doppler echocardiograhpy
Very large thrombi can be visualised on echocardiography
Arterial blood gas analysis
How is PTE treated?
- Oxygen support
- Sedation or anxiolytic
- Anticoagulant therapy- low molecular weight heparin
- Antiplatelet- low dose asprin, clopidogrel
- Treat the underlying disease
How can PTE be prevented?
In conditions where PTE is a significant risk- nephrotic synsdrome
Low doses of aspirin or clopidogreal
What can cause non-cardiogenic pulmonary oedema?
Electrocution
Upper airway obstruction
CNS disease
Vasculitis
What is ARDS?
Acute respiratory distress syndrome
What is ARDS?
non-cardiogenic pulmonary oedema- secondary to range of respiratory or systemic insults
Resp disease, oxygen toxicity, truama, electrocution, near drowning
How is ARDS treated?
- Emergency stabilisation of the patient, sedation
- Oxygen therapy
- Bronchodilation
- If not improving GA and IPPV
- Furosemide only miminally effective
- Fluid therapy for shocked patients
- Hypoproteinaemic require colloids or plasma to improve oncotic pressure
- Underlying disease treated aggresively
What dyspnoea can pulmonary oedema and idiopathic pulmonary fibrosis result in?
May result in both inspiratory and expiratory dyspnoea and increased RR, respiratory depth is shallow.
Pleural effusions, pneumothorax also result in combined dyspnoea
