3) diseases of the lungs Flashcards
Clinical evaluation of the respiratory tract
- Can be extremely challenging
- Evaluation and treatment on an emergency basis
- Signalment
• Juvenile patients
➢ Infectious disease
➢ Congenital abnormalities (brachycephalic breeds!)
• Siamese cats: feline asthma
• Old patients
➢ Chronic inflammatory disorders
➢ Tumour
History of lung disease
When did the owner obtain the animal?
➢ Adult/puppy
➢ Life history, vaccination
• Travel history (infectious or parasitic disease)
• Environment (exposure to toxins or infectious disease)
• Known hypersensitivities to dietary allergens or medications?
• Previous respiratory problems? Treatment? Examinations? Tests?
Physical examination of lungs
Varying degrees of respiratory distress, coughing, increased breathing, adventitial sounds (crackles or wheezes) upon auscultation
• Complete physical examination should be performed!
• Respiratory signs (dyspnoea, panting) without respiratory origin (metastatic tumour, gastric dilatation, metabolic acidosis: Kussmaul dyspnoea, encephalopathy, ARDS – Acute Respiratory Distress Syndrome, anaemia)
- → tentative diagnosis and treatment → ancillary diagnostics for definitive diagnosis
Laboratory diagnostics of lung diseases
Anaemia (hypoxia, toxicosis?), leucocytosis (infection, neoplasia), leukopenia (acute bronchopneumonia, sepsis), eosinophilia (eosinophilic broncho-pneumopathy, asthma, bronchitis, lungworm)
- Hypoalbuminemia, pancreatitis → ARDS
- Coagulopathy, thrombocytopenia
- Hypercalcaemia (neoplastic, fungal disease)
Radiography of lungs
LL and VD/DV
- Bronchial-, interstitial-, alveolar-, nodular pattern
- Bronchitis, oedema, pneumonia, haemorrhage, granuloma (eosinophilic, fungal, parasitic, foreign body)
addtional diagnsostic methods
Ultrasonography
- Fine needle aspiration
CT
- Metastatic pulmonary lesions
- CT angiography: pulmonary thrombo-emboli
Bronchoscopy
- Direct visualisation (oedema, inflammation, foreign body, ulceration, tumour)
Respiratory sampling
- BAL, cytology brush
- TTL
- Biopsy (open-chest lung biopsy, transbronchial biopsy)
Arterial blood gas analysis
- PaO2 = 90-100 mmHg, PaCO2 = 36-40 mmHg, pH = 7.35 – 7.45
- Alveolar ventilation and oxygenation of pulmonary arterial blood
Canine chronic bronchitis
Middle-aged to older dogs, small breed > large breed
- Self-perpetuating disease process where inflammation leads to fibrosis and mucus which leads to further airway inflammation
- No identifiable cause, possibly due to airborne allergens (e.g. smoke)
- Clinical signs
• Daily cough for more than 2 months (productive / non-productive), exercise intolerance
• Good condition / overweight, tracheal sensitivity, inspiratory crackles, expiratory wheezes
• Prolonged expiration and an expiratory push
• Increased vagal tone → sinus arrhythmia (+/-)
- Diagnosis
• Radiography
➢ 3 views: +/- bronchial / interstitial pattern
➢ Doughnuts sign, right-sided cardiomegaly, cor pulmonale
BAL, TTL
➢ Bacteria +/-, cytology, culture and sensitivity, PCR for Mycoplasma
➢ Non-degenerate neutrophils, eosinophils
➢ Increased mucus
• Bronchoscopy
➢ Hyperaemic mucous membranes
➢ Mucoid or purulent secretions
➢ Fibrous nodules on the mucosa
Treatment of canine chronic bronchitis
Can be controlled but never cured! → goals: control inflammation, prevent worsening airway disease
• Short acting anti-inflammatories: prednisolone (goal: to achieve alternate day dosing)
• Bronchodilators worth a try: theophylline, terbutaline, albuterol
• Antitussives: if inflammation has been effectively treated! Otherwise mucus can trap in the bronchi and worsen clinical signs
• Antibiotics
➢ If BAL cytology and microbiology +
➢ Doxycycline for possible Mycoplasma
• Adjunctive therapy
➢ Reduce airborne allergens, cool clean area (no smoke, dust, heat)
➢ Coupage, nebulization
➢ Weight reduction
➢ Harness instead of collar
Bronchiectasis
Irreversible dilatation of bronchi, with accumulation of pulmonary secretions (cocker spaniels!)
- Histopathologic response to long-standing inflammation / irritation (CCB, primary ciliary dyskinesia, smoke, dust)
- History
• Chronic productive cough
• Frequent bouts of pneumonia (initially respond to antibiotics but the recur)
- Symptoms • Loud bronchial sounds • Nasal discharge +/- (pneumonia) • Haemoptysis (= coughing up blood) - Diagnosis • Radiography • Bronchoscopy • CT - Treatment • Lobar bronchiectasis → lobectomy • Antibiotics based on culture • Bronchodilators • Cough suppressants MUST BE AVOIDED!
- Prognosis
• Chronic recurrent infection
• Resistance to AB treatment
• Pulmonary hypertension, cor pulmonale - Prevention
• Appropriate AB therapy in infectious disease
• Prompt removal of foreign bodies
• Appropriate management of CCB
Must be avoided in bronchiextasis
cough supressants
Feline bronchial disease/feline asthma aetiology
- Inflammation of the conducting airways (bronchi and bronchioles)
- Syndrome that encompasses
• Chronic bronchitis
➢ Clinically seen as a chronic cough
• Asthma
➢ Caused by acute reversible narrowing of the airways due to bronchoconstriction, clinically seen as acute onset dyspnoea, triggered usually by airborne allergens
➢ Diagnosis is based on clinical presentation, response to bronchodilators, an inflammatory bronchoalveolar lavage (typically eosinophilic) and evidence of hyperplasia of the mucus glands and smooth muscle
- Any age, Siamese cats!
- Not all cats affected by bronchial disease will have asthma, and some cats will present in acute distress due to asthma without a history of coughing
- Increased airway resistance (smooth muscle hypertrophy, bronchial wall oedema, glandular hyperplasia) → cough and respiratory distress
Feline asthma clinical signs
• Chronic cough more than 2 months
➢ Paroxysmal, dry, “hacking” cough, open mouth (loud) breathing, prolonged expiration
➢ Mild to severe respiratory distress usually obstructive expiratory dyspnoea
➢ Wheezing
➢ Auscultation: harsh lung sounds, crackles, expiratory wheezes or normal
➢ Percussion: increased resonance
Feline asthma diagnosis
• Blood test
➢ Eosinophilia in 30%, faecal examination (Paragonimus spp., Aelurostrongylus, Capillaria)
➢ Heartworm antibody tests (echocardiography)
• Radiography 3 views: +/- bronchial pattern and hyperinflation of lung fields
• Bronchoscopy: BAL cytology (eo, neu)
➢ PCR for Mycoplasma or culture
• Whole body plethysmography
➢ Airway reactivity to non-specific aerosol stimulant
Treatment of feline asthma in acute cases
• Acute stabilisation for emergency situation (cyanosis, open mouth breating!)
➢ Oxygen cage
➢ Sedation (butorphanol = anxiolytic and antitussive; acepromazine if certain that respiratory distress is not due to cardiac disease)
➢ Bronchodilator (terbutaline)
o If reduction in rate and effort, supportive of the diagnosis asthma
o If heart rate increases >200 bpm then drug is working
➢ Anti-inflammatories (glucocorticoids)
Treatment of feline asthma long term
Rule out parasitism as a cause of eosinophilic bronchoalveolar lavage by treating prophylactically with fenbendazole ➢ Glucocorticosteroids o Prednisolone o Inhaled fluticasone o Methyl-prednisolone acetate (inhaled preparations) ➢ Bronchodilators o Terbutaline: inhaled preparations o Salbutamol: as needed ➢ Antibiotics o Doxycycline o Culture for Mycoplasma before starting
