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
What should be avoided in feline asthma?
beta-blockers - propanolol, atenolol
Prognosis of feline asthma
anti inflammatories and bronchdilators alleviate acute clinical signs
recureence of signs
Airway foreign bodies
Due to
• Laryngeal paralysis, dental procedures (plant material, food, teeth)
- Clinical signs
• Acute or chronic cough (dry, unproductive), cyanosis, recurrent airway infection that partially responds to AB
- Diagnosis
• Radiography
• Bronchoscopy
• Culture for bacteria
- Treatment
• Foreign body removal + pulmonary abscess
• Bronchiectasis → lung lobectomy, long term AB
bronchial neoplasia
- Clinical signs • Cough, obstructive breathing pattern (loud respirations) - Diagnosis • Auscultation: harsh wheezing noises • Radiography: solitary mass lesion - Treatment • See above: pulmonary neoplasia!
bacterial pneumonia
- Primary bacterial pneumonia is rare, more commonly secondary to:
• Laryngeal dysfunction, viral pneumonia, aspiration, GI disease, encephalopathy - E. coli, Bordetella, Klebsiella, Pasteurella, Pseudomonas, Mycoplasma spp.
- Protection mechanisms
• Laryngeal function, coughing reflex, muco-ciliary clearance, epithelial barrier, IgA, alveolar macrophages, IgG - Symptoms
• Lethargy, fever, dyspnoea, coughing (dog»cat) acute / chronic, exercise intolerance, mucopurulent nasal discharge, haemoptysis
• Underlying disease (dysphagia, regurgitation, vomiting, muscular weakness)
• Increased lung sounds and crackles or wheezes - Diagnosis
• Haematology: WBC ↑↔
• Radiography: focal or diffuse alveolar pattern (aspiration: cranioventral lung regions), bronchiectasis, megaoesophagus, mass
• Bronchoscopy: TTL, BAL for culture or cytology, mass, foreign body, broncho-oesophageal fistula, lobar pneumonia (aspiration)
- Treatment • AB • Bronchodilators • Lobectomy (focal pneumonia, abscess) • Saline nebulization • Underlying disease (foreign body, neoplasia, GI disease)
Viral bronchpneumonia
- Distemper, Morbillivirus (Paramyxoviridae family)
- Exposure (inhalation, po. infected secretions) → replication in macrophages, tonsils → viremia (2 – 4 days: initial fever!) → several tissues (lung, bowel, skin, CNS) → bronchopneumonia, enteritis, encephalitis
- Clinical signs
• Mucopurulent oculo-nasal discharge
• Fever
• Lethargy
• Neurological symptoms (50%) - Diagnosis
• PCR (blood, urine)
• Radiography (interstitial, alveolar pattern) - Treatment
• Largely supportive
➢ AB, bronchodilators, fluid
• Seizure control
➢ Diazepam, KBr, phenobarbital)
• Antibodies
Aspiration pneumonia
- Aspiration of fluid, food, gastric contents results in pulmonary inflammation
- Causes • Megaoesophagus • Laryngeal and pharyngeal dysfunction ➢ Neuromuscular disease ➢ Anaesthesia, encephalopathy ➢ Brachycephalic airway conformation ➢ Forced feeding (contrast radiography) - Severity of lung injury • Volume, pH toxicity → obstruction, pulmonary haemorrhage, oedema, inflammation, necrosis, bronchoconstriction, infection (see bacterial pneumonia)
- Clinical signs
• Cough, tachypnoea, acute onset of respiratory distress, fever, lethargy, shock, cats: wheezes (bronchospasm) - Diagnosis
• History of vomiting, regurgitation
• Radiography: quite different (interstitial/alveolar, focal/diffuse), but interstitio-alveolar pattern in cranio-ventral and middle lung lobes
• Complete blood count: leucocytosis
• Bronchoscopy: BAL for culture, cytology - Treatment
• Respiratory distress
➢ Oxygen therapy (mask, oxygen cage, intubation and positive pressure ventilation)
➢ Fluid therapy (but increased capillary permeability can lead to oedema!)
• Antibiotics: after culture
• Saline inhalation, coupage
• Corticosteroids: CONTROVERSIAL!!!!
• Prognosis: severity of lung injury and the underlying cause
Eosinophilic bronchopneumopathy
- Inflammatory disease, unknown aetiology (hypersensitivity to an environmental or endogenous antigen)
- All breeds, Huskies
- History
• Coughing, gagging, difficulty breathing, nasal discharge (mucopurulent or serous), lethargy and anorexia - Clinical signs
• Nasal discharge
• Crackling sounds
• Increased lung sounds (or normal auscultation) - Diagnosis
• Rule out other causes!
➢ Migrating parasites
➢ Bacterial or fungal infections
➢ Heartworm
➢ neoplasia
• Radiography
➢ Diffuse interstitial, alveolar, bronchial, or combination, nodules or mass-like lesions (eosinophilic granulomatosis)
• Blood test: peripheral eosinophilia
• Bronchoscopy: green, green-yellow mucus, mucosal thickening, BAL, mucosal brushing (large number of eosinophils) - Treatment
• Glucocorticoids at immunosuppressive dosages lasting weeks to months
• allergy testing, hyposensitization? - Prognosis: generally good
Pulmonary edema
- Fluid accumulation in the interstitium and alveoli
- Causes
• Vascular hydrostatic pressure ↑: left-sided congestive heart failure (CHF), excessive fluid administration (anuric renal failure!)
• Plasma oncotic pressure ↓: hypoalbuminemia
• Vascular permeability ↑: vasculitis, ARDS
• Impaired lymphatic drainage: left-sided CHF, neoplastic process
• Decreased transpulmonary pressure: upper airway obstruction - Non-cardiogenic oedema
• Not as common as cardiac pulmonary oedema
• Due to high protein fluid extravasation
• Causes include
➢ Near drowning, aspiration, severe trauma, obstructive (acute upper airway obstruction – typically in young animals), neurogenic oedema (seizures, head trauma, electrocution), ARDS - Symptoms
• Dyspnoea > cyanosis > (coughing: in severe cases bloody expectoration of blood-tinged fluid)
• Auscultation
➢ Lung: crackles heard on inspiration and end-expiration (in dorso-caudal lung fields), in severe oedema quiet lung sounds in cats!
➢ Heart: murmur +/- (but mitral endocardosis, cardiomyopathy), arrhythmia, tachycardia
o Heart murmur without sinus tachycardia: pulmonary disease > cardiogenic oedema
Smoke inhalation
- Direct injury
• Heat, particulate matter, combustion gases - Aetiology
• Acute phase (0 – 36 hours)
➢ Tissue injury → capillary permeability ↑ → oedema, tissue hypoxia (CO gas inhibits oxygen binding to Hb!)
• Later phase (2 – 4 days)
➢ Oedema ↓, mucosal secretion ↑, decreased muco-ciliary clearance, secondary bacterial colonization → tracheobronchitis, pneumonia - Clinical signs
• Singed hair, smell of smoke, loss of consciousness, upper airway stridor (laryngeal oedema), ocular and nasal discharge, cyanosis
• Some patients have minimal signs but 24 to 36 hours later! (ARDS, infection, laryngeal oedema) - Diagnosis
• History, clinical signs, radiography (oedema, pneumonia), BAL for culture (later phase)
• Carboxyhaemoglobin is not distinguished from oxyhaemoglobin with blood gas analysis or pulse oximetry! - Treatment
• Observation for at least 24 – 48 hours
• Tracheostomy: severe laryngeal oedema, obstruction
• Oxygen cage: half-life of CO in room air 4 hours, in 100% O2: 30 minutes
• Bronchodilators, antibiotics (after culture)
• Fluid therapy (but oedema!)
• Analgesics
• Corticosteroids: laryngeal oedema / acute cardiovascular shock? - Prognosis: poor if severe respiratory distress, infectious pneumonia, neurologic signs and cutaneous burns
Acute respiratory distress
- Acute hypoxemic respiratory failure caused by lung injury and pulmonary capillary permeability ↑
- Usually secondary to
• Sepsis, pancreatitis, aspiration, shock, microbial pneumonia - Pathogenesis poorly understood
• Early phase: proteinaceous fluid (capillary permeability ↑)
• Later: inflammatory cells ↑, hyaline membrane formation, fibrosis → pulmonary hypertension - Clinical signs
• Extreme anxiety, tachycardia, cyanosis, crackles (end-inspiration, expiration), wheezes, underlying disease - Diagnosis
• Non-cardiogenic lung oedema
➢ Auscultation, radiography, echocardiography
• Protein (oedema) / protein (plasma): 80 – 90%, in cardiogenic oedema 50%
- Treatment • Oxygen therapy (intubation, PEEP) • Fluid therapy (low-normal circulatory volume) • Furosemide (early phase) • Glucocorticoids? • Blood gas analysis for control - Prognosis: generally poor
Lung lobe torsion
- Large, deep-chested dogs (Afghan) > toy
- Causes
• Idiopathic, pleural effusion, surgery, trauma - Lung lobe torsion → venous congestion → exudation (bloody pleural effusion), necrosis, anaemia
- Clinical signs
• Respiratory distress, tachypnea, cough, hypotension, dyspnoea, fever, lethargy - Diagnosis
• Deep-chested dog
• Pleural effusion
• Radiography: rounding of the lung lobe edges
• Bronchoscopy?
• Surgical exploration - Treatment
• Removal of pleural fluid
• Oxygen
• Fluid/shock therapy
• Surgery
Pulmonary fibrosis
- Interstitial lung disease (West Highland White, Staffordshire Bullterriers, (cats))
- Pathologically: alveolar septal fibrosis, interstitial fibrosis, epithelial hyperplasia, focal calcification
- Chronic and progressive pulmonary signs
• Dyspnoea, exercise intolerance, +/- cough, cyanosis, crackles - Diagnosis
• Radiography: diffuse interstitial pattern
• Echocardiography: moderate to severe pulmonary hypertension
• Biopsy - Prognosis: poor
- Treatment: glucocorticoids?, bronchodilators?
Pulmonary thromboembolism
- Middle-aged to older
- Usually secondary to:
• Heartworm disease, immune-mediated hemolytic anemia (= IMHA), neoplasia, DIC, hyperadrenocorticism, PLE, PL-nephropathy etc - PTE: abnormal gas exchange, pulmonary infarction
- Clinical signs
• Sudden onset of respiratory distress
• Tachypnea
• Cyanosis
Internal Medicine Final Small Animals 2018
17 - Diagnosis
• Antithrombin III
• Blood gas
• Radiography
• Echocardiography (located in the pulmonary artery?)
• Pulmonary angiography is the gold standard - Treatment
• Thrombolytic therapy (surgical, catheter, drugs: tissue plasminogen activator etc) + underlying disease
Pulmonary neoplasia
- Metastatic > primary (carcinoma, osteosarcoma)
- Clinical signs
• Chronic cough, exercise intolerance, respiratory distress, dyspnoea, weight loss, anorexia - Diagnosis
• Origin of metastasis! (abdominal mass, effusion, lameness)
• Auscultation, percussion
• Radiography: is the key tool in the diagnostic approach! (LL 2x, VD/DV)
➢ False negative: size, obscured by the heart or liver, periosteal proliferation! (hypertrophic osteopathy)
• Definitive diagnosis: BIOPSY (thoracoscopy) or fine needle aspiration - Treatment
• Primary pulmonary neoplasia: lobectomy
• Metastatic neoplasia: ???
➢ But pitfalls! (mycobacterial infections, eosinophilic granuloma
aspiration pneumonia x ray pattern
interstitio-alveolar pattern in cranioventral and middle lung lobes
