3. Diseases of the lungs in dogs and cats Flashcards
Clinical evaluation of the lungs?
Clinical evaluation of the lung
Can be extremely challenging; Evaluation & treatment is usually performed on an emergency basis
§ Signalment
§ General history
§ Physical exam
§ Lab. D
§ Diagnostic imaging
§ Bronchoscopy
§ Respiratory sampling
§ Blood gas analysis
SIGNALMENT
Juvenile patients: Infection; Congenital diseases (brachycephalic)
Old patients: Chronic inflammatory disorders; Tumour
STAGE I STAGE II STAGE III STAGE IV
Siamese cats: Feline asthma
HISTORY
§ When did the owner obtain the animal?
§ Travel history
§ Environment
§ Known hypersensitivities
§ Previous respiratory problems
PHYSICAL EXAM
§ Varying degrees of respiratory distress
§ Coughing
§ Dyspnoea
§ Panting
§ ↑Resp. rate
§ Adventitial sounds upon auscultation
LAB. D
§ Anaemia (hypoxia; toxicosis)
§ Leucocytosis (infection; neoplasia)
§ Leukopenia (acute bronchopneumonia; sepsis)
§ Eosinophilia (eosinophilic broncho-pneumopathy; asthma;
bronchitis; lungworm)
§ Hypoalbuminaemia
§ Pancreatitis (ARDS)
§ Coagulopathy
§ Thrombocytopathy
§ Hypercalcaemia (neoplastic; fungal)
DIAGNOSTIC IMAGING
Radiography
VD; LL (Make sure you perform the LL last to avoid lung
compression in the other x-rays)
Bronchial pattern
Interstitial pattern
Alveolar pattern
Nodular pattern
Dx: Bronchitis; Oedema; Pneumonia; Haemorrhage;
Granuloma
Ultrasound
US-guided thoracocentesis in cases of fluid accumulation
Fine needle aspiration
CT
Dx: Neoplasia; Abscess; Pulmonary fibrosis;
Bronchiectasis
CT Angiography: Pulmonary thromboembolism
BRONCHOSCOPY
Direct visualisation (oedema; inflammation; foreign body; ulcer;
tumour)
RESPIRATORY SAMPLING
BAL; TTL (Transtracheal lavage) Cytology brush
Biopsy (Open chest lung biopsy; Transbronchial biopsy)
ARTERIAL BLOOD GAS ANALYSIS
PaO2 = 90-100 mmHg; PaCO2 = 36-40 mmHg; pH = 7.35-7.45
Indicator of alveolar ventilation & oxygenation of pulmonary arterial blood
Diseases of the small airways?
Diseases of the Small Airways
BRONCHITIS (GENERAL)
Multiple causes & anatomical locations (tracheobronchitis;
bronchitis; bronchopneumonia)
Infectious
§ Canine infectious respiratory disease complex (CIRDC):
CRCoV
CIV
Kennel cough
FHV in cats
Parasites
Fungal infections
Non-infectious
§ Aspiration
§ Canine chronic bronchitis
§ Feline asthma
Canine Chronic bronchitis?
CANINE CHRONIC BRONCHITIS (CCB)
Middle aged/Older dogs; Small breeds > Large breeds
History: Daily cough for > 2 months (productive/non-productive);
Exercise intolerance
Dx
Physical exam: Good BCS or overweight; Tracheal
sensitivity; Inspiratory crackles; Expiratory wheezes
Prolonged expiration & an expiratory push
↑Vagal tone → Sinus arrhythmia
Lab. D → Bloods: Usually negative
Radiography: Donut sign; RS cardiomegaly; Cor
pulmonale; May also be negative
Bronchoscopy: Hyperaemic mucosa; Mucoid/purulent
secretions; Fibrous nodules on the mucosa
BAL; TTL: Bacteria; Nondegenerate neutrophils;
Eosinophils; Mucus
DDx
§ Infection (Kennel cough; Parasite; Fungi; D. immitis)
§ Aspiration
§ Eosinophilic broncho-pneumopathy
§ Endocardosis (CHF)
§ Pulmonary fibrosis
Tx
The condition can be controlled, but never cured!; Goals include
controlling any inflammation & prevent any worsening airway
diseases
§ Short-acting glucocorticoids (Prednisolone)
§ Bronchodilators (Theophylline; Terbutaline; Albuterol)
§ Antitussives (if inflammation has been treated effectively)
§ Antibiotics (If BAL cytology & microbiology are positive)
§ Ancillary therapy: Weight loss; Clean environment;
Nebulisation
Inadequate treatment may lead to: Pulmonary hypertension;
Bronchiectasis; Vascular remodelling
Bronchiectasis?
BRONCHIECTASIS
Irreversible dilation of the bronchi, with accumulation of pulmonary
secretions
Susceptible breed: Cocker Spaniel
Histopathologic response to long-standing inflammation/irritation
(CCB; Primary ciliary dyskinesia; Foreign body; Smoke; Dust)
History: Chronic productive cough; Frequent bouts of pneumonia
CSx: Loud bronchial sounds; Nasal discharge (pneumonia);
Haemoptysis (coughing blood)
Dx: Radiography; Bronchoscopy; CT
§ Lobar bronchiectasis → Lobectomy & antibiotics
§ Bronchodilators
§ Antitussives MUST be avoided!
Prevention: Appropriate Abx therapy if infectious; Removal of
foreign bodies ASAP; Appropriate CCB management
Prognosis: Chronic recurrent infection; Abx resistance; Pulmonary hypertension; Cor pulmonale
Feline lower airway diseases and feline bronchitis?
Feline asthma?
FELINE ASTHMA
Dx
§ Blood test: Eosinophilia in 30% of cases; Heartworm
antibody tests; (Echocardiography)
§ Faecal exam: Paragonimus spp.; Aelurostrongylus;
Capillaria
§ Radiography: Interstitial, bronchial or alveolar pattern;
May appear normal; Hallmarks: Peribronchial cuffing, infiltrated
medial lung lobe & pulmonary emphysema
§ Bronchoscopy: BAL cytology: Eosinophilia!; Culture
DDx
§ Infection
§ Aspiration
§ Allergic bronchitis
§ Idiopathic pulmonary fibrosis
§ Neoplasia
Tx
§ Acute (emergency) (Cyanosis & open mouth breathing)
Oxygen cage; Terbutaline; Glucocorticoids
§ Chronic
§ Glucocorticoids: Prednisolone; Fluticasone
§ Bronchodilators
§ Antibiotics
Prevention
Avoid use of beta-blockers, cigarette smoke & aerosol spray
Prognosis: Anti-inflammatories & bronchodilators alleviate acute
CSx; Recurrence of CSx
Foreign bodies?
FOREIGN BODIES
Incidence: Accidental; Laryngeal paralysis; Dental procedures
CSx: Acute/chronic cough; Cyanosis; Recurrent airway infection
that partially responds to abx therapy
Dx: Radiography; Bronchoscopy
A bacterial culture may be taken to diagnose any bacterial
contamination
Tx: Removal
Incidences of pulmonary abscess/bronchiectasis → Lung lobectomy
& long-term abx
Neoplasia?
NEOPLASIA
CSx: Cough; Obstructive breathing pattern (loud respiratory
sounds); Haemoptysis
Auscultation: Harsh wheezing noises
Dx: Radiography → Solitary mass
Tx: See “pulmonary neoplasia” later
Pneumonia in general?
PNEUMONIA IN GENERAL
Types based on Anatomy
§ Bronchopneumonia
§ Pneumonia
§ Interstitial pneumonia
§ Lobar
§ Diffuse
Types based on Origin
§ Infectious: Bacterial; Viral; Fungal; Parasitic
§ Non-infectious: Aspiration; Idiopathic
Types based on Duration
§ Acute
§ Subacute
§ Chronic
Bacterial pneumonia?
BACTERIAL PNEUMONIA
E. coli; Bordetella spp.; Klebsiella spp.; Pasteurella spp.;
Pseudomonas spp.; Mycoplasma spp.
Common complication of:
§ Laryngeal dysfunction
§ Viral pneumonia
§ Aspiration pneumonia
§ GI disease
§ Encephalopathy
Protection mechanisms: Laryngeal function; Coughing reflex;
Mucociliary clearance; Epithelial barrier; IgA; Alveolar
macrophages; IgG
CSx: Lethargy; Fever; Dyspnoea; Coughing; Exercise intolerance;
Nasal discharge; Haemoptysis
Acute/chronic
↑Lung sounds, crackles & wheezes
Dx
§ Haematology:↑WBC
§ Radiography: Focal or diffuse alveolar pattern;
Bronchiectasis; Megaoesophagus; Mass
§ Bronchoscopy: Mass; Foreign body; Broncho-oesophageal
fistula; Lobar pneumonia
§ BAL/TTL
Tx: Abx; Bronchodilators; Lobectomy; Saline nebulisation; Tx of
underlying disease
Viral bronchopneumonia?
VIRAL BRONCHOPNEUMONIA
Distemper virus; Morbillivirus (paramyoxviridae family)
CSx: Mucopurulent oculonasal discharge; Fever; Lethargy; CNS
symptoms
Dx: Radiography – Interstitial/alveolar pattern
Tx: Supportive (Abx; Bronchodilators; IVFT); Seizure control
(if necessary); Antibodies
Prevention: Vaccination
Fungal Pneumonia?
FUNGAL PNEUMONIA
Histoplasma capsulatum; Blastomyces dermatitidis; Coccidioides
immitis; Cryptococcus neoformans; Aspergillus fumigatus;
Pneumocystis carinii
Dx
§ BAL; FNA of lung → Cytology; Microbiology; PCR
§ Bloods → Serology
Tx
§ Itraconazole
§ Pneumocystis cases: Trimethoprim + sulfamethoxazole
Aspiration pneumonia?
ASPIRATION PNEUMONIA
Aspiration of fluid, food or gastric contents; Results in pulmonary inflammation
Disposition
§ Megaoesophagus
§ Laryngeal & pharyngeal dysfunction: Neuromuscular
disease; Anaesthesia; Encephalopathy; Brachycephalic airway
conformation; Forced feeding
Factors affecting the severity of lung injury
§ Volume; pH; Toxicity
§ Obstruction
§ Pulmonary haemorrhage
§ Oedema
§ Inflammation
§ Necrosis
§ Bronchoconstriction
§ Infection (see bacterial pneumonia earlier)
CSx: Cough; Tachypnoea; Acute respiratory distress syndrome
(ARDS); Fever; Lethargy; Shock
Cats only: Wheezing (bronchospasm)
Dx
§ History of vomiting/regurgitation
§ Radiography: Interstitio-alveolar pattern in cranioventral
& middle lung lobes
§ CBC: Leucocytosis
§ Bronchoscopy: BAL for culture; Cytology
Tx
Respiratory distress
Oxygen therapy; IVFT; Removal of content
Antibiotics: Culture & sensitivity; After fever/radiographic
lesions
Saline inhalation
Glucocorticoids are CONTRAINDICATED
Prognosis: Dependent on the severity of lung injury & and
underlying conditions
Eosinophillic bronchopneumopathy
EOSINOPHILIC BRONCHOPNEUMOPATHY
Inflammatory disease with unknown aetiology
Observed in all breeds, but especially in Huskies
History: Coughing; Gagging; Dyspnoea; Nasal discharge; Lethargy;
Anorexia
CSx: Nasal discharge; Crackling;↑Lung sounds
Dx
It is important to rule out outher causes before jumping to this
conclusion – Pathogens; Allergic causes
Radiography: Diffuse interstitial pattern; Alveolar pattern;
Bronchial pattern or a combination of these; Nodules;
Mass-like lesions
Bronchoscopy: Green; Green-yellow mucus; Mucosal
thickening; BAL; Mucosa brushing shows a large number
of eosinophils
Tx: Glucocorticoids (at immunosuppressive dosage) coure for weeks
to months
Prognosis: Generally good
Pulmonary oedema?
