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Bronchiectasis 133

• Respiratory distress ○ In dogs, multiple lung lobes are affected or obstructive disease, glucocorticoids may
not be indicated.
• Other signs that reflect underlying in 89% of cases; right cranial lung lobe ○ If secondary to noninfectious inflamma-
VetBooks.ir dyskinesia) be an overestimate because the right tory disease (e.g., chronic bronchitis), Diseases and Disorders
disease (e.g., nasal discharge with ciliary
overrepresented (93%), although this may
long-term, low-dose glucocorticoids often
cranial bronchus is more visible on lateral
PHYSICAL EXAM FINDINGS
radiographs.
will be needed.
• Cough may be inducible on tracheal palpa- • Evidence of concurrent/underlying pulmo- ○ Oral (e.g., prednisone 0.5 mg/kg q 24h)
tion, but an inducible cough is not specific nary disease is frequently present. initially to control inflammation
for bronchiectasis. • Radiographs may be unremarkable in the ○ Continuation of glucocorticoids is based
• Other findings may reflect underlying disease early stages of disease, although they are on the underlying disease contributing to
(e.g., fever with bacterial pneumonia). important to evaluate for other causes of bronchiectasis.
cough and respiratory distress. ○ Metered-dose inhalant glucocorticoids
Etiology and Pathophysiology (e.g., fluticasone: empirically start at 110
• Predisposing conditions lead to cycles of Advanced or Confirmatory Testing to 220 mcg per actuation, one puff using
damage to the bronchial epithelium and/ • CT is highly sensitive and may help a spacer q 12h, tapering slowly to the
or its cilia, inflammation, impairment detect subtle lesions, especially in cats. lowest effective dose) may minimize
of mucociliary function, and secondary Bronchoarterial ratio > 2.0 in dogs is systemic long-term side effects (pp. 136
infection. consistent with bronchiectasis in most and 1122).
• Cellular damage, inflammation, and infection cases. • If bronchiectasis is confined to a single lung
perpetuate the cycle of airway wall destruc- • Bronchoscopy and BAL (for cytology and lobe (e.g., due to prior bacterial pneumonia
tion, leading to bronchiectasis. culture) may identify underlying/concurrent or obstruction from bronchial tumor or
diseases (p. 1074). Depending on accessibility foreign body), lung lobectomy may be
DIAGNOSIS of the airway affected, distortion and dilation curative.
of the airway is recognized. Often, hyper- ○ A CT scan should be performed before
Diagnostic Overview emia, edema, airway excessive secretions, lung lobectomy to assess for occult areas
Diagnosis is usually accomplished by survey or inspissated mucus and debris may be of bronchiectasis and structural changes
thoracic radiographs; CT and/or histopathology recognized. in other lung lobes.
may be necessary to detect subtle lesions. A • Specialized functional and immunologic • Bronchodilators are unlikely to be helpful.
diagnosis of bronchiectasis warrants a thorough studies such as mucociliary scintigraphy, • Cough suppressants are contraindicated
diagnostic evaluation (including bronchoscopy CCDC39 mutation in Old English sheepdogs because they impair mucociliary clearance.
and bronchoalveolar lavage [BAL]) to identify with suspected primary ciliary dyskinesia,
underlying/concurrent diseases. immunoglobulin A (IgA) concentration, and Behavior/Exercise
others may be needed to evaluate patients Minimize exposure to irritants (dust, smoke,
Differential Diagnosis for suspected congenital disease. and aerosols); HEPA-type air filters may be
See Cough (p. 1209) and Respiratory Distress • Other tests, as guided by preliminary helpful.
(p. 879). information (e.g., Baermann fecal exam,
• Other airway diseases (e.g., chronic bron- serologic tests for specific pathogens) Possible Complications
chitis, eosinophilic bronchitis, secondary • Lung biopsy is sometimes needed to identify • Glucocorticoids may impair immunologic
bacterial bronchitis, obstructive airway underlying/concurrent disease. clearance of secondary infection. Bronchi-
disease) ectasis itself is associated with impaired
• Pneumonia (infectious, aspiration, foreign TREATMENT mucociliary function, which also predisposes
body) to bacterial infections.
• Neoplasia Treatment Overview • Frequent use of antibiotics may lead to
• Pulmonary thromboembolism (PTE) Any recognized cause of inflammation should development of bacterial resistance. With
• Cardiogenic/noncardiogenic pulmonary be addressed directly, if possible (e.g., chronic recurrent pneumonia/bacterial infections,
edema bronchitis, infection). Bronchiectasis is irre- culture and sensitivity should guide antibiotic
• Pleural effusion versible except focal disease treated by lung therapy.
• Pneumothorax lobectomy. Long-term management focuses on
• Interstitial lung disease (e.g., pulmonary decreasing inflammation, enhancing mucocili- Recommended Monitoring
fibrosis) ary clearance, and appropriate treatment for • Clinical signs at home
secondary infections. • Physical examination and repeat thoracic
Initial Database radiography, as warranted by signs or q 6-12
CBC: neutrophilia +/− band neutrophils may Acute General Treatment months
support underlying infection; peripheral Address underlying illness and secondary com- • Repeated airway cytology and cultures, as
eosinophilia may be present with eosinophilic plications (e.g., bacterial bronchopneumonia). indicated
bronchitis
Thoracic radiographs: Chronic Treatment PROGNOSIS & OUTCOME
• Bronchiectasis has a pathognomonic radio- • Humidification or nebulization enhances
graphic appearance mucociliary function by increasing water • If bronchiectasis is focal, lung lobectomy
○ Cylindrical: most common (70% of canine content of the mucociliary blanket. may be curative.
cases); dilated bronchi with nontapering • Treat recurrent secondary bacterial infections • Diffuse bronchiectasis cannot be cured and
ends if present, ideally based on culture and must be treated chronically by balancing
○ Saccular: cluster of grapes appearance to sensitivity with an antibiotic that penetrates antibiotics for secondary infections and
airways (advanced disease) the blood-bronchus barrier (e.g., tetracy- antiinflammatory doses of glucocorticoids
○ Cystic: rounded ends of very small bronchi clines, fluoroquinolones). (if inflammation is present). In the absence
(end stage of saccular form) • Glucocorticoids of life-threatening infection or serious
• Spatial classification ○ If inflammation minimal and bronchiec- underlying disease (e.g., neoplasia), long-term
○ Focal, multifocal, or diffuse distribution tasis is secondary to resolved pneumonia survival is possible.

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