Etiology and Epidemiology
Clinical Features
Physical Examination Findings
Diagnosis

Diagnostic Imaging
Treatment and Prognosis
Immunity and Vaccination
Prevention
Public Health Aspects
Case Example
Suggested Readings
References

Canine adenovirus
Canine influenza virus
Canine parainfluenza viruses
Canine respiratory coronavirus
Canine herpesvirus
Canine reoviruses
Canine pneumovirus

Overview
Clinical Approach
Lung Function Testing
Diagnostic Imaging
Airway Sampling
Pathophysiology
Treatment
Prognosis
Pulmonary Hypertension
What to do when the dog is still coughing?
Summary
References

Practical relevance

Lower respiratory tract infections (LRTIs) in cats can be due to bacteria, parasites, fungi and viruses.  This review details the practical investigation of these infections and highlights specific therapy where possible.  The aim is to avoid the all-too-frequent temptation in practice to treat cats with lower respiratory tract signs empirically for feline bronchial disease (FBD)/asthma.  This is potentially hazardous as immunosuppressive therapy for FBD/asthma could exacerbate disease due to a LRTI.  Empirical treatment of suspected LRTI is also difficult to recommend given the wide range of potential pathogens.

Clinical challenges

Making a clinical ante-mortem diagnosis of LRTI in a cat can be challenging.  Consistent historical, clinical, haematological and radiographic abnormalities are often lacking and findings may be non-specific.  Astute clinical acumen, thorough investigation and high quality laboratory analysis are usually required for a diagnosis. Bronchoalveolar lavage, if feasible, and tests for lungworm should be routine in cats with lower respiratory tract signs. Lung fine needle aspiration may be useful in cases of diffuse or nodular pulmonary disease.  Histopathology is rarely employed in ante-mortem investigations.

Evidence base

The authors have reviewed a substantial body of literature to provide information on many of the reported bacterial, parasitic, fungal and viral pathogens, including some that occur in Asia.  Attention has been given to specific therapy for each pathogen, with evidence-based comments when there is a deviation from routine recommendations.

Flexible endoscopy is a valuable diagnostic approach to the upper and lower respiratory tract, because it allows direct visualization and sample collection.  Techniques requiring a range of specialized equipment and varying levels of experience have been developed to access and evaluate each anatomic region.  Familiarity with appropriate indications for each procedure and normal appearance, cytology, and culture results from each region will enhance diagnostic success.

• Laryngoscopy
• Transtracheal wash - Endotracheal wash
• Tracheobronchoscopy
• Sample collection:  Bronchoalveolar lavage, bronchial brushing, biopsy
• Sample submission:  Cytology, culture
• Complications
• Summary
• References

Article Outline

Respiratory Problems
Dyspnea

Useful Tests

Coughing, Including Hemoptysis

Nasal Discharge, Sneezing, and Epistaxis

Nasal Radiography

Computed Tomography

Rhinoscopy

Nasal Lavage

Nasal Biopsy

Interpretation of Impression Cytology

Nasal Fine-Needle Aspiration Biopsy

Exploratory Rhinotomy

Serology/Antigen Detection For Nasal Fungal Disorders

Other Tests For Patients With Epistaxis

Laryngeal, Nasopharyngeal, And Pharyngeal Examination
 

Tracheal And Thoracic Radiography/Fluoroscopy

Transtracheal/Tracheal Aspiration
 

Bronchoalveolar Lavage

Tracheobronchoscopy

Fecal Examination

Baermann's Funnel Apparatus

Pulmonary Aspiration Biopsy

Serology/Antigen Tests For Pulmonary Diseases

Amino-Terminal Pro-B-Type Natriuretic Peptide (NT-probnp)

Cardiac Troponin I (cTnI)

Arterial Blood Gases

Partial Pressure of Oxygen

Partial Pressure of Carbon Dioxide

Diagnostic Evaluation of Blood Gases

Partial Pressure Of Oxygen In Venous Blood

Pulse Oximetry

Thoracocentesis

Thoracoscopy/Thoracotomy

References and Suggested Readings

Article Outline

• Control of alveolar ventilation:  Chemoreceptors and chemoreflexes, Mechanoreflexes
• Gas diffusion and transport during respiration:  Carbon dioxide, Oxygen
• The alveolar-arterial oxygen gradient
• Hypoxemia:  Low partial pressure of inspired O2 (Pio2), Hypoventilation, Diffusion impairment, Ventilation-alveolar perfusion mismatch (- Mismatch), Right-to-left shunt
• Respiratory acidosis:  
  Metabolic compensation in respiratory acidosis: Acute Respiratory Acidosis, Chronic Respiratory Acidosis
  Causes of respiratory acidosis
  Diagnosis and clinical features of respiratory acidosis
  Treatment of respiratory acidosis
• Respiratory alkalosis:  
  Metabolic compensation in respiratory alkalosis:  Acute Respiratory Alkalosis, Chronic Respiratory Alkalosis
  Causes of respiratory alkalosis
  Diagnosis and clinical features of respiratory alkalosis
  Treatment of respiratory alkalosis
• Dyspnea
• Summary
• References

Article Outline

THE NASAL CAVITY

• Normal Anatomy and Histologic Features
• Collection Techniques and Sample Preparation:  Nasal Swabs, Nasal Flush, Fine Needle Aspiration, Imprint and Brush Cytology
• Normal Cytology and Common Cytologic Changes:  Normal Nasal Cytology, Oropharyngeal Contamination, Hyperplasia / Dysplasia, Metaplasia
• Noninfectious Inflammatory Disease: Foreign Bodies, Allergic Rhinitis, Lymphoplasmacytic Rhinitis, Nasal Polyps, Chronic Sinusitis
• Infectious Causes:  Bacteria, Viral, Fungal, Parasitic, Protozoal, Algal
• Neoplasia of the Nasal Cavity and Paranasal Sinuses
• Epithelial Neoplasia, Neuroendocrine Carcinoma, Mesenchymal Neoplasia, Discrete Cell Neoplasia, Histiocytic Sarcoma, Miscellaneous Neoplasia
  
  

LARYNX

• Anatomic and Histologic Features
• Sample Collection
• Normal and Inflammatory Cytologic Features:  Normal, Inflammation, Granulomatous laryngitis, Reactive Lymphoid hyperplasia
• Laryngeal Neoplasia:  Lymphoma, Squamous Cell Carcinoma, Carcinoma, Laryngeal oncocytoma, Mesenchymal Neoplasia, Laryngeal Cysts and Mucoceles

TRACHEA, BRONCHI, AND LUNGS

• Normal Anatomy and Histology of the Airways and Lung
• Collection Techniques:  Transtracheal Wash, Bronchoalveolar Lavage, Bronchial Brushing, Transthoracic Fine-Needle Aspiration
• Normal Cytologic Features:  Normal Cytology of the Trachea and Bronchial Tree, Normal Cytology of the Lung, Oropharyngeal Contamination
• Inflammation of the Tracheobronchial Tract and Lungs:  Chronic Inflammation, Suppurative Inflammation, Macrophagic and Mixed Inflammation, Granulomatous Inflammation, Eosinophilic Inflammation
• Infectious Causes of Disease of the Tracheobronchial Tract and Lungs
• Bacterial Pneumonia, Viral Pneumonia, Protozoal Pneumonia, Fungal Pneumonia, Parasitic Infestations
• Tissue Injury:  Hemorrhage, Pulmonary Alveolar Proteinosis, Pulmonary Atelectasis or Collapse, Necrosis, Hyperplasia and Dysplasia of the Lung, Metaplasia of the Lung
• Neoplasia:  Carcinoma, Hemolymphatic Neoplasia, Mesenchymal Neoplasia
• Nonrespiratory Aspirate

REFERENCES