Chronic Bronchitis in Dogs
Other medical problems can lead to symptoms similar to those encountered in chronic bronchitis. Diagnostic testing such as radiographs (X-rays) and bronchoalveolar lavage (BAL]) will often diagnose chronic bronchitis. Further diagnostic testing may be needed to determine secondary factors such as active inflammation or to eliminate other causes of similar symptoms such as heart disease.
Diseases that can appear similar to those with chronic bronchitis include:
Aspiration (the act of inhaling) from chronic esophageal disease
Bronchopneumonia (bacterial or fungal)
Congestive heart failure
Inflammatory lung disease
Lung worm infection
Pneumonia (inflammation/infection of the lungs)
Pulmonary fibrosis (formation of fibrous tissue in the lungs)
Pulmonary neoplasia (lung tumors)
Tracheal (windpipe) collapse
In-depth Information on Diagnosis
Certain diagnostic tests are needed to confirm the diagnosis of chronic bronchitis in dogs and exclude other diseases that may cause similar symptoms. Tests may include:
A complete medical history and physical examination
Radiography (chest X-rays). The thoracic radiograph is abnormal in most cases. Typical findings include increased interstitial density.
An examination of the trachea and bronchi (tracheobronchial examination) including cytology and culture. Sputum (mucous secretions from the lungs, bronchi and trachea) may be obtained using different techniques. A tracheal wash, also called a trans-tracheal wash (TTW), is a procedure in which a fluid sample is obtained and analyzed. This test is involves placing a small needle into the trachea of a lightly sedated patient. Bronchoalveolar lavage is another method to obtain fluid samples.
Evaluation of collected sputum specimens. The sputum sample is cultured for bacteria and sensitivity testing is done. Cytology is also recommended to determine the cell time present (active infection, evidence of allergy, parasites, or cancer cells).
Bronchoscopy. This procedure consists of placing a small flexible fiberoptic tube into the airway that allows for direct visualization of the upper and lower airways. This test can establish the diagnosis and rule out other diseases, such as inflammatory disease, lungworms, fungal infections and cancer.
Other laboratory tests may be helpful in assessing your pet’s heart and lungs and eliminating the possibility of other diseases. These tests may include:
A complete blood count (CBC) to determine general health and check for secondary conditions. The CBC in dogs with chronic bronchitis is usually normal. Abnormal changes in the CBC can be noted with pneumonia, respiratory parasites, heartworm disease or other secondary diseases.
Biochemistry. Serum blood tests may be recommended to determine your pet’s general health and check for secondary conditions.
Heartworm test to determine presence of heartworm antibodies
Fecal test to evaluate for lungworms
Electrocardiogram (ECG) to determine the rhythm and look for abnormalities of the heart
Arterial blood gas tests. These tests may be used as a method for sampling arterial blood to determine oxygen levels. This is a sensitive test for verifying the presence of significant lung disease. Many veterinary hospitals do not have the equipment to run this test, but blood can be analyzed easily at a local human hospital.
In-depth Information on Treatment
Treatment of chronic bronchitis must be individualized based on the severity of the condition, the cause, secondary diseases or conditions and other factors that must be analyzed by your veterinarian. Therapy of idiopathic chronic bronchitis is frustrating because the underlying cause of inflammation is rarely determined or controlled. Rarely is a cure obtained; however, with diligent home care – that includes avoidance of risk factors and weight loss – and medical therapy, significant improvement of clinical signs does occur in many dogs. Patients with advanced changes including bronchiectasis (chronic dilation of the bronchi and bronchioles with secondary infection) or lobar atelectasis generally respond poorly to medical therapy. Complete suppression of the cough is rare.
Therapy of chronic bronchitis is guided by the cytology and culture of the tracheobronchial secretions (sputum), by the extent of radiographic changes and by response to therapy. Chronic, intermittent antibiotic or corticosteroid therapy, combined with the use of bronchodilators, antitussives and supportive care of the respiratory system, form the basis for medical therapy.
Antitussive therapy. The use of cough suppressants varies on a case-by case basis. In dogs with non-bacterial bronchitis, breaking the cough cycle is an essential part of treatment. Cough suppressants are contraindicated with pneumonia. Examples of cough suppressants used include hydrocodone (Tussionex® or Hycodan®) or butorphanol (Torbutrol®).
Bronchodilator therapy. Bronchodilators may increase the vigor of contraction of the respiratory muscles, which may be useful in dogs with chronic dyspnea (difficult breathing). Theophylline and its various salts are most commonly chosen. Long-acting theophylline (Theo-Dur®) if often used twice daily. Some dogs cannot tolerate the adverse effects of xanthines, which include anxiety, restlessness, tachycardia, polyuria and emesis.
Antibacterial therapy. This should be used in dogs with primary bacterial tracheobronchitis or a complicating bacterial infection. Drug choice is ideally chosen based on the results of the culture and sensitivity. In most dogs, however, antibiotic treatment causes little improvement, presumably due to a nonbacterial cause or lack of suitable culture and sensitivity testing. Antibiotic choices may include: amoxicillin-clavulanic acid (Clavamox®); trimethoprim-sulfonamide; cephalothin or cephalexin; enrofloxacin (Baytril®); or tetracycline for a minimum of three weeks. Other antibiotics may be chosen when Bordetella bronchiseptica is cultured. Gentamicin may be used via nebulization (a treatment in which an antibiotic is converted to a spray form in which your pet breaths in). This treatment is often administered twice daily for five days.
Anti-inflammatory therapy. Using prednisolone or prednisone is most effective for control of most cases of bronchitis and is the most efficacious treatment of bronchitis that has eosinophils on cytology. Drugs used include prednisone often give twice daily then tapered to lowest effective dose (often given every day or every other day).