Therapy andMonitoring
Given the paucity of therapeutic trials in patients with CCB, firm evidence-based recommendations are not possible, and the following section is based on the limited evidence and the opinion of the author.
Data obtained from well-structured trials will supersede that of the opinion of experts.The reality confronting most practicing veterinarians is that many owners have a limited budget, which does not necessarily preclude the successful management of CCB. Owners with limited funds should not be denigrated and excluded from compassionate and dedicated care. Indeed, it is often more challenging (and possibly rewarding) to successfully manage a chronic disease based on clinical data and limited diagnostics.
In cases where funds are limited and in the absence of a cytological confirmed diagnosis, a trial of doxycycline or fluoroquinolones (typically 10-14 days) can be considered to exclude bacterial diseases such as Bordetella and Mycoplasma. The combination of antimicrobials and glucocorticoids should be avoided, as this may obscure the interpretation of a therapeutic trial. It is this author's opinion that antimicrobial cover should be reserved for patients that have cytological/bacterial culture or clinic-pathological evidence of bacterial infection. Neutrophilia on blood smear, fever, productive cough, exposure to other coughing dogs, an elevated respiratory rate and systemic illness are compelling reasons to treat with antibiotics. Existing and emerging antimicrobial resistance is a concerning global phenomenon, threatening the health of human and animal patients (Weese et al. 2015). Therefore, clinicians should carefully consider the probability of bacterial infection before instituting a therapeutic antibiotic trial. Glucocorticoids (GC) is currently the recommended therapy in CCB. The response to GC is variable, and owners should be warned of this at the beginning of therapy.
Recent work has demonstrated the utility of inhaled GC in the management with CCB, which has the added advantage of having fewer unwanted GC side effects, and endocrine perturbations. The response to inhaled GC is variable, and doses required to control clinical signs vary from patient to patient; therefore, the author treats with oral GC first to assess whether the coughing is GC responsive. Inhaled GCs tend to be expensive, and some capital outlay for the spacers and mask is needed. Oral doses are typically initially high (e.g., prednisone 1.5-2 mg/ kg/d) for 7-10 days, and are tapered once a reduction in the clinical signs is documented. Worsening of clinical signs, or failure to respond should prompt a reassessment of the case, and possibly cessation of therapy. In cases where the response is encouraging; the dose is tapered gradually over 1-2 months, in an attempt to determine the minimal dose required to control clinical signs. If the dog tolerates an inhaler, the owner is shown how to use an inhaler with the spacer. If an inhaler is used, an inhaled bronchodilator such as salbutamol can also be used for symptomatic relief. If the patient tolerates the inhaler, oral GC is slowly withdrawn and the patient is maintained on inhaled GC. The author sometimes finds that pulse therapy of oral GC is needed to “buy back” control occasionally, but inhaled GC seems to reduce the requirement of oral GC and is associated with fewer side effects. This author prefers bude- sonide, given its negligible interference with the hypothalamic-pituitary-adrenal axis compared to fluticasone, but either of these drugs appear to be effective (Melamies et al., 2012). Owners who cannot afford inhaled GCs would need to titrate the oral GC dose to the minimum effective dose long term.In addition to GC therapy, weight-loss is important in overweight patients as it greatly improves comfort and ease of breathing. Where possible avoidance of cigarette smoke, dust, and environmental pollutants is advisable and if possible owners should humidify the air in very dry environments. In addition, in cases where the coughing is causing distress, and is unproductive, antitussives can be used for symptomatic relief, but should be reserved for patients that have worrisome coughing, as cough suppression will reduce the clearance of mucous and pathogens.