Breed-specific canine respiratory diseases
Being aware of breed-specific characteristics that affect the upper and lower airways will improve veterinary client education and patient safety, but dont jump to any diagnostic conclusions without a thorough workup.
jomkwan7/stock.adobe.comRespiratory issues are common in dogs, and certain conditions are more common in specific breeds due to their unique physical traits, among other factors. But that doesn't mean you should develop a one-track mind, Elizabeth Rozanski, DVM, DACVIM, DACVECC, associate professor at the Cummings School of Veterinary Medician at Tufts University, recently told dvm360.
“It's helpful to know about breed characteristics that may predispose a patient to particular diseases, but every patient needs to be considered individually,” she said.
Here are the diagnostic and management basics for five canine breed-specific respiratory diseases.
Brachycephalic airway syndrome
Upper airway disease is seen most commonly in bulldogs, pugs and other brachycephalic breeds. The stenotic nares, elongated soft palate, hypoplastic trachea and everted saccules of these patients create airflow obstructions at multiple sites in the upper airway. As a result, brachycephalic patients are at high risk for heat stroke and respiratory distress even with minimal exertion.
Dr. Rozanski suggested that all veterinary clinics develop special protocols for these patients to diminish stress and monitor for early signs of disquietude during the visit. Owners should be advised to minimize heat stress and maintain optimal body condition in these dogs. Definitive treatment of brachycephalic airway syndrome is surgical correction, which should be performed sooner rather than later.
Upper airway disease of Norfolk terriers
“Norfolk terriers have unique anatomy that can make intubation for anesthetic procedures challenging,” Dr. Rozanski warned. The larynx in these dogs is stenotic or collapsed, and they may display an elongated soft palate, everted saccules and narrow nose. Veterinarians should be aware that even though Norfolk terriers may weigh an average 20 pounds, endotracheal tube size will be much smaller than anticipated.
Another common upper airway disease is laryngeal paralysis, which is usually seen in older, large-breed dogs, such as Labrador retrievers. Patients with laryngeal paralysis have a characteristic increased inspiratory noise due to laryngeal collapse. This is a slowly progressive disease, but owners should be advised early on about the risks of heat stress. Additionally, many of these dogs will develop a generalized polyneuropathy over 18 to 24 months following the onset of laryngeal paralysis.
Medical management has minimal success, but dogs tend to do well with laryngeal tieback surgery, Dr. Rozanski said. “Because the nerves in the back of the throat are often affected,” she said, “these patients are at higher risk for aspiration pneumonia during sedation.” Thus, Dr. Rozanski recommended sedating the patient to confirm the diagnosis and perform corrective surgery at the same time instead of sedating the animal twice for two separate procedures.
Small-breed patients presenting with a goose-honking cough and wheeze, especially during periods of excitement, are likely to have tracheal collapse. This can be diagnosed with radiographs, although the full extent of disease may not be apparent because of the dynamic nature of the trachea during respiration. Bronchoscopy may aid diagnosis.
Yorkshire terriers are the hallmark breed for this disease. However, other small-breed dogs with tracheal collapse often have additional respiratory conditions, such as lower airway disease in pugs and Pomeranians or laryngeal disease in various breeds.
“Advise owners that tracheal collapse is a chronic disease,” Dr. Rozanski said. They should use a harness on the pet during walks, avoid respiratory irritants, limit barking and maintain the pet's ideal body weight. Medical management is successful in most cases and includes cough suppressants (hydrocodone is preferred), prednisone therapy and a short course of antibiotics (doxycycline or fluoroquinolones). Bronchodilators are not generally helpful for tracheal diseases but can be tried. Surgical management, such as the use of tracheal stents, can be pursued; however, these procedures are palliative, and the cough will continue to progress over time.
Pulmonary fibrosis of West Highland white terriers
West Highland white terriers are prone to pulmonary fibrosis, which presents in older dogs with a cough and a gradual onset of exertional respiratory distress. Diagnosis is made via clinical examination, interstitial changes on radiographs and evidence of inflammation on tracheal wash. The differential diagnosis should include chronic bronchitis, heart failure, "Cushing's disease" and neoplasia.
Many of these dogs will have concurrent pulmonary hypertension, which must be managed along with the pulmonary inflammation. Medical management includes cough suppressants, low-dose diuretics and sometimes immunosuppression.
Dr. Kate Boatright, a 2013 graduate of the University of Pennsylvania, is an associate veterinarian in western Pennsylvania. She is actively involved in her state and local veterinary medical associations and is a former national officer of the Veterinary Business Management Association.