Diagnostic Tests Cough/sneeze/gag/respiratory Distress

Introduction

Diagnostic tests are obviously required to confirm the presence of many respiratory diseases in small animals. However, respiratory medicine is an underdeveloped subspecialty in veterinary medicine, and there are relatively few sophisticated tests that are available to the clinician that actually diagnose specific pulmonary disorders. Instead, most of the commonly available tests are best used to point us in the right direction, and to rule out the presence of other potentially confounding disorders.

History

Age, Breed and Sex
The signalment frequently yields important clues regarding the patient’s condition. For example, sneezing and nasal discharge in a kitten suggests a viral etiology, while the identical signs in an aged cat suggest a more malignant process. Pulmonary neoplastic processes tend to occur in older animals, while mediastinal masses and nasopharyngeal polyps are commonly diagnosed in both young and middle aged cats. Particular breeds tend to have increased rates of certain respiratory disease, including asthma in Siamese breed felines.

Present Environment and Geographic Origin
I always ask clients if there are smokers in the house, if they have recently cleaned their fireplace, if they have changed carpeting or if their house has undergone significant renovation in the last 6 months. I also ask every owner about recent travel history to determine if their pet is at increased risk for “geographically specific” diseases such as mycotic infection, heartworm or aelurostrongylus infestation.

Present Complaint
Sick animals often hide, or shrink away from frequent contact with the owner. Clients often believe that their pet has “suddenly” stopped eating or playing when the disorder causing these signs has developed over a much longer period of time. So, if we ask our clients “how long has fluffy been ill?” they may tell us “He just started coughing” Instead, if we ask clients “when the last time fluffy was was normal?” they may reply “He really hasn’t seemed the same for about a month, but I was out of town a lot and I haven’t really seen him that much until this weekend.” 

Physical Examination

The most important part of the physical examination of the respiratory system is inspection, to determine whether the respiratory difficulty can be identified primarily during inspiration or during expiration. Even in situations in which the animal is in obvious respiratory distress, I rely upon the finding of inspiratory vs. expiratory difficulty to guide emergency interventions. Specifically, animals with noisy breathing during inspiration (stridor) or inspiratory difficulty most commonly have either upper airway obstruction or disease within the pleural space, including effusion, pneumothorax or mediastinal mass. Animals with labored breathing during expiration most commonly suffer from chronic bronchitis or asthma. Therefore, if a dog or cat has an increase in inspiratory respiratory effort without stridor, you can make a presumptive diagnosis of pleural space disease, followed by thoracocentesis. Similarly, a cat with an expiratory wheeze probably has bronchial obstruction, and should be treated for presumed bronchospasm even before the underlying cause is determined.
Animals with panting or open mouthed breathing are not so easily classified, and may suffer from congestive heart failure, pneumonia, pulmonary embolism or neoplasia, although clearly, patients may present in distress in the later stage of any respiratory disorder. The veterinarian should also keep in mind that other, nonpulmonary causes of abnormal ventilatory patterns are common and may mimic signs of respiratory disease. [...]