Dr. Danelia de Kock, DVM, BS Math.The below is my general clinical approach written as I have in my notebook - nothing fancy :). It does not include every differential diagnosis, diagnostic or treatment option, but rather goes over the main criteria to think about clinically including the diagnostic and treatment options most commonly considered for the particular topic covered, as well as any pertinent tips and client/owner communication. Feel free to print this out, edit as needed and MAKE IT YOUR OWN! You can also comment and add any of your own tips, experiences or any pertinent recent CE information for us to all learn and grow from - because as we know: in medicine, learning never stops 🤓.⁠

Dr. D from Vetpocket

Disclaimer: The information is intended to be used for educational purposes and as guidelines only. Medical recommendations and guidelines vary slightly among sources, and get updated and evolve periodically. Take into account a patient’s individual circumstances and don’t rely on this information alone. This information is not intended to replace clinical judgement or guide individual care in any matter. Please check any information and values prior to use and use at your own risk. Neither Vetpocket, the authors, nor any other party involved in the preparation, publication or distribution of any Vetpocket material shall be liable for any special, consequential, or exemplary damages resulting in whole or part from any use of or reliance upon this information.

The Coughing Dog (Antibiotics)

Differential diagnosis:

Infection (bacterial, viral, fungal, parasitic), heart disease, tracheal collapse, neoplasia (primary, metastatic), masses other than neoplastic, foreign body, overweight, inflammatory, allergic, trauma, degenerative or aging, noncardiogenic pulmonary edema, pleural effusion, open.

Diagnostics:

The signalment, a thorough history, physical exam including TPR and thorough heart and lung auscultation as well as tracheal palpation, radiographs (thoracic radiographs are always a good start to help assess the heart, lungs, trachea and remainder of the thoracic cavity), blood work (cbc with pathology review, full chemistry panel, heartworm antigen test, coccidioidomycosis titer, proBNP, etc.), fecal testing (screening for causes such as lungworm infection), urine antigen testing (screening for causes such as blastomycosis and histoplasmosis), echocardiogram, respiratory panel PCR assay via nasal and nasopharyngeal swab, airway samples for cytology and culture via TTW and/or via bronchoscopy BAL, etc.

Recall that the respiratory tract contains normal microbiota which needs to be taken into consideration when interpreting test results, as well as taking into consideration any possible contaminants and opportunists. Remember that false negative and false positive test results are always possibilities - discuss this with owners when going over the patient’s treatment plan.

Treatments:

Treat the cause. If heart disease is diagnosed then treat that. If tracheal collapse is diagnosed then treat that. If heartworm disease is diagnosed then treat that. If a lungworm infection is diagnosed then treat that. If a fungal infection is diagnosed then treat that. If neoplasia is diagnosed then treat that. And so on. Remember that it is always possible for a patient to have concurrent diseases present, and if so, then treat those.

Some infectious causes may NOT require treatment and may be self-limiting, such as acute upper respiratory tract infections. Remember the importance of practicing antimicrobial stewardship. It is typically recommended to not treat with antibiotics in the acutely coughing dog, but rather to monitor the patient for ~ 10 days to see if clinical signs resolve on their own. Treatment is based on the patient’s signalment, history, and the remainder of the diagnostic findings including the physical exam. Are there any additional clinical signs of a respiratory tract infection such as a productive cough, sneezing, mucopurulent nasal discharge, ocular discharge, conjunctivitis, crackles, wheezing, dyspnea, fever, lethargy and inappetence? If clinical signs are significant, including progressing or having progressed to pneumonia, then even in the acutely coughing dog, initiating treatment with an antibiotic can be considered. 

If a bacterial infection is suspected or confirmed, and if antibiotics are required, then unless diagnostics indicate a different antibiotic and dosage to be used, the antibiotic for a coughing dog that I typically use, which is the empirical first-line antibiotic for respiratory tract infections, is doxycycline at a dosage of 5 mg/kg PO q 12 hr for 7 to 10 days and then reassessing the patient. Doxycycline tablets and capsules can cause esophageal strictures (especially in cats) - have owners administer with a soft treat and should follow administration with water or food to ensure passage of the tablet or capsule. In young patients, tetracycline risks include teeth discoloration and effects on bone formation - these risks are lower with doxycycline compared to other tetracyclines. Keep the patient separated from others to help prevent disease spread. Note that significant pneumonia +/- sepsis likely requires broader spectrum antibiotic combinations such as clindamycin/enrofloxacin.