Veterinary Guide: Coughing Dog Diagnosis

Coughing Dog - Differential Diagnoses

• Possible causes for a coughing dog include foreign bodies, allergies, tracheal/bronchial collapse, left atrial enlargement, congestive heart failure, bronchitis, bronchopneumonia/fungal pneumonia, lungworm/heartworm, or lung/airway neoplasia.

Acute Infectious Tracheobronchitis (Kennel Cough)

• A common upper respiratory tract (URT) disease caused by various infectious agents (bacterial or viral).
• Symptoms include a hacking cough, possible retching at the end of a cough, a recent history of exposure to other dogs, normal or slightly harsh upper airway sounds, and cough that can be induced by tracheal pinching.
• Often self-resolves within 2-3 weeks but can be more severe in young, geriatric, immunocompromised animals, or those with pre-existing respiratory issues.

Treatment of Kennel Cough

• Restrict exercise to minimize cough triggered by increased tidal volumes.
• Avoid exposure to airborne pollutants or irritants; use harnesses or halters instead of collars.
• Provide sloppy food, avoiding dry biscuits, and avoid sudden changes in temperature, like moving from warm to cold air.
• Potential treatment options include antibiotics, antitussives, or anti-inflammatories.

Vaccination for Kennel Cough

• Vaccination using a canine parainfluenza and Bordetella vaccine contains a live strain.
• Vaccinated dogs may still show mild clinical signs.
• Vaccinated animals can spread the vaccine strains for several weeks post-vaccination.
• Administered intranasally.

Therapeutics of the Airway

• Covers various pulmonary medications and treatment protocols.
• Details are not provided in the initial pages.

Learning Outcomes

• To understand the principle functional problems caused by respiratory diseases.
• To identify drugs used to maintain a clear airway and differentiate between different types.
• To identify peripherally active drugs for respiratory disease treatment.
• To demonstrate examples of drug use for common respiratory diseases in dogs, cats, and horses
• To name some link modules (VMS1005, VMS1006, and VMS2004 are mentioned).

Functional Problems from Respiratory Diseases

• Cough
• Mucus production
• Sneezing
• Ulceration
• Inflammation
• Tracheal/pharyngeal obstruction
• Bronchoconstriction
• Dyspnea
• Trauma

Therapeutics (Drugs)

• Antitussives: Demulcents, centrally acting opiates (e.g., butorphanol, codeine).
• Decongestants/Mucolytics: Bromhexine.
• Bronchodilators: Anticholinergics (e.g., atropine, ipratropium), beta-2 adrenergic agonists (e.g., clenbuterol, salbutamol), methylxanthines (e.g., theophylline).
• Anti-inflammatory Drugs: Glucocorticoids (e.g., prednisolone, dexamethasone, beclomethasone, fluticasone), mast cell stabilizers (e.g., sodium cromoglycate).
• Antibiotics: Beta-lactam antibiotics (e.g., penicillin, amoxicillin), tetracyclines (e.g., oxytetracycline, doxycycline), trimethoprim.
• Antifungals: itraconazole, voriconazole, fluconazole.

Bronchodilators

• Muscarinic antagonists: (block ACh receptors, e.g. ipratropium, atropine)
• Beta-2 agonists: (mimic adrenaline) (e.g. clenbuterol, salbutamol)
• Methylxanthines: (e.g. theophylline)

Beta-2 Adrenergic Agonists

• Salbutamol and terbutaline: Stimulation of beta-2 receptors causes relaxation of smooth muscle, leading to bronchodilation.
• Clenbuterol; is particularly useful in horses with respiratory disease due to bronchospasm.

Methylxanthines - Theophylline

• Structure similar to caffeine and theobromine.
• Relaxes smooth muscle and relieves bronchospasm.
• Stimulates respiration.
• Affects intracellular calcium, catecholamine, and prostaglandin/adenosine processes.
• Improves strength of myocardial contraction, induces diuresis, and is a CNS stimulant.

Drugs to Reduce Airway Inflammation

• Main drugs are glucocorticoids, which prevent the production of mediators involved in airway inflammation.

Mast Cell Stabilizers

• Sodium cromoglycate: Precise mode of action not fully understood, but thought to prevent mast cell degranulation of histamine. Helpful in prophylactic situations but not used for acute issues due to short-term effect and lack of intrinsic dilation. Useful in horses with allergic respiratory diseases.

Glucocorticoids

• Main anti-inflammatory action. They affect the transcription of genes producing mediators of inflammation. Can be inhaled (more targeted, beclomethasone, fluticasone) or oral (e.g. prednisolone, dexamethasone). Useful for maintaining control and managing exacerbations.

Key points

• Respiratory problems are common and include cough, mucus, sneezing, ulceration, inflammation, and obstruction.
• Different types of drugs are used to treat different symptoms and underlying causes. Drug treatments should be aligned with the specific problems found and not used in a general way.
• Further reading is recommended for detailed information.

Homework

• Review multiple effects of glucocorticoids on respiratory issues.
• Review other therapeutic areas (MSK, Skin, Haematopoietic, Endocrine) where glucocorticoids are used. A quiz on this topic will take place in a future semester..

Beta-Lactam Antibiotics

• Inhibit bacterial wall synthesis, causing a bactericidal effect.
• Examples are penicillin, amoxicillin, and cephalosporins.
• Clavulanate potassium protects amoxicillin from breakdown by bacterial enzymes.

Tetracyclines

• Inhibit protein synthesis, resulting in a bacteriostatic effect.
• Examples are oxytetracycline and doxycycline.

Trimethoprim

• A folate antagonist, leading to a bacteriostatic effect.
• Often combined with sulphonamides (TMP/SMX) to enhance effects.

Antifungals

• Azole class (e.g., itraconazole, voriconazole, fluconazole).
• Inhibit fungal cytochrome P-450 isoenzymes, affecting ergosterol synthesis and membrane function in fungal cells.

CPR Information

• There is specific CPR training for dogs and cats (e.g., RECOVER Guidelines), which differs from human CPR.

Advanced Life Support for Dogs

• Vasopressor therapy (like epinephrine) to raise systemic blood pressure, boosting coronary and cerebral flow.
• Epinephrine is a non-selective adrenergic agonist impacting both alpha and beta receptors. Alpha activation is peripheral vasoconstriction and beta activation is positive inotropic and chronotropic effects.
• Low dose epinephrine is a standard part of canine BLS protocols.