Say the words “inflammatory airway disease” and expect to see fear flicker across the faces of clients waiting at a veterinary hospital.

 

Yes, for cat and dog owners alike, inflammatory airway disease sounds downright scary. However, (as with all illnesses) the more people know about the causes, symptoms, and treatments, the less frightening each diagnosis becomes.

 

There are two types of inflammatory airway disease we will be learning about today: canine chronic bronchitis and feline asthma. These are both characterized by a chronic cough and airway inflammation and may cause bronchoconstriction.1,2 Management of these airway diseases is focused on treating both acute flareups and chronic symptoms.

 

Time is of the Essence  

 

When a patient walks through the door, it’s necessary to treat them as emergent because they could be experiencing respiratory distress due to exacerbation of asthma or bronchitis.

 

A quick, thorough history from the owner should be taken. The goal? Discover what airway disease the patient may have.

 

The first step is to ensure the patient can breathe. Airway constriction and inflammation can progress to full airway obstruction quickly! Airways can be dilated by using an injectable steroid, such as dexamethasone. Dexamethasone is an anti-inflammatory glucocorticoid that is given at a dose of 0.1-0.5mg/kg intramuscularly (IM) or intravenously (IV).3 An inhaled or injectable bronchodilator should also be used. Terbutaline is a beta2 adrenergic agonist which opens the airways to help reduce constriction. It can be given IM or subcutaneously (SQ) at a dose of 0.01mg/kg.3 Inhaled bronchodilators come in short and long-acting formulations.

 

Short acting formulations are used as a ‘rescue’ medication. They typically last for 4-6 hours and relax smooth muscle in the airway to reduce bronchoconstriction. Albuterol is the most common rescue bronchodilator (but salbutamol may also be used).

 

Be careful…

 

Airway inflammation may worsen if albuterol is used long term, so these are truly used in emergent situations.

The Lifesaving Power of Inhaled Medications

 

Unlike humans, pets cannot speak using words. Naturally, they will not understand verbal commands such as “breathe deeply” or “wait ten seconds.” Therefore, veterinarians must get creative and use medical tools at their disposal when it comes to inhaled medications. Since an aerosol chamber is needed to make sure the patient successfully breathes in the medication, a mask can be placed over the muzzle. We want a tight fit. The inhaler is puffed into the chamber and the patient is allowed to take 5-7 breaths. These can be administered at a dose of 1-2 puffs every 30 min for less than 4 hours.3

 

Here is another good tip.

 

Rescue inhalers and aerosol chambers can be prescribed to owners. This way, they can help manage acute bronchoconstriction from the comfort of their home. That means less stressful car rides and anxiety for our furry friends.

 

Once acute bronchoconstriction has been addressed, management can focus on long term medication. A short term course of systemic steroid should be prescribed for 10 days to reduce ongoing airway inflammation. Prednisolone (1-2mg/kg every 24 hours) should be given to cats and prednisone (0.5-1mg/kg every 24 hours) should be prescribed to dogs.2 Corticosteroids are considered the cornerstone of treatment and must be administered orally, injectably or via inhalation. Inhaled steroids help limit systemic absorption which can prevent any adverse effects.

 

There are some unfavorable effects of systemic steroids, however.

 

These include behavioral changes, lethargy, weight gain, vomiting and diarrhea. Similarly, patients might be extra thirsty. Or experience urinary incontinence and be at increased risk for infections (such as urinary tract infections). Animals may also show immunosuppression and are at risk for iatrogenic hyperadrenocorticisim.3

 

In order to switch an animal from systemic steroids to inhaled steroids the systemic steroids must be tapered and inhaled steroids started. The systemic and inhaled steroids should overlap for two weeks to give the inhaled steroids time to take effect.  Fluticasone can be used at a dose of 1 puff of 110 ug every 12 hours for cats and dogs under 20kgs. Dogs over 20 kgs can be given 1 puffs of 220 ug fluticasone every 12 hours. A combination inhaler of an inhaled steroid and long acting bronchodilator may be used instead. Flutiocasone/salmeterol may be given to cats and dogs under 20kgs at a dose of 1 puff (115ug/21ug) every 12 hours. Dogs over 20kgs should be given 1 puff (230ug/21ug) every 12 hours.3

 

Compliance and Education Go Hand in Hand

Client compliance and education are two sides to the same coin.

 

Start by having an honest conversation with the family. Discuss disease management. For example, veterinarians can prompt with a leading question such as, “What environmental factors that may trigger attacks? Can you think of any steps that can be taken to minimize them?”

 

We want clients to feel empowered about their pet’s health! Cat owners may be instructed to administer rescue inhalers during flare ups to help stabilize their pets at home. Albuterol has not been shown to help manage canine bronchitis flare ups at home.3 Learning about pet health is an ongoing process, and clients should walk away educated on the importance of giving medications for long term disease control.

 

 

References

 

1.    Padrid, P. Chronic Bronchitis and Asthma in Dogs and Cats. Deleware Valley Academy of Veterinary Medicine. Available at: http://www.delawarevalleyacademyvm.org/pdfs/sep12/chronicbronchitis.pdf

2.    Padrid P.Use of inhaled medications to treat respiratory diseases in dogs and cats. J Am Anim Hosp Assoc. 2006;42(2):165-169.

3.    Managing Feline Asthma & Canine Bronchitis. [online] Trudell Medical. Available at: https://www.trudellanimalhealth.com/sites/default/files/documents/Feline_Asthma_and_Canine_Bronchitis_Treatment_Algorithm_and_Dosing%20Guidelines.pdf