Findings on Canine Pulmonary Hypertension

October 20, 2011
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Reading veterinary journals is tough. Yeah, sometimes the verbiage is difficult to wade through (and this coming from someone who’s written a veterinary dictionary), but my problem stems more from it being the last thing I want to do after a day of seeing patients or writing a veterinary-themed blog.

So, to give myself a bit more incentive, I’ve decided that every so often I will combine journal reading with blogging, thereby killing the proverbial two birds with one stone.

Give me a second, this looks like a good one … Canine Pulmonary Hypertension, from the September, 2011 issue of Veterinary Medicine. I’ve treated only one patient with this disease, and I was only involved in his follow up care after a referral. About all I remember from the case was that the dog was treated with Viagra (which made everyone giggle at the time), and he didn’t do very well.

Off to read now. I’ll be back in a few.

Yawn …OK, you still there? Here is the Cliffs Notes version of what I learned:

  • Vets used to think pulmonary hypertension (a higher than normal blood pressure within the lungs) was pretty rare, but it is now being diagnosed with increasing frequency (probably because we are looking for it).
  • The condition is complex and can develop as a result of a variety of underlying, oftentimes very serious diseases.
  • The easiest way to diagnose pulmonary hypertension is with an echocardiogram (an ultrasound of the heart), which is handy because heart disease is a leading cause of the disease, so the echo can give you a lot of good information.
  • The World Health Organization (WHO) has come up with a clinical classification (Class 1-5) for pulmonary hypertension, which helps in identifying its cause and coming up with an appropriate treatment plan.
  • A functional classification scheme (I-IV) is also in place with regards to the severity of the symptoms caused by the disease. Dogs in class I and II have few if any symptoms, while class III and IV dogs are more severely affected.
  • Common symptoms include exercise intolerance, coughing, difficulty breathing, a blue tinge to the mucous membranes, fainting, fluid build-up in the abdomen, and, when listening to the chest with a stethoscope, abnormal heart (e.g., a murmur) and lung sounds.
  • A full health work up, including routine blood work, a urinalysis, heartworm testing, chest X-rays, and the aforementioned echocardiogram is usually needed to look for an underlying cause.
  • Dogs that fall into functional class III or IV should receive treatment. The drug of choice for pulmonary hypertension is sildenafil (Viagra). Other medications are available but they are either prohibitively expensive or of questionable value. Any underlying disease process also needs to be treated aggressively.
  • Dogs tend to survive for about three months after a diagnosis of pulmonary hypertension when they are treated with sildenafil.  If they do not receive treatment, death often occurs within days of diagnosis.

I guess I can skip the pulmonary hypertension lecture at my next continued education meeting now.

Dr. Jennifer Coates

Image: Phase4Photography / via Shutterstock