Cushing’s dogs are more susceptible than other dogs to certain conditions. One common co-occurring condition that we have covered extensively (and that our products are formulated around) is the spectrum of insulin resistance-diabetic disorders. Another common co-occurring condition for Cushing’s dogs is hypertension (also known as high blood pressure). In this post we examine the frequency of this co-occurring condition and what you can do to avoid or treat it in your dog.
How Often Do Cushing’s Dogs Also Have Hypertension?
Researchers have found a broad range of estimates for the prevalence of hypertension in Cushing’s dogs–from 31 to 86%. However, a relatively recent study using American College of Veterinary Internal Medicine thresholds for high blood pressure found 82% of Cushing’s dogs had hypertension, with about half of Cushing’s dogs having “severe” hypertension. These numbers are in line with those for humans with Cushing’s syndrome–70-85%.
Why do Cushing’s Dogs Often Develop Hypertension?
The short answer is that we don’t know why any animal develops hypertension. There is no single cause. Rather a number of body systems (such as those involving the kidneys, vasculature, central nervous system, the adrenal hormone aldosterone, microbiome, inflammatory system, immune system and oxidative stress) likely contribute to the condition and in combinations that vary from animal to animal. Nonetheless, doctors, veterinarians and researchers have identified risk factors for developing hypertension. In humans, these risk factors include age, body mass index, sedentary lifestyle, stress, family history, smoking, and alcohol consumption. In addition, co-occurring conditions such as diabetes, kidney, thyroid or adrenal conditions, sleep apnoea and taking birth control pills are all considered risk factors. There is far less research on hypertension in dogs, but many of these same factors have been identified as risk factors for dogs as well.
Why Is Hypertension Bad?
Hypertension in and of itself is not a disease–it has no symptoms. However, prolonged increased blood pressure can lead to a range of diseases that result from the damage hypertension causes to organs throughout the body, including, to the adrenal gland, the thyroid, and the kidneys, and can lead to conditions such as diabetes.
Preventing Hypertension
The good news is that hypertension can be prevented or mitigated against by the same types of measures that humans with high blood pressure are advised to take. Specifically, the dog’s diet can be calibrated so as to bring its body weight into its target range and to minimize the intake of substances known to worsen the effects of hypertension, such as salt and foods high in sodium. (Although lower sodium levels do not seem to lower blood pressure directly, high levels of sodium can exacerbate the effects of hypertension.)
Unless your dog has heartworms or another condition that limits its activities, exercise is also important, both in its own right (for a host of benefits from improving cardiovascular health to reducing the likelihood of disorders such as diabetes) and also in achieving a target body weight. In addition, by managing the co-occurring conditions that have been identified as risk factors for hypertension, you will also be managing your dog’s hypertension. What is more, the treatments for managing co-occurring conditions such as Cushing’s syndrome and diabetes are generally complementary with those for managing hypertension. Finally, you should keep your dog’s heartworm prevention medication up to date, as heartworms themselves can cause high blood pressure and are difficult to clear once they have infected your dog.
Diagnosis of Hypertension
Diagnosis is a bigger challenge than one would expect. For humans, blood pressure is usually measured with a blood pressure cuff that gives readings that either show high, low or normal blood pressure. This forms the basis for a hypertension diagnosis in humans. However, there is no comparable, reliable method for measuring blood pressure in (conscious) dogs. Most veterinarians use Doppler ultrasonography or oscillometry to measure blood pressures in dogs. However, neither these nor any of the competing measuring technologies meet all of the validating criteria of the American College of Veterinary Internal Medicine. Thus, diagnosis may require a combination of multiple blood pressure readings and other clinical signs and findings.
Treating Hypertension
In addition to the adjustments to diet and exercise mentioned above, your veterinarian may prescribe one or more drugs to bring your dog’s blood pressure under control. If your dog has heartworms, then those will also need to be treated. As is often the case with humans, the starting point for medical treatment will likely be ACE inhibitors, with dosage adjustments made every few weeks based on then-current blood pressure readings. Additional or different drugs may be added if ACE inhibitors alone are insufficient to control your dog’s blood pressure.
Summary
Hypertension occurs in about 80% of dogs with Cushing’s syndrome. You can manage your Cushing’s dog’s high blood pressure or risk of developing high blood pressure, in consultation with your veterinarian, by avoiding high sodium foods and taking these steps:
- Determine your pet’s ideal body weight and design a diet to achieve that weight. Here’s a post we’ve done on this topic, if you need some help.
- Unless your dog has heartworms or another condition limiting its activities, implement a regular exercise program for your dog. Here’s a post we’ve done on this topic.
- Manage your dog’s co-occurring conditions. For Cushing’s syndrome, check out any of the articles on our blog. For diabetes, check out this one. For other conditions, your veterinarian can recommend a course of action.