Rare Diseases: Think Zebras, Not Horses

zebrasWritten by Layla Adrianovska
Master’s of Applied Health Sciences, Faculty of Health Sciences



Medical students are taught the following saying: “when you hear the sound of hooves, think horses, not zebras.” This means that it should be assumed that the simplest explanation is usually correct to avoid patients being misdiagnosed with rare illnesses. Doctors learn to expect common conditions; this means it can be more difficult to get a rare diagnosis and treatment (van de Laar et al., 2008).

Imagine the last time you were on a roller coaster, going down a very steep hill. Can you remember the burning feeling of your stomach “dropping” as you go down? This is a feeling I have had multiple times a week since I was eight. In my case, the feeling was accompanied by a sense of weakness, headaches, and difficulty standing or walking for long periods of time. These symptoms were not debilitating, but they followed me around like a dark cloud; always there, constantly weighing me down.

“Why are you so lazy? Why can't you keep up? Why are you so slow?” are phrases I heard repeatedly from peers, relatives, and my internal voice, too.

In May 2019, I went on a trip to Ethiopia to visit a family friend working at the British International School. Everything about this trip was incredible: the food, the people, and the nature. One of my best friends growing up was Ethiopian, and I have always admired the culture. To say this trip was life-changing is an understatement, in more than one way. On my last day in Ethiopia, I became sick with a parasite. The pain was intense, more than anything I had felt before, but it passed after about a week and a half. Between May and July 2019, I found myself becoming weaker and weaker. I could hear my heart beat so loudly in my ears, had debilitating migraines, experienced vision changes as if objects were coming out at me, and felt unbelievable overheating.

In July 2019, after multiple trips to my doctor, it was discovered that my blood pressure was 250/150. This is high enough to cause a stroke or heart attack, so I was admitted into the intensive care unit. There, I heard the word pheochromocytoma for the first time.

Pheochromocytomas are a rare disease in which one or more tumours develop in the adrenal glands. We have two adrenal glands, one above each kidney. The location of these tumours results in dangerously high hormone levels, which cause debilitating symptoms. Imagine your body being stuck in a severe fight-or-flight state, this is what it is like to have a pheochromocytoma.

In accordance with the recommended clinical approach for this condition, I underwent surgery to remove the tumour and my right adrenal gland in December 2019. Unfortunately, despite successful surgery, the past three years have been filled with ongoing symptoms. I have found many other individuals in a similar predicament worldwide through online support groups. I hope to research and examine the biopsychosocial constituents of pheochromocytomas through graduate studies at a PhD level. Mainly, I intend to focus on the prevalence of pheochromocytoma patients with ongoing symptoms post-surgery, despite in-range lab (hormone) results. In my scoping review, conducted as part of a Global Health class (APPLHSCI 9003) within my Master’s of Applied Health Sciences at Western University, I found a significant lack of research on this topic.

There is a lack of research and recommendations for these cases. Patients are often left without guidance leading to a significant decrease in quality of life. Some examples include unexplained pain, cardiac problems, and many more. Other points of focus that I hope to pursue will be on the damage caused by long-term exposure to high hormone levels from pheochromocytomas, as well as access to rare disease diagnosis and treatment in Canada and internationally.

Over the past three and a half years, I frequently think about how fortunate I am to live in Canada, where I can access care at no cost. In so many places worldwide, there is no help or education on rare diseases. For example, there were no hospitals in one of the parts of Ethiopia that I visited. I hope to spread awareness of pheochromocytoma to rural corners of the world, where this disease exists, but information and awareness may be lacking. I have already sent packages of information through email to as many hospitals in Ethiopia as I could find online.

I am so grateful for my trip to Ethiopia in 2019, not only because I could immerse myself in the rich culture, but because it ultimately saved my life. Remember to think of zebras, too, when you hear hoofbeats and that you may not know what someone is going through on the inside. They might not even know it, either.




van de Laar, F. A., Bor, H., & van de Lisdonk, E. H. (2008). Prevalence of zebras in general practice: Data from the Continuous Morbidity Registration Nijmegen. European Journal of General Practice, 14(sup1), 44–46. https://doi.org/10.1080/13814780802436176