Wait! Is that a zebra?

By Yajie Zhu, MD, Los Angeles, CA & Amy Yu, MD, Johns Hopkins Medicine  

During my observership in the hospital medicine department, I encountered an unusual situation with my attending. Mr. L, a 35-year-old man who’s been healthy his entire life, was admitted due to severe dysphagia that developed over several days. He couldn’t keep any solid foods down and had been surviving on soups alone. He even had difficulty handling his own saliva, constantly spitting into a vomit bag during our visits. Mr. L was anxious and tearful, as such severe symptoms are overwhelming. What’s more puzzling is that these symptoms seemed to have appeared out of nowhere. The only notable event he recalled was eating some bad sushi and macaroni salad, which had led to vomiting and diarrhea before his symptoms began. 

With the consultants we identified the objective weakness of his oropharynx muscles. Neurologic examination revealed subtle loss of pinprick sensation on one side of the body. Subsequent MRI uncovered subacute stoke in the posterior circulation, possibly due to vertebral artery dissection during the violent vomiting episodes. 

There’s a famous saying in medicine: “When you hear hoofbeats, think horses, not zebras.” This means a healthcare professional should first consider what’s more common and potentially a more likely diagnosis, rather than search at exorbitant length and cost, for low probability causes. Initially, we thought that Mr. L’s vomiting episodes might have caused some inflammation in the oropharynx and might simply be a slow healer, hence dysphagia. However, it turned out to be a “zebra” as the incidence of dissection of the cervical and cerebral arteries is reported to be approximately three cases per 100,000 individuals. 

“Zebras” do exist and identifying them presents a unique challenge for healthcare professionals. How can we effectively spot these elusive cases when they do appear? 

1. Trust and explore the patient’s statements. 

Patients with no significant medical history sometimes face skepticism when reporting unusual symptoms. It’s crucial for clinicians to recognize and overcome their own biases and preconceptions. By actively listening to patients, validating their experiences, and conducting comprehensive physical examinations, healthcare professionals can significantly improve patient-doctor relationships. This approach also increases the likelihood of revealing subtle signs that may not be apparent from the patient’s history alone, potentially uncovering important diagnostic clues. 

2. Look beyond the EMR and your initial assumptions.  

It’s important to recognize the limitations of EMR systems, as the documented information may not fully capture the severity or nuances of a patient’s condition. As in this example, it’s difficult to grasp the extent of dysphagia in a 35-year-old man based solely on electronic records. Direct patient evaluation is irreplaceable, allowing for a more accurate assessment of symptoms and providing opportunities to uncover details that may not be evident in electronic records. After meeting the patient, remain flexible in your thinking. Don’t let your first impressions anchor your decisions and keep an open mind to other possibilities. 

3. Consider the context.  

Environmental factors, travel history, and family background can give crucial context for identifying rare conditions. A seemingly improbable diagnosis may become more plausible when considering these factors. Always take a holistic view of the patient’s life circumstances when evaluating unusual symptoms. 

This piece expresses the views solely of the author. It does not necessarily represent the views of any organization, including Johns Hopkins Medicine.