Diagnosing dizziness: we are teaching the wrong paradigm!

Dizziness is common and can be caused by scores of diseases and conditions that involve nearly every system in the body. Many causes are trivial, but a substantial minority of dizzy patients presenting to an emergency department (ED) have dangerous, treatable cardiovascular, cerebrovascular, and other diseases. This is classic emergency medicine: we must identify the few patients (with any given complaint) with serious problems among the larger group with benign ones. However, unlike many chief complaints, dizziness seems to be especially vexing. The approach to patients with dyspnea or chest pain seems more straightforward. Why do most physicians feel more comfortable assessing these patients compared to dizzy ones? It is not just the numerous potential causes of dizziness; this is also true for these other chief complaints. Dyspnea could be due to various pulmonary or cardiac problems, but also from anemia or early sepsis or salicylate toxicity. I believe that the problem with diagnosing dizziness is that we are taught (and are teaching) the wrong diagnostic paradigm. The traditional paradigm uses “symptom quality”—the type of dizziness that the patient endorses— to drive the subsequent work-up. We are taught to ask, “What do you mean, dizzy?” The patient’s response of “vertigo,” “lightheadedness” or “near faint,” “disequilibrium,” or “other,” then determines the differential diagnosis, testing, and treatment. This symptom quality paradigm dates back to research done 45 years ago. An important article in 1972, to a modern eye, it has serious methodologic flaws. Over a 2-year period, the authors recruited only 125 dizzy patients who were evaluated in a dizziness clinic. Patients had to be available to return on 4 separate days of testing by a resident. Thirty of the 125 patients were excluded. A single investigator assigned a final diagnosis without any independent verification or long-term follow-up, and of course, brain imaging did not exist back then. The symptom quality approach can only work if three essential components are true: 1) patients reliably and consistently distinguish one type of dizziness from another, 2) patients endorse only one type at a time, and 3) the dizziness type truly correlates with a given list of possible diagnoses. Each of these components is demonstrably false. When dizzy patients were asked a series of questions about their dizziness type, and then reasked the same questions in a different sequence 10 minutes later, over 50% of patients changed their dizziness type. Many simultaneously endorsed multiple dizziness categories. In other studies, patients with benign paroxysmal positional vertigo (BPPV—the prototypical vestibular disorder, which “should” cause “vertigo”) often endorse lightheadedness (and not vertigo), and 37% of patients with cardiovascular causes of dizziness complain of vertigo (not lightheadedness). Finally, older ED dizzy patients’ use of the term “vertigo” as opposed to “dizziness” or “lightheadedness” does not correlate with a stroke diagnosis. Using the symptom quality approach in dizziness is akin to diagnosing a chest pain patient by asking, “What do you mean, chest pain?” Although “tearing” suggests aortic dissection, “pressure” myocardial ischemia, and “sharp” perhaps pleural or muscular inflammation, other elements of the history and examination are far more important. Is the chest pain intermittent or persistent? Do eating, exertion, or chest wall movement trigger it? Is it associated with fever and cough or leg pain and hemoptysis? On examination, are there unilateral diminished breath sounds and distended neck veins? So rather than base the evaluation of a dizzy patient purely on the symptom quality, using this same “timing and triggers” approach (that we use for every other chief complaint) is far more logical. In the same study in which patients changed their dizziness type 50% of the time, they were far more consistent about dizziness timing and triggers. Four timing and triggers patterns emerge: