Medical Excellence- Issue 1

Taken as a whole, these data suggest the following conclusions: 1. Most adult patients who present to the ED with acute dizzi- ness have general medical or cardiovascular conditions. 2. Although benign vestibular diseases are much more common than CNS causes of dizziness, when emergency physicians make these (benign) diagnoses, their use of imaging and meclizine is not in accordance with the best available evidence. 3. Of the CNS causes, acute cerebrovascular disease (isch- emic stroke or transient ischemic attack [TIA]) is the most common cause, and misdiagnosis in the ED is not uncom- mon in these patients. Origin of the “Symptom Quality” Approach to Diagnosing Dizziness and its Lack of Scientific Validity A publication in 1972 led to the “symptom quality” approach to the acutely dizzy patient [20]. Over a 2-year period, the authors enrolled 125 patients. The study suffers from several shortcomings that include a low number of patients, the fact that most patients were not evaluated during the acute phase of their illness, no veri- fication of diagnosis, no long-term follow-up, and others (Table 2). This study was the basis for the traditional approach to dizziness that starts by asking the patient, “What do you mean by ‘dizzy’?” For this “symptom quality” approach to work, two facts must be true. First, patients should be able to reliably and con- sistently choose one (and only one) dizziness type. Secondly, each symptom type should be tightly linked with a given differ- ential diagnosis. Both facts are demonstrably false [21]. Patients do not choose a single dizziness type. Sensory symptoms are difficult for many patients to describe. Patients with dizziness may use words like, “dizzy,” “light-headed,” “spin- ning,” “rocking,” “vertigo,” “giddy,” “like I’m going to faint,” “off- balance,” “spacey,” and others to describe what they feel. For this paper, I will use the word “dizziness” in a general way (incorpo- rating all of these descriptors). In a study published in 2007, research assistants asked a series of ED patients with dizziness a battery of questions aimed at determining “symptom quality” and timing and triggers of the dizziness [22]. Over 60% of the patients chose more than one dizziness type. The questions were then re-asked in a different sequence an average of 6 min later; more than 50% of the patients changed their primary dizziness type. The responses to timing and triggers of dizziness were much more consistent and reliable between the first and second responses. Thus, the history should be taken just as one does with a patient with chest pain or dyspnea. One does not evaluate a patient with chest pain differently if the pain is described as “sharp” or “dull” or “discomfort” or “pressure” [21]. One does not use the descriptor of the pain in a binary way; the timing and triggers are more important in rank-ordering a differential diag- nosis. We take histories of virtually all chief complaints using the concept of timing and triggers. Another concept that physicians use regularly to con- struct a differential diagnosis is that of context and presence or absence of associated symptoms. One thinks very differently about a patient with chest pain associated with: (a) leg swelling and dyspnea, (b) productive cough and fever, or (c) hypoten- sion, unilaterally diminished breath sounds, and distended neck veins. It is not simply the word that the patient uses that informs the differential diagnosis but also the timing, triggers, associated symptoms, and epidemiologic context. It should be no different with dizziness. Finally, the differential diagnosis is not tightly linked with a given use of the descriptors. The use of the word “vertigo” was not associated with a higher incidence of stroke in a large series of ED patients with dizziness [23]. Patients with a cardiovas- cular cause of dizziness do endorse “vertigo” in almost 40% of cases [24]. Patients with BPPV often say they feel light-headed and not vertiginous, especially elderly patients [25]. The reality is that the differential diagnosis should not be based on the word but rather on the timing, triggers, associated symptoms, and the epidemiologic context. Despite the fact that the “symptom quality” approach to diz- ziness is not based on strong science, it is the predominant para- digm used across specialties. Misdiagnosis of Patients with Dizziness and Resource Utilization Misdiagnosis of patients with dizziness is common. In the German ED study, neurologists seeing patients made diagnostic errors in 44% of patients. The authors of that study found three factors that contributed to misdiagnosis [14]. First, subsequent clinical course evolved, making the ultimate diagnosis more clear. This factor played a role in 70% of misdiagnoses. This is a regular event in emergency medicine, in which we see patients whose symptoms evolve in a variable way even over hours. The other two factors were insufficient brain imaging (mostly MRI, found to be a factor in half of cases) and failure to screen for vas- cular risk factors using advanced testing such as echocardiogra- phy, telemetry, or ultrasound of cervical arteries (24% of cases). There has never been a head-to-head comparison of emergency physicians versus neurologists diagnosing patients with dizziness at the same phase of care (and likely never will), but this German study clearly shows that dizziness is complicated, even to those with specialized training and focus. Issue-1  |  3 MEDICAL EXCELLENCE