Medical Excellence- Issue 1

Dizziness: An Evidence-Based Approach (Better Than MRI?) Jonathan A. Edlow Case Presentation A 45-year-old patient with a history of well-controlled hyperten- sion and mildly elevated cholesterol comes to the emergency de- partment (ED) for 8 h of continuous dizziness that began rapidly. The patient describes severe light-headedness. There is no head- ache or neck pain. Vital signs and general physical examination are normal. On examining the eyes, horizontal nystagmus that beats toward the left is present. Skew deviation is absent. On head impulse testing, there is a corrective saccade when moving toward the right. The remainder of the neurological examination is normal. Introduction Approximately 3.5% of emergency department (ED) visits are for dizziness [1, 2]. Numerous conditions, some benign and self- limiting and others extremely serious, can present with dizziness. This is a classic emergency medicine—sorting out the large ma- jority of patients with a given chief complaint who have a self- limiting or easily treatable condition from the smaller number that have life-, limb-, or brain-threatening problems. As of 2013, the direct ED-related costs of care for patients with dizziness in the USA were estimated to approach $4 billion [3]. In addition to economic, there is additional “cost” both in terms of patient- experienced anxiety and falls, attributed to dizziness, with their resultant morbidity. The existing paradigm for diagnosing dizziness is based on “symptom quality” (i.e., asking the question “what do you mean ‘dizzy’?”). This approach is taught in nearly all review articles and textbooks across specialties; however, newer research has shown that its scientific basis and its internal logic lack foundation. Currently, misdiagnosis in patients with dizziness is a problem in an environment that is paying increasing attention to diagnostic errors [4]. Misdiagnosis of patients with cerebel- lar stroke can have disastrous consequences [5]. This article will review the differential diagnosis of acute dizziness in adult pa- tients, discuss newer research about the diagnosis of dizziness, and suggest a modern evidence-based approach. The new approach emphasizes history and physical exami- nation that will hopefully lead to emergency physicians more frequently and confidently making a specific diagnosis. When a confident diagnosis is made of a peripheral problem, time- consuming consultation, expensive imaging, and hospitalization become unnecessary. When the evaluation suggests a central problem, especially stroke, steps can be taken to diagnose and treat the offending vascular lesion and institute secondary pre- vention measures. This new approach to the ED patients with dizziness should improve diagnostic accuracy and reduce length of stay and re- source utilization and would be expected to improve overall patient outcomes. Differential Diagnosis of Acute Dizziness Numerous disorders and conditions that span multiple organ systems can present with acute dizziness. Many of these diag- noses are benign; others are life-threatening. A study from the NHAMCS patient database over a 13-year period identified 9472 patients with dizziness [2]. These data suggest that most patients have general medical (including cardiovascular) diag- noses (~50%), oto-vestibular diagnoses (~33%), and neurologic (including stroke) diagnoses (~11%) [2, 6]. Studies of large administrative databases have the limita- tion that the accuracy of the charted diagnosis is unknown. In the NHAMCS study, 22% of patients received a “symptom only” diagnosis (e.g., dizziness, not otherwise specified). Although as- signing a diagnosis of the presenting symptom is common in emergency medicine practice, a “symptom only” diagnosis was three times more common in dizzy patients than in all other pa- tients. In addition, even if a specific vestibular diagnosis is made, J.A. Edlow, M.D., F.A.C.E.P Professor of Medicine and Emergency Medicine, Harvard Medical School, Vice-chair, Department of Emergency Medicine, Beth Israel Deaconess Medical Center, Boston MA, USA e-mail: jedlow@bidmc.harvard.edu Issue-1  |  1 MEDICAL EXCELLENCE