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PATIENT 
Mrs. S is a 70-year-old woman with a history of depression and anxiety who complains of dizziness. Over the last 1–2 months she notes increasing intermittent dizziness. When asked to describe her dizziness in more detail, she has trouble and describes neither vertigo, near syncope, nor dysequilibrium. She does mention that it seems to be worse while standing. Mrs. S has also been under more stress than usual. Her daughter died several years ago and her husband has been chronically ill and is scheduled for surgery next month.
At this point, what is the leading hypothesis, what are the active alternatives, and is there a must not miss diagnosis? Given this differential diagnosis, what tests should be ordered?
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RANKING THE DIFFERENTIAL DIAGNOSIS
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Mrs. S has described ill-defined light-headedness (Figure 14-1). Identifying the cause in such patients is complex because it can arise from neurologic, cardiac, or inner ear diseases; be due to orthostatic hypotension; or be a symptom of depression and anxiety (Figure 14-7). Her psychiatric history and social stressors are a clue suggesting she may be suffering from nonspecific dizziness due to depression, anxiety, or her social stressors. This is the leading hypothesis. Additionally, Mrs. S mentioned that her symptoms are worse while standing, raising the possibility of orthostatic hypotension. Finally, nonspecific dizziness is frequently caused by medications. Table 14-6 lists the differential diagnosis.
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Mrs. S readily admits to a loss of interest in her activities and anhedonia. Her only medication is a bisphosphonate for her osteoporosis that she has been taking for years.
Is the clinical information sufficient to make a diagnosis? If not, what other information do you need?
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Mrs. S. history further increases your suspicion that her symptoms are better classified as nonspecific dizziness due in turn to her active depression. She has no incriminating medications.
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Mrs. S confirms your suspicion that she is depressed and you feel that this is the likely cause of her nonspecific dizziness. You still wonder if she might have orthostatic hypotension.
Have you crossed a diagnostic threshold for the leading hypothesis, nonspecific dizziness? Have you ruled out the active alternatives? Do other ...