Chapter 13: Dizziness Assessment & Diagnosis

Dizziness Assessment & Diagnosis categorizes vertigo based on etiology—separating peripheral causes involving the inner ear and vestibular apparatus from central causes stemming from the brainstem or cerebellum, as well as systemic issues like cardiovascular or metabolic disorders. Key peripheral conditions are detailed, including Benign Paroxysmal Positional Vertigo (BPPV), which is attributed to canalithiasis and identified by brief, position-provoked episodes; Meniere disease, characterized by the classic triad of vertigo, sensorineural hearing loss, and tinnitus; and inflammatory conditions like vestibular neuronitis and labyrinthitis, distinguished by the presence or absence of auditory symptoms. The summary outlines the critical pathophysiology of central vertigo, often associated with vascular insufficiency, stroke, multiple sclerosis, or migraines, and notes that these presentations frequently include accompanying neurologic signs such as diplopia, ataxia, or paresthesia. The text explores diagnostic reasoning strategies, emphasizing the timing and duration of episodes to narrow the differential diagnosis—for instance, noting that episodes lasting seconds suggest BPPV, while those lasting hours or days may indicate Meniere disease or stroke. Physical examination techniques are extensively covered, focusing on the differentiation of nystagmus characteristics (peripheral nystagmus is typically unidirectional, horizontal-rotary, and fatigable with fixation, whereas central nystagmus may be vertical, immediate, and persistent). Essential clinical maneuvers are described, including the Dix-Hallpike maneuver as the reference standard for diagnosing BPPV, the Head Thrust test to assess the Vestibular Ocular Reflex (VOR), and evaluating orthostatic blood pressure to rule out hypotension. The chapter also reviews the utility of diagnostic studies such as audiometry, electronystagmography, and MRI, while addressing systemic contributors like psychogenic dizziness, neurosyphilis, and the impact of ototoxic or salt-retaining medications.