________________________________________________________________________ Dizziness and Vertigo
Unlike t-EVS, dizziness episodes in s-EVS cannot be provoked and diagnostic evaluation relies almost entirely on patient his- tory [36]. Vestibular migraine is the most common cause of s-EVS, with a population prevalence of roughly 1% [36]. The classical Ménière disease symptom triad of episodic vertigo, unilateral tinnitus and aural fullness, and reversible sensori- neural hearing loss is initially present in only 25% of patients. Patients with suspected Ménière disease should generally be referred to an otolaryngologist, but care should be taken to avoid missing TIA mimics with audio-vestibular symptoms [36]. Reflex (vasovagal) syncope is also a common cause. In reflex syncope, episodes of near-syncope without loss of conscious- ness substantially outnumber true syncope. Patients usually have prodromal symptoms for 3 to 30 minutes, most commonly dizziness (70% to 75% of cases) that can manifest in vertigo. Diagnosis is based on clinical history, exclusion of dangerous mimics (especially cardiac arrhythmia), and confirmation (if needed) by formal head-up tilt table testing [8; 36]. s-EVS has been reported in panic attacks; episodes begin rapidly, usually peak within 10 minutes, and are accompanied by additional autonomic, cognitive, and perceptual symptoms. Panic attacks can be precipitated by situational stress, such as airplane travel, but often occur spontaneously [116]. Panic attack mimics include ictal panic attacks from temporal lobe epilepsy that usually last seconds with altered mental status, hypoglycemia, cardiac arrhythmias, and basilar TIA, which can produce dizziness and neurologic and autonomic features [8]. Another cause of s-EVS is vestibular paroxysmia, a condition that should be considered when the patient reports 10 or more spontaneous vertigo attacks per day lasting less than one minute (sometimes mere seconds). These attacks respond to a carbamazepine or oxcarbazepine trial [44]. The most common dangerous causes of s-EVS are vertebrobasi- lar TIA and cardiac arrhythmias. Less commonly, episodes have been observed with other cerebrovascular (e.g., subarachnoid hemorrhage), cardiorespiratory (e.g., unstable angina, pulmo- nary embolus), and endocrine (e.g., hypoglycemia) disorders. Carbon monoxide exposure is a rare serious cause [36]. Vestibular symptoms associated with s-EVS cannot be repro- duced by bedside examination, and patients may be asymptom- atic by the time they present to outpatient care. The history is used to distinguish vestibular migraine from TIA or other causes. Diagnosis of benign s-EVS causes can be clear-cut in typical cases, but as mentioned, classical features of vestibular migraine, vasovagal syncope, Ménière disease, or panic attacks are often absent [36].
According to the American Academy of Otolaryngology, if the patient has a history compatible with BPPV and the Dix-Hallpike test exhibits horizontal or no nystagmus, the clinician should perform, or refer to a clinician who can perform, a supine roll
test to assess for lateral semicircular canal BPPV. (http://journals.sagepub.com/doi/pdf/10.1177/ 0194599816689667. Last accessed September 30, 2024.) Strength of Recommendation : Recommendation (Benefits exceed the harms, but the quality of evidence is not as high) The Dix-Hallpike maneuver also provokes vertigo and nystag- mus in BPPV affecting the anterior canal (ac-BPPV), which shows downbeating nystagmus, sometimes with a torsional component, toward the affected ear. Downbeating positional nystagmus may reflect brainstem or cerebellar lesion, which should be ruled out [20; 39]. BPPV can also mimic orthostatic hypotension by producing dizziness on arising and often goes undiagnosed in the elderly. Serious Causes of Orthostatic Hypotension As noted, vertigo is a common but under-appreciated symptom in orthostatic hypotension. Older patients taking antihyperten- sives can show incidental orthostatic hypotension. Orthostatic dizziness and hypotension are not always related; orthostatic dizziness without systemic orthostatic hypotension may indi- cate hemodynamic TIA or intracranial hypotension [8]. Serious causes of orthostatic hypotension include fluid loss from bleeding, vomiting, diarrhea, and excessive urination/ sweating. Occult internal bleeding is the primary dangerous concern [2]. Concomitant chest, back, abdominal, or pelvic pain suggests an intrathoracic or intra-abdominal emergency [36]. Myocardial infarction, occult sepsis, adrenal insufficiency, or diabetic ketoacidosis may present with severe orthostatic hypotension without other overt signs [8]. Spontaneous EVS s-EVS is marked by recurrent, spontaneous episodes of dizzi- ness that range in duration from seconds to days, with most lasting minutes to hours. Spells sometimes occur up to several times per day, but they are usually less frequent and can be separated by months or even years, depending on etiology [8].
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