Chapter 022. Dizziness and Vertigo (Part 4)

In Ménières disease, the direction of the fast phase is variableVertigo maybe a manifestation of a migraine aura (Chap. 15), but some patients with migraine have episodes of vertigo unassociated with their headaches. Antimigrainous treatment should be considered in such patients with otherwise enigmatic vertiginous episodes.Vestibular epilepsy, vertigo secondary to temporal lobe epileptic activity, is rare and almost always intermixed with other epilepticmanifestations.Psychogenic VertigoThis is sometimes called phobic postural vertigo and is usually a concomitant of panic attacks (Chap. 386) or agoraphobia (fear of large open spaces, crowds, or leaving the safety of home).It should be suspected in patients...
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Chapter 022. Dizziness and Vertigo (Part 4) Chapter 022. Dizziness and Vertigo (Part 4) a In Ménières disease, the direction of the fast phase is variableVertigo maybe a manifestation of a migraine aura (Chap. 15), but some patients with migrainehave episodes of vertigo unassociated with their headaches. Antimigrainoustreatment should be considered in such patients with otherwise enigmaticvertiginous episodes. Vestibular epilepsy, vertigo secondary to temporal lobe epileptic activity, israre and almost always intermixed with other epilepticmanifestations.Psychogenic Vertigo This is sometimes called phobic postural vertigo and is usually aconcomitant of panic attacks (Chap. 386) or agoraphobia (fear of large openspaces, crowds, or leaving the safety of home). It should be suspected in patients so incapacitated by their symptoms thatthey adopt a prolonged housebound status. Most patients with organic vertigoattempt to function despite their discomfort. Organic vertigo is accompanied bynystagmus; a psychogenic etiology is almost certain when nystagmus is absentduring a vertiginous episode. The symptoms often develop after an episode ofacute labyrinthine dysfunction. Miscellaneous Head Sensations This designation is used, primarily for purposes of initial classification, todescribe dizziness that is neither faintness nor vertigo. Cephalic ischemia orvestibular dysfunction may be of such low intensity that the usualsymptomatology is not clearly identified. For example, a small decrease in blood pressure or a slight vestibularimbalance may cause sensations different from distinct faintness or vertigo butthat may be identified properly by provocative testing techniques (see below). Other causes of dizziness in this category are hyperventilation syndrome,hypoglycemia, and the somatic symptoms of a clinical depression; these patientsshould all have normal neurologic examinations and vestibular function tests.Depressed patients often insist that the depression is secondary to the dizziness. Approach to the Patient: Dizziness and Vertigo The most important diagnostic tool is a detailed history focused on themeaning of dizziness to the patient. Is it faintness (presyncope)? Is there asensation of spinning? If either of these is affirmed and the neurologic examination is normal,appropriate investigations for the multiple causes of cephalic ischemia, presyncope(Chap. 21), or vestibular dysfunction are undertaken. When the meaning of dizziness is uncertain, provocative tests may behelpful. These office procedures simulate either cephalic ischemia or vestibulardysfunction. Cephalic ischemia is obvious if the dizziness is duplicated duringmaneuvers that produce orthostatic hypotension. Further provocation involves theValsalva maneuver, which decreases cerebral blood flow and should reproduceischemic symptoms. Hyperventilation is the cause of dizziness in many anxious individuals;tingling of the hands and face may be absent. Forced hyperventilation for 1 min isindicated for patients with enigmatic dizziness and normal neurologicexaminations. The simplest provocative test for vestibular dysfunction is rapid rotationand abrupt cessation of movement in a swivel chair. This always induces vertigothat the patients can compare with their symptomatic dizziness. The intense induced vertigo may be unlike the spontaneous symptoms, butshortly thereafter, when the vertigo has all but subsided, a lightheadednesssupervenes that may be identified as my dizziness. When this occurs, the dizzy patient, originally classified as suffering frommiscellaneous head sensations, is now properly diagnosed as having mildvertigo secondary to a vestibulopathy. Patients with symptoms of positional vertigo should be appropriately tested(Table 22-1). A final provocative and diagnostic vestibular test, requiring the useof Frenzel eyeglasses (self-illuminated goggles with convex lenses that blur outthe patients vision, but allow the examiner to see the eyes greatly magnified), isvigorous head shaking in the horizontal plane for about 10 s. If nystagmus develops after the shaking stops, even in the absence ofvertigo, vestibular dysfunction is demonstrated. The maneuver can then berepeated in the vertical plane. If the provocative tests establish the dizziness as avestibular symptom, an evaluation of vestibular vertigo is undertaken.