Dizziness, Vertigo, and Hearing Loss



Dizziness, Vertigo, and Hearing Loss


J. Kirk Roberts



INTRODUCTION

Dizziness is an imprecise term used to describe a variety of symptoms including but not limited to vertigo, light-headedness, faintness, giddiness, disequilibrium, confusion, etc. It affects nearly one quarter of the general population and is a common complaint in the emergency room and in the office of the neurologist, otolaryngologist, and internist. The causes of dizziness are varied, span across medical subspecialties, and range from the relatively benign to life threatening. The evaluation of dizziness is made more difficult by the fact that the symptom is difficult for the patient to describe. A first step is an attempt to categorize dizziness into vertigo, presyncope, disequilibrium, and other or nonspecific dizziness as noted in Table 4.1.

Vertigo is an illusion of motion, either the environment or the self, most commonly rotatory but may be translational or tilting. Presyncope is the sensation encountered before loss of consciousness and is discussed in Chapter 5. Dysequilibrium is not a sensation of motion but a feeling of imbalance or unsteadiness and is discussed in Chapter 14. Other or nonspecific dizziness include those whose symptoms do not easily fit into one of the aforementioned categories or fall into more than one category. Rather than using the qualitative description of dizziness to categorize the subtype, it is often more helpful to use characteristics such as onset, duration, triggers, history of prior episodes, and associated symptoms in evaluating these patients.








TABLE 4.1 Dizziness Subtypes














































Vertigo


Presyncope


Disequilibrium


Nonspecific Dizziness


Symptom description


Illusion of motion, imbalance


Going to pass out, faint


Imbalance, unsteady, symptoms not in the head


Light-headed, foggy, floating


Onset


Usually sudden


Usually sudden


Sudden to slow


Poorly defined


Duration


Seconds to hours


Seconds to minutes


Acute to chronic


Subacute to chronic


Triggers


Head motion, position change


Orthostatic maneuvers, urination, cough, dehydration


Standing or walking, not when sitting or lying


Stress, situational, nonspecific


History


None or episodes


None or episodes


Chronic


Chronic


Associated symptoms


Nausea, ear symptoms (hearing loss, tinnitus), brain stem symptoms (diplopia, slurring, numbness, weakness, incoordination, ataxia)


Graying vision, warmth, diaphoresis, nausea, palpitations, chest pain


Slurring, incoordination


Many



VERTIGO


NEUROANATOMY

Vertigo primarily results from disorders of the vestibular system, which includes the vestibular labyrinth, vestibular nerve, vestibular nuclei in the brain stem, vestibular portions of the cerebellum, connections between these structures, and only rarely higher in the cerebrum. The vestibular labyrinth, located in the temporal bones, is composed of the three orthogonally oriented semicircular canals (anterior, posterior, and lateral) and the vestibule, which contains the otolith organs, the utricle and saccule, which are also angled at approximately 90 degrees to each other. The former responds to angular acceleration and the latter to linear acceleration including translation or tilt. When the head is rotated, endolymphatic fluid in the semicircular canals lags behind, leading to a deflection of the gelatinous cupula within the canal, which activates or inhibits the firing of hair cells. Activation on one side is paired with inhibition in the complementary canal on the other. The otolith organs, the utricle and saccule, contain hair cells on which calcium carbonate crystals, the otoconia, rest. Translational motion or tilt (via gravity) will activate or inhibit these cells. From the vestibular labyrinth, neurons travel centrally through the vestibular portion of the eighth cranial nerve into the brain stem to the vestibular nuclei and then project on to the cerebellum, ocular motor nuclei, spinal cord, and, via some less well understood pathways, to the
cerebrum. Integration of the combinations of activations and inhibitions of the various components of the vestibular system of both ears, along with visual input and proprioceptive input, detects motion, rotation, translation, and tilt and affects eye movements and posture.








TABLE 4.2 Peripheral versus Central Vertigo
























Peripheral


Central


Nausea/vomiting


Severe


Mild/moderate


Imbalance


Mild/moderate


Severe


Ear symptoms (hearing loss, tinnitus, pain)


Common


Rare


Other neurologic symptoms


Rare


Common


Vertigo can result from disorders of the peripheral vestibular system (labyrinth or nerve) or central vestibular system (brain stem, cerebellum, connections, and rarely, cerebrum) and this localization is the natural next step in the evaluation of vertigo. Table 4.2 lists some differentiating features.


MANAGEMENT STRATEGY

In the patient with the acute first presentation of vertigo, the most significant concern is evaluating for stroke (ischemic or hemorrhagic) and differentiating from vestibular neuritis. A history of vascular risk factors and other neurologic symptoms, headache, and complaints related to the brain stem is particularly important. However, the lack of those symptoms does not exclude an ischemic etiology. Patients presenting with isolated vertigo have a threefold increased risk of stroke compared to the general population that increases with the presence of multiple vascular risk factors. In the patient presenting with recurrent attacks of vertigo, the major differential includes benign positional paroxysmal vertigo (BPPV), Ménière syndrome, and migraines. Vertebral artery compression from neck rotation is a very rare case of episodic dizziness or vertigo.


FOCUSED HISTORY

Loss of vestibular function affects eye movements and image stabilization, balance, and spatial orientation. In addition to vertigo, patients may feel tilted, the world jiggling while walking (oscillopsia), spatially disoriented, imbalanced, and rarely, suffer from drop attacks, where they may feel pulled or pushed to the ground. These drop attacks, known as Tumarkin crises, are most commonly seen in Ménière syndrome but also may occur in other vestibular conditions.

Jul 27, 2016 | Posted by in NEUROLOGY | Comments Off on Dizziness, Vertigo, and Hearing Loss
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