Why are you dizzy – an update

Why are you dizzy – an update – includes related articles

Dizziness is among the top five reasons for physician visits, especially among the elderly, but reassuringly it seldom signals a life-threatening disorder. In the vast majority of cases there is no worrisome reason for the dizziness. In one clinic, over a third of all dizziness investigated was attributed to stress, lack of sleep or emotional problems.

Dizzy spells different things to different people

People use the term “dizziness” to describe a wide variety of symptoms ranging from mental confusion, lightheadedness, whooziness or imbalance to faintness, weak legs or the spinning sensation known as vertigo. The challenge for doctors is to find out what people mean by dizziness and what causes it. Dizziness can arise from many causes, both psychological and organic — from anxiety, hyperventilation (rapid breathing), standing up quickly after lying down or from inner ear, neurological or cardiovascular disorders. Certain “ototoxic” medications can also cause dizziness — for instance, diuretics, antihypertensive (blood pressure) pills, some antibiotics (streptomycin and gentamicin), certain heart drugs, tranquillizers, sedatives and some antidepressants. Discontinuing the medication responsible can relieve the dizziness.

How the human body keeps its balance

In order to maintain the body’s balance in space and stand upright, three interacting sensory systems must work correctly — an ocular or visual component, the vestibular (balance) system and proprioceptive (touch) mechanisms that tell us where we stand relative to gravity. The inner ear’s vestibular (balance) system acts somewhat like a tiny gyroscope and has two main components — the semicircular canals and the otolithic organs (utricle and saccule) — which jointly monitor our position in space.

[CHART OMITTED]

Distinguishing vertigo from other types of dizziness

Although many people use the terms dizziness and vertigo interchangeably, they are not the same thing. Doctors distinguish between vertigo — a circling sensation — and other forms of dizziness. “While all vertigo is dizziness,” notes one University of Toronto specialist, “not all dizziness is vertigo.” Dizziness means general lightheadedness, imblance or just feeling faint. True vertigo, from the Latin “vertere,” to turn, is a distinct, often severe form of dizziness that’s a movement hallucination. It is aptly described as “a twirling sensation,” a feeling that “the room is swirling around one” or that one is “spinning in space.” Vertigo arises from abnormalities of the vestibular balance system — either inner ear (peripheral causes) or disruption of brain pathways (central causes).

Vertigo due to peripheral (inner ear) problems, accounting for about 85 per cent of cases, often starts suddenly, is severe, can last seconds or hours (as with Meniere’s disease) and is frequently accompanied by nausea, hearing loss and tinnitus or “ringing in the ears.” The nervous system compensates for the defect so that the vertigo remits or disappears.

Vertigo due to central disorders accounts for 15 per cent of cases, tends to appear gradually, may be long-lasting and is frequently accompanied by neurological symptoms such as numbness, swallowing difficulties, clumsiness or speech impairment. It may slowly worsen over time.

Vertigo is often accompanied by jerky, rhythmic to-and-fro eye movements called nystagmus. The direction of the eye jerks can reveal the cause of vertigo and whether it is due to an inner ear defect or brain disorder.

Dizziness in elderly people

Dizziness or unsteadiness (ataxia) is a common and sometimes serious problem in the elderly. In one study of individuals over age 60, 18 per cent had dizzy spells severe enough to interfere with daily activities. Dizziness in older people is often due to a circulation problem called vertebral basilar insufficiency, where arteries deliver too little blood to the brain stem and cause a momentary oxygen shortage. Or it can result from an inner ear disorder, sensory deficits or orthostatic hypotension (a drop in blood pressure). The unsteadiness predisposes to falls and bone fractures, which account for many accidental deaths in the elderly. The imbalance is worse in the dark when the eyes can’t assist balance and good lighting, especially a night-light, is essential.

How dizziness and vertigo are diagnosed

To discover the type and cause of dizziness, physicians take a thorough history, paying special attention to the first time it appeared. “It is not always easy to distinguish organic from psychological dizziness,” explains one specialist, “but in general, patients with psychogenic (psychological) dizziness tell a long, rambling story, while those with an organic cause or true vertigo describe the dizzy spells crisply, pinpointing their onset, duration and precipitating events.” Although dizzy people may have told their story to many doctors, it is essential to repeat it each time, as the events that precipitate the dizziness may give clues to its cause. For example, if turning over in bed or moving the head set off dizziness, it suggests positional vertigo. Dizziness from vasovagal causes is often traceable to anxiety (which affects the circulation).

Special tests for dizzy people

Following a complete history-taking, the ears, eyes and parts of the nervous system are examined. The ability of the eyes to follow an object (“pursuit”) is tested with careful examination for tell-tale eye-jerks. The physician may try to reproduce the dizzy attacks — for example, by having the person hyperventilate for 60 seconds. (If attacks occur when hyperventilating, psychological causes are frequently responsible.)

In those with true vertigo, the physician will try to trace the defect, test for hearing loss and nervous system dysfunction. If there is a suspicion that vertigo arises from an inner ear problem, a hearing test (audiogram) and a special balance test called the electronystagmogram (ENG) may be done. The ENG involves caloric (heat) stimulation with water of different temperatures to determine whether there’s any loss of the inner ear’s balance mechanism. Dynamic posturography is a method in which the dizzy person, attached to recording electrodes, is rotated on a movable platform to try and localize the cause of dizziness. If there are hints of a neurological abnormality, imaging (MRI) may be advised.

Treatments for dizziness

Treatment depends on the diagnosis, but first and foremost, dizzy people need reassurance that the problem is usually not serious or life-threatening. For those with psychogenic or anxiety-provoked dizziness, the best remedy is to avoid precipitating factors and to provide reassurance and possibly a mild sedative or tranquilizer. Those with stress-related dizziness need encouragement to “worry less,” perhaps take relaxation courses and improve sleep habits.

Vestibular neuronitis may respond to antinanuseants and drugs such as meclizine. Dizziness from inner ear disorders often has long periods of remission between attacks, requiring no treatment. Those with acute attacks of vertigo are advised to rest during the episode and take an appropriate (prescribed) sedative until the attack subsides. For Meniere’s disease, salt-restriction and diuretics may help.

People with BPPV (see sidebar) or positional vertigo may benefit from special head-tilting exercises, done several times daily, that purposely bring on and “fatigue” the vertigo so that the dizzy spells resolve faster. Another recently suggested treatment employs special, physician-guided head movements or “liberating manoeuvres” that try to displace the inner ear’s malpositioned crystals thought to cause the dizziness.

Medications that diminish some types of dizziness include antinauseants — such as Gravol, antihistamines — such as meclizine (Antivert) and dimenhydrinate (Dramamine), phenothiazines such as chlorpromazine and tranquillizers — such as the benzodiazepines.

Surgery may be considered for serious cases of vertigo and includes various operations on the inner ear’s balance structures or the more drastic labyrinthectomy that totally destroys the inner ear’s vestibular organs and banishes dizziness, but also abolishes hearing in that ear.

Chemical ablation of the inner ear’s balance system is occasionally tried, using agents that preferentially destroy the balance structures (semicircular canals and otoliths), leaving hearing intact. But great care is needed for the procedure.

For more information, consult your family physician or perhaps a dizziness clinic (at some large hospitals) such as the Multidisciplinary Neurology Clinic at the Toronto Hospital or the Dizziness Clinic at Sunnybrook Health Sciences Centre (tel. no: 416/480-4138). For a more detailed chart about dizziness, call the Health News office.

Main categories of dizziness

Vertigo — a swirling, “merry-go-round” sensation — usually due to peripheral (inner ear) or central (brain) abnormalities.

Near-syncope or presyncope (a near-faint or sense of an impending faint) without loss of consciousness. This mild form of dizziness is often due to orthostatic hypotension (a momentary drop in blood pressure that lessens bloodflow to the brain), sometimes experienced in young adults when suddenly arising from a lying position. It can also result from heart problems, diabetic hypoglycemia (low blood sugar), vasovagal attacks (due to fear, which affects the circulation) or from certain medications.

Dysequilibrium — imbalance or unsteadiness — most frequent in the elderly, can stem from multiple causes including ear defects, a recent cataract operation or the deterioration of sensory pathways. Typically, the unsteadiness occurs only when standing or walking and may contribute to falls in older people.

Lightheadedness — a vague or confused sensation — can arise from stress, anxiety or other psychological disturbances, or through hyperventilation (rapid breathing that lowers the blood’s [CO.sub.2] content and constricts cerebral blood vessels).

Types and causes of vertigo

Benign positional paroxysmal vertigo, BPPV for short, is the commonest form of vertigo, with attacks lasting 30-60 seconds, typically set off when rolling over in bed, moving the head to one side or reaching for something (“top-shelf vertigo”). Sufferers can usually describe specific head movements that trigger it, perhaps several times a day. Although BPPV often occurs for no known reason, it can follow an ear infection, a head or ear injury and is thought to result from the dislodgement of normal crystalline structures in the ear’s balance detectors. People with BPPV are often relieved to learn that it’s due to an inner ear condition and does not signify some serious disorder such as a stroke or tumour. Dizziness from BPPV usually fades in a few months without any treatment. Special head exercises can help to “fatigue” the response, mute the dizzy spells and speed recovery.

Vestibular neuritis (or neuronitis), arising from viral infections (perhaps following a cold, flu or middle ear infection) that affect the eighth cranial nerve may produce sudden vertigo, often accompanied by nausea, but no hearing loss, usually lasting one to three weeks. After recovery, a slight feeling of fullness in the ear and dizziness may persist for weeks to months.

Acute labyrinthitis resembles vestibular neuronitis.

Meniere’s disease, thought to arise from abnormal fluid accumulation in the inner ear, produces episodic attacks of intense vertigo — perhaps lasting several hours — accompanied by fullness in the ear, tinnitus and some hearing loss, usually just on the affected side. (For more on Meniere’s disease, see Health News, August 1988.)

A perilymph fistula or abnormal channel between the middle and inner ear — perhaps due to pressure changes, a head-blow, whiplash or other injury — is a rare cause of vertigo.

Central nervous system disorders that cause vertigo as a symptom include: multiple sclerosis, epilepsy (temporal lobe types), neck injuries, certain forms of migraine, acoustic neuroma (benign tumour on the auditory nerve), cerebellar and brain stem tumours, and TIAs (transient ischemic attacks or “mini strokes”).

COPYRIGHT 1994 Strategic Inc. Communications Ltd.

COPYRIGHT 2004 Gale Group