Dizziness

• A sense that you or your surroundings are spinning or moving (vertigo)
• A loss of balance
• Nausea
• Unsteadiness
• Wooziness
• Lightheadedness
• Faintness
• Weakness
• Fatigue
• Difficulty concentrating
• Blurred vision during quick head movements

Causes

Under normal circumstances, your sense of balance is controlled by a number of signals that your brain receives from several locations:

• Eyes. No matter what your position, visual signals help you determine where your body is in space and how it's moving.
• Sensory nerves. These are in your skin, muscles and joints. Sensory nerves send messages to your brain about body movements and positions.
• Inner ear. The organ of balance in your inner ear is the vestibular labyrinth. It includes loop-shaped structures (semicircular canals) that contain fluid and fine, hair-like sensors that monitor the rotation of your head. Near the semicircular canals are the utricle and saccule, which contain tiny particles called otoconia. These particles are attached to sensors that help detect gravity and back-and-forth motion.

Good balance depends on at least two of these three sensory systems working well. For instance, closing your eyes while washing your hair in the shower doesn't mean you'll lose your balance. Signals from your inner ear and sensory nerves help keep you upright.

However, if your central nervous system can't process signals from all of these locations, if the messages are contradictory or if the sensory systems aren't functioning properly, you may experience loss of balance.

Dizziness may have a number of potential causes, depending on the type of dizziness. The causes of dizziness may include:

Vertigo

Vertigo — the false sense of motion or spinning — is a common type of dizziness. Sitting up or moving around may make it worse. Sometimes vertigo is severe enough to cause nausea and vomiting.

Vertigo usually results from a problem with the nerves and the structures of the balance mechanism in your inner ear (vestibular system), which sense movement and changes in your head position. Abnormal rhythmic eye movements (nystagmus) almost always accompany vertigo. Causes of vertigo may include:

• Benign paroxysmal positional vertigo (BPPV). BPPV causes intense, brief episodes of vertigo immediately following a change in the position of your head, often when you turn over in bed or sit up in the morning. It occurs when normal calcium carbonate crystals (otoconia) break loose and fall into the wrong part of the canals in your inner ear. When these particles shift, they stimulate sensors in your ear, producing an episode of vertigo. Doctors don't know what causes BPPV, but it may be a natural result of aging. Trauma to your head also may lead to BPPV.
• Inflammation in the inner ear. Signs and symptoms of inflammation of your inner ear (acute vestibular neuronitis or labyrinthitis) include sudden, intense vertigo that may persist for several days, along with nausea, vomiting and imbalance. It can be incapacitating, requiring bed rest. Fortunately, vestibular neuronitis generally subsides and clears up on its own. Recovery time may be shorter with vestibular rehabilitation exercises and — if started within two days of symptom onset — a course of oral prednisone. Although the cause of this condition is unknown, it may be a viral infection.
• Meniere's disease. This disease involves the excessive buildup of fluid in your inner ear. It may affect adults at any age and is characterized by sudden episodes of vertigo lasting 30 minutes to an hour or longer. Other signs and symptoms include the feeling of fullness in your ear, buzzing or ringing in your ear (tinnitus), and fluctuating hearing loss. The cause of Meniere's disease is unknown.
• Migraine-related vertigo. Migraine is more than a headache disorder. Just as some people experience a visual "aura" with their migraines, others can get vertigo episodes and have other types of dizziness between migraines. Attacks of migraine-related vertigo can last from a few minutes to several days. If you are affected by migraine-related vertigo, you may be motion-sensitive as well, with a history of carsickness. Dizziness and vertigo caused by a vestibular migraine may be provoked by common migraine triggers, such as certain foods, altered sleep, stress, or hormonal changes related to your menstrual cycle. A vestibular migraine may cause feelings of imbalance or unsteadiness, hearing loss, "muffled" hearing, or ringing in your ears (tinnitus), sometimes mimicking Meniere's disease or other inner ear disorders. For most people with migraine-related vertigo, the attacks of vertigo don't necessarily happen at the same time as the headache.
• Acoustic neuroma. An acoustic neuroma (vestibular schwannoma) is a noncancerous (benign) growth on the vestibular nerve, which connects the inner ear to your brain. Signs and symptoms of an acoustic neuroma may include dizziness, loss of balance, hearing loss and tinnitus.
• Rapid changes in motion. Riding on roller coasters or in boats, cars or even airplanes may make you dizzy.
• Other causes. Rarely, vertigo can be a symptom of a more serious neurological problem such as a stroke, brain hemorrhage or multiple sclerosis.

Feeling of faintness (presyncope)

"Presyncope" is the medical term for feeling faint and lightheaded without losing consciousness. Sometimes nausea, pale skin and a sense of dizziness accompany a feeling of faintness. Causes of presyncope include:

• Drop in blood pressure (orthostatic hypotension). A dramatic drop in your systolic blood pressure — the higher number in your blood pressure reading — may result in lightheadedness or a feeling of faintness. It can occur after sitting up or standing too quickly.
• Inadequate output of blood from the heart. Conditions such as partially blocked arteries (atherosclerosis), disease of the heart muscle (cardiomyopathy), abnormal heart rhythm (arrhythmia) or a decrease in blood volume may cause inadequate blood flow from your heart.

Loss of balance (disequilibrium)

Disequilibrium is the loss of balance or the feeling of unsteadiness when you walk. Causes may include:

• Inner ear (vestibular) problems. Abnormalities with your inner ear can cause you to feel like you are floating, have a heavy head or are unsteady in the dark.
• Sensory disorders. Failing vision and nerve damage in your legs (peripheral neuropathy) are common in older adults and may result in difficulty maintaining your balance.
• Joint and muscle problems. Muscle weakness and osteoarthritis — the type of arthritis that involves wear and tear of your joints — can contribute to loss of balance when it involves your weight-bearing joints.
• Medications. Loss of balance can be a side effect of certain medications, such as anti-seizure drugs, sedatives and tranquilizers.

Lightheadedness and other kinds of 'dizziness'

Feeling lightheaded is the feeling of being "spaced out" or having the sensation of spinning inside your head. It can also give you the sensation that if your lightheadedness worsens, you might lose consciousness. Causes may include:

• Inner ear disorders. These abnormalities of your inner ear can lead to illusions of motion and make you feel like you're floating.
• Anxiety disorders. Certain anxiety disorders, such as panic attacks and a fear of leaving home or being in large, open spaces (agoraphobia), may cause dizziness. Sometimes one cause — such as a vestibular disorder — may produce symptoms, but then anxiety causes your dizziness to persist even after your inner ear problem has resolved.
• Hyperventilation. Abnormally rapid breathing that often accompanies anxiety disorders may make you feel lightheaded. 

Complications

Dizziness can increase your risk of falling and injuring yourself. Experiencing dizziness while driving a car or operating heavy machinery can increase the likelihood of an accident. You may also experience long-term consequences if an existing health condition that may be causing your dizziness goes untreated.

Diagnosis

Doctors can usually determine the cause of dizziness. To pinpoint what's causing your symptoms, you may be asked to perform positioning tests in the office so that your doctor can observe you and ask how you feel when you tip your head back or lie on a particular side.

You may need additional tests in a vestibular and balance laboratory, including:

• Posturography testing. This test tells your doctor which parts of the balance system you rely on the most and which parts may be giving you problems. You stand in your bare feet on a special platform and work to keep your balance under various conditions.
• Rotary-chair testing. During this test, you sit in a computer-controlled chair that moves very slowly in a full circle. At faster speeds, it moves back and forth in a very small arc.
• Eye movement testing. Your eye movements in response to certain stimuli also can provide helpful information in making a diagnosis. For example, your doctor may watch the path of your eyes when you track a moving object. You may also be given what's called a caloric test, in which the movement of your eyes is observed when cold and warm water are delivered to your ear canal at different times.

In some cases, you may need magnetic resonance imaging (MRI). This technique uses a magnetic field and radio waves to create cross-sectional images of your head and body. Your doctor can use these detailed, clear images to identify and diagnose a wide range of conditions. MRI may be performed to rule out acoustic neuroma - a noncancerous brain tumor of the vestibular nerve, which carries sound from the inner ear to the brain - or other abnormalities in the brain that may be the cause of vertigo.

Even if no cause is found or if your dizziness persists, prescription drugs and other treatments may make your symptoms more manageable.

Treatments and drugs

Doctors base treatment of dizziness on the cause and your symptoms.

• BPPV. Treatment of BPPV is with canalith repositioning, a simple procedure in which your doctor or physical therapist maneuvers the position of your head. This procedure is usually effective after one or two treatments.
• Inner ear conditions. Balance retraining exercises (vestibular rehabilitation) are used to treat acute vestibular neuronitis or labyrinthitis. These are exercises you learn from a physical therapist or occupational therapist and then do at home. To provide immediate relief of nausea and dizziness, your doctor may prescribe medications such as diazepam (Valium) or may recommend dimenhydrinate (Dramamine), available over-the-counter. A short course of corticosteroids may improve your vestibular function.
• Meniere's disease. Treatment of Meniere's disease involves reducing your body's retention of fluids through diuretic use and often dietary changes, such as a low-salt diet. Occasionally, surgery is an option.
• Migrainous vertigo. To combat vertigo associated with a vestibular migraine, your doctor will likely try to help you determine and avoid the triggers for your attacks, focusing on diet, stress, sleep and exercise. Certain medicines may help prevent attacks of migrainous vertigo or make them less uncomfortable by providing relief for nausea and vomiting. You may also learn specific exercises to help make your balance system less sensitive to motion (vestibular rehabilitation).
• Anxiety disorders. Your doctor may suggest medications and psychotherapy, either alone or in combination, to help you deal with your anxiety and manage your dizziness.

Lifestyle remedies

If you experience dizziness, consider these tips:

• Be aware of the possibility of losing your balance, which can lead to falling and serious injury.
• Fall-proof your home by removing tripping hazards such as area rugs and exposed electrical cords. Use nonslip mats on your bath and shower floors.
• Sit or lie down immediately when you feel dizzy.
• Avoid driving a car or operating heavy machinery if you experience frequent dizziness.
• Use good lighting if you get out of bed at night.
• Walk with a cane for stability.
• Avoid using caffeine, alcohol and tobacco. Excessive use of these substances can restrict your blood vessels and worsen your signs and symptoms.
• Work closely with your doctor to manage your symptoms effectively.

References:

https://en.wikipedia.org/wiki/Dizziness

http://www.healthline.com/symptom/dizziness

http://www.medicinenet.com/dizziness_dizzy/article.htm

https://www.hse.ie/eng/health/az/D/Dizziness/

http://www.emedicinehealth.com/dizziness/article_em.htm