|Classification and external resources|
Vertigo (from the Latin vertigin-, vertigo, "dizziness," originally "a whirling or spinning movement," from vertō "I turn") is a specific type of dizziness, a major symptom of a balance disorder. It is the sensation of spinning or swaying while the body is actually stationary with respect to the surroundings.
Vertigo is qualified as height vertigo when referring to dizziness triggered by heights. "Vertigo" is often used, incorrectly, to describe the fear of heights, but the correct term for this is acrophobia.
Vertigo is typically classified into one of two categories depending on the location of the damaged vestibular pathway.  These are peripheral or central vertigo. Each category has a distinct set of characteristics and associated findings.
The most common cause is benign paroxysmal positional vertigo (BPPV) but other causes include Ménière's disease, superior canal dehiscence syndrome, labyrinthitis and visual vertigo. Any cause of inflammation such as common cold, influenza, and bacterial infections may cause transient vertigo if they involve the inner ear, as may chemical insults (e.g., aminoglycosides) or physical trauma (e.g., skull fractures). Motion sickness is sometimes classified as a cause of peripheral vertigo.
Migraine headaches can also cause vertigo.
Central vertigo can also be caused by lateral medullary syndrome.
Vertigo is also a symptom of other illnesses such as multiple sclerosis.
If vertigo arises from the balance centers of the brain, it is milder, and has accompanying neurologic deficits, such as slurred speech, double vision or nystagmus. Alternately, brain pathology can cause a sensation of disequilibrium which is an off-balance sensation.
Discontinuation of antidepressant medication, also known as selective serotonin reuptake inhibitor discontinuation syndrome can result in a wide variety of withdrawal symptoms. Vertigo is a frequently found symptom, along with brain shivers, insomnia, nausea, confusion, imbalance, sweating, and many more as withdrawal symptoms are different for each individual.
Vertigo can also occur after long flights or boat journeys where the mind gets used to turbulence, resulting in a person's feeling as if he or she is moving up and down. This usually subsides after a few days. Another source of vertigo is through exposure to high levels of sound pressure, rattling the inner ear and causing a loss of balance.
Rarely, vertigo-like symptoms may appear as paraneoplastic syndrome (PNS) in the form of opsoclonus myoclonus syndrome, an extremely rare multi-faceted neurological disorder associated with many forms of incipient cancer lesions or viruses.
Also, it has been reported that Vertigo can be triggered by constant stress which continues over a long period of time. Constant high levels of stress can change the brain chemicals of Serotonin, Norepinephrine, and possibly Dopamine, causing vertigo symptoms such as: feeling like the room is spinning even when you're lying down, nystagmus, where your eyes have a rapid movement, difficulty focusing your eyes, difficulty concentrating, possible nausea, and anxiety. SSRI's that affect these brain chemicals, have been shown to relieve the vertigo symptoms of this particular type of vertigo.
Glutamate maintains the resting discharge of the central vestibular neurons, and may modulate synaptic transmission in all 3 neurons of the VOR arc. Acetylcholine appears to function as an excitatory neurotransmitter in both the peripheral and central synapses. GABA is thought to be inhibitory for the commissures of the medial vestibular nucleus, the connections between the cerebellar Purkinje cells and the lateral vestibular nucleus, and the vertical VOR.
Three other neurotransmitters work centrally. Dopamine may accelerate vestibular compensation. Norepinephrine modulates the intensity of central reactions to vestibular stimulation and facilitates compensation. Histamine is present only centrally, but its role is unclear. It is known that centrally acting antihistamines modulate the symptoms of motion sickness.
The neurochemistry of emesis overlaps with the neurochemistry of motion sickness and vertigo. Acetylcholine, histamine, and dopamine are excitatory neurotransmitters, working centrally on the control of emesis. GABA inhibits central emesis reflexes. Serotonin is involved in central and peripheral control of emesis but has little influence on vertigo and motion sickness.
Tests of auditory system (hearing) function include pure-tone audiometry, speech audiometry, acoustic-reflex, electrocochleography (ECoG), otoacoustic emissions (OAE), and auditory brainstem response test (ABR; also known as BER, BSER, or BAER).
Treatment is specific for the underlying cause of vertigo: