n. 1. the small dome at the end of the cochlea. 2. any of several dome-shaped anatomical structures.
Causes The simplest cause of vertigo is some mechanical disturbance of the body affecting the ?uid in the internal ear; such as that produced by moving in a swing with the eyes shut, the motion of a boat causing sea-sickness, or a sudden fall. (See also MOTION (TRAVEL) SICKNESS.)
Another common positional variety is benign paroxysmal positional vertigo (BPPV) caused by sudden change in the position of the head; this causes small granular masses in the cupola of the posterior semicircular canal in the inner ear to be displaced. It may subside spontaneously within a few weeks but can recur. Sometimes altering the position of the head so as to facilitate return of the crystals to the cupola will stop the vertigo.
The cause which produces a severe and sudden giddiness is MENIÈRE’S DISEASE, a condition in which there is loss of function of the vestibular mechanism of the inner ear. An acute labyrinthitis – in?ammation of the labyrinth of the ear – may result from viral infection and produce a severe vertigo lasting 2–5 days. Because it often occurs in epidemics it is often called epidemic vertigo. Vertigo is sometimes produced by the removal of wax from the ear, or even by syringing out the ear. (See EAR, DISEASES OF.)
A severe upset in the gastrointestinal tract may cause vertigo. Refractive errors in the eyes, an attack of MIGRAINE, a mild attack of EPILEPSY, and gross diseases of the brain, such as tumours, are other causes acting more directly upon the central nervous system. Finally, giddiness may be due to some disorder of the circulation, for example, reduced blood supply to the brain produced by fainting, or by disease of the heart.
Treatment While the attack lasts, this requires the sufferer to lie down in a darkened, quiet room. SEDATIVES have most in?uence in diminishing giddiness when it is distressing. After the attack is over, the individual should be examined to establish the cause and, if necessary, to be given appropriate treatment.
Vertigo and nausea linked to Menière’s disease – or following surgery on the middle ear – can be hard to treat. HYOSCINE, ANTI HISTAMINE DRUGS and PHENOTHIAZINES – for example, prochlorperazine – are often e?ective in preventing and treating these disorders. Cinnarizine and betahistine have been marketed as e?ective drugs for Menière’s disease; for acute attacks, cyclizine or prochlorperazine given by intramuscular injection or rectally can be of value. Research in America is exploring the use of virtual-reality technology to change subjects’ visual perception of the outside world gradually during several 30-minute sessions, helping them to adjust to the abnormal sensations that occur during an attack. Early results are promising.... vertigo
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