A condition in which the affected person loses the power of balancing him or herself, and has a false sensation as to their own movements or those of surrounding objects (‘giddiness’). The sense of balance depends upon sensations derived partly through touch, partly from the eyes, but mainly from the semicircular canals of the internal EAR – the vestibular mechanism. In general, vertigo is due to some interference with this vestibular ocular reflex mechanism or with the centres in the cerebellum and cerebrum (see BRAIN) with which it is connected. It is often associated with headache, nausea and vomiting.
The simplest cause of vertigo is some mechanical disturbance of the body affecting the fluid 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) occurring with any 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 repeatedly. 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 (inflammation of the labyrinth of the ear) may result from viral infection and produce a severe vertigo lasting 2–5 days. Because it occurs in epidemics it is often called epidemic vertigo. Vertigo is sometimes produced by the removal of wax from the ear, or by syringing out the ear. (See EAR, DISEASES OF.)
A severe upset in the gastrointestinal tract may cause vertigo. Refractive errors in the eyes, MIGRAINE, 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.
While the attack lasts, this requires the sufferer to lie down in a darkened, quiet room. SEDATIVES have most influence 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, ANTIHISTAMINE DRUGS and PHENOTHIAZINES – for example, prochlorperazine – are often prescribed in preventing and treating these disorders. Cinnarizine and betahistine have been marketed as effective drugs for Menière's disease; for acute attacks, cyclizine or prochlorperazine given by intramuscular injection or rectally can be of value. (see also EPLEY'S MANOEUVRE.)