VERTIGO, OR GIDDINESS.
Vertigo, or giddiness, though unattended with pain, is, in general, of a more dangerous nature than the severest headach. Vertigo consists in a disturbance of the voluntary power, and in some degree of sensation, especially of vision; and thus it shows itself to be an affection of the brain itself; while mere pain in the head does not necessarily imply this, it being for the most part an affection of the membranes only. In vertigo, objects that are fixed appear to be in motion, or to turn round, as the name implies. The patient loses his balance, and is inclined to fall down. It often is followed immediately by severe headach. Vertigo is apt to recur, and thus often becomes frequent and habitual. After a time the mental powers become impaired, and complete idiocy often follows; as was the case in the celebrated Dean Swift. It frequently terminates in apoplexy or palsy, from the extension of disease in the brain.
Causes.—Vertigo is induced by whatever is capable of disturbing suddenly the circulation of the brain, whether in the way of increase or diminution: thus the approach of syncope, whether produced by loss of blood, or a feeling of nausea; blows on the head, occasioning a concussion of the brain; stooping; swinging; whirling; or other unusual motions of the body, as in sailing, are the ordinary exciting causes of the disease. Vertigo is exceedingly frequent at an advanced period of life, and generally indicates the approach and formation of disease in the brain. Accordingly, it is a frequent forerunner of apoplexy and palsy.
The immediate or proximate cause of giddiness, or vertigo, that is, the actual condition of the brain at the moment, is probably some partial disturbance in the circulation there; which all the occasional causes mentioned are obviously calculated to produce. It is more or less dangerous, according to the cause inducing it, and the state of the brain itself, which may be sound or otherwise. And as this cannot be certainly known, nor the extent of it when actually present, the event is of course uncertain. At all times, your prognosis should be guarded; because vertigo seldom occurs under favourable circumstances of age and general health; unless when produced by so slight a cause as bloodletting, or a trifling blow upon the head. Whenever vertigo recurs frequently, and at an advanced period of life; and more particularly when it is accompanied with drowsiness; weakness of the voluntary muscles; impaired memory, or judgment; or, in short, any other disturbance or imperfection in the state of the sensorial functions; an unfavourable result is to be expected; because all these afford decisive evidence of a considerable degree and extent of disease in the brain—Dr. Clutterbuck's Lectures on the Nervous System.