Gastric Vertigo.—Trousseau certainly misled the profession as to the frequency of this form, but he did little more than represent popular medical views, and we may now feel sure that a good many so-called gastric vertigoes are due to lithæmia or to troubles of ear or eye. There are, I think, three ways in which the gastro-duodenal organs are related to the production of vertigo. Acute gastric vertigo arises in some persons inevitably whenever they eat certain articles, and the limitations are odd enough. Thus, I know a gentleman who cannot eat a mouthful of ice-cream without terrible vertigo, but otherwise his digestion is perfect. I know another in whom oysters are productive of vertigo within ten minutes; and a curious list might be added, including, to my knowledge, milk, eggs, oysters, crabs, etc. In these cases digestion is arrested and intense vertigo ensues, and by and by there is emesis and gradual relief.
In other cases, owing to over-feeding or any of the numerous causes of acute dyspepsia, an individual has a sudden attack of acid stomach, and as this gets to its worst he has alarming vertigo. In these cases the room whirls around or the pavement rocks; the balancing power is disturbed or lost; the sense of movement in the brain itself is sometimes felt; there are slight buzzing or humming sounds in one or both ears; there may be double vision, which comes and goes, while the power to think is lessened and the terror created is quite unendurable. At last come the sweat of nausea, emesis, and relief, with a gradual fading away of all the symptoms.
As a rule, such an attack need cause no uneasiness as to a fatal result, but, unless the case be handled with skill, it is apt to repeat itself with or without repetitions of the originating cause, until what I have called the status vertiginosus is created, and we have more or less steadily present a slight sense of defective balance, of confusion of mind, of blurred vision, and, more rarely, of slight noises in the ears. After two or three grave attacks, attacks are added for which the patient sees no cause. He lives in a state of constant terror, and the status vertiginosus attains its highest development, and may last for unlimited periods, while the brain becomes endowed with new morbid susceptibilities. To read, to write, to face sudden sunlight, to see moving bodies or passing crowds, cause vertigo. Loud sounds disturb the balance; even music will affect it. Emotions or any decided mental efforts are equally competent to bring on attacks, while fatigue or sudden changes of posture have to be alike avoided.
I have sketched an extreme case, but whatever causes grave vertigo is able to bring on the set of symptoms here described, which are, after all, more apt to be due to aural than gastric states.
Vertigo as a result of chronic dyspepsia in any of its forms is rare, and as a rule is less severe than that which grows out of acute gastric dyspepsia. The sensory symptoms are trifling, and the confusion of head and the lack of balance less notable, while the vertigo, which is more or less constant, seems to be most often met with two to four hours after meal-time, so that it is usually doubtful as to how much is due to reflected impressions from the digestive tracts, and how much to the direct influence of imperfect material in the circulation.
In a third form the gastro-intestinal tract is but indirectly concerned. In a person who is anæmic, or who is nervous and perhaps hysterical without being anæmic, but in whom it is impossible to detect in the stomach or bowels, in the feces or urine, any sign of defective digestion or of malassimilation, we find that during the act of digestion there is at some time, and in a few cases constantly, some transient but not grave vertigo.
This is due simply to the influence exerted on an over-sensitive head of a normal functional activity, which may act directly as any peripheral cause would act, or may be due, in the anæmic, with this to the withdrawing of blood from other parts of the body which occurs in digestion. It is an illustration of what is too often overlooked, the capacity of a healthy functional act to disturb morbidly a sensitive brain.
Aural Vertigo.—Vertigo may be due to a variety of irritative causes acting on the outer, middle, or inner ear. We shall consider them separately.
Vertigo from Causes acting on the External Ear.—In animals I have found that the injection of iced water or a rhigolene jet into the meatus is at once the cause of convulsive movements in the rabbit, and that repetitions of this cause at last a permanently vertiginous state, so that when a rabbit or guinea-pig thus disordered was shut up in darkness for some hours, sudden sunlight caused it to be for a few moments vertiginous. It is remarkable that while in birds many parts of the skin are competent under irritations (Weir Mitchell, Ott, Brown-Séquard) to give rise to vertiginous phenomena, in mammals only the skin of the external auditory meatus appears to be thus responsive. The author was himself the best illustration of this fact. Some years ago, when by mishap water at about 52° F. was thrown into his left ear, he fell instantly on his left side, with slight disturbance of vision, the room seeming to rock in the direction of the fall—that is, to the left. He arose with some difficulty, his head swimming, and with a distinct sense of lack of power in the whole left side, and with, for a half hour at least, an alarming tendency to stagger to the left.
Thus, injections of cool water in some cases (or in others of water at any temperature), and in certain persons very hot water, will cause vertigo. Foreign bodies—hardened wax, aspergillus, ulcers—or any inflammation may occasion it, while it is curious that usually the painful abscesses of the ear do not, especially in children, who are, as a rule, less liable to vertigo than are adults.