- Education and Science
Vertigo is the state of being dizzy or lightheaded, caused by varying degrees of loss of equilibrium. True equilibrium is controlled by the labyrinthine and vestibular apparatus of the ear, the eyes, which transmit position information to the brain, the cortex of the brain, which coordinates position sense, the cerebellum, and finally the proprioceptive nerve fibers in tendons and muscles, which tell us the positions of our arms and legs without visual association.
Vertigo has always been a challenge to the clinician. The sufferer gives a varied history of attacks. He may have a mild dizzy or giddy feeling or he may have a more acute sense of objects rotating about him, associated with nausea and vomiting. This may cause him to stagger or even fall violently to the ground. The mechanism of this last type of vertigo centers in the labyrinths of the ear or the vestibular portion of the eighth nerve. Ocular causes of vertigo include paralysis of extra ocular muscles with double vision, or a temporary readjustment when the individual has acquired bifocal lenses. Direct brain involvement in the cortex or cerebellum is very rare and should be investigated by a trained neurologist when other more obvious causes have been ruled out.
There are a number of medical conditions which cause vertigo, most of which produce brain anoxia. Chronic pulmonary disease, such as emphysema, asthma, and pulmonary fibrosis, may cause repeated episodes of vertigo. Severe anemia, particularly pernicious anemia, is another cause. Patients with hypertension easily become dizzy or giddy, especially when there is a paroxysmal rise in blood pressure. Old, debilitated, or invalid patients are prone to become dizzy or black out when they change position from the reclining to the upright. This is called postural hypotension. Certain drugs produce vertigo by causing a chronic toxic labyrinthitis when used in large doses. These are quinine, salicylates, and streptomycin. Tension or hysterical states in which the individual hyperventilates and blows off his reserve supply of carbon dioxide can cause vertigo and fainting.
Of all the causes mentioned, labyrinthitis, or fluid and irritation in the middle and inner ear, is by far the most common reason for the vertigo sufferer to consult a doctor. Dehydration programs with ammonium chloride diuretics and salt restriction, heavy supplementary vitamin use of B12 and thiamine, control of nausea with Bonamine and Dramamine, and finally local ear attention generally relieve the symptoms.