Definition.—Hyperemia of the brain is an abnormal amount of blood in the cerebral capillaries, and may be active or passive.
Active Hyperemia.—This probably attends any increase in the general circulation,-and is found in greater or less degree in all inflammatory diseases. It may follow prolonged exposure to the sun, to the ingestion of certain drugs, notably nitroglycerin, amyi nitrate, and alcohol. Excessive brain-work will give rise to cerebral hyperemia, while not infrequently the cause is reflex. The infections that are attended by restlessness, delirium, or other cerebral disturbances, also give rise to it.
Passive Hyperemia.—Any cause that obstructs the cerebral sinuses or veins, retarding the free flow of blood from the brain, will give rise to passive hyperemia. Of the most common are pressure upon the superior vena cava and jugular veins by tumors or aneurisms, though valvular lesions of the right heart, emphysema, and asthma bear an almost equal share as causal factors.
Pathology.—There are no characteristic changes from hyperemia, either active or passive. In the active form there may be a slight increase in the puncta vasculosa and a darkening of the white substance, while the veins and sinuses may be filled with dark blood in passive congestions, and there is more or less edema of the tissues.
Symptoms.—Active hyperemia is characterized by the flushed face, bright eyes, contracted pupils, and throbbing of the carotids. There is more or less headache of a throbbing character; the patient is irritable and restless, with more or less insomnia. In the rare cases there will be delirium or convulsions. There is hyperesthesia of the special senses.
In passive hyperemia there is dullness of the intellect, the pupils are dilated, and the patient lies passive. If there be headache, it is dull in character. The face is pale or dusky in color. The pulse is small, the tissues relaxed, and the extremities are cold.
Treatment.—In gelsemium we have a specific for active hyperemia of the brain. It acts nicely with either aconite or veratrum, or it may be given alone. Add from twenty to sixty drops of the specific tincture (according- to the age of the patient and the irritability of the nervous system) to four ounces of water, and give a teaspoonful every one, two, or three hours, as may be indicated.
Passiflora.—In nervous children, with insomnia as the chief symptom, add from one to four drams of passiflora to four ounces of water, and give a teaspoonful every one or two hours. When very wakeful, we may give the agent in still larger doses. Thus—
|Simple Syrup||1 ounce each.|
Sig. A teaspoonful every two or three hours.
Rhus Tox.—Where the child is restless and there is a sharp stroke to the pulse, and the child startles at the slightest sounds, or, if asleep, wakens with a sharp cry, ten drops of specific rhus to a half a glass of water, and a teaspoonful every hour, will be found an efficient agent.
A saline cathartic and a hot foot-bath will materially assist the above medication.
In passive hyperemia, where possible, remove the cause of the obstruction, and the hyperemia will disappear. If the congestion be not due to pressure upon the veins, specific belladonna will be the specific that will give relief. Ten drops of the agent to four ounces of water, and a teaspoonful every hour, will not disappoint.