Definition.—An insufficient amount of blood circulating in the capillaries.
Etiology.—This may be due to general or local causes. Thus cerebral anemia may attend the general anemia coming from a severe hemorrhage or from profuse diarrhea, or from pernicious anemia, leukemia, and various cachexias, or it may be due to the accumulation of a large quantity of blood in the peritoneal cavity following the removal of ascitic fluid. A more serious condition would be anemia due to aortic stenosis. Among local causes may be mentioned obliterative endarteritis, compression of the brain from tumors, or a partial destruction of the circle of Willis.
Pathology.—The puncta vasculosa are so lessened many times as to escape detection, while there may be an increase in the cerebro-spinal fluid. The gray matter assumes a characteristic pallor.
Symptoms.—These are due to profuse, exhausting, diarrheal discharges, and, especially where due to hemorrhage, the symptoms are characteristic; there is dizziness, faintness, pallor of face, ringing in the ears, confusion of ideas, and marked dyspnea, and frequently terminating in a "dead faint." Where the anemia is sudden and intense, the syncopal attack may terminate fatally.
Where the anemia is more chronic in character, there is pallor of face, the skin is cool, and the pulse is feeble and irritable. The patient is listless and stupid, though we may meet cases with general irritability. There is a dull headache, vertigo, buzzing in the ears, spots before the eyes, and weakness of the muscles.
The hydrocephaloid symptoms, occurring in young children, so named by Marshal Hall, are pallor, dullness, contracted pupils, and depressed fontanels.
Treatment.—This will depend upon the cause giving rise to it. Where the attack is acute and sudden, the patient should be placed in the recumbent position, with the head depressed. A diffuse stimulant, like ammonium carbonate, gives prompt results. In severe cases, where there has been excessive hemorrhage, a subcutaneous injection of normal saline solution should be used. In the more chronic form, and when secondary, the treatment suggested for general anemia will be followed with nourishing food and gentle exercise in the open air.