A handbook of the theory and practice of medicine / by Frederick T. Roberts.
- Frederick Thomas Roberts
- Date:
- 1873
Licence: Public Domain Mark
Credit: A handbook of the theory and practice of medicine / by Frederick T. Roberts. Source: Wellcome Collection.
968/1060 page 964
![9G4 Cerebral Congestion or Hyperemia. Etiology.—The causes of hyperemia of the brain are—1. General plethora, .especially from excessive eating or drinking, and luxurious habits with want of exercise. 2. Increased flow ofi blood into the brain, active hyperamiia from undue cardiac action] whether merely functional or associated with hypertrophy of the left ventricle; local irritation, especially in connection with in- flammatory affections; diminished resisting power of the arteries, particularly in connection with vaso-motor paralysis, as from ex- cessive mental labor, strong emotion, sunstroke, or the effects of) alcohol and other poisons; interference with the general arterial or capillary circulation, in consequence of which an extra amount of blood flows into the main arteries of the neck; it is said atrophy of the brain. 3. Interference with the escape of blood out of the brain —mechanical hypertonia—especially from cardiac and extensive lung affections; violent expiratory efforts, with the glottis closed, as in coughing, or straining at stool; hanging the head down; or direct pressure upon the veins returning the blood from the brain, as by an aneurism or other tumor, or strangulation of the neck. > Anatomical Characters.—The post-mortem appearances usually described as' indicative of cerebral congestion are over-' loading of the venous sinuses and of the vessels of the membranes] including the finer branches, as well as the larger veins, so that the pia mater appears extremely vascular and opaque; undue redness of the gray matter of the convolutions; and increased-; number and size of the drops of blood which are seen on making sections of the brain. The convolutions may be compressed, and the ventricles contracted. Niemeyer wrote at considerable lengtja on this subject, and justly remarks that it is often difficult to decide whether the vessels of the membranes, and still more sol whether those of the brain-substance, have been congested during life. He considered that the number and size of the drops of blood on section depend chiefly on its fluidity, and that oedema may result from congestion, so that the brain-substance becomes unusually pale and presents but few and small blood-spots. As a rule, the signs of hyperemia are equally distributed throughout, but sometimes they are more evident in some parts than others.](https://iiif.wellcomecollection.org/image/b20402740_0968.jp2/full/800%2C/0/default.jpg)
