SHOCK.
Definition.—A general depression of the vital functions due to lowered blood pressure, brought on by vasomotor pare sis of central origin, and occurring either as the result of considerable loss of blood, the accumulation of blood in the larger abdominal venous trunks, or contusion of the sensory nerves.
Symptoms.—Shock may present itself in forms varying in intensity from slight depression to profound collapse approx imating death. The surface is pale or livid and cool; the eyes are staring or half-closed; the respiration is shallow and irregular; the pulse weak and rapid or imperceptible. These symptoms in severe cases are accompanied by loss of consciousness. The weakness of the mus cles is a striking feature, those of the sur face being flabby and impotent; the sphincters also fail to functionate from this cause, and involuntary evacuations result. Hiccough and vomiting are also frequent manifestations. The mind is dull and apathetic. Hypothermia, though seldom reaching to 3° F., is usual. The mental torpor gradually deepens, syncope comes on. and death follows. This course depicts that observed in great injury in volving considerable loss of blood, com plicated probably with abdominal or cere bral lesions. Neurotic individuals and drunkards are also exposed to this rap idly fatal form.
In some cases the picture is quite dif ferent. Maniacal furor seems suddenly to develop, and the patient throws himself or his limbs in every direction, rolls his eyes, strikes right and left, and cries out at the top of his voice. Usually exhaus tion soon conies on through recurrence, probably, of haemorrhage on account of the violent exertion, and the patient lapses into the form previously described.
In cases that proceed favorably, the change for the better is termed the "re action." All the abnormal symptoms dis appear gradually, the return of the mus cular tone being manifested by turning, shifting position, etc., while the cardiac symptoms lessen in intensity as the facial color returns. Some cases at this stage go through the maniacal type of shock through unduly rapid resumption of cerebral blood-pressure. In some cases it becomes a sign of septic infection. The temperature in a favorable case re mains near the normal, though it may exceed this to a marked degree in chil dren without indicating that a complica tion has occurred. This reaction fever sometimes lasts a couple of days, then gradually disappears.
Etiology and Pathology.—The prevail ing view is that shock is mainly due to reflex paresis of the vasomotor centres, as a result of violent commotion or con tusion of sensory nerves. Mechanical in
jury of the abdominal organs is also capa ble of inducing this central disturbance. Goltz's well-known experiments in this direction were recently repeated by Para scandola (Archives de Pathologic, p. 138, '98), who utilized guinea-pigs instead of frogs. He stretched the animals out fiat by their feet and gave them a sharp blow upon the abdomen with a flat ruler. The animals reacted in various ways to the traumatism; the greater number of them, after a period of temporary quiet, became apparently well; but in from thirty-six to forty-eight hours they died with the symptoms of exhaustion or shock. The cerebrum, cerebellum, medulla, and cord were removed and preserved in appro priate fixatives, and studied by the Golgi, Marchi, and Xissl methods. The altera tions found by the Golgi method con sisted in a deformity of the cell-body advancing to the grade of actual atrophy, node-like swellings on the dendrites, and fragmentation of the same. By the Marchi methods he noted simple mar ginal degeneration of Lissauer's zone and of the posterior roots proceeding to degeneration of the posterior columns; in some instances Gowers's tract, the crossed pyramiclals, and the direct cere bellar tracts were involved, and some times there was a total degeneration of the entire cord. As observed by the methods of Nissl, the cytological altera tions were various, but pronounced. Chromatolysis was present in a large number of cells. In those affected in a mild degree only, the chromatolysis was more peripheral than central; in the se verer grades the chromatolysis was com plete. In a large number of the cells peculiar abnormalities in the distribu tion of the chromophilic granules were noted; there were peculiar perinuclear bonnet-shaped masses, or fusiform, or like a crown about a rarefied perinuclear space. Further changes in the proto plasm were noted, rarefaction going on to vacuolization and to total disappear ance of the cytoplasm. Changes in the achromatic reticulum were noted by the author, consisting in a widening of the mesh and a contraction of the protoplasm within the mesh, resembling an atrophy. Changes in the nucleus were also served. At times there was an unimpor tant dislocation, but the gravest changes consisted in a vesicular swelling of the nuclear protoplasm, which varied to a notable degree—at times very slight, at times marked. In some sections there were pronounced abnormalities in the coloration of the nucleus.