56 Amer. Jour. of Med. Sci., July, 1867, p. 23.
57 Dublin Quart. Jour., May, 1867, p. 441.
58 Jaffé, Phila. Med. Times, xii. 599.
It does not seem difficult to reconcile the conflicting statements now given of the condition of the blood in epidemic meningitis. One of them points to an excess and the other to a loss of the spontaneously coagulable element of the blood. It is evident that venesection, which was necessary for procuring the living blood for analysis, would only be performed when the type of the disease authorized it—that is, when the type was sthenic; whereas the blood examined after death had necessarily undergone changes which tended to, if they did not actually, occasion death. Hence we find among the former cases, when fatal, the most extensive and massive exudation, and always among the latter less evidence of inflammation, but, on the other hand, a greater or less manifestation of those appearances which denote a loss of the vitality and organization of the blood. In the one case death may fairly be attributed, above all other causes, to the pressure upon, and the disorganization of, the cerebro-spinal organs essential to life; in the other, primarily, to the death of the vital elements of the blood produced by the specific cause of the disease. It is probable that the post-mortem fluidity of the blood exists under two conditions. In the one the morbid cause is powerful enough from the very commencement rapidly to destroy the life of that fluid, and in the other it acts less violently, but continuously, to exhaust the powers of life.
Our conception of the pathology of epidemic meningitis is implicitly contained in the foregoing discussion. Of its essential cause and of the conditions that call it into existence nothing whatever is known. The disease is most probably due to some atmospheric agency that is capable of acting at the same time upon widely separated localities. Its specific cause appears to enter the blood first of all, and doubtless through the lungs, and to be capable of destroying life by its action upon the blood alone. Failing this effect, its force is spent upon the cerebro-spinal pia mater, and it may become fatal by the mechanical interference of the products of inflammation with the nutrition of those parts of the central nervous system which are essential to life. An inflammatory and a septic element together constitute the fully-developed disease; either may be in excess and overshadow the other. According to the relative predominance of one or the other, the disease assumes more of a typhoid or more of an inflammatory type, and it is doubtless this diversity in its physiognomy, as well as in the lesions that attend it, which has led to the most opposite doctrines respecting its nature and its nosological affinities.
DIAGNOSIS.—The most distinctive phenomena of epidemic meningitis are suddenness of attack and rapidity of development of the following symptoms: acute pain in the head, neck, spine, and limbs; faintness, vomiting; stiffness or spasm of the cervical or spinal muscles; hyperæsthesia of the skin; delirium, alternating with intelligence and merging afterward into dulness or coma; occasional convulsive spasms; paralysis of the face or of one side of the body. The evidences of associated blood-poisoning are, the epidemic prevalence of the disease, various eruptions upon the skin (herpes, roseola, petechiæ, etc.), ecchymoses, debility out of proportion to the evidences of local disease, redness of the eyes, foulness of the tongue and mouth, and more or less of the other conditions which characterize the typhoid state. To these features must be added the rate of mortality, which is greater in most epidemics of meningitis than that of any disease with which it is liable to be confounded.
It is distinguished from sporadic meningitis by the fact that the latter disease is never primary, but is always either an epiphenomenon of some other and previous malady (various fevers and chronic blood diseases) or is traumatic in its origin. The thermometer readily distinguishes it from various functional nervous affections, chiefly hysterical, in which the temperature remains normal.
From typhoid fever it differs as widely as possible by its rapid onset, the exquisite pain in the head, the neuralgic pains, the opisthotonos, and the convulsions. The alternate delirium or coma and clearness of mind in meningitis contrast with the persistent hebetude, stupor, or muttering delirium and the muscular relaxation in typhoid fever. The sordes on the tongue, the diarrhoea, the meteorism, the intestinal hemorrhage of the latter, instead of the moist or merely dry tongue and the transient vomiting and torpid bowels of the former; high or continuous fever on the one hand, slight or variable increase of temperature on the other; diffluence of blood in the one and an increase in the proportion of its fibrin in the other; in the one suppurative inflammation of the cerebro-spinal meninges, in the other specific lesions of the intestinal and mesenteric glands,—these, as well as the very different modes of origin of the two affections, draw a broad and manifest line of distinction between them.
It would scarcely be necessary to point out the contrasts between epidemic meningitis and typhus fever were it not that, notwithstanding the abundance of instruction on the subject in medical treatises and lectures, a large number of physicians confound typhus fever, typhoid fever, and the typhoid state of inflammatory diseases with one another. The confusion was intensified at one time by designating the disease we are studying as spotted fever—a term originally applied and properly belonging to typhus fever (typhus petechialis). It is true that New England physicians soon became aware of their error, which was distinctly pointed out and condemned by North, Strong, Miner, Foot, Fish, and others in the early part of this century. A similar error was at first committed both in Ireland and England, but was corrected by maturer experience. In order to contrast the two diseases as strongly as possible, we place their distinctive features side by side in the following table: