In the early stage the respiration presents nothing abnormal, but when the pulse becomes slow and irregular the breathing is similarly affected. Sighing is very common in the prodromal period and first stage. Toward the end of the second stage the increasing paralysis of the respiratory centre gives rise to the phenomena known as the Cheyne-Stokes respiration, consisting of a succession of respiratory acts diminishing in force until there is a complete suspension of the breathing, lasting from a quarter to three-quarters of a minute, when the series begins again with a full inspiration. In general, the variations in the rate of the respiration follow those of the pulse, though the correspondence is not always exact.
In the early stage of the disease the pupils are usually contracted and unequal. They are sluggish, but still respond to the stimulus of light. At a later period they become gradually dilated, and react even more slowly to light or not at all, the two eyes often differing in this respect. Ophthalmoscopic examination frequently shows the appearance of choked disc and commencing neuro-retinitis. In rare cases tubercles are seen scattered over the fundus of the eye. They are about the size of a small pin's head, of a yellowish color, and of sharply-defined contour. Neuro-retinitis and choked disc are not, of course, pathognomonic of tubercular meningitis, and choroidal tubercles are so rarely seen as to be of little avail in diagnosis. In fact, they are less frequent in this disease than in general tuberculosis without meningitis. In twenty-six cases of tubercular meningitis examined by Garlick at the London Hospital for Sick Children they were found only once.6 The effect upon the conjunctiva of the unclosed lids has been already described.
6 W. R. Gowers, M.D., Manual and Atlas of Medical Ophthalmoscopy, Philada., 1882, p. 148. See, also, Seitz, op. cit., p. 347; Steffen, op. cit., pp. 452 and 472; and “Tubercle of the Choroid,” Med. Times and Gazette, Oct. 21, 1882, p. 498.
The tongue is somewhat coated soon after the beginning of the disease, and the breath is offensive. The appetite is lost, and there is decided emaciation in many cases during the prodromic period. The thirst is usually moderate. Vomiting is one of the most constant symptoms during the first period, and its occurrence on an empty stomach is characteristic of tubercular meningitis. It is not usually preceded by nausea, and often takes place without effort, by mere regurgitation, the rejected fluid consisting chiefly of bile mixed with mucus. Although constipation is the most common condition in the early stage, and is often rebellious to treatment, yet in some cases diarrhœa is observed, which may mislead the physician in respect to the diagnosis. From the beginning of the second stage, and sometimes earlier, the discharges from the bowels and the bladder are involuntary.
DURATION.—The duration of tubercular meningitis, apart from the prodromic period, which often can hardly be determined, averages from two weeks to two weeks and a half. In exceptional cases death may take place in a few days or a week, and occasionally a patient may linger for several weeks,7 the difference being apparently due to the rapidity of the tubercular deposit and of the resulting inflammation and exudation. The patient usually takes to his bed at the beginning of the first stage, but he may be up during a part of the day until the beginning of the second. In rare instances the child will be about, and even out of doors, until a few days before death.
7 Such a case is reported by Michael Collins in the London Lancet, March 8, 1884.
PATHOLOGICAL ANATOMY.—The essential lesion of tubercular meningitis consists in a deposit of miliary tubercles in the pia mater of the brain, giving rise to inflammation of that membrane and exudation of serum and pus. In the early stage both surfaces of the pia are reddened and more or less thickened, and present an opaline appearance, while between them—that is, in the meshes of the pia—we find a colorless and transparent fluid which is effused in greater or smaller amount, resembling jelly when viewed through the arachnoid. These conditions are sometimes observable on the convexity of the hemispheres, but are much more abundant on the lateral surfaces, and especially at the base. More distinct evidence of inflammation is shown by the presence of a yellowish or greenish-yellow creamy deposit on the surface of the pia, consisting chiefly of pus, which is also much more abundant at the base than elsewhere, especially about the optic commissure, infundibulum, pons Varolii, and the anterior surface of the medulla. The cranial nerves may be deeply imbedded in the deposit, which often extends into the fissure of Sylvius, gluing together the adjacent surfaces of the lobes, and accompanies the vessels, forming narrow streaks along the sides of the brain up to the convexity.
The miliary tubercles or granulations consist of semi-transparent bodies, grayish or whitish in color, varying in size from that of the head of the smallest pin, indeed almost invisible to the naked eye, to that of a millet-seed (whence their name). Larger masses are frequently seen, formed by the aggregation of smaller granulations. The tubercles are usually found on the inner surface of the pia, always in the immediate neighborhood of the blood-vessels, which they accompany in their ramifications, and are also scattered, in greater or less numbers, throughout the purulent exudation from the surface of the pia. They are most abundant at the base of the brain, ascending the sides along the course of the vessels. Sometimes, though rarely, they are more abundant on the convexity. The total number varies; it is usually very large, but sometimes only a limited number exists, even in well-marked cases, and along with intense inflammation of the pia. The granulations are found in different degrees of development—sometimes all of them similar in color, size, and consistency, at others in various stages of fatty degeneration. The distribution may be symmetrical in the two hemispheres or irregular. Under the microscope (after suitable preparation of the part) the bacillus tuberculosus in considerable numbers may be found in the pia, in places adjacent to the arterioles.8
8 See a case reported by Y. Dawson in the London Lancet, April 12, 1884, in which tubercles were visible only by the microscope with numerous bacilli.
The ventricles of the brain are usually distended with a clear or opalescent, rarely bloody, fluid, the amount of which generally corresponds to the intensity and extent of the meningeal inflammation, although sometimes it is not above the normal quantity. The two lateral ventricles are affected in an equal degree; the third and fourth ventricles are more rarely implicated. According to Huguenin,9 it is doubtful whether acute inflammation of the ependyma takes place in tubercular meningitis. Steffen also10 says that the ependyma is not inflamed, and that it is not the seat of the deposit of tubercles. This latter statement is denied by other authorities, and Huguenin is inclined to believe that they may exist in that membrane. In the following case, under my care, abundant granulations were found on the surface of the ependyma: