DISEASES OF THE MENINGES Of the pathological changes the acute and subacute, due to bacterial inflammations, chiefly interest us; after these come the chronic forms, serous meningitis as a consequence of angioneurotic disturbances (first observed by Quinckc), and meninges] tumors, discussed elsewhere.
With the exception of headache, which is a consistent though dubi ous symptom in young children, the clinical symptoms upon which we base a diagnosis of meninges] disease are secondary, due to pressure upon, infiltration or circulatory disturbance of, the underlying tissues. These conditions evoke numerous manifestations of irritation and paraly ses, the manifold combinations of which present the various clinical pictures which will be discussed.
There is no pathognomonic symptom, which by its absence, pre cludes the diagnosis of meningitis. However, there appear in the con fusingly varied field of vision some symptoms which, on account of their frequency and relative importance, deserve to be advanced as cardinal symptoms, prior to a. discussion of the various froms of menin gitis classified etiologically and pathologically.
The first symptom is headache, a syn3ptorn hardly ever wanting in meningitis, at any rate in a child rnore than a year old. Comment upon the significance of this symptom is unnecessary.
The second symptom is disturbance of the sensorium, or, as usually learned, psychical disturbance. Beginning with change of disposition, as for example diSinclination to play, peevishness, and repugnance to occurrences and impressions formerly disregarded ;as eating for instance); proceeding to drow-siness and weariness without actually sound sleep, then to apathy which can be overcome only with difficulty, finally to deep reactionless coma, this disturbance runs a most varied, and as must be emphasized, a most enigmatical course. But, it is important to keep in mind that it is never absent when there is continuous observation.
As a third symptom we may mention fever. We must, how-ever, except hamiorrhagic pachymeningitis and Quincke's serous meningitis; and we must emphasize the fact that fever may be entirely absent throughout limited periods of observation and for long periods it may be slight. It is unnecessary to dilate upon the ambiguity of this symp tom; however it may not be superfluous to recall how frequently in any single case a most careful observation fails to explain fever of days or of even weeks duration in children.
Frequently, though not invariably, inflammatory processes in the meninges cause increased intraeranial pressure, with more or less con stant symptoms. These are vomiting (cerebral), disturbances of the pupillary reaction, unevenness and irregularity of the pulse, brachy cardia at the beginning and tachycardia (explained by paralysis of the vagus nerve) toward the end of the disease, hypertony of the muscles, etc. A special form of hypertony occurs almost invariably when the meningeal process is localized in the occiput, that is rigidity of the neck (opisthotonos). This symptom appears in pronounced cases as a pain ful contraction of the cervical muscles, which draws the head backward so that it bores into the pillow; in milder cases there is opposition (offered reflexly as the result of pain) to passive forward, less to lateral movement or rotation of the head. Hypertony can be detected in the
milder cases also by Kernig's phenomenon—(when the patient sits upright the knee, on account of spasm of the flexors, cannot be straight ened). It is noteworthy, particularly when the spinal meninges are considerably involved, that pronounced spinal rigidity may ensue and likewise induce Kernig's symptom. Cervical and spinal rigidity are very valuable symptoms of meningeal affection when the other causes (spondylitis, muscular rheumatism, enlarged glands associated especially with nasopharyngeal disorders (Pfeiffer's glandular fever), and hysteria can be excluded. However, in very many cases it does not occur. It it evident that increased intracranial pressure is most trustworthy as a guide in the diagnosis of meningitis when it is directly demonstrable and not deduced from other symptoms, which are themselves capable of various interpretations. This is possible in infants with sufficiently large anterior fontanelles. In fact the daily increasing bulging and tension of the fontanelle is one of the most reliable signs of meningitis in early life, and its value is still further enhanced by the fact that at this time it is difficult to establish other symptoms referred to or rely upon them on account of their ambiguity. Increased tension of the fontanelle, however, is indicative of meningitis only when the child is quiet and if moreover other causes, pneumonia, etc., can be excluded. We have seen a pulseless fontanelle notwithstanding severe deple tion of fluids following diarrhcea in a case of sinus thrombosis, in a septic infant, without meningitis.
If, in conclusion, we remark that under certain conditions men ingitis may run a perfectly symptomless course, or occasionally its symptoms may be obscured by the symptoms of another (primary) disease it is at once understood how inestimably we are indebted to Quinekc for introducing lumbar puncture as an aid to our diagnostic methods. We shall consider the subject of lumbar puncture under the separate forms of meningitis. While the acute inflammatory changes which occur in the meninges may be scrolls or purulent, they do not differ essentially; although certain infective agents fat-or the production of one or the other variety. It is important to note that for purulent meningitis to supervene, an interval of considerable time between infection and death must have elapsed.
When, in consequence of the powerful toxic effect of the infective agent, death occurs within a few hours, we find merely a serous exudate, notwithstanding that the infective factor may have extremely potent pyogenic properties.
The difficulty of recognizing the earlier stages of the inflammation in the cadaver makes it comprehensible that the purulent varieties and those beginning with copious serous exudation (as, tuberculous men ingitis) have been known longer and are better understood than those in which only a slight serous moistening and delicate microscopical changes of the leptomeninges and of the cerebral cortex are found. And yet these very cases have recently been so zealously studied and have attained such clinical importance, that their discussion in this chapter is imperative. The various avenues and modes of infection will be discussed under the separate captions.