By the term spasmophile diathesis of infants we mean a constitu tional anomaly which is recognized by a mensurable mechanical and electrical overexcitability of the nervous system, and which produces a pathologic predisposition to certain partial and general clonie and tonic convulsions.
Accordingly, a number of convulsive diseases, which we shall pres ently have to describe, are considered together as being by virtue of this abnormal reaction of an identical type and only different manifes tations of the pathologic spasmophilia of early infancy.
The exaggerated irritability which constitutes the peculiarity of the spasmophilc diathesis, can in marked cases be determined by the presence of increased mechanical irritability in one or several peripheral nerves. Tapping the nerves with the percussion hammer at accessible points, such, for example, as the well-known nerve points of Erb, elicits a short and more or less violent contraetion in the region which these nerves supply with motor impulses. The phenomenon is most clearly seen in the facial nerve, tapping of which produces unilateral contraction of the muscles of the face—the facial phenomenon or so-called Chvosteck phenomenon--which will be discussed again later in more detail.
It requires not a little experience on the part of the investigator to determine the effect, i.e., the amplitude of the contraction produced by the stimulation; and one is also in danger of being led into error when the mechanical irritability of the muscle is increased. The latter has no pathognomonic significance whatever, as it also occurs in vari ous conditions of increased irritability as, for example, in neurasthenia and the various cachexias.
As no clinical method has as yet been devised for measuring the mechanical irritability of a nerve, electrical examination is of much greater practical value. Erb established an increased faradic and gal vanic irritability in the tetany of adults. After this had been con firmed in the case of children Burekhardt, Kalischer, Escherich, Ganghofner and Hauser, Mann and Thiemich carried out a series of comparative investigations on a large number of children, some healthy and some suffering from tetany. which yielded a typical law of contrac tion, and thus rendered possible a still more delicate differentiation of normal and pathologic findings. The results may be tabulated as follows:
The figures in this table were obtained by examining the median nerve at its most irritable point in the bend of the elbow. and the values are given in milliamperes. The children were never ancesthetized. The indifferent electrode, 50 square cm. in size, was placed on the chest, and a Stintzing normal electrode, 3 square cm. in size, was used for the active electrode. It should also be mentioned that the normal children were all more than eight weeks of age, because below this age the irritability of the peripheral nerves is much less (Westphal, Mann). The tetany cases were all more than eight weeks olcl.
A glance at the average figures collected in the table shows the greater irritability of children suffering from manifest or latent tetany, and the return to the normal immediately after the subsidence of the disease; but owing to the wide individual variations, which do not appear in the average figures, it is important to take account of the extreme values also. While referring for details to the above-men tioned thesis of Thiemich, we may mention the following diagnostic points: tetany (the spasmophile diathesis in general) the values for CIC are for the most part lower than in normal children, although they may reach the normal level or even exceed it. The almost regular preponderance of AnOC over AnCIC in tetany is of importance, as it very rarely occurs under normal conditions. The criterion, however, is the behavior of KOC. T'alues below 5.0 cu.a. must be regarded as patho logic, while values above 5.0 m.a. are normal: Testing for KCIT is un certain in children without amusthesia and cannot be substituted for KOC; nor is faradic; examination of greater value.
These abnormalities in the reaction of the nerve to the irritation of the galvanic current, which can he determined by anyone possessing a little practice and dexterity, constitute the chief characteristic of the spasmophile diathesis.
This anomaly is the basis of the clinical pictures with convulsions of tctany, eclampsia, lary-ngospasm and apinea, with which we have long been faniiliar, and also stands in close etiologic relationship to some at least of the cases of sudden death in early infancy without ade quate anatomical findings.