A system of practical medicine. By American authors. Vol. 5

by Unknown

³¹ Medico-Chirurgical Transactions, vol. xli. p. 1, 1876.

The embolic theory of chorea has been held by several investigators, among them Hughlings-Jackson. It is undoubtedly an attractive and reasonable view, especially when we consider the large proportion of cases in which there is valvular disease of the heart. Dickinson, however, does not consider this hypothesis tenable. In none of the cases in which he made post-mortem examinations did he find evidences of embolism. “In none of the instances described were decolorized fibrin, detached clots, or signs of impaction detected, and the erraticism of embolic accident was wanting: the constancy indeed with which the changes repeated themselves in certain positions, and the equality with which they affected both sides of the body, are conclusive objections to this hypothesis. The corpora striata, for example, were affected with almost absolute symmetry, notwithstanding that these bodies receive their blood respectively from the right and left carotids and different parts of the aortic arch.”

Rheumatism is associated with or precedes chorea in a large proportion of cases, and this was pointed out by Kirkes in 1850 and again in 1863. This connection between rheumatism and chorea, and the frequent occurrence of endocarditis in chorea, has led some authors to believe that the endocarditis is always rheumatic, and that the chorea is the result of the endocarditis. Dickinson, however, points out that in cases in which there is a distinct history of the chorea beginning suddenly from fright there are often well-marked cardiac murmurs heard. He believes that in all cases of chorea in which there are cardiac murmurs they are due to endocarditis, and suggests that in these cases from fright the endocarditis is due to irregularity of cardiac action. This, of course, is mere hypothesis, and we must bear in mind that in all cases of chorea there is anæmia, and that the murmur may be purely functional.

H. C. Wood, in a communication read before the College of Physicians of Philadelphia,³² gives his views of the pathology of chorea, based upon the results of post-mortem examinations made in a number of dogs who had the disease. He believes the history of chorea to be this: “Owing to emotional disturbance, sometimes stopping of various vessels of the brain, or sometimes the presence of organic disease, there is an altered condition of the ganglionic cells throughout the nerve-centres. If the cause is removed and the altered condition of the nerve-cells goes only so far, it remains what we call a functional disease. If it goes so far that the cells show alteration, we have an organic disease of the nervous system.”

³² Philada. Med. News, May 30, 1885.

In two dogs which were choreic the movements continued after section of the cord. This shows that in dogs, at any rate, the movements originate in the cord. In four instances of canine chorea in which Wool made autopsies there were found in the cords of three mild grades of infiltration of leucocytes in the gray matter. In the fourth, in which the dog had died of the disease, the ganglion-cells were degenerated, and in some places had disappeared. He concludes, therefore, that choreic movements may depend upon a diseased condition of the motor cells of the cord.

Although there are several recorded cases of human chorea in which lesions of the spinal ganglionic cells have been found, we cannot believe that this can be a constant lesion in chorea. The disease is too transient in many cases, and presents too many variations and anomalies, for the cord to be always the seat of the diseased condition.

In an interesting paper read by Angel Money before the London Medical and Chirurgical Society in 1885 he detailed some experiments in which, by injecting a fluid containing arrowroot, starch-granules, or carmine into the carotids of animals, he produced movements closely resembling chorea; and this was found to be associated always with embolism of the capillaries of the cord. In the discussion which followed Broadbent and Sturges expressed their disbelief in the embolic origin of chorea in man. Hughlings-Jackson said that he held the view of the cerebral origin of chorea, one of his reasons being the frequency with which the face-muscles are affected in this disease.

The probabilities are that in chorea there is a disordered condition of the brain and cord more or less general. The lesions are no doubt slight in mild cases of short duration, but in severe cases of long standing there occur well-marked changes in portions of both brain and cord. We cannot do better than to sum up the pathology of chorea in the words of Dickinson: “A widely-distributed hyperæmia of the nervous centres, not due to any mechanical mischance, but produced by causes mainly of two kinds—one a morbid, probably a humoral, influence which may affect the nervous centres as it affects other organs and tissues; the other, irritation in some mode, usually mental, but sometimes what is called reflex, which especially belongs to and disturbs the nervous system, and affects persons differently according to the inherent mobility of their nature.”