Rheumatism is the most important eti ological factor of chorea, the cardiac le sions being closely associated with it. Both the rheumatic diathesis and cardiac morbid conditions predispose to the dis ease.
Study of the relations existing between chorea, rheumatism, and diseases of the heart: 1. Neither rhetunatism nor heart disease is essential to chorea. 2. The preponderance of evidence points toward the conclusion not only- that rheumatism and organic heart disease conjointly ap pear more frequently in the choreic sub ject than can be accounted for by coin cidence, but that the same is true of each of these affections separately. It follows, therefore, that rheumatism predisposes to chorea, and organic heart disease has the same tendency. 3. Fatal cases are gen erally associated with organic heart dis ease, and probably with organic disease of the central nervous system, notably cerebral embolism. 4. There is a large class of functional cases, mainly reflex and fostered by circumstances tending to produce functional symptoms in gen eral. 5. The pathological connection be tween rheumatism and chorea, except ing in the cases where emboli are pro duced by acco:npanying endocarditis, is still obscure; probably no one theory is applicable to all cases. 6. The mechan ism by which the peculiar phenomena of chorea are produced is unknown. 1Valton and Vickery (Amer. Jour. Med. Sci., May, '92).
Examination of 140 persons having suffered from chorea at least two years previously. In 51, heart normal; in 72, symptoms of organic lesion; in 17, car diac disturbances. No rheumatic history in 66 per cent. Cause: an infection al lied to rheumatism, but differing from it. Osler (Pa.cific Med. Jour., Aug., '95).
Six cases, all in young women of ages varying from 17 to 21, in which the dis ease was very grave, and proved fatal in two. The previous association of scarla tina or rheumatism—articular, endocar dial, and prcecordial—noted in every case; likewise recurrence of chorea on the same side as the former rheumatic affection had existed. Napier (Glasgow Med. Jour., Feb., '97).
Out of 20 choreic patients personally examined, in 7 there was a previous history of rheumatic fever in the pa tient; in 4 there was a strong family history of rheumatic fever, and in the remaining 9 there was no history of rheu• matic fever, but, out of these 9, 2 had mitral stenosis, 5 had mitral regurgita tion, and only 2 had no valvular affection of the heart. Out of the 20 cases, 5
gave a history of fright or shock. In the 20 cases 18 came on between the fourth and the fifteenth year, 5 of which oc curred at the fourteenth or fifteenth year. This refers only to first attacks of chorea. Sixteen occurred in females and only 4 in males. Purves Stewart (Med. Brief, June, '98).
About 21 per cent. of all choreic eases give a. rheumatic history, either in their parents or themselves prior to the disease. Chorea follows an attack of scarlet fever in children in about 25 per cent. of all cases. Forcing children at school is a most important factor in producing the disease. Ocular defects may lie at the bottom of some cases of chorea. Edwin Williams (Memphis Lancet, Aug.. '99).
View that chorea is associated with rheumatism opposed. Of seventeeu con secutive cases of chorea at personal clinic, only one bad rheumatism before or dur ing the attack, and of several who re turned after recovery none had shown any sign of the latter disease. Gilles de la Tourette (Rev. Neurol., June 30, 1900).
Forty-seven cases of chorea ininor studied. Age of patients varied from 3 to 16 years, and in 28 the disease had begun from seven to eleven years pre viously; 39 were girls and 8 boys. In 24 cases there was the family history of rheumatism or of psychical affections. Among the 47 there were 15 who had had rheumatic fever, either before or dur ing the chorea, and in 16 chorea had be gun or had been accompanied by febrile phenomena with angina, articular afTec tions, or erythema nodosum. T. Frolich (Norsk Mag. f. Laegevidensk., Sept., 1900).
The frequency of fibrinous accretions upon the cardiac valves and the undis puted frequency of embolism of the cerebral arteries give origin to the often mentioned "embolic theory" of the causa tion of chorea, a theory first advanced by Kirkes and supported especially by Hughlings-Jackson, according to which the inco-ordinate movements of chorea are due to multiple capillary embolism of the corpus striatum. This explana tion is, however, somewhat far-fetched and it is also insufficient, since there are many cases of chorea which show no evi dence of embolism and in which there is no endocarditis.