So far as we now know all cases of the Stokes-Adams syndrome are caused by heart block which is only another name for disease in the auriculoventricular bundle. Of interest here is the fact that besides gummata, ulcers, and other lesions of the bundle, definite arteriosclerotic changes have been found.
"The investigation of a typical case of Stokes-Adams disease has shown that the symptoms of this case are caused by some lesion in the heart which gives rise to the condition now generally termed heart block. Practically all degrees of heart block have been observed, namely, complete heart block and partial block with 4:1, 3:1, and 2:1 rhythm, and occasionally ventricular silences. These stages occurred during recovery.
"Experiments testing the reaction of the heart to various extrinsic influences demonstrate that when the block is complete the ventricles do not respond to influences presumably of vagus origin, although the auricles still respond normally to such influences, that effects exerted upon the heart presumably through the accelerators still influence the rate of the ventricles as well as that of the auricles.
"When the block is partial the rate of the ventricular contraction varies proportionally with the rate of the auricular contractions but only within certain limits. When these limits are exceeded the block becomes more complete, i. e., a 2:1 rhythm may be changed into a 3:1 rhythm, this into a 4:1 rhythm, and this into complete block, and vice versa.
"The syncopal attacks are, in all probability, directly dependent upon a marked reduction of the ventricular rate. Such reductions of the ventricular rate are always associated with an increase of the auricular rate, and it is believed that the latter is the cause of the former." (Erlanger.)
The epileptiform seizures of the syndrome may be caused by the anemia of the brain resulting from failure of the heart to supply a sufficient quantity of blood.
The apoplectiform attacks are most probably caused by venous congestion when the slowing of the ventricular contractions is not sufficient to cause convulsions, but will just cause complete unconsciousness.
Renal
Chronic nephritis, hypertension, arteriosclerosis form a most important trinity. Some stoutly affirm that in all cases of high tension there is chronic renal disease. Certainly the very highest blood pressures which we see occur in the chronic interstitial forms of kidney disease. The cause is most probably to be sought in some poison which is elaborated in the kidney, is absorbed into the circulation and acts powerfully either on the vasoconstrictor center as a stimulus, or directly on the musculature of the small arteries all over the body. Usually hypertension is progressive but it may be temporary.
A man, 43 years old, entered the Milwaukee County Hospital in uremic coma. The systolic blood pressure was 280-290 mm. Hg, the diastolic pressure 220 mm. (Janeway instrument). Under treatment his blood pressure gradually became lower, at the same period the albumin and casts gradually disappeared from the urine. In two weeks from admission he seemed perfectly well, there were no albumin or casts found in the urine, and the systolic blood pressure was 136 mm., not a high figure for a muscular man of the laboring class. It must be admitted, however, that such cases are the exception, not the rule.