The marked urEemic symptoms which occur at the close of preg nancy, and are known under the name of puerperal eclampsia, differ from ordinary unemic attacks in that they may occur without marked structural changes in the kidneys. A variety of explanations have been offered as to their causation.
The older British and American obstetricians taught that puer peral convulsions were caused by determination of blood to the head— cerebral congestion. Traube's theory of altered blood, increased arterial tension, with aninia and cedema of the brain can be applied to the puerperal cases of uremia as well as to those associated with kidney disease.
A retention in the blood of some toxic agent, with consequent poisoning of the blood centres, has been a favorite theory with many. The toxic material has been thought to be : urea, carbonate of am monia, urea with kreatiu and other excrementitious substances, or ptomaines produced by the growth of bacteria.
The convulsions are attributed by some to cerebro-spival disturb ance from peripheral stimulation quite independently of the kid neys. Others believe that the convulsions are due to blood poison ing, but that the renal disturbance which causes the blood poisoning is clue to vasomotor spasm of the small renal vessels with conse quent degenerative changes in the kidneys, the vasomotor spasm re sulting from some reflex irritation.
It is also believed that some puerperal convulsions are simply acute epileptic attacks, the area of distribution of the sciatic nerve being the epileptogenic zone.
More recently attention has been called to the probability that the so-called urmnic symptoms are due to a poison in the blood, but that this poison is not clue to any disturbance of the function of the kidneys. This idea is only a theory, but it offers a promising field for study. It may very well be that we must look for the cause of these symptoms altogether outside of the kidneys. • It is evident from what has been said that there is no entirely sat isfactory way of accounting for the so-called ummic symptoms. At the present time the only very useful thing to do is to try and state as clearly as possible the conditions of the problem which we wish to solve.