ETIOLOGY - PEURPERAL ECLAMPSIA.
A number of theories have been entertained as to the causes of puerperal eclampsia. It must be confessed that none of them is satisfactory, and that the subject is still obscure. The most 'promi nent explanations are as follows : 1. Pressure on the renal veins by the gravid uterus produces a chronic congestion of the kidneys, which interferes with their func tions.
2. Pressure of the uterus on the ureters renders it necessary for the kidneys to secrete against a higher pressure so that they are un able to get rid of the proper quantity of excrementitious substances.
3. The kidneys are obliged to excrete waste products not only from the mother, but also from the enlarged uterus and the foetus, and this extra work they are unable to perform.
4. It has been demonstrated in some cases that before the convul sions there is a diminished quantity of excrementitious products in the urine, and after the cessation of the convulsions an increase of these products ; therefore the convulsions are due to the retention of these excrementitious substances in the blood.
5. That for some reason the patients have cerebro-spinal conges tion.
6. That for some reason they have cerebro-spinal 7. That the convulsions are of the nature of acute epileptic at
tacks due to irritation of nerves in the pelvis.
8. That the enlarged uterus acts as an irritant to the vasomotor nerves and so causes a contraction of the arteries throughout the body.
9. That the enlarged uterus causes irritation of the vasomotor nerves which supply the renal arteries ; the contraction of the renal arteries causes death or degeneration of the renal epithelium; the changes in the renal epithelium render the kidneys unable to excrete poisonous substances; the accumulation of these substances in the blood causes the convulsions, etc.
10. There is at the time of childbirth in some women a toxic sub stance produced in some unknown way, which is not caused by any change in the function of the kidneys, but which is capable of causing transudation of serum from the vessels, contraction of the arteries, acute degeneration of the kidneys, and acute nephritis. In other words, the changes in the kidneys are not the cause of the convul sions, etc., but they are the result of the same poison which produces the albuminuria and the cerebral symptoms.