The question made me interested, so I did some Googling. Here are some interesting arguments/quotes I found on the Straight Dope's message board: I was taught, only a few years after it became law, that it was done by the Republican majorities in both houses of Congress as a form of spite or revenge against FDR.
And Nephrotic Syndrome is always accompanied by serious edema which is observable swelling from fluid accumulation in the body. With damaged kidney function, it cannot excretes wastes and extra fluid from the body and a large amount of fluid will pile up in the body, thus leading to swelling.
Nephrotic syndrome is a condition where the 'filters' in the kidney become 'leaky' and large amounts of protein leak from your blood into your urine. The main symptom is fluid retention (oedema) which is mainly due to the low protein level in the blood.