Thursday, January 12, 2012
It must be remembered that proteinuria, and even nitrogen retention, are not necessarily signs of primary renal disease but may be due to cardiac failure, in which instance the specific gravity of the urine is high and not low as in renal failure. Some physicians believe that for the treatment of oedema associated with severe cardiac failure, or of chronic resistant oedema, mersalyl is to be preferred because hypocalcaemia is less likely to be produced. Hypocalcaemia in acute cardiac failure is particularly dangerous, since it may cause increased sensitivity to digitalis and finally digitalis poisoning. For the majority of cases of oedema chlorothiazide is the drug of first choice. In some cases a better dieresis cab is obtained with mersalyl than with oral diuretics and in others it is best to alternate the two drugs. The complications of electrolyte and acid-base balance which may result from intensive diuretic therapy are discussed in. They include potassium depletion, especially after chlorothiazide and its derivatives, much more rarely sodium depletion, and hypochloraemic alkalosis (the low salt syndrome) which only occurs after long continued use of mercurial diuretics.