Conservative treatment of acute and chronic lymphoedema with benzo-pyrones

Abstract

Generally, the success of conservative therapy is only limited to a transient reduction in oedema. Concomitant with this, subjective improvements such as a reduced feeling of heaviness, a lessening of pain and of the bursting feeling of the affected limb are frequently reported. Once the oedema is reduced, the reduction must be maintained by elevation, elastic compression bandages, and by careful attention to infection. A failure to observe these points results in a very rapid reformation of the oedema. Experimental results have shown the benzopyrones to be very useful in reducing high protein oedemas, particularly those of lymph and thermal oedema. They do this by enhancing the lysis and removal of the abnormal accumulated protein from the affected part. They also enhance glucose uptake by the various cells, thus allowing them to survive in a viable state in severe conditions such as those of metabolic acidosis characteristic of stagnant tissue fluids. Since the benzopyrones remove the excess protein, the tendency for further fibrotic tissue formation is reduced. In addition, like some other anti-inflammatory drugs, the benzopyrones may be able to enhance the removal of existing fibrotic tissue by causing its lysis. The cells involved in this action seem to be the macrophages. The remarkable reductions of lymph and thermal oedemas obtained in animal experiments with the benzopyrones have not been reported in many clinical trials. There seem to be two main reasons for this. Firstly much lower doses are used than have been shown to be optimal. Secondly, the follow up periods of observations have usually only been short. Some clinical trials even with these lower doses have however been very promising, and this is especially enlightening when it is considered that such doses in animals only result in minimal changes in the oedema volume. This may be the reason for the high proportion of "subjective improvement only" reports in clinical trials.