The pathophysiology of lymphedema.

BACKGROUND

All edemas result from an imbalance between capillary filtration and tissue (lymph) drainage. This basic approach was adopted to investigate mechanisms for chronic arm edema following breast carcinoma treatment.

METHODS

A review of causes of lymphedema is presented plus the traditional pathophysiology of breast carcinoma related lymphedema (postmastectomy edema; PME). A summary of recent research that explored capillary filtration as a surrogate for lymph flow in the steady state is presented.

RESULTS

A reduced interstitial protein concentration (relative to plasma) argues against lymphatic obstruction. Evidence exists that total arm blood flow (in some patients) and vascular bed size are increased in PME.

CONCLUSIONS

The primary insult to the axillary lymphatic system by surgery and radiotherapy presumably is the root cause of PME; however, there is strong evidence to suggest that hemodynamic factors are contributory to the chronic swelling.