The occurrence of swollen legs can be as a result of a fluids accumulation (so-called water retention) or an inflammation associated with trauma or diseases of the tissues or the joints. Often its cause is easily identified, but one should not underestimate the risks that are associated with serious conditions, such as heart disease or blood clots.

 
What kind of diseases can be associated with swollen legs?
The diseases that may be associated with swollen legs are the following:
    •    Rheumatoid arthritis
    •    Arthrosis
    •    Bursitis knee
    •    Prostate cancer
    •    Cardiomyopathies
    •    Cellulite
    •    Liver cirrhosis
    •    Baker's cyst
    •    Embolism
    •    Gout
    •    Infections
    •    Heart failure
    •    Kidney failure
    •    Chronic venous insufficiency
    •    Lymphedema
    •    Chronic kidney disease
    •    Pericarditis
    •    Polycythemia vera
    •    Pre-eclampsia
    •    Premenstrual syndrome
    •    Thrombophlebitis
    •    Deep vein thrombosis
    •    Varicose veins

Remember that this is not an exhaustive list and it is highly recommended to consult your doctor, in case of symptom’s persistence. 
 
What is the therapy for swollen legs?
The swollen legs can be remedied with activities like sleeping with a pillow under the calves or avoiding prolonged immobility. In some cases it may be necessary to modify the intake of a certain drug. On other times particular medical conditions may, however, help to reduce the pain. There are also cases where a specific treatment is needed which depends on the underlying cause of the swelling.
 
When is most likely to contact your doctor in case of  swollen legs?
You should seek medical attention if the legs remain swollen for a long time for no apparent reason. It is however good to go to the emergency room if they are associated with the symptoms that may indicate the presence of a blood clot in the lungs or of a serious heart problem, such as a pain in the chest that lasts more than a few minutes, breathing difficulties, fainting and dizziness, confusion. It is also good to go to the emergency room even when the swelling is associated with physical trauma.