Many people suffer from conditions which can cause swelling of the legs. You will notice the leg swelling because your shoes won’t fit. Your pants might be tighter down lower than usual.
Many conditions cause swelling of the legs. Some are serious others are not as serious
If your heart is not pumping as well as it should, fluid can back up into your legs. It might be because of a leaky valve, poor muscle performance such as from a heart attack, fluid around the heart or elevated pressure in your lung vessels. A blood clot in the lungs can make it harder for the heart to work.
If your liver or kidneys are working well, this can lead to fluid retention as well. Low levels of an important protein called albumin will do the same. Leaky valves in the veins will make it harder for the blood to return to the heart and thus cause swelling.
A blood clot or infection in your leg will cause inflammation and with the inflammation swelling
Of course many drugs can lead to swelling of the legs.
If the swelling comes on suddenly. is severe and or associated with shortness of breath, fever, weakness, chest pain or rapid heart rate,you should really be seen right away in the emergency room. For swelling that is slowly becoming worse you can make an appointment to be seen by your doctor, who can order the necessary studies.