If the calf suddenly becomes thicker, there are usually several factors as follows: 1, if the calf muscle is abnormally developed due to excessive exercise, the calf will suddenly become thicker. 2, if in a non-physiological situation, pathological factors can also lead to sudden thickening of the calf, such as lower limb venous embolism or lower limb arterial reflux abnormalities and problems, this vascular disease will lead to sudden thickening of the calf, because of 3, the sudden thickening of the calf is also related to renal insufficiency, in the acute attack of chronic renal insufficiency, because the body fluid and water can not be filtered out and excreted in a timely manner, there will be a sudden thickening of the calf. 4, some infection factors, such as from the legs and feet can lead to bacterial, viral and fungal infections, at this time will produce cellulitis around the calf, will also lead to the sudden thickening of the calf. It will lead to the sudden thickening of the calf.