Dialysis causes a bulge in the arm, clinically known as an aneurysm. Common causes include: long-term fixed-point puncture, oversized anastomosis, and poor puncture technique. 1. Prolonged puncture at a fixed point leads to thinning of the local blood vessel wall, which is prone to bulge and form an aneurysm. 2. The anastomosis is too large, resulting in high blood flow velocity and pressure, which makes the endovascular vein locally dilated. Local stenosis or central venous stenosis caused by repeated fixed-point puncture is more likely to form aneurysms at the distal end of the stenosis. 3. poor puncture technique, puncture damage to blood vessels, or even lead to blood vessel rupture, bleeding to form hematoma, also easily lead to dialysis arm bulging. Other reasons: such as poor blood pressure control, premature use of endovascular fistula immaturity, inadequate suture during anastomosis and other causes. During the period of dialysis, it is recommended to eat a light diet, regular rest and relaxation, reduce the amount of drinking water, any discomfort, timely regular hospital consultation.