Bursitis can cause a bursa to produce and fill up with fluid. A bursa that is swollen with fluid can be diagnosed and treated by drawing the fluid out with a needle and syringe (aspiration), although fluid often builds up in the bursa again. Draining the bursa can provide relief, but the underlying cause of fluid buildup may also require treatment. Once the fluid is tested for signs of infection or inflammation, proper treatment can be prescribed.