Dr. Shiel received a Bachelor of Science degree with honors from the University of Notre Dame. There he was involved in research in radiation biology and received the Huisking Scholarship. After graduating from St. Louis University School of Medicine, he completed his Internal Medicine residency and Rheumatology fellowship at the University of California, Irvine. He is board-certified in Internal Medicine and Rheumatology.
Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.
A bursa is a fluid-filled sac that cushions an area of friction between tissues, such as tendon and bone. Bursae reduce friction between moving parts of the body, such as in the shoulder, elbow, hip, knee, and heel.
The number varies, but most people have about 160 bursae throughout the body. Bursae are lined with special cells, called synovial cells, which secrete a fluid rich in collagen and proteins. This synovial fluid acts as a lubricant when parts of the body move. Inflammation of a bursa is referred to as bursitis.
The most common causes of bursitis are repetitive motions (for example, repeated throwing of a ball), trauma (extensive kneeling), infection, and preexisting rheumatoid conditions.
Trauma causes inflammatory bursitis from repetitive injury or direct impact.
Chronic bursitis: The most common cause of chronic bursitis is
minor trauma that may occur to the shoulder (subdeltoid) bursa from repetitive motion, for example, throwing a baseball. Another example is prepatellar bursitis
(in front of the knee) from prolonged or repetitive kneeling on a hard surface
to scrub a floor or lay carpet.
Acute bursitis: A direct blow (let's say you accidentally bang your knee into a table) can cause blood to leak into the bursa. This causes pain as well as swelling.
Bursae close to the surface of the skin are the most likely to get infected with bacteria, a condition that is called septic bursitis. The most common bacteria to cause septic bursitis are
Staphylococcus aureus or Staphylococcus epidermis. People with diabetes, alcoholism, certain kidney conditions, those taking cortisone medications (steroid treatments), and those with wounds to the skin over a bursa are at higher risk for septic bursitis. About 85% of septic bursitis occurs in men.
People with certain diseases such as gout and pseudogout can develop bursitis from crystal deposits. When these crystals form in a bursa, they cause inflammation leading to bursitis.
Ischial bursitis is inflammation of the bursa that separates the gluteus maximus muscle of the buttocks from the underlying bony prominence of the bone that we sit on, the ischial tuberosity. Ischial bursitis is a form of bursitis that is usually caused by prolonged sitting on hard surfaces that press against the bones of the bottom or mid-buttocks.