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 with suppressed immune systems such as from 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.
The most critical diagnosis to make early in this group is the femoral neck stress fracture. This is usually found in the patient who is involved in an endurance sport. Another group at increased risk is women with the female athlete triad (amenorrhea, eating disorder and osteoporosis). 14 The typical history in these cases is progressively increasing pain with exercise that eventually becomes pain at rest. Femoral neck stress fractures can progress to unstable fractures and are at increased risk for avascular necrosis of the femoral head. Bone scans are a useful “negative” test because they are up to 100 percent sensitive 15 for stress fractures of the femoral neck. Positive scans are nonspecific and may require MRI or other imaging to be certain of a diagnosis.