How lupus affects the bones
Lupus can affect any part of the body, including the bones and bone tissue. Two especially common complications of lupus on the bones are osteoporosis and avascular necrosis.
The lupus-osteoporosis link
Osteoporosis is a condition in which the bones become less dense and more likely to fracture.
Studies have found an increase in bone loss and fracture in individuals with lupus. In fact, women with lupus may be nearly five times more likely to experience a fracture from osteoporosis. Individuals with lupus are at increased risk for osteoporosis for many reasons.
To begin with, the steroid medications often prescribed to treat lupus can trigger significant bone loss. In addition, pain and fatigue caused by the disease can result in inactivity, further increasing osteoporosis risk.
Studies also show that bone loss in lupus may occur as a direct result of the disease. Of concern is the fact that 90 percent of the individuals affected with lupus are women, a group already at increased osteoporosis risk.
Risk factors for developing osteoporosis include:
- having a family history of the disease
- for women, being postmenopausal, having an early menopause, or not having menstrual periods (amenorrhea)
- using certain medications, such as corticosteroids (steroids, glucocorticoids)
- not getting enough calcium
- not getting enough physical activity
- drinking too much alcohol.
Osteoporosis is a silent disease that can often be prevented. However, if undetected, it can progress for many years without symptoms until a fracture occurs.
Understanding avascular necrosis of the bone
Avascular necrosis (AVN) of the bone (also called aseptic necrosis or osteonecrosis) is characterized by reduced blood flow and increased pressure within a portion of the bone. Weakening of the bone occurs, causing tiny breaks, and eventually the bone surface collapses.
The causes of AVN are not known, but it is associated with long-term use of high doses of corticosteroids, alcohol abuse, sickle cell anemia, pancreatitis, trauma and other conditions. When AVN develops in people with lupus, it is almost always a result of corticosteroid use.
AVN affects the hips, shoulders and knees most commonly. The initial symptom is pain in these joints, especially when engaging in weight-bearing activities such as walking, running and lifting objects. These types of motions lead to stiffness, muscle spasms and limited movement of the affected joint.
As AVN becomes more advanced, pain may occur at rest, especially at night. Currently there is no effective medical treatment that can reverse this condition. In advanced cases, surgery (including artificial joint replacement) can be effective in relieving pain and improving mobility and function.