Bone Health in SLE - An Insight

Introduction

Systemic lupus erythematosus (SLE) is a chronic, inflammatory disease with a high incidence rate in women relative to men. Out of 10 people affected by SLE, 9 of them identify as female. The disease is a common autoimmune condition that impacts various organ systems of the body. Because it is autoimmune, the exact cause of the illness is unknown. Several suggested factors contribute to this illness. The diagnosis of lupus poses a challenge to every clinician. One needs to rely on the doctor’s expertise for a timely diagnosis and accurate treatment plan that is instantaneously brought into action. The clinical manifestations of SLE are observed in almost all organ systems present throughout the body. Some examples include the renal, cardiovascular, neuropsychiatric, ocular, and endocrine systems as well. This specific article reviews the effect of SLE on bone health, also called the skeletal system.

What Is Considered as Good Bone Health?

Bone health is considered good when a perfect balance is maintained between the rate of bone formation and the rate of bone resorption. The human bone undergoes constant remodeling that typically involves destroying weak, fatigued bone and simultaneously producing strong, resilient bone. This particular cycle of removing old bone and forming new healthy bone must be kept in a state of balance (bone homeostasis) in order to achieve optimum bone health. With advancing age, this balance is naturally disrupted. The bone strength and density begin to deteriorate each passing year after the age of 30. This imbalance in bone homeostasis contributes to a weaker, less resilient bone structure that is subjected to an increased risk of developing osteoporosis or osteopenia. The poor quality of bone increases one’s risk of getting fractures upon the slightest of trauma, like tripping over or falling from a standing position.

How Does Lupus Affect Bone Health?

SLE is an autoimmune disorder characterized by inflammation in several parts of the body. The inflammation in bone results in a diminished bone mineralization process, which in turn contributes to the development of weak, brittle bones. Bone remineralization is the process by which essential minerals like calcium, magnesium, phosphorus, sulfur, potassium, and iron are taken from the blood and deposited into the bone to aid in its strengthening process.

The inflammation induced into the bone owing to the lupus results in a decreased bone mineral density, leading to the weakening of the bone structure. The conditions borne from this phenomenon are namely:

1. Osteopenia: This condition involves a moderate decrement in the bone mineral density.

2. Osteoporosis: This condition is characterized by a higher decrease in bone mineral composition.

3. Avascular Osteonecrosis: This condition is observed in bones that have an insufficient blood supply, thus contributing to weakly developed bones and joints.

The rest of the article focuses on discussing these conditions a little in detail.

What Is Osteoporosis?

Osteoporosis is nothing but a remarkable loss of mineral content from bone structure, resulting in a dangerously lower bone mineral density. The bone formation rate is not able to match up to the increasingly faster bone resorption rate, resulting in the formation of fragile bones susceptible to fractures. Women tend to be more prone to acquiring osteoporosis than men. Apart from inflammation, there are several other reasons that contribute to lower bone mass and density. These are listed below:

• Prolonged use of corticosteroids and glucocorticoids can lead to weakened bone structure. These drugs may help with lupus symptoms but, at the same time, limit the absorption of calcium, leading to decreased bone mineral density.

• Reduced physical activity due to existing weak bones and muscular fatigue accompanied by joint pain experienced by lupus patients. Exercise and movement have been proven to increase bone strength and muscle mass.

• Women nearing the age of menopause tend to suffer from bone loss due to lower production of estrogen. Estrogen hormone is said to be bone-protective in nature.

• Reduced bone mineral density due to a lack of source for remineralization. Inadequate amounts of bone-friendly minerals ingested may lead to the formation of weak and fragile bones.

• Debilitating habits like smoking, tobacco use, nicotine addiction, or alcohol consumption may also contribute to ill bone health.

Osteoporotic SLE patients tend to undergo a relatively higher amount of fractures and bone loss compared to healthy individuals of similar age and origin. Patients with neurological clinical manifestations of SLE are more prone to falls, and imbalance. This makes such patients more susceptible to fractures.

What Is Osteonecrosis?

Osteonecrosis is a common finding in SLE patients. It is one of those conditions that is characterized by increased pain and decreased range of motion of the affected patient. The disease involves impaired blood flow to the bones, resulting in the necrosis of bone marrow and the trabecular structures comprising the bone. The most frequently involved joints include the hip and knee joints. Other joints that may be involved include the shoulder, elbow, and ankle joints. The incidence of avascular necrosis has significantly reduced in recent times owing to the advanced medical research and treatment options available to the mass population.

What Is the Treatment for Bone-Related Disorders Induced by Lupus?

The non-pharmacological treatment options to reduce decreasing bone mineral density include:

1. Quitting habits like smoking and tobacco consumption. Cessation of alcohol consumption is also advisable.

2. Supplementation with vitamin D and calcium along with a well-balanced diet consisting of all the essential nutrients required to keep the bones and joints healthy.

3. Implementing regular physical activity, preferably weight-bearing or resistance exercise, can help gradually increase bone strength and mass.

The pharmacological treatment for bone loss includes the administration of drugs like bisphosphonates, parathyroid hormone agonists, Denosumab, and Teriparatide.

Conclusion

The musculoskeletal manifestations are reported in about 90 percent of SLE patients. Compromised bone health is one of the leading causes of death in SLE patients. The disability of the patient, along with increased dependability due to a weak and brittle skeletal framework, is a terrible setback for SLE patients to undergo. Timely diagnosis of lupus and keeping a cautious eye on all aspects of the supposed clinical manifestations produced by the disease is essential for overall longevity and quality of life.