Systemic lupus erythematosus (SLE), commonly known as lupus, is a chronic autoimmune disease that can affect various organs and systems throughout the body. The thyroid gland, a butterfly-shaped organ located at the base of the neck, produces hormones that regulate the body’s metabolism, growth, and energy levels. A connection often exists between lupus and thyroid health, with individuals living with lupus frequently experiencing thyroid problems. This link is largely due to the shared underlying autoimmune nature of both conditions.
The Autoimmune Link
Both lupus and many thyroid disorders are classified as autoimmune conditions, meaning the body’s immune system mistakenly attacks its own healthy tissues. In lupus, the immune system can target various organs, leading to widespread inflammation and tissue damage. Similarly, in autoimmune thyroid diseases, the immune system produces antibodies that specifically attack components of the thyroid gland. The immune system’s general predisposition to self-attack can extend beyond a single target. Researchers have identified common genetic and immunological mechanisms that link lupus with autoimmune thyroid disease.
Specific Thyroid Conditions
Individuals with lupus are more prone to developing specific thyroid conditions, with hypothyroidism being the most common. Hypothyroidism, an underactive thyroid, occurs when the thyroid gland does not produce enough thyroid hormones. This condition is significantly more frequent in lupus patients, affecting 15% to 19% of them, compared to approximately 4.6% in the general population.
The primary cause of hypothyroidism in lupus patients is often Hashimoto’s thyroiditis, an autoimmune disease where the immune system gradually destroys thyroid cells, leading to reduced hormone production. While less common than hypothyroidism, hyperthyroidism (an overactive thyroid) also occurs at a higher rate in lupus patients than in the general population, with prevalence rates ranging from 3% to 9% in lupus patients compared to about 1.3% in the general population. Hyperthyroidism is frequently caused by Graves’ disease, another autoimmune condition where antibodies stimulate the thyroid gland to produce an excess of hormones.
Identifying Thyroid Symptoms
Recognizing thyroid symptoms in individuals with lupus can be challenging because many symptoms overlap with those of lupus itself. Hypothyroidism can manifest as increased fatigue, unexplained weight gain, heightened sensitivity to cold temperatures, dry skin, constipation, and feelings of depression. Conversely, hyperthyroidism symptoms include unintended weight loss despite increased appetite, a rapid heartbeat, anxiety, heat intolerance, and tremors. Therefore, it is important for individuals with lupus to report any new or worsening symptoms to their healthcare provider for professional assessment.
Diagnosis and Treatment
Diagnosing thyroid conditions in individuals with lupus involves specific blood tests. The most common tests include measuring thyroid-stimulating hormone (TSH) levels, along with free thyroxine (FT4) and free triiodothyronine (FT3). Elevated TSH levels with low FT4 often indicate hypothyroidism, while low TSH with elevated FT4 and FT3 suggest hyperthyroidism. Thyroid antibody tests, such as anti-thyroid peroxidase (TPOAb) and anti-thyroglobulin (TgAb) antibodies, are also performed to identify autoimmune thyroid conditions like Hashimoto’s thyroiditis or Graves’ disease. Given the increased risk, regular screening for thyroid dysfunction is recommended for individuals with lupus.
Treatment approaches for thyroid disorders in lupus patients generally mirror those for the general population. Hypothyroidism is managed with daily synthetic thyroid hormone replacement, such as levothyroxine, which is a lifelong treatment. For hyperthyroidism, treatment options include anti-thyroid medications to reduce hormone production, radioactive iodine therapy, or, in some cases, surgical removal of part or all of the thyroid gland.