Some patients with hypothyroidism can experience symptoms that mimic the symptoms of rheumatoid arthritis with pain in multiple joints, stiffness, and swelling. However, this occurs in patients with low thyroid levels and high TSH (thyroid-stimulating hormone, also known as thyrotropin). Once you have used thyroid medication and your TSH is normal, your arthritis-like symptoms should resolve. Some forms of hypothyroidism are considered "autoimmune," where thyroid antibodies can be seen in connective tissue. Patients with autoimmune hypothyroidism may also have other connective tissue diseases that can cause arthritis.