Hormones produced by the thyroid gland are distributed throughout the body, where they play a vital role in regulating metabolism and growth. The thyroid gland is the manufacturing center for three hormones, thyroxine, or T4, triiodothyronine, or T3 and calcitonin. Thyroid problems that alter the production of these hormones can cause wide-reaching effects throughout the body’s organ systems.
Ocular Disorders
Graves’ opthalmopathy is a form of hyperthyroidism that affects the eyes. This disease can cause swelling behind the eye sockets that makes the eyes bulge outward, a condition known as exophthalmos. Visual disturbances such as blurry vision, double vision and light sensitivity are symptoms commonly reported by those with Graves’ opthalmopathy.
The Merck Manuals Online Medical Library reports that eye movement can be restricted due to muscle inflammation caused by hyperthyroidism. Exophthalmus and retraction of the eyelid muscles can make it difficult to close the eye. The eyes lose moisture and are at increased risk of irritation from dust or other foreign substances.
Skin Conditions
Graves’ hyperthyroidism can cause the skin on the lower legs to develop a thick, orange peel texture. Itchiness and redness of the skin over the shins is sometimes experienced by those with Graves' disease
Hypothyroid conditions are those wherein the thyroid produces inadequate amounts of hormone. This can result in thick, dry, coarse skin, according to the University of Maryland Medical Center. In some cases the skin on the soles of the feet and palms of the hands turns orange.
Cardiac Dysfunction
Dr. Bahaa M. Fadel of Stanford University states that conditions in which thyroid hormone levels are increased have a marked impact on the cardiovascular system. An increase in thyroid hormone prompts the heart rate to increase and the systolic blood pressure to rise. These factors stress the heart, causing it to perform strenuously even when the patient is at rest.
Hyperthyroid patients may experience arrhythmic heartbeat. Fadel cites rapid, irregular heartbeat as hyperthyroidism’s most common cardiac complication.
Hypothyroid diseases cause the opposite effect. The body uses less oxygen, lessening the demands on the heart. The heart rate reduces, as does its output, while resistance in the blood vessels increases, according to Dr. Irwin Klein of NYU School of Medicine. This constriction of blood vessels can result in high blood pressure in up to 40 percent of those with hypothyroid conditions.
