What are the physical signs of Graves' disease?

Many of the physical signs that may be identified in patients with Graves' disease reflect the effects of exposure to excess amounts of thyroid hormone. Patients who develop Graves' disease may be noted to have an accelerated heart rate as a result of increased stimulation of the cardiovascular system. If measurement of the pulse reveals that a patient's heart is beating at a rate faster than 100 beats per minute, this acceleration is called tachycardia. Increased stimulation of the cardiovascular system may also lead to the development of abnormal heart rhythms called arrhythmias. An arrhythmia may first be detected as an irregular pulse. In most situations when an irregular pulse is detected, an electrocardiogram must be performed to determine if an underlying arrhythmia is present. Different types of arrhythmias that may be develop in the setting Graves' disease include sinus tachycardia, atrial fibrillation, atrial flutter, and paroxysmal atrial tachycardia. Examination of patients who develop Graves' disease may reveal warm moist skin that is very smooth in texture. Characteristic skin changes may be related to increased blood flow in the tissues supporting the skin and increased stimulation of the sweat glands. Neurologic testing of patients who develop Graves' disease may reveal characteristic findings related to increased stimulation of the nervous system. Testing of the reflexes may reveal sharp forceful contraction of muscles when tendons in the arms, knees, and ankles are tapped with a reflex hammer. Further testing may reveal evidence of a fine tremor when a patient is asked to hold a hand out to keep it steady. Muscle strength may be noted to be decreased when a patient is asked to push or pull against fixed resistance.

Patients with Graves' disease may have findings that become evident when their eyes are examined. Some of these findings may be related to exposure to excess levels of thyroid hormone, while others may be related to inflammation caused by exposure to TSIs. Increased contraction of the muscles that open the upper eyelids may be associated with a finding called retraction. This may become apparent when examination of the eyes reveals a delay in closure of the upper eyelids. This delay is called lid lag. Patients with retraction and lid lag may look like they are staring, even when they are completely relaxed. Inflammation of the tissues that surround the eyeballs may lead to swelling of the layer of tissue that lines the front of the eyeball and the inside of the eyelids. This swelling is called chemosis. It may be accompanied by reddening of the visible portions of the eyeball and eyelids. Moderate swelling of the muscles that control the movement of the eyeballs in the eye sockets and the soft tissue that surrounds these muscles may cause the eyeballs to protrude forward. This protrusion is called proptosis. It can be measured with a special instrument called an exophthalmometer. Severe swelling of the muscles that control the movement of the eyeballs may cause them to become trapped against the walls of the eye socket. This entrapment may become apparent when movement of the eyes is tracked during physical examination.

Examination of the thyroid gland itself may reveal enlargement that may be directly visible to outside observers. This enlargement reflects the growth of thyroid tissue stimulated by the binding of TSIs to TSH receptors. Growth of thyroid tissue may lead to enlargement of a small strip called the pyramidal lobe that extends upward from the isthmus of the thyroid gland. The pyramidal lobe is normally too small to be identified as a separate structure. In the setting of active Graves' disease, it may enlarge to the point where it can be felt on physical examination. Progressive growth of tissue may also be associated with an increase in the amount of blood that flows through the thyroid gland. The vibrations created by this increased blood flow can often be felt as a pulsing sensation called a thrill. When increased blood flow can be heard as a rush through a stethoscope held up against the thyroid gland, the rush is called a bruit.

Pretibial myxedema that develops as a complication of Graves' disease may be evident as thickening of the skin that runs along the front of the shins. This thickening may be accompanied by the appearance of lightened or darkened spots. Extensive thickening may lead to enlargement of hair follicles, giving the skin a texture and appearance that resembles an orange peel. In rare cases, pretibial myxedema may be accompanied by swelling of the soft tissues that surround the bones and muscles in the fingers, hands, and feet. This swelling is called acropachy.