Lesson 8: Accompanying Conditions and Complications
In this lesson students will learn to recognize the conditions that often accompany hyperthyroidism or develop as a result of hyperthyroidism or its treatment.
Topics include:
Thyroid eye disease (Graves' ophthalmopathy)
Acropachy
Pretibial myxedema
Muscle weakness/atrophy
Cardiac arrhythmias
Hypothyroidism
Topics for discussion
Introduction
This section focuses on the extrathyroidal manifestations of thyroid disease. The term extrathyroidal, with the prefix meaning away from, is often used by endocrinologists to describe other organs and systems, besides the thyroid gland, that are affected by thyroid disease. In this lesson, students will learn about several conditions that can occur as a consequence or complication of hyperthyroidism such as arrhythmia; emerge as an accompanying autoimmune disorder, for instance, thyroid eye disease; or develop as a result of treatment for hyperthyroidism, for instance hypothyroidism.
Hyperthyroidism can cause a number of temporary medical conditions, such as cardiac arrhythmia, hypertension, headaches, anxiety, bone loss and myopathy, which usually resolve when thyroid hormone levels are corrected. In some cases, patients are treated for these conditions for years before their thyroid disorder is properly diagnosed. Hyperthyroidism can also cause conditions with long-term effects, such as muscle atrophy, periodic paralysis and osteoporosis. Behavioral symptoms in hyperthyroidism can also escalate into a condition of Graves' rage, a psychological occurrence which is discussed in this section.
Because of their autoimmune nature, Graves' disease and thyroiditis can be accompanied by several different conditions related to autoimmunity. These include thyroid eye disease, pretibial myxedema, vitiligo and acropachy. These conditions are also either caused or worsened by the thyroid antibodies and other immune system chemicals responsible for the thyroid disorder. Patients who have had radioiodine ablation experience a dramatic increase in these antibodies, and often, these related conditions emerge years after the initial thyroid disorder. Thyroid eye disease may also precede the development of thyroid disease.
A number of other conditions can occur as a result of treatment or from disease progression induced by treatment that stimulates the immune system. These conditions include hypothyroidism, dental cavities, salivary gland injury, hypoparathyroidism, and the development of other autoimmune disorders, such as fibromyalgia. Hypothyroidism occurs as a result of thyroidectomy surgery or radioiodine and is related to the loss of thyroid tissue capable of producing thyroid hormone. After radioiodine therapy, hypothyroidism progressively worsens over time because of continued cell destruction and autoimmune changes, whereas after surgery, hypothyroidism may improve over time. In patients with Graves’ disease, a milder form of hypothyroidism may occur spontaneously in about 20 percent of patients. Like the hyperthyroidism, this form of hypothyroidism may also resolve spontaneously.
In this section, we’ll also discuss risk factors and differences in patient population that may make a particular group susceptible to different consequences of hyperthyroidism. Bone loss, hypertension, muscle weakness, atrial fibrillation and cardiac arrhythmias are more likely to occur in elderly patients, whereas muscle weakness and Graves’ rage can occur in patients of any age. In addition, periodic paralysis is more likely to occur in Asian men.
In this section, students will also learn about disease progression. While the cardiac conditions and bone loss generally resolve after thyroid hormone levels are corrected, Graves’ rage and anxiety can be triggered or exacerbated by a sudden fall in thyroid hormone levels related to treatment. Muscle weakness can persist after treatment for hyperthyroidism especially if nutrient deficiencies are present.
