Hypothyroidism - Risk Factors

Complications

Hypothyroidism increases the risk for physical and mental problems.

Emergency Conditions

Myxedema Coma. Myxedema coma is a rare, life-threatening complication of untreated hypothyroidism. Symptoms include a severe drop in body temperature (hypothermia), delirium, reduced lung function, slow heart rate, constipation, urine retention, seizures, stupor, fluid build-up, and finally coma. It is uncommon, but may develop in untreated patients subjected to severe stress, such as infection, surgery, or extreme cold. Certain drugs (such as sedatives, painkillers, narcotics, amiodarone, and lithium) may increase the risk. Emergency treatment is required. Mortality rates are high (30 - 60%) with the highest risks in older patients and those with persistent hypothermia or heart problems.

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Suppurative Thyroiditis. Suppurative thyroiditis is a life-threatening infection of the thyroid gland. It is very rare, since the thyroid is normally resistant to infection. People with pre-existing thyroid diseases, such as Hashimoto's thyroiditis, however, may be at higher than average risk for suppurative thyroiditis. It often begins with an upper respiratory infection. Symptoms include fever, neck pain, rash, and difficulty swallowing and speaking. Immediate treatment is required.

Effects of Hypothyroidism and Subclinical Hypothyroidism on the Heart

Thyroid hormones, particularly triiodothyronine (T3), affect the heart directly and indirectly. They are closely linked with heart rate and heart output. T3 provides particular benefits by relaxing the smooth muscles of blood vessels. This helps keep the blood vessels open so that blood flows smoothly through them.

Hypothyroidism is associated with:

• Unhealthy cholesterol levels. Hypothyroidism raises levels of total cholesterol, LDL ("bad" cholesterol), triglycerides, and other lipids (fat molecules) associated with heart disease. Treating the thyroid condition with thyroid replacement therapy can significantly reduce these levels.
• Mild high blood pressure. Hypothyroidism may slow the heart rate to less than 60 beats per minute, reduce the heart's pumping capacity, and increase the stiffness of blood vessel walls. All of these effects may lead to high blood pressure. Indeed, patients with hypothyroidism have triple the risk of developing hypertension. All patients with chronic hypothyroidism, especially pregnant women, should have their blood pressure checked regularly.
• Heart failure. Hypothyroidism can affect the heart muscle’s contraction and increase the risk of heart failure in people with heart disease.