Sat | Sep 24, 2022

Hypothyroidism and hypertension

Published:Wednesday | August 3, 2022 | 12:07 AM

For most, high blood pressure, or hypertension, can be attributed to family history or lifestyle. For some, however, high blood pressure is the result of either an overactive or underactive thyroid.

An overactive thyroid, known as hyperthyroidism, is a condition where the thyroid gland produces too much of the thyroid hormone. When too much of this hormone is produced, the heart is forced to work harder than usual, which increases heart rate and raises blood pressure. Hyperthyroidism is the more common thyroid disorder that can cause hypertension.

Conversely, hypothyroidism occurs when the thyroid gland is underactive and does not produce enough hormones. Hypothyroidism can weaken the heart muscle and heart rate, reducing the heart’s pumping capacity and increase the stiffening of blood-vessel walls. The combination of these changes can lead to hypertension.

If a thyroid disorder is the reason for high blood pressure, adjustments in diet and lifestyle won’t resolve the problem and medications may not be effective. If a patient’s blood pressure does not respond to conventional treatment, a doctor can perform tests to see if the thyroid is the cause.

In cases where hypertension due to a thyroid disorder is diagnosed, medications or supplemental hormones can be prescribed to control the thyroid gland and better control blood pressure.

If you suspect you have a thyroid condition that is affecting your blood pressure, you should speak with a doctor.

Hypothyroidism has been recognised as a cause of secondary hypertension. Previous studies on the prevalence of hypertension in subjects with hypothyroidism have demonstrated elevated blood pressure values.

Increased peripheral vascular resistance and low cardiac output has been suggested to be the possible link between hypothyroidism and diastolic hypertension.

Basic causes of primary hypothyroidism are autoimmune, silent, postablative, goitrous, athyreotic and nonautoimmune (e.g., Riedel’s), and subacute thyroiditis. Chronic autoimmune lymphocytic thyroiditis (Hashimoto’s disease) is the most common cause of thyroid gland dysfunction.

Hypertension, most commonly diastolic, is increased in patients with hypothyroidism because of increased peripheral vascular resistance. Hypertension is caused by hypothyroidism in three per cent of patients with high blood pressure.

Hypercholesterolemia and an increase in fatty acids are also associated with low thyroid function, thus increasing the risk of cardiovascular disease.

keisha.hill@gleanerjm.comSOURCE: Harvard Health