Hormonal Imbalance - A Cause Of High Blood Pressure : Secondary Hypertension (Part-II)
Hormonal Imbalance can be a cause of blood pressure that is resistant to routine medicines
The Endocrine Or Hormonal System
The functions of our body are regulated by two major control systems, which include the following:
- The nervous system.
- The hormonal or endocrine system.
Hormonal system is concerned principally with control of different metabolic functions of our body, such as the rates of chemical reactions in the cells, or transport of substances through cell membranes, or other aspects of cell metabolism like growth and secretion.
Some hormonal effects occur in seconds, whereas others require several days to start but then continue for weeks, months, or even years.
An Overview Of Important Endocrine Glands And Their Hormones
A hormone is a chemical substance that is secreted into the body fluids by one cell or a group of cells and exerts control on other cells of the body.
The important endocrine glands and hormones produced by them include the following:
- Anterior Pituitary : The hormones secreted from anterior lobe of pituitary gland include the Growth Hormone (causes growth of almost all cells of the body); Adrenocorticotropin (causes adrenal cortex to release its hormones); Thyroid stimulating hormone (causes the thyroid gland to release its hormones);Prolactin; Follicle stimulating hormone; and the Luteinizing hormone.
- Posterior Pituitary: The hormones released by the posterior lobe of pituitary gland include Antidiuretic hormone (ADH) that causes the kidneys to retain water, and Oxytocin.
- Adrenal cortex: This produces hormones cortisol (controls the metabolism of proteins, carbohydrates, and fats); and aldosterone (causes sodium retention and potassium excretion by the kidneys).
- Thyroid: The chemical messengers produced by the thyroid include T3 (Triiodothyronine) and T4(Tetraiodothyronine) both of which increase the rates of chemical reactions in the body, and Calcitonin that promotes deposition of calcium in bones.
- Islets of Langerhans of Pancreas: This endocrine organ produces two major hormones - Insulin(promotes glucose entry into most cells of the body, thus controlling the rate of metabolism of most carbohydrates) and Glucagon(increases the release of glucose from the liver into circulating body fluids)
- Ovaries and testes: Produce their respective hormones.
- Parathyroids: They release the parathormone that plays a role in controlling calcium levels in the blood.
Hormones are required in minute quantities to cause significant changes throughout the body.
Dysbalanced Hormones Can Be A Cause Of High Blood Pressure
An imbalance in the concentration of certain hormones in our body can cause an increase in blood pressure levels. The conditions associated with such hormonal; irregularities include the following:
Imbalance in cortisol levels leads to hypertension
1. Adrenal Hypertension
High blood pressure is a feature of a variety of adrenal cortical abnormalities. These glands sit on top of the kidneys and are crucial for producing adrenaline and various other hormones.
In this condition, a benign tumor or adenoma of the adrenal gland (Conn's syndrome) or a generalized increase in size called hyperplasia of the adrenals causes overproduction of the hormone aldosterone. This in turn causes retention of salt, leading to volume expansion, and an increase in blood pressure. This condition is characterized by potassium depletion leading to an imbalance in electrolytes in our body that causes muscle weakness and fatigue. It also causes an increase in diastolic blood pressure (the bottom number) along with frequent headaches. Increased frequency of urination (polyuria) resulting from impairment of urinary concentrating ability and excessive thirst (polydipsia) are also present.
This condition is associated with increased secretion of hormone cortisol by the adrenal glands. It could be a result of a tumor of pituitary gland in the brain that causes overproduction of ACTH (AdrenoCorticoTropic Hormone) which stimulates the adrenals to release more cortisol; a defect in hypothalamus or higher neural centers, certain non-endocrine tumors like cancer bronchus, pancreas, and thymus secreting chemical factors that resemble ACTH; a benign or malignant tumor of adrenal gland; or prolonged intake of steroids or ACTH for various other medical conditions. In this disease, a high blood pressure is often associated with truncal obesity, fatigue and weakness, excess growth of facial and body hair in females (hirsutism), stretch marks or abdominal striae, edema or generalized swelling, glucose in urine, osteoporosis and easy bruising. High blood pressure is a result of salt and water retention.
In this condition, increased secretion of adrenaline and noradrenaline by a tumor located in the medulla of adrenal gland causes over stimulation of adrenergic system, which results in constriction of blood vessels and stimulation of the heart. Most individuals with this tumor develop paroxysms of high blood pressure or hypertensive crisis, seizures, and anxiety attacks. The high blood pressure responds poorly to the conventional treatment. A person with this tumor may also suffer from headaches, excessive sweating, and/or palpitations feeling the thumping of heart).
2. Excess Growth Hormone - A Cause of High Blood Pressure
Acromegaly or excess production of Growth Hormone from the pituitary in middle age results in this rare disease. Most people suffering from this disease have enlargement of hands and feet, the hat size increases, lower jaw and tongue increase in size, and teeth become widely spaced, along with coarsening of facial features. The affected individual develops a hollow sounding voice due to enlargement of larynx or voice box and sinusitis, along with a doughy, moist, and warm handshake, skin tags, increased heel pad, oily skin, dark patches around the neck, on underarm area, hips, and thighs. Basal Metabolic Rate (BMR) is increased, causing weakness, fatigue, and sweating. Headaches, tingling, numbness and joint pains are also common. High blood pressure occurs with the expansion of blood volume and an increase in total body sodium and is often accompanied by heart failure.
Tumors or enlargement of parathyroid glands may cause hyperparathyroidism. This causes increased absorption of calcium present in the diet from intestines, reduced excretion of calcium from the kidneys, and increased bone calcium release. The net result is an increase in blood calcium levels. This condition is accompanied by high blood pressure which is attributed to two main reasons:
- Kidney damage from the deposition of calcium causing kidney stones.
- An increase in serum calcium levels. This causes accumulation of calcium in the cells of the inner lining of blood vessels, increasing their reactivity and causing blood vessel constriction.
Hormonal Causes Of High Blood Pressure
Increased secretion of cortisol
Truncal obesity, fatigue, hirsutism
Increased Growth Hormone levels
Enlargement of hands, coarsening of facial features
Increase in thyroid hormone levels
Heat intolerance, increased appetite
In this condition thyroid gland makes too much hormone. Also known as overactive thyroid, this may be a result thyroiditis or inflammation of thyroid due to viral infections, some medicines, or after pregnancy, eating too much foods that contain iodine, non-cancerous growths of thyroid or pituitary, or taking a high dose of thyroid hormone. It results in difficulty in concentration, fatigue, frequent bowel movements, thyroid swellings, hand tremors or shakiness, heat intolerance, increased appetite, increased sweating, nervousness, sleeplessness, and weight loss. It also results in a high systolic pressure (the first number of blood pressure reading), and increased heart rate.
5. Post menopausal High Blood Pressure
Hot flushes are common in women during the menopausal transition. They can cause physical discomfort, disturbed sleep, fatigue, irritability, and depression. In a publication from the Study of Women's Health Across the Nation (SWAN) Heart Study, Thurston et al showed that compared to their counterparts, women with hot flashes had increased subclinical or latent heart diseases. Eindhoven Perimenopausal Osteoporosis Study (EPOS), a large-scale screening program established in the Netherlands to assess the determinants of low bone mineral density in perimenopausal women showed that they had higher mean cholesterol levels, body mass index, and diastolic blood pressure measurements. This risk further increased with increasing age, smoking status, and alcohol intake.
6. Birth Control Medicines
Several years ago, the use of synthetic estrogens in birth control medicines was the main cause of high blood pressure in women. This is no longer true, owing to the lower estrogen content in these medicines now. In women taking these medicines, those who become hypertensive, the mechanism is activation of the angiotensin-aldosterone system. The synthetic estrogen hormones increase the production of chemical angiotensinogen from the liver, which in turn favors increased production of angiotensin-II and an increase in hormone aldosterone. Only a small number of women taking these medicines have an increase in blood pressure to a level greater than 140/90 mm Hg, and in about half of these, the increased blood pressure will come back to normal within 6 months of stopping the medicines. The reason why some women taking these medicines develop high blood pressure, while others do not, include-
- Some women have an increased blood vessel sensitivity to angiotensin-II.
- A mild kidney disease is already present.
- The family history of high blood pressure.
- Age (>35 years).
- High estrogen content of the medicine.
High blood pressure is often symptomless, yet is a leading cause of cardiac problems and stroke. The condition is defined as having blood pressure readings above 140/90. The risk of stroke doubles with every 20 point rise in systolic blood pressure above 115 mm Hg. Early detection and treatment through various lifestyle measures and medications, is necessary to prevent its damaging effects on vital systems of our body.
- Hyperthyroidism and other causes of thyrotoxicosis: Management Guidelines of the American Thyroid Association and American Association of Clinical Endocrinologists.
- Menopausal Complaints are associated with cardiovascular risk factors. Hypertension 2008:51:1492-1498.
Disclaimer: The information in this hub is for educational purposes. It does not intend to replace your doctor or healthcare professional's advice.