Thyroid stimulating hormone, usually conicida by its acronym in English, is manufactured by the pituitary gland.
The release of TSH stimulates the thyroid to produce T3 and T4, the hormones responsible for thyroid function.
If the thyroid stops working, TSH levels increase as the body tries to “force” the thyroid to produce hormones.
This reaction, known as a feedback loop, causes TSH levels to rise above their normal range.
High levels of TSH in the blood indicate an underactive thyroid or hypothyroid, a condition that affects up to 10 percent of women and six percent of men over 65, according to the Merck Manual, and causes a variety of symptoms.
High TSH levels due to an underactive thyroid cause many changes in the skin and hair.
The skin often becomes dry, scaly, thick and pale.
The palms and soles of the feet may appear yellowish due to the deposit of carotene.
The hair becomes thin and becomes dry and rough.
Fluid retention and weight gain can occur, along with swelling of the face and swelling around the eyes.
The facial expression may seem boring and the eyelids may fall.
The nails become brittle and break easily. The tongue can increase its size.
People with high TSH often experience mental changes.
They may become depressed, suffer memory loss and have difficulty processing information.
Speech may be slow and dementia may occur.
If TSH hormone levels are extremely low for long periods of time, a life-threatening condition called myxedema coma may occur.
The high TSH levels of thyroid disease cause muscle and joint pain, along with stiffness and swelling.
There may be weakness and loss of deep tendon reflexes.
Numbness and tingling in the extremities, are recurring effects.
The systemic symptoms of high TSH of the underactive thyroid include sensitivity to cold due to low body temperature, slowness and fatigue.
If a myxedema coma develops, seizures may occur.
High levels of TSH in the low-functioning thyroid can increase cholesterol levels.
Heart enlargement and heart failure can occur even in people with subclinical thyroid disease, which has few symptoms.
Fluid can accumulate around the heart and lungs and the heart rate can become bradycardic or slower than normal.
Women with high TSH levels may have heavier than normal periods or no periods at all.
Infertility can occur due to lack of ovulation. Sexual desire often decreases.
There are several possible causes that can influence TSH levels:
- Poisonous substances and exposure to radiation.
- Inflammation of the thyroid gland
- Deficiency or excess of iodine in the body.
- The pregnancy.
- Certain medications such as antidepressants, medications to reduce cholesterol, chemotherapy drugs, steroids.
- Thyroid cancer.
The hypothyroidism is one of the most common causes of elevated TSH levels according to the National Institute of Diabetes and Digestive and Kidney Disorders.
The pituitary produces TSH to stimulate the production of thyroid hormones.
These hormones, in turn, inhibit the production of TSH by the pituitary, which allows the pituitary gland to decrease TSH production when there are adequate amounts of thyroid hormone in the blood.
This type of system, where the presence of a hormone inhibits the production of another hormone, is known as a feedback loop.
When there are insufficient levels of thyroid hormones in the blood, the pituitary gland will produce additional TSH in an attempt to start the thyroid.
The most common cause of hypothyroidism is called Hashimoto’s disease, in which the immune system attacks the thyroid.
The thyroid can also become inflamed, resulting in a low production of thyroid hormone.
Certain medications can also cause low secretion of thyroid hormone.
Finally, some people have thyroid glands that do not work properly, for reasons that doctors do not fully understand.
Pituitary adenomas are a form of brain cancer that arises from hormone-secreting cells.
In most cases, the Department of Neurosurgery at UCLA explains that pituitary adenomas secrete a growth hormone, prolactin or the adrenocorticotropin-releasing hormone.
However, in some cases, a pituitary adenoma will secrete TSH, resulting in high levels of TSH in addition to high levels of thyroid hormone.
In such cases, the pituitary adenoma does not stop secreting TSH in the presence of high levels of thyroid hormone.
Resistance to the Thyroid Hormone:
Resistance to thyroid hormone is a condition in which the body does not respond adequately to thyroid hormones, says the Manager of Thyroid Diseases.
In most cases, resistance to thyroid hormone is caused by a mutation in the gene that encodes the thyroid hormone receptor, a protein responsible for binding and detecting the hormone.
If this protein does not work properly, the pituitary gland will behave as if there were low levels of thyroid hormone even in the presence of normal or elevated levels.
All this results in high levels of TSH in the blood.
Normal levels of TSH
Normal TSH levels for the average adult range between 0.4 and 4.0 mIU / l (milli-international units per liter).
However, many organizations agree that a reading of 2.5 or less is really ideal, compared to the amount of 2.6 to 4.0 mIU / L considered “a risk”.
For those with thyroxine, the target TSH level is 0.5 to 2.5 mU / L.
The reference ranges change slightly as we get older and if you are pregnant.
Normal levels of TSH during pregnancy:
- First quarter: 0.3-4.5 mIU / L.
- Second trimester: 0.3-4.6 mIU / L.
- Third trimester: 0.8-5.2 mUI / L.
Results may vary depending on the laboratory, the time of day your blood was taken, and the methods used.
Niveles altos de TSH
A TSH reading above 4.0 mIU / L is considered high (elevated).
High levels of TSH usually indicate an underactive thyroid gland, which produces too little thyroid hormone.
This is medically known as hypothyroidism.
Common causes of hypothyroidism include an autoimmune disease (known as Hashimoto’s disease), radiation therapy, or surgical removal of the thyroid gland.
For a safe and effective treatment of an underactive thyroid, it is crucial to replace the thyroid hormone and alter your diet.
TSH in infants
TSH levels in babies should be regulated to keep them healthy and develop properly.
TSH levels are measured during the first days of a baby’s life by drawing blood.
Because the mother’s thyroid hormones cross the placenta, it may not be immediately apparent if her baby’s TSH is within the normal range just after birth.
Your newborn baby may need another series of blood tests between the ages of 2 and 6 weeks to confirm the readings; your TSH level in this age range should be between 1.7 and 9.1 milliunits per liter – mU / L.
High TSH levels in a baby usually point to congenital hypothyroidism, a condition that can have dire consequences if not treated quickly.
Hypothyroidism is a condition in which the body does not produce enough thyroid hormone, which is indicated by a high TSH test of 40 mU / L.
Congenital hypothyroidism that is not treated during the first weeks of a baby’s life can cause mental retardation.
Other factors that can create higher-than-normal TSH readings in older babies who are not diagnosed with congenital thyroid disease are environmental toxins.
Environmental Health News reported in July 2010 that three different chemicals that are present in water, some foods and tobacco smoke can inhibit the production of thyroid hormones, which causes TSH levels to rise.
Chemists, thiocyanate, perchlorate and nitrate can contaminate drinking water and become an unwanted ingredient but is commonly seen in baby formula mixed with drinking water, in breast milk produced by mothers who drink water and in babies who drink water on their own.
Is it possible to have a high TSH and normal level of T3 and T4?
If, in some cases, the serum levels of T3 and T4 can be kept relatively within the range of normal, despite the elevation of TSH levels.
Some people assume that this is a reactive response, but you must realize that serum thyroid hormone levels do not necessarily reflect tissue levels of thyroid hormone.
The important thing is not the serum concentration but the amount of thyroid hormone that enters the cells and activates the genetic transcription.
TSH reflects the tissue concentration of the pituitary gland, but does not reflect the concentration of, say, your liver.
We can use SHBG as an indirect marker to evaluate the concentration of thyroid function in the liver and this can actually be used as a somewhat sensitive marker for tissue levels in other parts of the body.
The metabolism of proteins and fats, respiration, heat production, heart function and appetite are important functions of the body in which thyroid hormone contributes.
The time when TSH levels rise is because the thyroid gland generates more thyroid hormone than it should, but it could also be because your thyroid is not active and does not respond to TSH.
In any case, when tests indicate that your TSH levels are high or fluctuate widely, it could indicate an endocrine problem that requires medical attention.
Similarly, there are certain lifestyle and dietary practices that, if followed, will help stabilize or suppress TSH levels in your body.
If you think that your TSH levels are above normal, consult your doctor.
The symptoms mentioned above occur when Graves disease or Hashimoto’s thyroiditis, which happens when the immune system incapacitates or damages the thyroid gland causing it to become inflamed.
You should normalize your fiber intake.
A diet high in fiber provides many benefits, but fiber can also affect the way the thyroid absorbs hormones and can ultimately affect your TSH level.
Do not stop eating foods that are high in fiber.
If you have just started eating a high-fiber diet, give your body and your thyroid gland time to adjust to the new regimen.
Avoid hesitation in fiber intake, as it may contribute to erratic TSH absorption and lead to sporadic increases in TSH.
While you are taking thyroid medication, avoid taking iron and calcium supplements, vitamins and iron tablets.
The mixture of iron and calcium can alter the absorption of TSH in the body.
However, if you must take an iron and calcium supplement, it is recommended to wait between 2 and 4 hours between one medication and another.
TSH levels may increase due to excessive consumption of soy foods, so you should avoid them as much as possible.
The condition of the thyroid can be aggravated thanks to soy protein powder or other products with high concentrations of soy and over-the-counter menopause supplements.
Avoid eating too many goitrogenic foods, because they enlarge the thyroid and reduce their ability to respond to TSH.
Gobiogenic foods include turnips, Brussels sprouts, kohlrabi, radishes, cauliflower, kohlrabi, cabbage and kale.
However, it can eliminate or minimize its negative effect on the thyroid if they are cooked very well.
For most people, eating a moderate amount of these foods does not cause problems.
Control and restrict your use of certain herbal supplements.
Seaweed, iodine-containing products, vitamins, guggul, tyrosine, bladderwrack supplements and some other supplements can affect thyroid function, causing changes in your TSH.
Manage your diet, stress and sleep.
Your entire endocrine system responds to lack of sleep and periods of extreme stress.
Patients with Graves disease and Hashimoto often experience an exacerbation of their symptoms when they are tired, stressed or eat poorly.
If you feel that anxiety and stress are too many, it is best to find a way to address your problems and ease your mind, seeking the help of a professional or talking to a trusted friend who can listen to you.
The best way to stabilize your TSH levels and improve your mood is by: eating a healthy and balanced diet and improving your sleep habits.