Subclinical Hyperthyroidism: Symptoms, Causes & More

Subclinical hyperthyroidism is a condition in which the fundamental sign is the appearance of low or suppressed TSH levels, with normality of peripheral thyroid hormones, the appearance is associated with multiple processes such as endemic iodine deficiency, autoimmune processes, tumors…

It can be included within a syndrome or syndromic picture because it is a situation that is reached and not an entity in itself, since the analytical values may not be significant enough to give the diagnosis of subclinical hyperthyroidism.

Although ultrasensitive determinations are currently used, a TRH stimulation test is usually required, showing a flat profile, in order to rule out situations in which we can find reduced TSH levels secondary to depression, TSH insufficiency, pregnancy, use of drugs and in those situations in which thyroid treatment is partial, all these secondary causes of subclinical hyperthyroidism.

The causes of primary subclinical hyperthyroidism

In the case of primary subclinical hyperthyroidism, they are observed in Graves’ disease, in toxic multinodular goiter, subacute thyroiditis in its destructive phase, fundamentally in gestation.

As we can see, hyperthyroidism can derive from inflammatory responses to autoimmune mechanisms, passing through hormonal changes such as those that occur in pregnancy, due to iodine deficiency or thyroid enzyme dysfunction.

Endocrinologists name two main reasons that cause an increase in TSH with normal levels of thyroid-stimulating hormones T3, T4.

Destruction and dysfunction of the thyroid gland against the background of:

• Autoimmune failures
• Surgical removal of an organ
• Radiation exposure
• Transient hypothyroidism with thyroiditis
• Infiltrative and infectious pathologies
• Developmental anomalies – agenesis and dysgenesis of the thyroid gland.

Dysfunction of the production of hormones with:

• Defects in biosynthesis of congenital genesis
• Severe deficiency or excess of iodine.

The negative effect on the thyroid gland of thyrostatics, antidepressant drugs, amiodarone, alpha-interferon, etc. has been proven.

Symptoms of subclinical hypothyroidism

Subclinical hyperthyroidism
Subclinical hyperthyroidism

There are no exact clinical manifestations yet for Subclinical hyperthyroidism. The appearance of dry skin, fatigue, pastosity of the face, cognitive disorders indicate a clear pathology.

The subclinical type of hypothyroidism can initiate cardiac diseases complicated by cardiovascular insufficiency, dysfunction of the left ventricle. Patients with hypothyroidism have an increased risk of atherosclerosis and myocardial infarction.

• Pain in the heart
• Shortness of breath
• Weakness
• Swelling of the lower extremities, etc.

Against the background of hyperthyrotropinemia, there is a risk of developing dementia in people over 75 years of age. Memory impairment, the development of depression are more typical for overt hypothyroidism.

Infertility and problematic pregnancy. Infertility is associated with impaired ovulation and a lack of progesterone synthesis. During pregnancy against the background of uncompensated hypothyroidism, the likelihood of:

• Intrauterine growth retardation and fetal death
• Premature birth
• Placental abruption
• Severe gestosis (impaired kidney function with a simultaneous increase in blood pressure, eclampsia)
Gestational diabetes mellitus
• Dementia in a child.

Hyperthyrotropinemia is considered as one of the reasons for the failure of in vitro fertilization.

How to diagnose subclinical hyperthyroidism

An excess of thyroid-stimulating hormone in the blood is laboratory confirmed twice with an interval of 3-6 months. Additionally, look at the level T4. After assessing the history of the disease, palpation of the thyroid gland, the doctor may order an ultrasound examination of the neck.

For differentiation with primary hypothyroidism, with a decrease in T3-T4 and a simultaneous increase in TSH, magnetic resonance or computer scanning of the pituitary gland is performed. Autoimmune thyroiditis is ruled out if there are no antibodies to thyroid peroxidase in the blood test.

Which doctor to contact

In most cases, the therapist, cardiologist, gynecologist directs the patient to an appointment with an endocrinologist after detecting changes in the hormonal profile.

How to treat subclinical hypothyroidism

Currently in subclinical hyperthyroidism there are different opinions on the use of early treatment of affected patients, although some of the studies show long-term cardiovascular and osteoarticular pathology, the patient’s context must be taken into account to determine the therapeutic guidelines to follow.

However, therapeutic treatment will be used on few occasions and in this case the clinician is the one who must act, in relation to the patient’s context and the clinical experience obtained.

The normal level of thyroid-stimulating hormone is 0.5 – 2.0 mU / l. The appointment of hormone replacement therapy with levothyroxine in the subclinical type of hypothyroidism implies an individual approach, taking into account: the patient’s age, lipid profile indicators, concomitant cardiovascular pathology, pregnancy or its planning.

The dosage of the drug is individual.



Preventive measures for subclinical hyperthyroidism include:

• A balanced diet with enough iodine, eating seafood
• Regular blood donation for thyroid hormones when taking thyrotoxic drugs
• Timely rehabilitation of infectious foci in the body
• Dynamic ultrasound of the thyroid gland in chronic pathology
• Observation by an endocrinologist after surgery, radiation therapy.

Subclinical hyperthyroidism as a result of epigenetics?

At present, aspects of lifestyle and diet are being associated with the appearance of diseases of multifactorial origin, epidemiological studies guide us, at present, to understand that we can modify what was thought unchangeable, benefiting from it, and also science Experimental seems to have one of the keys to this enigma “epigenetics”.

With epigenetics it seems that one can approximate, to what was empirically intuited, that what enters through our mouth or what comes out of it, can modify us in the depths of our nature, that is, how we think and act, the environment in which we live and feed ourselves, are capable of modifying our genetic characteristics, but without modifying our DNA, but rather its expression.

In some studies, the effect of the environment and our relationship with it can be inferred in the activation of certain silent diseases, as in the case of subclinical hypothyroidism and hyperthyroidism.

It was C. Waddington who, in 1942, coined the term epigenetics for the mechanisms responsible for controlling genetics, its expression.

At present, it has been seen how different studies have given particular characteristics to foods for being able to act on the pressure of genes, that is, on epigenetics. But we should not ask ourselves, what should we take for the expression of the genome? But rather, what prevents epigenetic modifications.

Starting from René Quinton ‘s laws of constancy, in many aspects of life there is a tacit order that must be preserved, despite evolution, and therefore a good epigenetic function is one that does not excessively modify the constant, which preserves its primordial activity.

Marine therapy in genome expression

Therefore, according to the propositions of René Quinton and seawater being the original broth where life developed, it is the characteristics of seawater that offer the hydromineral pool and the necessary dynamism for proper cell function. In addition, it is not surprising that the machinery of gene expression uses a number of mineral elements for its function, since it was in this environment that life develops and becomes more complex.

For this reason, Marine Therapy can act on the epigenome, not modifying its expression, but maintaining the function of gene expression agreed upon by life.

One could speak metaphorically of a reprogramming of the cell since, if we resolve the deficiencies that have occurred throughout not only a lifetime but generations, cell normalization could offer more than interesting results.

For this reason, the important thing is not to stimulate or inhibit the expression of the genome, rather it is the search for harmony with nature through and in it.

Read more – Thyroid diseases: Hypothyroidism, Hyperthyroidism, Goiter And Nodules

Read more – Thyroid disease: Hypothyroidism can be cure?

Dr. Ashwani Kumar is highly skilled and experienced in treating major and minor general medicine diseases.