Hypothyroidism is insufficiency of thyroid hormone required for normal growth and functioning of the body.
Thyroid Hormone and its Physiology
Thyroid Hormones are produced in body only by thyroid glands , its a butterfly shaped glands situated in neck each lobe on either side of trachea connected with isthemus on midline behind hyoid bone.
T3 or tri-iodothyronine or liothyronine and T4 or thyroxine are active thyroid hormones partially composed of Iodine, so iodine is required for production of T3 and T4.
Hypothalamus releases Thyrotropin Releasing Hormone(TRH) which stimulates Pitutary glands to secret Thyroid Stimulating Hormone(TSH) which stimulates thyroid glands to produce thyroglobulin which is precursor of thyroid hormones, the residue of thyroglobulin is protien tyrosin which undergoes iodination with help of thyroperoxidase forming thyroid hormone.(1 molecule of thyroglobulin has 100-120 residual tyrosin of which only 20 undergoes iodination with help of thyroperoxidase in follicular colloid and rusultant formation of upto 10 thyroid hormone molecule from 1 thyroglobulin molecule.)Hypothalamo-pitutary-thyroid axis regulates levels of thyroid hormone in blood, increased level of T3 and T4 inhibibits TSH and TRH. Thus regulating proper balance of blood level of thyroid hormone.
T4 is converted into T3 with help of Deiodinases , these Deiodinases are Selenium based compounds, So sufficient selenium is required for production of T3 , its then converted into T1a (iodothyronamine)and T0a (thyronamine) by decarboxylation and deiodination.
In blood almost 99.97% thyroxine is bound to Thyroxine binding globulin only free thyroxine is biologically active.
Thyroid hormones helps in protien, fat and carbohydrate metabolism and stimulates vitamin metabolism. It is essential for proper development and differentiation of cells, it influences almost each and every cell bt binding with thyroid hormone receptor on neucleus of cells and it activates gene to express cell specific protiens to neucleus of the body and on cell membrane it attaches to integrin αvβ3 stimulating sodium-hydrogen anti-porter and activating processes like cell growth and formation of blood vessels. it also helps in maturation of neurons and bone growth, it promotes catecholeamines sensitivity.
Regulation of thyroid hormone levels is influenced by many different physiological and pathological stimulus.
Hypothyroidism may be caused due to
- Defective Thyroid Gland itself , functioning inadequately, its called Primary Hypothyroidism. It is caused due to Iodine Deficiency, autoimmune Thyroiditis like Hashimato’s Thyroiditis where auto antibodies are driven against Thyroglobulin, Thyroxine peroxidase, TSH receptors which infilterate thyroid glands, post partum thyroiditis, subacute lymphocytic thyroiditis, subacute granulomatous thyroiditis, certain medications , radio-iodine procedure, thyroidectomy.
- Lack of sufficient stimulus by Thyroid stimulating Hormone (TSH), which is secreted from pitutary glands, it is called Secondary Hypothyroidism.
- Inadequate Thyroid Releasing Hormone(TRH), which is secreted from Hypothalamus, its called Tertiary Hypothyroidism.
A person can suffer from one or above all three types of causes of hypothyroidism.
Central Hypothyroidism, any hypothyroidism which can be classified under Secondary or Tertiary cause is termed as Central Hypothyroidism, their causes are any lesions compressing the pitutary, injury to pitutarty due to surger or other reasons , pitutary irradiation, certain drugs influencing pitutary, vascular disorders affecting pitutary, intracranial heamorrhages, certain autoimmune diseases like lymphocytic hypophysitis, certain infiltrative diseases, infection and congenital disorders.
Signs and Symptoms
- Fatigue , patient gets tired easily, frequently complaints of aching sensation in limbs and very occasionaly complaints of sensation of trembling of limbs
- Somnolence, sleepy feeling throughout the day and Insomnia, cant get proper sleep at night
- Weakness and lethargy, pt complaints of general weakness and lack of interest to do any physical activity.
- Coldness, cold feet and hands , slightly lower body temperature, cant tolerate cold climate.
- Dry thick and coarse skin
- Hoarseness in voice
- Tendency to catch cold easily
- Lack of concerntration and weak memory
- Depression, lack of interest , gloomy and melancholic.
- Delayed cycles with initial heavy flow and later very scanty flow.
- Oedematous swelling of limbs and face
- Hearing deteriorates
- Slow Pulse Rate
- Carpel Tunnel Syndrome
- Delayed Tendon Relaxation Reflexes.
T4 and TSH levels helps diagnose the condition
- Low T4 and elevated TSH suggests Hypothyroidism
- Low T4 and normal/low TSH suggests Hypothyroidism of central origin.
- Normal T4 and elevated TSH suggests Subclinical Hypothyroidism.
T3 levels are just extra parameter and should not be considered primary parameter, according to current guidelines T4 and TSH levels are considered first and T3 is used for extra guidance.
In many cases, patient shows signs and symptoms of hypothyroidism but their FT3 FT4 and TSH levels are absolutely normal in such cases antithyroglobulin and anti TPO antibodies test should be done to rule out Hashimoto’s Thyroiditis.
Homoeopathic medicines for Hypothyroidism based on symptoms and condition.
- Calcarea Carb