Hypothyroidism also called as an underactive thyroid is a condition in which the thyroid gland does not produce thyroid hormone as per requirement.
It is a disorder of the endocrine system.
SIGNS & SYMPTOMS OF HYPOTHYROIDISM
- Problems with memory & concentration
- Dry coarse skin
- Weight gain
- Loss of appetite
- Shortness of breath
- Hoarse voice
- Heavy menstruation in women
- Hair loss
- Abnormal sensation
- Poor hearing.
- A rare condition of extreme hypothyroidism, called myxedema coma;
- Low body temperature
- Extremities of the body are cold
- Slow heart rate
- Reduced breathing rate
- Swelling/Fluid accumulation in the legs
- Delayed reflex & reaction
- Enlargement of the tongue
- Carpal tunnel syndrome
- Fluid accumulation in the heart cavity
- Fluid accumulation in the lungs
- Also fluid accumulation in the liver.
- Increased risk of miscarriage
- An offspring with lower intelligence
- Infant death after birth
- Gestational diabetes
- Premature birth (even before 37 weeks of pregnancy)
- Abnormal birth weight & height
- Enlarged head & tongue
- Dry skin & decreased muscle tone
- Low body temperature
- Drowsiness & intellectual impairment
- Delayed puberty
CAUSES OF HYPOTHYROIDISM
- Inadequate function of the thyroid gland (primary hypothyroidism)
- Inadequate function of the pituitary gland. The pituitary gland is responsible for secretion of the thyroid stimulating hormone (TSH). (secondary hypothyroidism)
- Inadequate function of the hypothalamus, by decreased secretion of thyrotropin releasing hormone.
- Autoimmune disease called Hashimoto’s thyroiditis
- Postpartum thyroiditis
- Deficiency of iodine in the diet
- Various types of thyroid inflammation
- Previous thyroid surgery
- Previous radioiodine therapy
- Drugs like lithium & amiodarone
- Cancer of the pituitary gland
- Cancer of the meninges
- Surgery of the pituitary gland
- Bursting of the internal carotid artery
- Overload of iron in the blood
- Myasthenia gravis
- Rheumatoid arthritis
- Infections like tuberculosis & syphilis
- Congenital related hypothyroidism due to iodine deficiency in the pregnant mother
- Mutations in the chromosomes.
- Measurement of TSH levels:
a) Laboratory testing of TSH levels in the blood. Two tests are done separated by 2 weeks.
b) A low level of TSH indicates as central hypothyroidism due to inadequate function of the pituitary gland.
c) When the TSH level is more than 5mlU/L but the levels of T3 & T4 are low, the conditioned is diagnosed as overt hypothyroidism.
d) When the TSH level is ranging between 5-10mlU/L, but the serum level of T3 & T4 is normal, it is diagnosed as a milder form of hypothyroidism called as Hashimoto’s thyroiditis.
- Testing of the levels of creatine kinase, liver enzymes, cholesterol & LDL, since their levels usually are elevated in hypothyroidism.
- In severe hypothyroidism, a low sodium level in blood is associated along with low level of anti-diuretic hormone & worsening of kidney function.
- Imaging of the thyroid gland for detection of any abnormal lumps.
- Biopsy of the thyroid gland for differential diagnosis.
- In pregnancy:
a) The TSH level when between 2.5-5mlU/L or when over 10mlU/L, can be cause of hypothyroidism.
b) Free thyroxine levels are low during to incomplete binding to albumin.
c) Detection of presence of antibodies against TPO.
- Assessment of the dietary iodine & the level of iodine absorbed by the the thyroid gland by radioiodine test.
- Screening for hypothyroidism is performed in the newborn period in many countries, generally using TSH.
TREATMENT FOR HYPOTHYROIDISM
- Synthetic thyroxine is the primary medication for hypothyroidism in the form of levothyroxine.
- The dosage depends on the age & underlying condition of the patients, although usually one dose daily is prescribed.
- Levothyroxine is given in combination dose with liothyronine (synthetic T3) for better management of symptoms.
- Desiccated thyroid extract is an animal-based thyroid gland extract, most commonly from pigs. It is a combination therapy, containing forms of T4 and T3.
- Calcitonin is also added along with it, which is required for regulation of calcium in the body.
- No treatment required when the level of TSH is between 10-20 mlU/L.
- In severe hypothyroidism like myxedema, admission to intensive care is required.
- Breathing aid is provided by mechanical ventilation.
- Monitoring of sodium levels by prescribing a saline solution.
- Corticosteroids for management of adrenal insufficiency.
- Fluid replacement
- Vasopressor agents for management of low blood pressure.
- Administration of thyroid hormones by a nasogastric tube.
MANAGEMENT & PREVENTION
- Hypothyroidism is preventable by adding iodine to commonly used foods.
- More consumption of iodine rich foods like fish & dairy products.
- Iodine deficiency is treatable by addition of iodine in salt.
- Dosage of 250 micrograms of iodine is recommended for pregnant & breast feeding women.