Causes of Hypothyroidism

Hypothyroidism is common in our country as it is all over the world. The incidence of hypothyroidism increases in women related to advancing age. The most common cause of hypothyroidism; Hashimoto's thyroiditis, removal of the thyroid gland by thyroid surgery, radioactive iodine treatment  and other thyroiditis types.


Hypothyroidism Signs

The levels of T3 and T4 hormones are found to be low, TSH level is found to be high.  The levels of T3 and T4 hormones are found to be normal and TSH level is found to be high in subclinical hypothyroidism that does not cause clinical symptoms.  Thyroid antibody (anti TPO) is elevated.

Malaise, fatigue, joint pain, gaining weight, skin dryness, hair loss, matted hair, feeling cold, constipation, irregular menstruations, infertility, depression, perceptual disorder and change in voice (coarse voice/hoarseness) are the signs of hypothyroidism.

Dry skin, decreased pulse (bradycardia), coarse voice, slow reflexes, in some patients growth of the thyroid gland (goitre development) and edema are significant findings encountered during the examination.


Hypothyroidism treatment

Thyroid hormone treatment (levothyroxine) is started according to the complaints of the patient and the hormone results. The target TSH in young people is 0.5 to 2.5 mIU/L. The target TSH is 1-4 mIU/L in patients with cardiac disease, atrial fibrillation (heart rhythm disorder), osteoporosis (bone loss) and in patients over 65 years of age. The target TSH in the first trimester of pregnancy is 0.1-2.5 mIU/L and the target TSH in the second and third trimesters is 0.2-3 mIU/L. The upper limit of TSH is accepted as 6 mIU/L in people between the age of 70-80 years, and the upper limit of TSH in people over 80 years is accepted as 7.5 mIU/L.


How to use thyroid hormone

The drug dose is adjusted by testing TSH level . TSH level is examined at 6- to 8-week intervals until the hormones reach normal levels. The drug dose should be increased or decreased with doses of 12.5-25 microgram. The patient should not take the drug in the morning of the hormone test, it should be taken after the blood is collected.

TSH levels should be frequently monitored in patients underwent surgery, in pregnancy, during the use of other drugs, during intercurrent illness and drug changes.  Thyroid hormone should be taken as a single dose, with water, without crushing and before meals.  The patient should have breakfast 30 minutes after taking the drug.


Conditions that adversely affect the absorption of thyroid hormone

The conditions that affectthe absorption of thyroid hormone  are advanced age, proton pump inhibitors (gastroprotective drugs), celiac disease, absorption disorders. The conditions that affect the absorption of thyroid hormone drug are iron medications, cholestyramine, sucralfate, anti-acids. Such drugs should be used at least 4 hours before or after levothyroxine is taken.  


Treatment in subclinical hypothyroidism without clinical findings

Before hormone therapy is started, it is decided whether thyroid dysfunction is permanent or not. This decision is made depending on the age of the patient and accompanying diseases.Levothyroxine therapy is started in patients with TSH higher than 10 mIU/L.


Levothyroxine therapy is administered to the patients with TSH levels between of 4-10 mIU/L in the following cases. 1) Goitre 2) Pregnants and patients who receive prenancy treatment 3) Those with positive antibodies 4) Patients with increased TSH levels during the follow up of the disease 5) Patients with psychiatric diseases