What is central hypothyroidism?
hypothyroidism is a thyroid disorder caused by low levels of the circulating hormone of the thyroid gland. Central hypothyroidism is the subtype of this thyroid disorder, which includes hypothalamus or pituitary than the thyroid. Like other forms of hypothyroidism, central hypothyroidism is characterized by weight gain, cold intolerance, reduced sweat, coarse skin, hair loss, fatigue and weakness. Proper identification and diagnosis of central hypothyroidism from other forms is essential for therapy and is performed through laboratory and imaging tests.
The thyroid hormone secretion control is performed by endocrine signaling in the path called Thyrenas-Thyrene. First, hypothalamus releases a hormone called hormone releasing thyrotropin (market). When this substance reaches the pituitary, cells called thyrotrophs secrete another hormone called hormone stimulating thyroid (TSH) into the bloodstream. The blood then transmits the tshroid gland, which is also called the target organ.
The amount of TSH determines how much thyroid gland is stimulated. The correct levels of TSH production will lead to sufficient secretion T3 and T4. These hormones, especially T3, are important in maintaining the metabolic processes of the body. If these hormones are excreted inadequate, metabolic processes slow down, leading to symptoms of hypothyroidism.
hypothalamus and pituitary are considered central for two reasons. First, they are parts of the brain. Secondly, they are the highest in the hierarchy of the endocrine system because they provide stimulating signals to endocrine glands such as thyroid, adrenal glands, ovaries and testicles. Therefore, when the defect occurs in the signal runway due to disruption of the functioning of the hypothalamus and pituitary, central hypothyroidism occurs.
Secondary and tertiary classification of central hypothyroidism are also diagnosed. The secondary form occurs when only pituitary gland is affected, while tertiary formIt occurs when only hypothalamus is affected. On the other hand, hypothyroidism caused by thyroid disease, such as Hashimoto's thyroiditis, thyroid adenoma or thyroid cancer, is called primary or peripheral hypothyroidism.
The causes of central hypothyroidism include the adenoma of the pituitary gland and brain tumors that compress the hypothalamus. Medicines such as dopamine or lithium may also cause this disease inhibiting the function of the hypothalamus. This condition can also lead traumatic damage or lack of blood supply to the brain.
Blood tests for determining hormone levels of TSH and thyroid are the first step to diagnose central hypothyroidism. If the doctor finds that TSH is low or normal and T3 and T4 levels are reduced, it suspects central causes. A imaging test, such as PC Tomography (CT) or magnetic resonance (MRI), is performed.
The treatment of central hypothyroidism depends on its cause. If the cause is a tumor or adenoma is a prefErogged surgical removal. On the other hand, if the drug causes a condition, it could be given at a lower dosage or its intake could be stopped. However, these measures do not have to restore the function of hypothalamus or pituitary. In this case, levothyroxine, synthetic thyroid hormone is prescribed.