ANATOMY

ANATOMY

The thyroid is located at the base of the neck, in front of the trachea (windpipe) and the esophagus (upper digestive tract).

The thyroid is composed of two cone-like lobes, right and left, connected via the isthmus.

PHYSIOLOGY

The thyroid gland produces hormones (T3 and T4) which help regulate the level of metabolic activity of the whole body, such as 

-body heat, 

-physical activity, 

-weight control, 

-intestinal activity,

-the heartbeat, 

-Child growth. 

The thyroid hormones (T3 and T4) contain iodine.

The thyroid gland is controlled by another hormone called TSH (Thyroid Stimulating Hormone) which is produced and secreted by the pituitary gland (hypophysis), in the brain.

ADDITIONAL EXAMS

In most cases, palpation is enough to determine the existence of a goiter, its size and the presence or absence of nodules.

Biological exam :

-Thyroid hormones levels: T3, T4, and TSH.

An elevated level of TSH points to hypothyroidism, a low level of TSH to hyperthyroidism, and a normal level to euthyroidism.

-Antibodies levels: if an auto-immune disease is suspected we test for anti-thyroglobulin and anti-peroxidase antibodies.

Ultrasounds (echography):

It allows for a precise measuring of the thyroid’s volume, and the diameter of nodules if any.

Thyroid scan by scintigraphy (using radioactive iodine): much less common.

     It shows if the goiter is hyper secreting. 

Fine Needle Aspiration (FNA):

     It consists in taking a sample of cells on a nodule with a very fine needle. It is done under local anesthesia, with the help of the ultrasounds. These cells are then analyzed for signs of cancer.

This test is reliable only if the nodule is less than 2 cm in diameter.