Thyroid

What is a normal thyroid size ?

The normal size of the thyroid varies with his activity and dysfunction. A simple size anomaly can be detected on routine clinical examination. It can indicate something wrong by a simple lower neck palpation by the physician. This act may detect an overall volume increase, called a goiter, or a specific increased area, called a nodule. A thyroid ultrasound may be useful to exclude the malignancy of a nodule or to confirm a goiter by measuring the size of the thyroid. Explanations.
Why is it important to check your thyroid size?
The thyroid is a gland which has a fundamental role in the good functioning of the body system. It is located at the base of the neck and measures 5 cm. In France, the average thyroid dimensions lobes are 1.5 cm for the thickness and the width, and approximately 5 cm for the height.

It is an endocrine gland, specialized in the production of hormones regulating the growth, the development and the metabolism of the body. A dysfunction of this gland can lead to many different complaints and symptoms. Hypothyroidism leads to hypometabolism (fatigue, weight gain, depression...) as opposed to hyperthyroidism which results to hypermetabolism (insomnia, weight loss, hot flashes...).

How does the thyroid work ?
The thyroid produces hormones affecting the growth, development and body temperature of every human being. The thyroid controls those functions producing specific hormones: T4 (thyroxine) and T3 (triiodothyronine).

The thyroid cells are called follicular cells, they absorb iodine from the blood and use it to synthesize hormones. These hormones bind to their specific receptors, nuclear receptors (located inside the nucleus of the cells). These receptors are situated in different organs and their binding will trigger a serie of actions contributing to the modification of the body's metabolism.

But to ensure our organs have a good rhythm, the thyroid hormone amount must be controlled. This production is managed by our orchestra leader of the body's glands: the pituitary gland. Located in a bony cavity called the pituitary gland, this pea-sized gland is located below the brain. It controls the amount of thyroid hormone in the blood producing another hormone : TSH (thyroid stimulating hormone). Thyroid problems can be caused by thyroid disorders itself, the pituitary gland or the hypothalamus. It is essential for your doctor to check the thyroid size regularly, simply through palpation of the thyroid gland. A blood test including a TSH can also be asked, which may be followed by a thyroid ultrasound if there is a suspicion of thyroid dysfunction.
What are thyroid nodules and goiters?
The goiter is an overall increase of the thyroid size. It can mean a lack of thyroid hormones production.

A thyroid nodule is a localized thyroid growth. In most cases, these nodules are harmless and do not show any symptoms. It is essential to check thyroid nodules with regular clinical examination because although nodules are benign in the majority of cases, they can also be malignant, meaning revealing a cancer. The presence of nodules is more common for women than for men. Age and lifestyle of each person influence their existence (smoking, diet...).
Why does the volume of the thyroid vary and how to boost thyroid function?
When the thyroid becomes lazy and produces less thyroid hormone, the pituitary gland produces more TSH which affects the thyroid hormone production. Hypothyroidism is defined with a low thyroid hormones amount and a high TSH amount. Attempts to stimulate the thyroid gland with TSH lead to an increased thyroid size, which grows without increasing the thyroid hormone blood levels. The body is functioning at a slower rhythm, the patient could be constipated, and gain weight.
On the other hand, in a hyperthyroid situation, the body will be hyperfunctional: increased heart and respiratory rates, accelerated digestion, weight loss...

As we said, the thyroid gland mainly functions with the help of iodine. It can be interesting to boost the thyroid through your diet. You can consume seaweeds such as kelp or wakame which are naturally rich in iodine. Salted nuts such as Brazil nuts and hazelnuts are important sources of selenium which helps to maintain optimal thyroid function. Some fishes are also great sources of iodine such as salmon and shellfish. Diet and lifestyle have a very important role to maintain a healthy thyroid. 

Good to know

  • Thyroid disorders have to be managed before and during pregnancy. They are monitored with regular blood tests during a pregnancy. Thyroid hormones are essential for a healthy fetus development. In the first three months of a pregnancy, the need for hormones is more important. If you have pre-existing thyroid dysfunction, it is even more essential to monitor hormone levels before and during your pregnancy.
Increased thyroid volume can sometimes be noticed by the patient himself with a swelling neck. The gland size depends on the weight, body type, age, iodine diet and geographical origin of each person. Further investigations could be necessary to treat thyroid dysfunction.