What are the signs of thyroid disorders?
Thyroid pathologies are revealed:
- Either by an excess of hormone secretion: hyperthyroidism
- Either by their insufficient production: hypothyroidism
Clinical signs (especially in the case of hypothyroidism) can be both subtle and trivialized by patients. Weight gain or fatigue sometimes makes diagnosis difficult. This is why doctors tend to perform a TSH (thyroid-stimulating hormone) test fairly easily when faced with sometimes unclear charts. This test is performed during a blood test that can be done in any laboratory.
What are the causes of hyperthyroidism?
Graves’ disease
This is the most common cause of hyperthyroidism. It is an autoimmune disease linked to the natural production of antibodies. These antibodies bind to receptors in the same place as TSH, and thus stimulate the production of thyroid hormones. Other antibodies may be present (antithyroid antibodies), but they are not specific to Graves’ disease. It is most often observed between the ages of 30 and 50 and mainly affects women. In its characteristic form, the disease combines:
- A soft, painless goiter (= enlarged thyroid gland),
- ocular signs such as exophthalmos (protrusion of the eyeball outside its orbit), eye pain, tearing, photophobia, eyelid edema,
- pretibial myxedema. More rarely, it is a purple, orange-peel infiltration of the anterior surface of the leg.
Toxic adenoma
It is a thyroid nodule that autonomously secretes excess thyroid hormones. This condition mainly affects women over the age of 50. Treatment is most often surgical or with radioactive iodine if surgery is contraindicated.
Toxic multiheteronodular goiter
It is a goiter that contains several toxic adenomas. Treatment is generally surgical.
De Quervain’s thyroiditis
This is an inflammation of the thyroid caused by a virus (coxsackievirus, mumps, or adenovirus). In this case, the thyroid gland is most often painful. Pain in the front of the neck can radiate to the ears and is aggravated by swallowing, coughing, or neck movements.
Postpartum thyroiditis
Autoimmune thyroiditis manifests in the months following childbirth (between 6 weeks and 3 months). The intensity of symptoms varies. The outcome is most often favorable without specific treatment.
Other causes of hyperthyroidism
Certain drug treatments, such as Cordarone® (a cardiac treatment), can be the cause, as can the ingestion of thyroid hormones (certain illegal slimming cocktails).
Spontaneous atrophic hypothyroidism
Hypothyroidism is linked to the progressive atrophy (destruction) of the thyroid gland (the gland is then impalpable). The cause is likely autoimmune in origin. It is mainly observed in postmenopausal women. Treatment consists of lifelong supplementation with thyroid hormones (L-Thyroxine = Levothyrox®).
Hashimoto’s thyroiditis
This is the most common form of hypothyroidism with goiter. It is an autoimmune thyroiditis with the detection of high levels of antithyroid antibodies (antithyroperoxidase and antithyroglobulin) in the blood. Note that the disease can begin with a phase of hyperthyroidism. It typically affects women between the ages of 20 and 60. Treatment consists of lifelong supplementation with thyroid hormones (L-Thyroxine = Levothyrox®).
Congenital hypothyroidism
Hypothyroidism is either linked to a malformation of the gland or its dysfunction. It is common: 1 in 4,000 newborns. All newborns in France benefit from screening at birth (TSH measurement).
Post-therapeutic hypothyroidism
These are hypothyroidisms secondary to:
- Partial or total removal of the thyroid (treatment of multinodular goiters, thyroid cancers),
- Radioactive iodine treatments,
- External radiotherapy. Thyroid problems can then appear late (several years after treatment).
Iatrogenic hypothyroidism
These are hypothyroidisms secondary to:
- Taking certain antithyroid substances, such as synthetic antithyroid drugs used in the treatment of Graves’ disease or lithium (used in the treatment of certain manic-depressive disorders).
- Iodine overload (Cordarone® or iodinated contrast products used for medical imaging).
Hypothyroidism due to iodine deficiency
It is linked to a dietary deficiency of iodine, which is essential for the production of thyroid hormones. This cause is rare in France, especially since table salt is supplemented with iodine.