Riedel thyroiditis

With Riedel’s thyroiditis, thyroid- refers to the thyroid gland, and -itis means inflammation. So, Riedel’s thyroiditis is a condition where there is inflammation of the thyroid gland, which slowly causes fibrous tissue to replace the normal thyroid tissue.

The condition is named after the German surgeon - Dr. Bernhard Moritz Carl Ludwig Riedel - who first described it.Normally, the hypothalamus, which is located at the base of the brain, secretes thyrotropin-releasing hormone, known as ΤRH, into the hypophyseal portal system - which is a network of capillaries linking the hypothalamus to the anterior pituitary gland.

The anterior pituitary then releases a hormone of its own, called thyroid-stimulating hormone, thyrotropin, or simply TSH.

TSH stimulates the thyroid gland, which is a gland located in the neck that looks like two thumbs hooked together in the shape of a “V”.

If we zoom into the thyroid gland, we’ll find thousands of follicles, which are small, hollow spheres whose walls are lined with follicular cells and are separated by a small amount of connective tissue.

Follicular cells convert thyroglobulin, a protein found in follicles into two iodine-containing hormones, triiodothyronine or T3, and thyroxine or T4.Once released from the thyroid gland, these hormones enter the blood and bind to circulating plasma proteins, but only a small amount of T3 and T4 will travel unbound in the blood and these two hormones get picked up by nearly every cell in the body.Once inside the cell, T4 is mostly converted into T3, and then it can exert its effect.

T3 speeds up the basal metabolic rate. So as an example, they might produce more proteins and burn up more energy in the form of fats and sugars.

It’s as if the cells are in a bit of a frenzy.T3 increases cardiac output, stimulates bone resorption - thinning out the bones, and activates the sympathetic nervous system, the part of the nervous system responsible for our ‘fight-or-flight’ response.Thyroid hormone is important - and the occasional increase can be really useful when you need a boost to get through the final rounds of a sporting competition or to stay warm during a snowstorm!Meanwhile, Thyroid hormones are involved in a number of other things, such as normal functions of sebaceous and sweat glands, growth of hair follicles, and regulation of the synthesis of proteins and mucopolysaccharides by skin fibroblasts.It’s not entirely clear why, but sometimes the immune system begins to attack certain organs and tissues.

More specifically, there’s a pattern of autoimmune diseases that involves T cells and plasma cells that overproduce a specific type of IgG antibody called IgG4, it goes rogue and attacks multiple organs like the thyroid, pancreas, lacrimal or tear glands, and salivary glands.

When the thyroid is severely affected it’s called Riedel’s thyroiditis.In Riedel’s thyroiditis, we don’t know what IgG4 antibodies do exactly, but we do know that the T cells release cytokines that attract macrophages and neutrophils which in turn damage the thyroid follicles.Over a period of weeks to months the loss of healthy thyroid tissue eventually leads to hypothyroidism.

The cytokines also activate fibroblasts which are cells that normally reside in the tissue between follicles. Fibroblasts produce fibrous connective tissue and when they’re activated chronically, they generate so much protein that the thyroid gland simply fills up with dense fibrous tissue, making it large and hard.

The enlarged thyroid gland is called a goiter.What sets Riedel’s thyroiditis apart from other autoimmune thyroid inflammation, like Hashimoto’s thyroiditis, is that the fibrosis doesn’t stop with the thyroid gland.

The inflammation destroys tissue planes and extends beyond the thyroid capsule. Once the fibrosis sets in, the nearby structures like the parathyroid glands, trachea, and muscles, nerves and blood vessels of the neck can all fuse together.

The neck structures all join into one solid fibrous mass, like an iron collar.The most common symptom of Riedel’s thyroiditis is a goiter that’s about as hard as a rock - and it may be on one side or both sides of the neck.

The goiter can put pressure on surrounding structures like - nearby airways, which causes shortness of breath or on the esophagus, which causes dysphagia or difficulty swallowing.

It can also put pressure on the recurrent laryngeal nerves supplying the vocal cords, which can make the voice hoarse. Hypothyroidism can cause symptoms like a lack of energy, constipation, dry skin, or cold intolerance.Diagnosis of Riedel’s thyroiditis typically involves low thyroid hormone levels and increased TSH levels.

Radiological imaging with an ultrasound, CT scan, or an MRI might show an enlarged thyroid gland which may compress surrounding structures.

A tissue biopsy usually shows lots of fibrous tissue along with a large number of T cells and IgG4 antibody-producing plasma cells.Treatment of Riedel’s thyroiditis includes corticosteroids to suppress the immune system, and thyroid hormone replacement to correct hypothyroidism.

Surgery may be done to remove a goiter, but it can be difficult if it’s spread to nearby structures.All right, as a quick recap… Riedel’s thyroiditis results from T cells infiltrating the thyroid gland and IgG4 antibody-producing plasma cells generating antibodies that attack the thyroid gland.

Typically there’s a large goiter that can put pressure on nearby structures like the trachea, esophagus, and recurrent laryngeal nerves, as well as symptoms of hypothyroidism like weight gain and cold intolerance.

nearby structures All right as a quick recap Riedel's thyroiditis results from T cells infiltrating the thyroid gland and I G four antibody producing plasma cells generating antibodies that attack the thyroid gland Typically there's a large goiter that can put pressure on nearby structures like the trachea esophagus and recurrent laryngeal nerves as well as symptoms