Myxedema

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Myxedema of the hands and lower legs

The myxedema is by a disturbance in thyroid hormone levels triggered, localized infiltrative skin disease . The skin (plus subcutaneous tissue and fatty tissue) is typically doughy, swollen, cool, dry and rough due to connective tissue proliferation, especially on the extremities and face. In contrast to other edematous changes in the skin, myxedema does not leave dents after pressure, as is the case with edema due to increased water retention in the tissue. Overall, the patients look bloated.

The clinical picture of myxedema can develop both in the course of an underactive thyroid ( hypothyroidism ) and in the context of Graves' disease (an immunogenic hyperthyroidism).

The most severe form of hypothyroidism is called myxedema coma , whereby the (untreated) myxedema is not the cause, but merely a symptom and the eponym.

Pleural effusion can rarely occur as part of myxedema .

Hypothyroidism

Classic myxedema due to an underactive thyroid (hypothyroidism) is a generalized deposition of glycosaminoglycans (also called mucopolysaccharides ) such as hyaluronic acid and chondroitin sulfate in the skin. A reduced breakdown of these is assumed to be the cause. Among other things, a reduced expression of hyaluronidase as a result of a deficiency of the thyroid hormone triiodothyronine (T 3 ) is assumed to be the decisive factor. A complete removal of the thyroid gland (for example as part of a “goiter operation”) can lead to myxedema.

In healthy people, high concentrations of glycosaminoglycans can be found, especially in cartilage . These molecules are polarized and thereby bind water molecules, which gives the cartilage its elasticity and compressive strength.

Graves disease

Localized pre- tibial myxedema (swellings and reddish skin rash or painless nodules on the front of the legs and feet that can be treated with cortisone ointment) can occur primarily in immunogenic hyperthyroidism , i.e. in Graves' disease . Here the subcutaneous fibroblasts are stimulated by the TRAKs that cause this clinical picture. The incidence here is 10%. The same mechanism triggers the typical Graves' exophthalmos.

Concept origin and history

The expression "myxedema" (American "myxedema", British "myxoedema"; from the Greek myxa "mucus", and edema "swelling", referring to the thickened skin with a peculiar mucous consistency) that occurs in this disease goes to the Scottish doctor William Miller Ord (1834–1902), who in 1877 was the first to diagnose fibrosis of the thyroid tissue in autopsies of patients and found this with the typical symptoms of the Ord thyroiditis named after him (now better known as Hashimoto's thyroiditis ) or the symptoms caused by it Hypothyroidism.

The English doctor George R. Murray successfully treated myxedema with thyroid extract in 1891.

literature

  • Ludwig Weissbecker: Diseases of the thyroid. In: Ludwig Heilmeyer (ed.): Textbook of internal medicine. Springer-Verlag, Berlin / Göttingen / Heidelberg 1955; 2nd edition, ibid. 1961, pp. 1033-1051, here: pp. 1039-1042 ( Das Myxödem and Das Kindliche Myxödem ).

Individual evidence

  1. ↑ Ursus-Nikolaus Riede, Martin Werner, Hans-Eckart Schäfer: General and special pathology . 5th edition. Georg Thieme Verlag, Stuttgart 2004, ISBN 3-13-683305-8 , p. 1016 .
  2. ↑ Berthold Jany, Tobias Welte: Pleural effusion in adults - causes, diagnosis and therapy. In: Deutsches Ärzteblatt. Volume 116, Issue 21, (May) 2019, pp. 377–385, here: p. 379.
  3. ^ Hans-Christian Pape, Armin Kurtz, Stefan Silbernagl: Physiology . 7th edition. Georg Thieme Verlag, Stuttgart 2014, ISBN 978-3-13-796007-2 , p. 626 .
  4. ↑ Löffler, Petridas: Biochemistry and Pathobiochemistry . 9th edition. Springer-Verlag, Berlin 2014, ISBN 978-3-642-17972-3 , pp. 522 .
  5. ↑ Lois Jovanovic, Genell J. Subak-Sharpe: Hormones. The medical manual for women. (Original edition: Hormones. The Woman's Answerbook. Atheneum, New York 1987) From the American by Margaret Auer, Kabel, Hamburg 1989, ISBN 3-8225-0100-X , pp. 295, 359 and 384.
  6. ^ Otto Westphal , Theodor Wieland , Heinrich Huebschmann: life regulator. Of hormones, vitamins, ferments and other active ingredients. Societäts-Verlag, Frankfurt am Main 1941 (= Frankfurter Bücher. Research and Life. Volume 1), p. 22.
  7. ^ Otto Westphal , Theodor Wieland , Heinrich Huebschmann: life regulator. Of hormones, vitamins, ferments and other active ingredients. Societäts-Verlag, Frankfurt am Main 1941 (= Frankfurter Bücher. Research and Life. Volume 1), p. 23 f.