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hypothyroidism marked by dry skin and swellings around lips and nose as well as mental deterioration (同)myxoedema

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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2015/04/27 02:30:05」(JST)

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Myxedema or myxoedema is a term used synonymously with severe hypothyroidism. It is also used to describe a dermatological change that can occur in hypothyroidism, and some forms of hyperthyroidism. This article discusses the dermatological changes.

In this context, myxedema refers to deposition of mucopolysaccharides in the dermis, which results in swelling of the affected area. One manifestation of myxedema occurring in the lower limb is pretibial myxedema, a hallmark of Graves disease, an autoimmune form of hyperthyroidism. Myxedema can occur in Hashimoto's thyroiditis and other long-standing forms of hypothyroidism, as well as Graves disease.

The word myxedema originates from μύξα, taken from ancient Greek to convey 'mucus' or 'slimy substance', and ὁίδημα for "swelling".

Signs and symptoms

Man with myxedema or severe hypothyroidism showing an expressionless face, puffiness around the eyes and pallor

Additional finding include swelling of the arms and legs and significant ascites.

Myxedema can occur in the lower leg (pretibial myxedema) and behind the eyes (exophthalmos).

Cause

Myxedema is known to occur in various forms of hypothyroidism, and also in Graves' disease. One of the hallmarks of Grave's disease is pretibial myxedema, myxoedema of the lower limb.^[1]

Myxedema is more common in women than in men.^[2]

Myxedema can occur in:

Hyperthyroidism, associated with pretibial myxedema and exophthalmos. Pretibial myxedema can occur in 1–4% of patients with Graves' disease, a cause of hyperthyroidism.^[3]
Hypothyroidism, including Hashimoto's thyroiditis.^{[citation needed]}

Pathophysiology

Myxedema describes a specific form of cutaneous and dermal edema secondary to increased deposition of connective tissue components. These can include glycosaminoglycans, hyaluronic acid, and other mucopolysaccharides.^[4] The increased deposition of glycosaminoglycan is not fully understood, however two mechanisms predominate:

Fibroblast stimulation. It is thought that fibroblast stimulation by the thyroid stimulating hormone (TSH) receptor increases the deposition of glycosaminoglycan, which results in an osmotic edema and fluid retention. It is thought that many cells responsible for forming connective tissue react to increases in TSH levels.^{[citation needed]}
Lymphocyte stimulation. In Basedow-Graves' thyroid disease, lymphocytes react against the TSH receptor. Lymphocytes react not only against thyroid receptors, but also any tissue with cells expressing the receptor. This can lead to tissue damage and scar tissue formation, explaining the deposition of glycosaminoglycans.^{[citation needed]}

References

^ Berger, William D. James, Dirk M. Elston, Timothy G. Andrews' Diseases of the skin : clinical dermatology. (11th ed. ed.). [London]: Saunders/ Elsevier. ISBN 978-1-4377-0314-6.
^ Schneider, Arthur S.; Kim, Philip A. Szanto; with special contributions by Sandra I.; Swanson, Todd A. (2009). Pathology (4th ed. ed.). Philadelphia: Wolters Kluwer Health/Lippincott Williams & Wilkins. p. 314. ISBN 1451109067.
^ "Pretibial Myxedema". Retrieved 2009-03-27.
^ Berger, William D. James, Dirk M. Elston, Timothy G. Andrews' Diseases of the skin : clinical dermatology. (11th ed. ed.). [London]: Saunders/ Elsevier. ISBN 978-1-4377-0314-6.

UpToDate Contents

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1. 甲状腺機能低下症の診断およびスクリーニング diagnosis of and screening for hypothyroidism
2. 甲状腺機能低下症の治療 treatment of hypothyroidism
3. 甲状腺機能低下症の臨床症状 clinical manifestations of hypothyroidism
4. 甲状腺機能低下症の原因となる疾患 disorders that cause hypothyroidism
5. 先天性甲状腺機能低下症の臨床的特徴および検出 clinical features and detection of congenital hypothyroidism

English Journal

Periorbital Myxedema.

Huy JT, Doig CT.
The Journal of the American Osteopathic Association.J Am Osteopath Assoc.2016 Nov 1;116(11):753. doi: 10.7556/jaoa.2016.148.
PMID 27802562

Pretibial myxoedema: a case report with scanning electron microscopy.

da Cunha Filho RR1, de Almeida HL Jr2, Sabei JD3, Camiña RH4, de Castro LA5.
Journal of the European Academy of Dermatology and Venereology : JEADV.J Eur Acad Dermatol Venereol.2016 Oct 12. doi: 10.1111/jdv.14006. [Epub ahead of print]
PMID 27730666

Morbidity and Mortality Risks of Premature Enteral Nutrition During the Recovery of Myxedema Coma (A Response to the Article Entitled "Pediatric Patient With Altered Mental Status and Hypoxemia").

Leow MK1.
Pediatric emergency care.Pediatr Emerg Care.2016 Oct;32(10):738.
PMID 27583414

Japanese Journal

PUVA療法が奏効した甲状腺機能亢進症に伴う脛骨前粘液水腫の1例 (特集代謝異常症・沈着症・黄色腫)

中島有紀子,二井谷舞,濱崎洋一郎 [他]
皮膚科の臨床 57(3), 257-260, 2015-03
NAID 40020382567

症例 Basedow病術後の甲状腺ホルモン内服自己中断後に発症したpretibial myxedemaの1例

新生忠司,岡田洋右,松下幸司 [他]
内科 113(4), 788-792, 2014-04
NAID 40020028683

粘液水腫性昏睡 (特集内分泌緊急症)

大野洋介,白石美絵乃,山本頼綱 [他]
内分泌・糖尿病・代謝内科 38(2), 117-123, 2014-02
NAID 40020003139

Related Pictures

Myxedema - Page 1 - Medical information and advice Pretibial myxedema - Wikipedia, the free encyclopedia THYROID DISEASE & TESTING Pretibial Myxedema - Pictures, Treatment, Symptoms, Causes | HubPages Myxedema: Coma, Symptoms, Pictures, Treatments and More WUSM15 Dermatology Pictures at Washington University - St. Louis - StudyBlue Myxedema or Gull’s Disease|Causes|Symptoms|Treatment Figure 031_2_7184. Thyroid dermopathy (pretibial myxedema) in Graves disease

★リンクテーブル★

リンク元	「myx」「成人型甲状腺機能低下症」「粘液水腫」
拡張検索	「scleromyxedema」

「myx」

Myxedema
	Hyaluronan, an example of a mucopolysaccharide
Classification and external resources
ICD-10	E03.9
ICD-9	244.9
DiseasesDB	6558
MedlinePlus	000353
eMedicine	med/1581 derm/347
MeSH	D009230