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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 |
This article is about skin changes that occur in hypothyroidism. The word myxedema was historically used to refer hypothyroidism in general. For the related medical emergency, see myxedema coma.
Myxedema (British English: 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".
Contents
- 1 Signs and symptoms
- 2 Cause
- 3 Pathophysiology
- 4 References
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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English Journal
- Autoimmune disease preceding amyotrophic lateral sclerosis: An epidemiologic study.
- Turner MR, Goldacre R, Ramagopalan S, Talbot K, Goldacre MJ.SourceFrom the Oxford University Nuffield Department of Clinical Neurosciences (M.R.T., K.T.), John Radcliffe Hospital; Oxford University Unit of Health-Care Epidemiology (R.G., M.J.G.), Department of Public Health; and Oxford University Department of Physiology, Anatomy and Genetics (S.R.), Oxford, UK.
- Neurology.Neurology.2013 Oct 1;81(14):1222-1225. Epub 2013 Aug 14.
- OBJECTIVE: To study whether the risk of amyotrophic lateral sclerosis (ALS) is increased in people with prior autoimmune disease.METHODS: An all-England hospital record-linkage dataset spanning 1999-2011 was used. Cohorts were constructed of people with each of a range of autoimmune diseases; the in
- PMID 23946298
- The origin of Woltman's sign of myxoedema.
- Burkholder DB, Klaas JP, Kumar N, Boes CJ.SourceDepartment of Neurology, Mayo Clinic, 200 First St. SW, Rochester, MN 55905, USA.
- Journal of clinical neuroscience : official journal of the Neurosurgical Society of Australasia.J Clin Neurosci.2013 Sep;20(9):1204-6. doi: 10.1016/j.jocn.2012.09.047. Epub 2013 Mar 19.
- Woltman's sign of myxoedema, named after Henry Woltman in 1956, is the delayed relaxation phase of the muscle stretch reflex in patients with myxoedema. Although a change in these reflexes was mentioned as being clinically evident possibly as early as the 1870s, no formal description was published u
- PMID 23517675
Japanese Journal
- 石田 芳也,片山 昭公,安達 正明 [他],原渕 保明
- 耳鼻咽喉科臨床 103(12), 1121-1125, 2010-12-01
- … He was diagnosed with myxoedema with severe laryngeal obstruction, given replacement levotyroxine (50 mg/day), and underwent tracheostomy. …
- NAID 10027449709
- 各種皮膚疾患に対する308nmエキシマランプによるターゲット型光線療法
- 横川 真紀,高田 智也,永野 弓枝 [他],池田 光徳,佐野 栄紀
- 日本皮膚科学会雑誌 119(11), 2173-2180, 2009-10-20
- NAID 10028277454
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- myx·e·de·ma (miks'ĕ-dē'mă) Nonpitting waxy edema of the skin, often most pronounced in the face and shins (pretibial myxedema), owing to subcutaneous deposition of mucoid material in hypothyroidism. Synonym(s): myxoedema.
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