WordNet

any pathology of the muscles that is not attributable to nerve dysfunction
of or relating to any disease of the muscles that is not caused by nerve dysfunction

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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2015/06/08 15:17:47」(JST)

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In medicine, a myopathy is a muscular disease^[1] in which the muscle fibers do not function for any one of many reasons, resulting in muscular weakness. "Myopathy" simply means muscle disease (myo- Greek μυο "muscle" + pathos -pathy Greek "suffering"). This meaning implies that the primary defect is within the muscle, as opposed to the nerves ("neuropathies" or "neurogenic" disorders) or elsewhere (e.g., the brain etc.). Muscle cramps, stiffness, and spasm can also be associated with myopathy.

Capture Myopathy, or Shock Disease, is a little-studied condition observed in wild animals such as hares and birds that have been captured or handled.^[2] The condition is usually lethal and stress has been identified as the single most determining factor, exacerbated by muscle exertion.

Muscular disease can be classified as neuromuscular or musculoskeletal in nature. Some conditions, such as myositis, can be considered both neuromuscular and musculoskeletal.

1 Myopathy in systemic diseases
2 Classes
- 2.1 Inherited forms
- 2.2 Acquired
- 2.3 Differential diagnosis of systemic myopathy based on age of onset<ref>{{cite journal|first=Myopathy|title=Systemic Myopathy|pmc=3153853|last1=Chawla|volume=2|pages=49|doi=10.3389/fneur.2011.00049|journal=Frontiers in Neurology|year=2011|pmid=21886637}}</ref>
3 Symptoms
4 Treatments
5 References
6 External links

Myopathy in systemic diseases

Myopathies in systemic disease results from several different disease processes including endocrine, inflammatory, paraneoplastic, infectious, drug- and toxin-induced, critical illness myopathy, metabolic, and myopathies with other systemic disorders. Patients with systemic myopathies often present acutely or sub acutely. On the other hand, familial myopathies or dystrophies generally present in a chronic fashion with exceptions of metabolic myopathies where symptoms on occasion can be precipitated acutely. Most of the inflammatory myopathies can have a chance association with malignant lesions; the incidence appears to be specifically increased only in patients with dermatomyositis.^[3]

Classes

There are many types of myopathy. ICD-10 codes are provided here where available.

Inherited forms

(G71.0) Dystrophies (or muscular dystrophies) are a subgroup of myopathies characterized by muscle degeneration and regeneration. Clinically, muscular dystrophies are typically progressive, because the muscles' ability to regenerate is eventually lost, leading to progressive weakness, often leading to use of a wheelchair, and eventually death, usually related to respiratory weakness.
(G71.1) Myotonia
- Neuromyotonia
(G71.2) The congenital myopathies do not show evidence for either a progressive dystrophic process (i.e., muscle death) or inflammation, but instead characteristic microscopic changes are seen in association with reduced contractile ability of the muscles. Congenital myopathies include, but are not limited to:
- (G71.2) nemaline myopathy (characterized by presence of "nemaline rods" in the muscle),
- (G71.2) multi/minicore myopathy (characterized by multiple small "cores" or areas of disruption in the muscle fibers),
- (G71.2) centronuclear myopathy (or myotubular myopathy) (in which the nuclei are abnormally found in the center of the muscle fibers), a rare muscle wasting disorder
(G71.3) Mitochondrial myopathies, which are due to defects in mitochondria, which provide a critical source of energy for muscle
(G72.3) Familial periodic paralysis
(G72.4) Inflammatory myopathies, which are caused by problems with the immune system attacking components of the muscle, leading to signs of inflammation in the muscle
(G73.6) Metabolic myopathies, which result from defects in biochemical metabolism that primarily affect muscle
- (G73.6/E74.0) Glycogen storage diseases, which may affect muscle
- (G73.6/E75) Lipid storage disorder

Acquired

(G72.0 - G72.2) External substance induced myopathy
- (G72.0) Drug-induced myopathy
  - Glucocorticoid myopathy is caused by this class of steroids increasing the breakdown of the muscle proteins leading to muscle atrophy.^[4]
- (G72.1) Alcoholic myopathy
- (G72.2) Myopathy due to other toxic agents
(M33.0-M33.1)
- Dermatomyositis produces muscle weakness and skin changes. The skin rash is reddish and most commonly occurs on the face, especially around the eyes, and over the knuckles and elbows. Ragged nail folds with visible capillaries can be present. It can often be treated by drugs like corticosteroids or immunosuppressants. (M33.2)
- Polymyositis produces muscle weaknesss. It can often be treated by drugs like corticosteroids or immunosuppressants.
- Inclusion body myositis is a slowly progressive disease that produces weakness of hand grip and straightening of the knees. No effective treatment is known.
(M61) Myositis ossificans
(M62.89) Rhabdomyolysis and (R82.1) myoglobinurias

The Food and Drug Administration is recommending that physicians restrict prescribing high-dose Simvastatin (Zocor, Merck) to patients, given an increased risk of muscle damage. The FDA drug safety communication stated that physicians should limit using the 80-mg dose unless the patient has already been taking the drug for 12 months and there is no evidence of myopathy. "Simvastatin 80 mg should not be started in new patients, including patients already taking lower doses of the drug," the agency states.

Differential diagnosis of systemic myopathy based on age of onset^[5]

Myopathies presenting at birth:- None as systemic causes; mainly hereditary

Myopathies presenting in childhood:-

Inflammatory myopathies – dermatomyositis, polymyositis (rarely)

Infectious myopathies

Endocrine and metabolic disorders – hypokalemia, hypocalcemia, hypercalcemia

Myopathies presenting in adulthood

Inflammatory myopathies – polymyositis, dermatomyositis, inclusion body myositis, viral (HIV)

Infectious myopathies

Endocrine myopathies – thyroid, parathyroid, adrenal, pituitary disorders

Toxic myopathies – alcohol, corticosteroids, narcotics, colchicines, chloroquine

Critical illness myopathy

Metabolic myopathies

Paraneoplastic myopathy

Symptoms

Common muscle weakness. Also (R25.2) cramps (M25.6) stiffness, and (R29.0) tetany

Treatments

Because different types of myopathies are caused by many different pathways, there is no single treatment for myopathy. Treatments range from treatment of the symptoms to very specific cause-targeting treatments. Drug therapy, physical therapy, bracing for support, surgery, and massage are all current treatments for a variety of myopathies.

References

^ "Myopathy - Definition from the Merriam-Webster Online Dictionary".
^ Rendle, M. (2006). "Stress and Capture Myopathy in Hares" (PDF). Irish Hare Initiative. Retrieved 2013-09-15.
^ Chawla, Jasvinder (2011). "Stepwise Approach to Myopathy in Systemic Disease". Frontiers in Neurology (Front Neurol. 2011; 2: 49) 2: 49. doi:10.3389/fneur.2011.00049. PMC 3153853. PMID 21886637.
^ Seene T (July 1994). "Turnover of skeletal muscle contractile proteins in glucocorticoid myopathy". J. Steroid Biochem. Mol. Biol. 50 (1–2): 1–4. doi:10.1016/0960-0760(94)90165-1. PMID 8049126.
^ Chawla, Myopathy (2011). "Systemic Myopathy". Frontiers in Neurology 2: 49. doi:10.3389/fneur.2011.00049. PMC 3153853. PMID 21886637.

External links

GeneReviews/NCBI/NIH/UW entry on Myopathy with Deficiency of ISCU
See http://neuromuscular.wustl.edu/ for medical descriptions.

UpToDate Contents

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1. 筋力低下患者へのアプローチ approach to the patient with muscle weakness
2. 全身性疾患のミオパシー myopathies of systemic disease
3. 代謝性ミオパチーへのアプローチ approach to the metabolic myopathies
4. 薬物誘導性ミオパシー drug induced myopathies
5. 先天性ミオパシー congenital myopathies

English Journal

Diagnostic yield of muscle fibre conduction velocity in myopathies.

Blijham PJ, van Engelen BG, Drost G, Stegeman DF, Schelhaas HJ, Zwarts MJ.SourceDepartment of Clinical Neurophysiology, Institute of Neurology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands.
Journal of the neurological sciences.J Neurol Sci.2011 Oct 15;309(1-2):40-4. Epub 2011 Aug 16.
We prospectively assessed diagnostic yield of muscle fiber conduction velocity (MFCV) studies in patients with signs and symptoms suggestive of a myopathy. Results were analysed with respect to the final diagnosis, and compared to the reference standard, which was qualitative electromyography (EMG),
PMID 21849172

Mitochondrial neurogastrointestinal encephalopathy in an Indian family with possible manifesting carriers of heterozygous TYMP mutation.

Nalini A, Gayathri N.SourceDepartment of Neurology, National Institute of Mental health and Neurosciences, Bangalore, India.
Journal of the neurological sciences.J Neurol Sci.2011 Oct 15;309(1-2):131-5. Epub 2011 Jul 26.
BACKGROUND: Mitochondrial neurogastrointestinal encephalomyopathy (MNGIE) is a distinctive autosomal recessive disorder with mitochondrial alterations due to mutations TYMP gene encoding thymidine phosphorylase.MATERIALS AND METHODS: Study of clinical and biochemical characteristics of a family with
PMID 21794876

Japanese Journal

亜急性期の皮膚筋炎患者に対する運動療法における運動負荷量の検討

山内真哉,森下慎一郎,眞渕敏,児玉典彦,道免和久
理学療法学 38(2), 114-120, 2011-04-20
【目的】本研究の目的は,亜急性期の皮膚筋炎患者2症例に対して運動療法を実施し,運動負荷量の検討を行うことである。【方法】皮膚筋炎患者2名に対し,一定の運動負荷量を設定したうえで運動療法を実施した。筋力トレーニングについては,主観的運動強度としてボルグスケールを用いて筋疲労を指標に負荷量を設定した。持久力トレーニングについては,心肺運動負荷試験を実施して有酸素運動の負荷量を設定した。約4週間の運動療 …
NAID 110008608083

糖尿病とミトコンドリア機能

尾形真規子
東京女子医科大学雑誌 81(E2), E85-E88, 2011-03-31
糖尿病はインスリン分泌能の低下とインスリン抵抗性により高血糖が起きる疾患群である。膵β細胞存続にミトコンドリア機能が重要であり、また、発症後の高血糖によるミトコンドリア遺伝子の脆弱性から、標的臓器の二次的な障害にミトコンドリア障害が関与する可能性が指摘されていた。1990年代に入り、ミトコンドリア遺伝子異常症による糖尿病が報告され、糖尿病の発症という観点からミトコンドリア機能異常が注目されている。 …
NAID 110008441449

Related Pictures

★リンクテーブル★

リンク元	「100Cases 14」「筋疾患」「muscle injury」「myopathic」「高乳酸血症と脳卒中様症状をもつ脳筋症」
拡張検索	「ischemic dilated cardiomyopathy」「burned-out phase of cardiomyopathy」「end-stage phase of cardiomyopathy」

「100Cases 14」

Myopathy
Classification and external resources
ICD-10	G71-G72, M60-M63
ICD-9	359.4-359.9, 728-728
DiseasesDB	8723
eMedicine	emerg/328
Patient UK	Myopathy
MeSH	D009135

　　[★]

☆case14　複視

■glossary

diplopia n. 複視

筋力低下、筋無力、筋脱力 muscle weakness, muscular weakness

sunken

vt. sinkのpp.

adj.

沈没した、沈んだ、水中の

沈下した、一段低いところにある

落ち込んだ、くぼんだ

3,4-ジアミノピリジン 3,4-diaminopyridine 3,4-DAP K+チャネル阻害薬;ランバート・イートン筋無力症治療

■症例

43-year-old woman

cheif complaint: diplopia

present history: diplopia and holding her head up ; more marked in the evenings, for the last 3 months. difficulty of chewing. voice has become quieter. weight loss (3kg / 6months). non-smoker. drinks about 15 units/week. no regular medication.

past history: no significant previous medical illnesses.

family history: lives with her husband and three children.

・診察 examination

looks well.

organ systems: normal; cardiovascular, respiratory, and abdominal systems.

muscle power; grossly normal. decrease after testing a movement repetitively.

motor function: normal; tone, coordination, reflexes and sensation.

bilateral ptosis. exacerbated by prolonged upward gaze

eye: normal; pupillary reflexes, eye movements, and funduscopy

■答え

diagnosis: myathenia gravis

differential diagnoses:

CASES

上位and/or下位運動ニューロン motor neurone disease　運動ニューロン疾患：線維束性攣縮。進行例では筋力低下

筋 muscular dystrophy　筋ジストロフィー：ある種の筋肉が選択的に筋力低下する。家族歴がある。

筋 dystrophia myotonica　強直性筋ジストロフィー：咬筋、側頭筋、胸鎖乳突筋の筋萎縮、四肢遠位端の筋萎縮。顔貌が特徴的(前頭部脱毛、無表情、窪んだ頬)。家族歴ある。筋電図が診断に有用(急降下爆撃音)。

筋 polymyositis　多発筋炎：普通は皮疹と関節痛が出現。CKが上昇。筋生検が診断に有用

筋 myopathy　ミオパチー：甲状腺中毒性ミオパチー、甲状腺機能低下症によるミオパチー、クッシング症候群によるミオパチー、アルコール性のミオパチー

神経筋接合部？ non-metastatic associations of malignancy (paraneoplastic syndrome(傍腫瘍性症候群 = 腫瘍随伴症候群)のこと)：胸腺腫の症例の10%に重症筋無力症がみられる。ランバート・イートン筋無力症症候群は小細胞癌と関連がある。

HIM.2674

神経筋接合部 congenital myasthenia syndrome　先天性筋無力症症候群
神経筋接合部 drug-induced myasthenia　薬剤性筋無力症

Treatment with penicillamine (used for scleroderma or rheumatoid arthritis) may result in true autoimmune MG, but the weakness is usually mild, and recovery occurs within weeks or months after discontinuing its use.

　重症筋無力症の誘発：ペニシラミン(強皮症や関節リウマチの治療に用いられる)。

　　mildだし、薬剤の中断で改善する。

Aminoglycoside antibiotics or procainamide can cause exacerbation of weakness in myasthenic patients; very large doses can cause neuromuscular weakness in normal individuals.

　重症筋無力症の悪化：アミドグリコシド系抗菌薬、プロカインアミド

　　MGの患者の筋脱力が悪化する。

神経筋接合部 Lambert-Eaton myasthenic syndrome　ランバート・イートン筋無力症症候群：全身の筋肉が冒されるが、特に下肢の近位筋が冒される。MGと同じように～70%の患者で脳神経所見(眼瞼下垂、複視など)が認められる。MGと違うのは(1)反射が消失・減弱すること、(2)自律神経系の変化(口渇、勃起不全)を生じる、(3)神経刺激検査で漸増(waxing)が見られることである。病因は神経筋接合部のP/Q type calcium channelsに対する抗体の出現であり、85%の患者で見いだされる。治療はMGのように血漿交換や免疫抑制薬が使われる。3,4-DAPやpyridostigmineは症状に対する治療のために用いる。前者は運動神経の終末部でカルシウムチャネルをブロックし活動電位を延長させる。後者はアセチルコリンエステラーゼを阻害してシナプスにおける神経伝達物質の濃度を上げる。
精神疾患 neurasthenia　神経衰弱症：歴史的な用語。器質的な障害を伴わない筋無力症のような脱力を伴う症候群。患者は筋脱力や疲労を訴えてやってくる。筋肉の検査では器質的変化は認めないが"jerky release"あるいは"give-away weakness"が認められる。患者の主訴は反復動作による筋力低下よりむしろ疲労や感情鈍麻である。
内分泌疾患 hyperthyroidism　甲状腺機能亢進症：MGが疑われる患者にはthyroid function testをルーチンにやる。甲状腺機能異常は筋無力症の筋力低下を大きくすることがある。
神経筋接合部 botulism　ボツリヌス症：ボツリヌス毒素はシナプス前膜からの神経伝達物質の開口分泌を妨げる。症状はbulbar weakness (複視、構音障害、嚥下困難)。感覚障害はない。深部腱反射は初期には保たれている。進行すれば反射は見られなくなる。筋脱力は全身性。呼吸困難に陥ることがある。精神状態は正常。自律神経症状(麻痺性イレウス、便秘、urinary retention、瞳孔の散大、瞳孔の反応性低下、口渇)。確定診断は血清中の毒素の検出だけど、見つかることはまれ。神経伝導検査(nerve conduction studies)：compound muscle action potentials (CMAPs)の低下。高頻度の刺激で振幅が増加。治療：intubation for airway protection、呼吸補助、aggressive inpatient supportive care(e.g., nutrition, DVT prophylaxis)。馬の抗毒素を検査結果が帰ってくる前に投与する(？)。
上位運動ニューロン intracranial mass lesions　頭蓋内占拠病変：複視はintracranial mass lesionが外眼筋の神経を圧迫することにより生じる。
筋 progressive external ophthalmoplegia　進行性外眼筋麻痺：外眼筋の筋脱力を伴う。四肢の近位筋の筋力低下やそのほかの全身症状を伴うことがある。ミトコンドリアの異常を有する。

■参考文献

HIM = Harrison's Principles of Internal Medicine 17th Edition

CASES = 100 Cases in Clinical Medicine Second edition

IMD = 内科診断学第2版

「筋疾患」

　　[★]

英: myopathy, muscular disease, muscular disorder
同: ミオパシー、ミオパチー、筋原性疾患、筋症
関: 筋萎縮

神経系 091125IV

筋疾患と神経疾患

	筋疾患	神経疾患
	myopathy	neuropathy
筋力低下	近位筋優位	遠位筋優位

筋疾患と末梢神経疾患の鑑別

	神経原性	筋原性
	下位運動ニューロン障害	筋原性
筋萎縮	遠位筋中心	近位筋中心
線維束性攣縮	あり	なし
筋電図	高振幅	低振幅
	long duration	short duration
	giant spike
	(代償的な筋線維の興奮)
筋逸脱酵素	ー	CK↑
筋生検	群性萎縮(小角化線維)	孤発性萎縮(筋線維の大小不同、中心核の増加)
疾患	ALS	筋ジストロフィー
疾患	SPMA	多発性筋炎

分類

遺伝性	遺伝性ミオパチー	筋ジストロフィー
遺伝性	遺伝性ミオパチー	ミトコンドリアミオパチー
非遺伝性	外因性筋障害	ステロイドミオパチー
		crush syndrome
		ischemia
	炎症性ミオパチー	多発筋炎・皮膚筋炎
	内分泌性・代謝疾患性	甲状腺機能低下症
		低カリウム性ミオパチー
		アルコール性ミオパチー
	その他