Polymyositis - Polymyositis

Japanese: 多発性筋炎 - たはつせいきんえん（英語表記）Polymyositis

What is the disease?

Polymyositis is a condition in which inflammation of skeletal muscles occurs for unknown reasons, primarily Proximal limb muscles ( Lion's Neck ) , neck ( Keibu ) , Pharyngeal muscles ( Invoice ) It is a disease that causes symmetric muscle weakness and the resulting disability. If it is accompanied by skin symptoms at the same time, it is called dermatomyositis. Since there is no difference in the characteristics of the muscle symptoms in both cases, they are often treated together as polymyositis and dermatomyositis.

Polymyositis has two aspects: a muscle disease and a systemic autoimmune disease. It is often accompanied by other autoimmune diseases or malignant tumors. It often occurs in women aged 40 to 60.

What is the cause?

The cause of the disease is unknown. The prevailing theory is that it is caused by an autoimmune reaction in the muscles (a reaction in which autoantibodies are produced in one's own muscles for some reason, destroying one's own muscle cells).

How symptoms manifest

The initial symptom is often muscle weakness of the proximal muscles of the lower limbs (muscles close to the center of the body) that progresses subacutely over a period of several weeks to several months, making it difficult to walk or climb stairs. It is not uncommon for patients to also have difficulty standing up from a sitting position.

When the proximal muscles of the upper limbs are affected, it becomes difficult to reach objects that are high up. neck ( Keibu ) Weakness in the neck muscles can cause symptoms such as being unable to lift your head off the pillow. Swallowing ( Engage )・Articulation disorders are sometimes seen. Muscle pain is one of the relatively characteristic symptoms seen in about half of the patients, and is often seen in the acute phase. Muscle atrophy is not seen at first, but appears when the condition becomes chronic.

Furthermore, if any symptoms appear on the skin ( Eyelids ( Hard work ) With swelling in the area Erythema ( Kohan ) , erythema on the dorsal side of the finger joints), and if skin symptoms are predominant, the possibility of dermatomyositis is high.

Respiratory lesions include interstitial pneumonia and hypoventilation due to weakened respiratory muscles. Myocarditis can lead to arrhythmia and heart failure, which are major causes of death.

Testing and diagnosis

Blood tests show elevated levels of skeletal muscle-specific enzymes creatine kinase, aldolase, and serum myoglobin. Antinuclear antibody tests check for anti-Jo1 antibodies specific to this disease. Electromyograms show myogenic changes. Muscle biopsy shows inflammatory cell infiltration in the endomysium and around blood vessels.

Based on the above, the diagnosis is based on the presence of myositis and skin rash. Progressive muscular dystrophy is important as a differential diagnosis.

Treatment methods

The earlier treatment begins, the more effective it is. Drug therapy includes steroids, immunosuppressants, Gamma ( gamma ) and intravenous globulin therapy.

In the acute phase, rest and keeping warm are necessary. In the recovery phase, rehabilitation begins with light stretching, and in the chronic phase, joint Contracture ( Education ) and Disuse atrophy ( Hire a competent ) We provide daily living guidance to prevent this and to avoid excessive exercise.

In many cases, the functional impairment improves and the patient is able to live a normal social life without much inconvenience. However, some patients will remain with severe functional impairment for a long time, and it will gradually progress.

What to do if you notice an illness

Please consult an internal medicine or dermatology specialist.

Masashi Fujii

Polymyositis
Polymyositis
(Childhood illnesses)

What is the disease?

It is an inflammatory disease of unknown cause that damages muscles. It can be seen in all ages, from children around 7 years old to the elderly, and there are various types. If skin symptoms are seen along with myositis, Dermatomyositis ( Hifukien ) It is said that...

What is the cause?

The cause is unknown, but it can occur in conjunction with an autoimmune disease in which the body produces antibodies against its own body, causing unpleasant symptoms.

How symptoms manifest

Fever and whole body Fatigue ( Health test ) Along with the thigh and upper arm muscles neck ( Neck ) Muscle weakness is seen in the area of the skin. The muscle weakness progresses over the course of several weeks to several months. It becomes difficult to get in and out of the bath, and to lift the head off the pillow. Muscle pain is also common. Skin symptoms include purple-red swelling of the skin around the eyes and the backs of the joints of the fingers.

Complications include inflammation of blood vessels throughout the body and a tendency to fall into respiratory failure. Interstitial ( Observation ) Pneumonia may occur. In the case of elderly people, caution is also required regarding the development of malignant tumors.

Testing and diagnosis

Blood tests show elevated levels of muscle-derived enzymes (CK, LDH, AST, aldolase). Electromyography, in which a needle is inserted into the affected muscle, and muscle biopsy, in which part of the muscle is removed and examined under a microscope, are necessary for diagnosis.

Treatment methods

Oral administration of corticosteroids is effective. If this is ineffective, if the condition is severe, or if there are complications, then concentrated administration of large amounts of steroids intravenously, known as pulse therapy, is performed.

What to do if you notice an illness

Since this is a disease that is not limited to the muscles, please have a thorough check of your entire body. It is necessary to understand the disease and medication, so be sure to cooperate closely with your doctor.

Kozaburo Hiramatsu

Polymyositis
Polymyositis
(Brain, nerve and muscle diseases)

What is the disease?

Collagen disease ( Public health center ) Polymyositis, a type of myositis, is the first well-known. There are many patients, and it is often difficult to diagnose. It is thought that for some reason, autoantibodies are produced in one's own muscles, destroying one's own muscle cells.

How symptoms manifest

Fever, arthritis (red, swollen, painful joints), muscle pain, and muscle weakness progress over a period of several months. If skin symptoms occur, the condition is called dermatomyositis (column), but it is essentially the same disease.

Testing and diagnosis

Increased serum CK (creatine kinase) levels and muscle cell counts in muscle biopsies (a test in which a small piece of tissue is taken and examined) Necrosis ( Replying to @sarah_mcdonald ) Regenerative findings and cells infiltration ( Shinjun ) The diagnosis can be made by the appearance of serum Jo1 antibodies.

Treatment methods

Since it is a type of collagen disease, administration of corticosteroids is effective. It is important to start treatment within 6 months of the onset of the disease. In cases where steroids are not effective, there are also reports that high-dose intravenous immunoglobulin therapy is effective.

You should rest while you have muscle pain, but once the pain goes away it is important to actively engage in rehabilitation.

Nearly half of cases of polymyositis in middle-aged and older people are malignant. tumor ( Main ) It is one of the symptoms of cancer. Cancer is often not detected at the time of onset, and is often only discovered several years later.

Source: Houken “Sixth Edition Family Medicine Encyclopedia” Information about the Sixth Edition Family Medicine Encyclopedia

Japanese:

どんな病気か

　多発性筋炎は、骨格筋に原因不明の炎症が生じ、主として四肢近位筋(ししきんいきん)、頸部(けいぶ)、咽頭筋(いんとうきん)の対称性筋力低下と、それによる障害を起こす病気です。同時に皮膚症状を伴うと皮膚筋炎と呼ばれます。どちらも筋症状の特徴には差がないため、一括して多発性筋炎・皮膚筋炎と表して扱われることが多いです。

　多発性筋炎は、筋疾患と全身性自己免疫疾患の2つの側面があります。ほかの自己免疫疾患や悪性腫瘍を合併することが少なくありません。40～60歳の女性に多く発症します。

原因は何か

　病因は不明です。筋肉を中心に自己免疫反応（何らかの原因で自分の筋肉に自己抗体を作り、自分の筋細胞を破壊する反応）が生じて発症するとの考えが有力です。

症状の現れ方

　初発症状として、数週から数カ月にわたって亜急性に進行する下肢近位筋（体の中心に近い筋肉）の筋力低下が多くみられ、歩行や階段昇降に困難を生じます。座位から立ち上がることが困難になってくることも少なくありません。

　上肢近位筋が侵されると高いところの物がとれなくなり、頸部(けいぶ)（首）の筋力低下では頭を枕から挙上できないなどの症状が出ます。咽頭筋の筋力低下により嚥下(えんげ)・構音(こうおん)障害もときにみられます。筋痛は約半数に認められる比較的特徴的な症状のひとつで、急性期に多くみられます。筋萎縮は最初ありませんが、慢性化すると出現します。

　さらに皮膚に何らかの症状（眼瞼(がんけん)部の浮腫を伴った紅斑(こうはん)、手指関節背側の紅斑など）が多くみられ、皮膚症状が主であれば皮膚筋炎の可能性が大きくなります。

　呼吸器病変として間質性肺炎(かんしつせいはいえん)や呼吸筋筋力低下による低換気を認めます。心筋炎から不整脈や心不全となり、重要な死因のひとつとなっています。

検査と診断

　血液検査では、骨格筋特異的酵素であるクレアチンキナーゼ、アルドラーゼや血清ミオグロビン値が上昇します。抗核抗体の検査では、本疾患に特異的な抗Jo1抗体について調べます。筋電図では筋原性変化をみます。筋生検では筋内膜や血管周囲に炎症性細胞浸潤を認めます。

　以上から、筋炎の存在と皮疹を検討して診断をします。鑑別診断としては進行性筋ジストロフィー症が重要です。

治療の方法

　治療の開始が早いほど治療効果が期待できます。薬物療法としては、ステロイド薬、免疫抑制薬、γ(ガンマ)グロブリン大量静注療法などがあります。

　急性期には安静と保温が必要です。回復期になれば軽いストレッチからリハビリテーションを開始し、慢性期には関節拘縮(こうしゅく)と廃用性萎縮(はいようせいいしゅく)の予防と、過度の運動は避けるような日常生活指導をします。

　多くの場合で機能障害の改善がみられ、社会生活をあまり不自由なく送ることができるようになります。しかし、一部は長期間にわたり高度な機能障害が残り、徐々に進行します。

病気に気づいたらどうする

　内科あるいは皮膚科を受診してください。

藤井　正司

多発性筋炎
たはつせいきんえん
Polymyositis
(子どもの病気)

どんな病気か

　筋肉を障害する原因不明の炎症性疾患です。7歳前後の小児から老人まですべての年齢にみられ、いろいろなタイプがあります。筋炎とともに皮膚の症状がみられる場合は皮膚筋炎(ひふきんえん)といわれます。

原因は何か

　原因不明ですが、自分の身体に対する抗体が現れてきて、不都合な症状を引き起こしてくる自己免疫性疾患に伴って起こることがあります。

症状の現れ方

　発熱や全身の倦怠感(けんたいかん)とともに大腿、上腕の筋肉や頸(くび)の筋力低下がみられます。数週～数カ月の経過で筋力低下は進んでいきます。お風呂に出入りするのがつらくなったり、頭を枕から持ち上げにくくなったりします。筋肉に痛みを感じることも多いようです。皮膚の症状としては、眼の周囲の皮膚や手指の関節の背面が紫赤色にはれぼったくなったりします。

　合併症として、全身の血管に炎症が起こったり、呼吸不全に陥りやすい間質性(かんしつせい)肺炎がみられたりします。高齢者の場合は悪性腫瘍の発生にも注意が必要です。

検査と診断

　血液検査で筋肉由来の酵素（CK、LDH、AST、アルドラーゼ）の値の上昇がみられます。障害を受けた筋肉に針を刺して検査する筋電図と、筋肉の一部を切開して筋肉を取り、顕微鏡で調べる筋生検が、診断のために必要な検査です。

治療の方法

　副腎皮質ステロイド薬の内服が有効です。効果がみられない場合や重い場合、合併症がある場合は、パルス療法といわれるステロイド薬の集中大量点滴投与を行います。

病気に気づいたらどうする

　筋肉だけにとどまらない病気なので、全身的なチェックを十分に受けてください。病気や薬に対する理解が必要なので、医師との十分な連携をとるようにします。

平松　公三郎

多発性筋炎
たはつせいきんえん
Polymyositis
(脳・神経・筋の病気)

どんな病気か

　膠原病(こうげんびょう)の一種としての多発性筋炎がまず有名です。患者さんの数も多く、診断に苦慮することも多い病気です。何らかの原因で自分の筋肉に自己抗体をつくり、自分の筋細胞を破壊すると考えられます。

症状の現れ方

　発熱、関節炎（関節が赤くはれ、痛い）、筋痛とともに筋力低下が数カ月の間に進行します。皮膚症状が合併すると皮膚筋炎（コラム）と呼ばれますが、本質的には同じ病気と考えます。

検査と診断

　血清CK（クレアチンキナーゼ）値の上昇と、筋生検（組織の一部を採取して調べる検査）での筋細胞の壊死(えし)・再生所見と細胞浸潤(しんじゅん)の出現によって診断できます。血清Jo1抗体の出現もみられます。

治療の方法

　膠原病の一種ですから、副腎皮質ステロイド薬の投与が効果的です。発病後6カ月以内に治療を開始することが大切とされています。ステロイド薬の効果が思わしくない症例では、免疫グロブリン大量静注療法が有効だという報告もあります。

　筋痛がある間は安静にしているべきですが、筋痛がなくなったら積極的にリハビリテーションを行うことが大切です。

　中年以降の多発性筋炎の半分近くが、悪性腫瘍(しゅよう)（がん）の一症状です。発症した時点ではがんが見つからないことが多く、数年経過してから初めてがんが見つかることも少なくありません。

出典　法研「六訂版家庭医学大全科」六訂版家庭医学大全科について　情報

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What is the disease?

What is the cause?

How symptoms manifest

Testing and diagnosis

Treatment methods

What to do if you notice an illness

Polymyositis Polymyositis (Childhood illnesses)

What is the disease?

What is the cause?

How symptoms manifest

Testing and diagnosis

Treatment methods

What to do if you notice an illness

Polymyositis Polymyositis (Brain, nerve and muscle diseases)

What is the disease?

How symptoms manifest

Testing and diagnosis

Treatment methods

どんな病気か

原因は何か

症状の現れ方

検査と診断

治療の方法

病気に気づいたらどうする

多発性筋炎たはつせいきんえんPolymyositis(子どもの病気)

どんな病気か

原因は何か

症状の現れ方

検査と診断

治療の方法

病気に気づいたらどうする

多発性筋炎たはつせいきんえんPolymyositis(脳・神経・筋の病気)

どんな病気か

症状の現れ方

検査と診断

治療の方法

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