Pleurisy - Pleurisy

Japanese: 胸膜炎 - きょうまくえん（英語表記）Pleurisy

What is the disease?

The pleura is the membrane that covers the surface of the lungs. Visceral ( Puzzle ) Pleura and chest wall, diaphragm ( Oukakuma ) , Mediastinum ( 100 ) Cover Wall side ( Hexagon ) The area surrounded by both pleura is the pleural cavity, and the accumulation of pleural fluid here is called pleurisy.

What is the cause?

The main causes of pleurisy are infection and malignant tumors. Collagen disease ( Public health center ) , Pulmonary infarction ( Fast ) , Asbestosis ( Countermeasures ) can also cause pleural effusion. Hypoproteinemia ( Temporary housing contest ) Pleural effusion can also occur in congestive heart failure.

Among infectious diseases, tuberculosis ( Results ) Most of the cases are caused by bacterial infections, while most malignant tumors are caused by lung cancer. Tuberculous ( Results ) It is called pleurisy, bacterial pleurisy, or malignant pleurisy.

How symptoms manifest

The first symptom is often chest pain, which can be easily relieved by deep breathing or other physical actions. cough ( cough ) in Exacerbation ( Zooac ) If the cause is an infectious disease, it will be accompanied by a fever. The patient will have a cough but will not produce much phlegm, and as the amount of pleural fluid increases, the patient will start to feel short of breath.

Testing and diagnosis

Pleurisy can sometimes be diagnosed by a doctor using only auscultation. Voiced consonants ( Dakuon ) The patient shows weak breath sounds and characteristic pleural Fricatives ( Masatsuon ) (The sound of the visceral pleura rubbing against the parietal pleura can be heard.

A chest x-ray will reveal the presence of pleural fluid (Figure 45). In cases where the fluid is small, a chest CT scan may be the only way to make the diagnosis.

To determine the cause of pleurisy, a pleural fluid test is performed. A thin needle is inserted between the ribs to collect pleural fluid. If the collected pleural fluid is bloody, tuberculosis or a malignant tumor is suspected.

Next, check the specific gravity and protein concentration of the pleural fluid. If either is high (specific gravity 1.018 or higher, protein 3.0 g/dL or higher), Exudate ( Exit station ) These are called "anti-inflammatory drugs" and are used to suspect infections, malignant tumors, etc. Transudate ( Departure station ) It is caused by hypoproteinemia and congestive heart failure.

If the number of neutrophils in the pleural fluid is increased, bacterial infection is suspected; if the number of lymphocytes is increased, tuberculosis or a malignant tumor is suspected.

The definitive diagnosis of malignant tumors and tuberculosis is to demonstrate malignant cells or tuberculosis bacteria in pleural fluid. Also, an increase in ADA (adenosine deaminase) in pleural fluid (50 U or more) is a useful method for diagnosing tuberculosis.

If a diagnosis cannot be made based on pleural fluid examination alone, a thoracoscope may be used to visually observe the inside of the thoracic cavity and a biopsy may be performed on any area suspected to be affected to make a definitive diagnosis.

Treatment methods

If it is a bacterial infection, antibiotics will be administered intravenously. In the early stages, penicillin or cephalosporin drugs are often administered, and if the causative bacteria is identified, a more sensitive drug will be selected. In severe cases, a strong antibiotic called carbapenem is administered.

If tuberculosis is the cause, it is treated with antituberculous drugs such as streptomycin, rifampin, isonicotinic acid hydrazide, ethambutol, or pyrazinamide.

If the cause is a malignant tumor, thoracic drainage is performed. Thoracic drainage is a method in which a thin tube is inserted between the ribs into the thoracic cavity and a machine is used to pump the pleural fluid out of the body. Once the pleural fluid has decreased, anticancer drugs such as Adriamycin or Picibanil are injected to prevent the pleural fluid from building up again. At the same time, anticancer drugs such as cisplatin are administered systemically.

The prognosis for pleurisy caused by bacteria or tuberculosis is generally good, but that caused by malignant tumors is extremely poor.

What to do if you notice an illness

If you experience chest pain that worsens with deep breathing or coughing, you should suspect pleurisy and see an internal medicine doctor as soon as possible. In particular, if a smoker experiences symptoms of the early stage, they should see an internal medicine doctor as soon as possible, as they may be due to a malignant tumor.

Jiro Okimoto

Figure 45. Pleural effusion (chest X-ray image)
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Figure 45. Pleural effusion (chest X-ray image)

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

Japanese:

どんな病気か

　胸膜とは、肺の表面をおおう臓側(ぞうそく)胸膜と、胸壁、横隔膜(おうかくまく)、縦隔(じゅうかく)をおおう壁側(へきそく)胸膜からなっています。両胸膜に囲まれた部分が胸膜腔で、ここに胸水がたまる病気を胸膜炎と呼びます。

原因は何か

　胸膜炎の原因としては、感染症、悪性腫瘍が主なものであり、膠原病(こうげんびょう)、肺梗塞(はいこうそく)、石綿肺(せきめんはい)も胸水がたまる原因になります。低蛋白血症(ていたんぱくけっしょう)や、うっ血性心不全でも胸水がたまります。

　感染症のなかでは、結核(けっかく)や細菌感染によるものが多く、悪性腫瘍では肺がんによるものが多いといわれ、それぞれ、結核性(けっかくせい)胸膜炎、細菌性胸膜炎、がん性胸膜炎と呼ばれています。

症状の現れ方

　最初の症状としては胸痛が多く、この胸痛は深呼吸や咳(せき)で増悪(ぞうあく)するのが特徴です。原因が感染症であれば、発熱を伴います。咳も出ますが痰は少なく、胸水が増えてくると呼吸困難を感じるようになります。

検査と診断

　胸膜炎は、医師の聴打診のみでも診断がつくことがあります。胸水のたまった部位が打診で濁音(だくおん)を示し、呼吸音が弱くなり、特徴的な胸膜摩擦音(まさつおん)（臓側胸膜と壁側胸膜がすれる音）が聞かれる場合です。

　胸部X線検査で胸水がたまっているのが明らかにされます（図45）。胸水が少量の場合には、胸部CT検査で初めて診断がつく場合もあります。

　胸膜炎の原因を調べるために、胸水検査が行われます。肋骨と肋骨の間から細い針を刺し、胸水を採取します。採取した胸水が血性であれば、結核や悪性腫瘍を疑います。

　次いで胸水の比重や蛋白濃度を調べ、いずれも高値（比重1.018以上、蛋白3.0g／㎗以上）であれば滲出液(しんしゅつえき)と呼び、感染症、悪性腫瘍などを疑います。いずれも低値であれば漏出液(ろうしゅつえき)と呼び、低蛋白血症やうっ血性心不全が原因です。

　胸水中の白血球分類が行われ、好中球が増えていれば細菌感染が原因であり、リンパ球が増えていれば、結核や悪性腫瘍が原因として考えられます。

　悪性腫瘍や結核の確定診断は、胸水から悪性細胞や結核菌を証明することです。また、胸水中のADA（アデノシン・デアミナーゼ）の上昇（50U以上）は、結核を診断する有力な方法です。

　胸水の検査だけで診断が得られない場合には、胸腔鏡を用いて胸腔内を肉眼的に観察し、病変と思われる部位を生検して確定診断をする場合もあります。

治療の方法

　細菌感染によるものであれば、抗菌薬の点滴が行われます。抗菌薬は、初期にはペニシリンやセフェム系の薬剤が投与される場合が多く、起炎菌がわかれば、より感受性のある薬剤が選択されます。重症例にはカルバペネムという強力な抗菌薬が投与されます。

　結核が原因であれば、ストレプトマイシン、リファンピシン、イソニコチン酸ヒドラジド、エタンブトール、ピラジナマイドなどの抗結核薬で治療します。

　悪性腫瘍が原因であれば、胸腔ドレナージを行います。胸腔ドレナージとは、肋骨と肋骨の間から細いチューブを胸腔内に挿入し、器械で胸水を体外に汲み出す方法です。胸水が減った時点で、アドリアマイシンなどの抗がん薬やピシバニールを注入し、胸水が再びたまるのを予防します。同時にシスプラチンなどの抗がん薬の全身投与を行います。

　細菌や結核による胸膜炎の予後は一般的には良好ですが、悪性腫瘍によるものでは極めて不良です。