PNEUMONIA, is an inflammation of the lung resulting from any of a variety of causes. Pneumonia is caused by many infectious agents, including bacteria, viruses, yeast and other fungi, and rickettsia. It can also be caused by inhaled chemical agents, by radiation, and by allergic reactions to foreign particles in the lung. Pneumonia sometimes occurs in various diseases, including systemic lupus erythematosus---a collagen vascular disease involving connective tissues in the small blood vessels---and certain other diseases that are probably caused by disturbances in the body’s immune mechanisms.

肺炎，是由各种原因引发的肺部炎症。肺炎是由许多传染性病原体引起的，包括细菌、病毒、酵母菌和其它真菌以及立克次体。吸入化学制剂，辐射以及肺部对异物的过敏反应也会引起该病。有时，肺炎会发生在各种疾病中，包括全身性红斑狼疮---一种涉及小血管中结蒂组织胶原血管的疾病---还有可能因身体免疫机制失调引发的某些其它疾病。

Pneumonia Organisms. The vast majority of pneumonias are caused by infectious agents. Infectious pneumonias are an important cause of death. They are most frequent in the winter, particularly among infants and the old and infirm. The most common of the bacterial pneumonias are caused by Diplococcus pneumonia, commonly known as pneumococcus. But a variety of other bacteria---including Steptococcus, Staphylococcus, and many others---also cause pneumonia. The psittacosis organism, a tiny bacterium formerly thought to be a virus, causes an unusual form of pneumonia characterized by protracted high fever, severe headache, and slow heart rate.

肺炎有机体。绝大多数肺炎是由传染的病原体引起的。传染性肺炎是死亡的重要原因。它们大多在冬季发生，尤其是婴儿、老人和体弱多病的人。最常见的细菌性肺炎是由肺炎双球菌引起的，通常称为肺炎球菌。但是，各种其它的细菌---包括链球菌、葡萄球菌，以及许多其它细菌---也会引发肺炎。鹦鹉热有机体，一种以前被认为是病毒的微小细菌会引发一种不同寻常的肺炎，特征是持续高烧，剧烈头痛和心率降低。

An unusual type of pneumonia that often involves several parts of one or both lungs is caused by Mycoplasma, an organism that resembles a degenerate bacterium without a cell wall. Mycoplasmal pneumonia, also called primary atypical pneumonia, was formerly known as virus pneumonia, because so many of its features were characteristic of those of virus disease and it was long impossible to cultivate the organisms by the usual techniques for culturing bacteria.

由支原体，一种无细胞壁的类似退化细菌的有机体引发的一种不寻常的肺炎常常会涉及肺的单叶或双叶的不同部位。支原体肺炎，也称为原发性非典型性肺炎，以前被称为病毒性肺炎，因为它如此多的特性都是病毒疾病的特性，而且长期以来，不可能通过培养细菌的通常技术来培养这些有机体。

Among the viruses, the influenza viruses are probably the most important cause of pneumonia. Others known to cause pneumonia include smallpox virus, rubeola (measles) virus, and several adenoviruses.

在病毒中，流感病毒大概是肺炎最重要的原因。已知的引发肺炎的其它病毒包括天花病毒、风疹（麻疹）病毒和几个腺病毒。

Lobar Pneumonia and Bronchopneumonia.  Pneumonias can also be classified by the extent of the infected area in the lungs. Before antibiotics, the most common form of pneumonia was lobar pneumonia, which was nearly always caused by pneumococcus bacteria. In lobar pneumonia a whole lobe of a lung was uniformly infected. Today most patients are treated with antibiotics before this full-blown infection can develop, so this type is now rare. Most pneumonias now take the form of patchy areas of infection in one or more lobes of a lung, or of both lungs. These more restricted types are known as bronchopneumonias.

大叶性肺炎和支气管性肺炎。根据肺部感染区域的范围也可对肺炎进行分类。在抗生素之前，肺炎最常见的形式是大叶性肺炎，它几乎总是由肺炎球菌引起的。在大叶性肺炎中，整个肺叶都被感染。今天，大多数患者在这种全面感染可能发展之前已用抗生素进行治疗，所以现在很少见到这种类型。大多数肺炎现在都以肺部一个或多个肺叶或双肺叶斑片状感染的形式出现。这些更多限定的类型被称为支气管肺炎。

Symptoms and Diagnosis.  The symptoms of pneumonia vary greatly, depending on four principal factors: the causative agent, the amount of lung tissue involved, the capacity of the patient’s immune mechanisms to defend the body against infection, and the general health of the patient in general, however, patients with pneumonia have fever, often accompanied by chills, and a cough that often brings up puslike sputum. Many pneumonia patients breathe more rapidly than normal, are short of breath, and—if a considerable part of the lung is involved—are hungry for air. Chest pains in pneumonia patients sometimes indicate pleurisy, an inflammation of the pleural membranes that enclose the lungs.

症状与诊断。肺炎的症状差别很大，取决于四个主要因素：涉及肺部组织数量的病原体，患者的免疫机制防御身体感染的能力，以及一般而言患者的总体健康状况，然而，得了肺炎的患者会发烧，常常伴有发冷，以及咳嗽时常常带有脓状的炎。如果肺部相当大的部分出了问题，许多肺炎患者的呼吸比正常人会更快，而呼吸短促是对空气的渴望。在肺炎患者的胸痛，有时暗示了胸膜炎，一种附在肺上的胸膜炎症。

Patients with pneumococcal pneumonia, particularly when it is lobar in extent, are usually short of breath and breathe rapidly. They often complain of sharp chest pains in breathing, a sign of pleurisy. Their usually puslike sputum often has a rusty appearance caused by the presence of old blood, derived from breakdown of lung tissues. They usually have shaking chills with high fever, and often appear a little cyanotic, or bluish, as a result of oxygen deficiency in the blood.

患有肺炎球菌性肺炎的患者，尤其是大叶肺炎时，通常都呼吸困难，且呼吸急促。他们常常抱怨呼吸时剧烈胸痛，一种胸膜炎的征兆。通常他们有像脓包一样的痰，常常带有来自肺部组织损坏的陈血引起的赭色外观。他们通常打摆子，伴有高烧，由于血液中缺乏氧气，常常看上去有点发紫或发青。

Staphylococcal pneumonia is often preceded by influenza or other respiratory infections, is usually viral in nature. Patients with staphylococcal pneumonia tend to have fevers with sharp peaks and experience more chills than those with pneumococcal pneumonia.

在许多情况下，葡萄球菌性肺在流感或呼吸道感染前，通常是病毒性质的。患有葡萄球菌肺炎的患者比那些患有肺炎球菌性肺炎的患者更易于剧烈发烧和经历更多的寒颤。

In general, patients with typical bacterial pneumonias tend to have more fever, more sputum, and fewer generalized constitutional symptoms—such as aching, fatigue, and loss of appetite—than do patients with pneumonias caused by viruses, Mycoplasma, and the psittacosis and rickettsial bacteria. The latter types of patients more often have dry hacking coughs and lower fever, accompanied by general aches and pains.

一般而言，患有典型性细菌肺炎的患者相比患有病毒，支原体，以及鹦鹉热和立克次体细菌引起肺炎的患者更易于发烧，痰更多，以及更少的全身症状—诸如疼痛，疲乏和食欲不振。后者的患者类型常常有干咳和低烧，伴有全身疼痛。

Chest Examination.  When a doctor taps on the chest of a pneumonia patient, the normal resonant note is replaced by a flatter note, indicating that some of the underlying lung tissue is infiltrated or consolidated—that is, the air sacs are filled with fluids, bacteria, and white blood cells. Listening with the stethoscope, the doctor may hear change in the sound of breathing caused by solidification of the underlying lung. Faint clicking sounds, called rales, which indicate the presence of moisture in the air sacs, are usually also heard.

胸部检查。当医生轻敲肺炎患者的胸部，正常的共振音被更平坦的音调所替代，这表明肺部的一些潜在组织被浸润或固化---换言之，肺气囊充满了液体、细菌以及白血球。用听诊器听时，医生可以听到肺部的基础固化引起呼吸声的变化。通常也会听到称为水泡音的微弱碎裂声，表明在肺气囊中存有水分。

X Rays.  Chest X rays of pneumonia patients show the extent of the lung’s infected areas and also indicate the degree of consolidation. In lobar pneumonia, a whole lobe appears consolidated. In bronchopneumonia, patches of consolidation with intervening areas of normal lung tissue are revealed little cavities in the lung tissue where abscesses have formed at points of severe tissue destruction. If pleurisy is associated with the pneumonia, the X rays may show evidence of fluid in the chest cavity. In tuberculous pneumonia there is often evidence of the healed tubercular lesion in the upper portion of one of the lungs. In the case of pneumonias associated with viruses, Mycoplasma, and the psittacosis and rickettsial bacteria, the X ray appearance is often less dense, but it may show the infection spread widely throughout both lungs.

X射线。肺炎患者的胸部X光片可显示肺部感染的区域，也会显示固化的程度。在大叶性肺炎中，整片肺叶会呈现出固化的状况。在支气管肺炎中，介于正常肺组织中间固化的斑块显示肺部组织中有小空腔，在组织严重受损的点上形成了脓肿。如果胸膜炎与肺炎有关，那么X光片可显示胸腔内有液体。在结核性肺炎中，常常在一则肺的上部会有已愈合的结核病灶。在与病毒，支原体，鹦鹉热和立克次体有关的病例中，X射线常常呈现的密度较低，但它可以显示广泛散布在双肺的感染情况。

Laboratory Tests.  Blood tests usually show a high white-blood-cell count when a typical bacterial pneumonia is present, and a normal or low count in virus pneumonia. In tuberculous pneumonia, the white blood count is usually normal. In the various pneumonias caused by yeast and other fungi and by the rickettsial organisms of Q fever, the counts are variable but generally within normal limits.

实验室测试。当出现典型性细菌肺炎时，验血通常会显示白血球的高计数，以及在病毒性肺炎中的正常或低计数。在由酵母菌和其它真菌以及Q热立克次体有机体引起的各种肺炎中，计数是可变的，但一般都在正常的范围内。

In order to diagnose the exact cause of pneumonia, the patient’s sputum must be examined in a bacteriological laboratory. Often the appearance of a stained smear of the sputum is useful in identifying the causative organism. However, in order to identify the organism positively—particularly in cases where the smear is not helpful in making a diagnosis—the sputum is cultured so that it can be identified. Once the organism has been identified, the appropriate antibiotic therapy can be administered. This technique is useful only for identifying the typical bacterial pneumonias. The viruses, Mycoplasma, fungi, and even the tuberculosis bacterium either cannot be cultured routinely or form cultures too slowly to be useful in diagnosis.

为诊断肺炎的确切原因，必须在细菌实验室中检测患者的痰液。痰的染色涂片的外观在确认致病有机体时很有用。然而，为明确地识别有机体---尤其是在涂片对诊断没有帮助的情况下，对痰进行培养，以用于识别。一旦认定有机体，就可使用合适的抗生素进行治疗。这项技术只对识别典型性细菌肺炎有用。病毒，支原体，真菌，甚至结核细菌要么无法进行常规培养，要么培养太慢，无法用于诊断。

Noninfectious Pneumonias.  Most of the previous discussion applies only to pneumonias caused by infection. Other types of pneumonias are generally identified primarily by the medical history of the patient, as well as by other findings that may be associated with the specific disorder of which the pneumonia is only one manifestation. In allergic pneumonias, for example, any eosinophils may be detected in the white-blood-cell count. Eosinophils are a type of white blood cell that increase in the course of allergic reactions. In pneumonias associated with collagen-vascular diseases or immunological diseases, manifestations of the underlying diseases occur in organ systems other than the lungs.

非感染性肺炎。之前讨论的大多数内容只适用于由感染引起的肺炎。其它的肺炎类型一般主要通过患者的病史来识别，以及通过其它可能与肺炎只是一种表现的特定疾病相关的调查结果来识别。例如，在过敏性肺炎中，在白血球计数中可检测到任何嗜酸性粒细胞。嗜酸性粒细胞是一种在过敏性反应过程中增加的白血球。在与胶原血管疾病或免疫性疾病相关的肺炎中，基础疾病会发生在肺以外的器官系统中。

Treatment.  Pneumonia generally is treated with antibiotics, particularly when the doctor suspects that it is caused by a bacterium. If a particular bacterium is identified as the causative agent, it is usually possible to prescribe an antibiotic that will be effective. If no causative organism is definitely identified, then the doctor must pick the treatment that he feels is most likely to be effective under the circumstances. The treatment may be penicillin, or one of the broad-spectrum antibiotics such a tetracycline, or one of the newer antibiotics such as cephalosporin. When Mycoplsma or a virus is suspected as the causative agent, tetracycline is likely to be more effective than other antibiotics. Tuberculous pneumonia requires special anti-tubercular agents, and fungal pneumonias are treated with antifungal agents. The treatment appropriate for noninfectious pneumonias depends on the cause.

治疗。肺炎通常用抗生素治疗，尤其是当医生怀疑病是由细菌引起的。如果已确认细菌是病原体，那么通常使用抗生素是有效的。如果没有确定致病有机体，那么医生必须选择他认为在这种情况下最可能有效的治疗方法。治疗可能用青霉素，或一种广普抗生素，如四环素，或更新的抗生素，比如头孢菌素。当怀疑支原体或一种病毒是病原体时，四环素可能比其它抗生素会更有效。结核性肺炎需要特定的抗结核药物，而真菌性肺炎要用抗真菌的药物治疗。对非感染性肺炎的适当治疗取决于原因。

In most cases an antibiotic is administered immediately. After the cultural reports are available, other antibiotics or other drugs can be used if they would be more appropriate for the particular organism identified as causing the infection. Meanwhile, supportive measures, including rest; plenty of fluids; and medication to control coughing, pain, and fever are prescribed. If the patient has difficulty breathing, oxygen may be administered.

大多数情况下，会立刻使用抗生素。培养报告出来后，如果确定了其它的抗生素或药物对引起感染的特定有机体更合适的话，就可以使用。与此同时，采用各种辅助措施，包括休息；多饮水；以及推荐使用控制咳嗽、疼痛和发烧的药物等。如果患者呼吸困难，可以吸氧。

Complications.  A number of complications may occur in pneumonias. Some of them are serious even when appropriate antibiotic therapy is given. Pleural effusion, or fluid in the chest cavity, may develop, particularly in patients with pneuno-coccal or streptococcal pneumonias.

并发症。肺炎会出现许多并发症。即使当给予了合适的抗生素治疗时，其中一些也会很严重。可能会发展成胸膜积液或胸腔里有液体，尤其是在患有肺炎球菌或链球菌肺炎的患者中。

If the amount of fluid is so large as to compress the underlying lung and interfere with breathing, the fluid may have to be removed with a hollow needle. If the pleural membranes become infected, surgery to remove the fluid may be indicated. Occasionally, lung abscesses develop, particularly in staphylococcal pneumonia but also in pneumonias caused by several other organisms. Occasionally, pneumonia bacteria may invade the bloodstream and cause abscesses to the brain and in the joints. Also, fluid sometimes accumulates in the pericardial sac around the heart, adjacent to a pneumonia-infected area of the lung. Finally, in many pneumonia patients, super-infection occurs.

如果液体数量大到压迫到下层肺部，并干扰呼吸，就不得不用空心针将液体引出。如果胸膜受到感染，可能要用手术清除液体。偶尔，肺部会现出脓肿，尤其是在葡萄球菌性的肺炎中，但也会出现由一些其它有机体引起的肺炎。有时，肺炎细菌可能侵入血流中，并导致大脑和关节脓肿。此外，液体有时会积累在毗邻肺部肺炎感染区的心脏周围的心包内。最终，在许多肺炎患者中会发生超级感染。

After one antibiotic, particularly penicillin, has been used to wipe out the bacterium that caused the pneumonia, another organism resistant to the antibiotic may super-infect (re-infect) the area of the lung from which the original pneumonia bacterium was eradicated. Super-infection by yeast and tuberculosis organisms also may occur, particularly in elderly people, whose immune mechanisms tend to be less effective than those of younger people, and in cancer patients who are taking anticancer drugs, many of which adversely affect the ability of the body to fight infection.

在使用一种抗生素，特别是青霉素消灭引发肺炎的细菌后，另一种对抗生素产生耐药性的有机体会重复感染（再感染）已根除了原有肺炎细菌的那个肺部区域。酵母菌和结核病有机体也可能发生重复感染，尤其是在老年人中，他们的免疫机制往往不如年轻人，而正在服用抗癌药物的癌症患者，其中很多会对身体抵抗感染的能力产生不良影响。

Other complications occur in certain special groups of pneumonia patients. For example, in elderly patients pneumonia may be complicated by heart failure, kidney disease, or other common geriatric disorders. Patients with underlying chronic lung disease have an increased possibility of lung failure. In patients whose resistance to infection has been weakened by a severe chronic disease, pneumonia organisms may multiply almost without restraint. This is particularly true for patients being treated with anticancer drugs.

在某些肺炎患者的特殊群体中会出现其它的并发症。例如，在老年肺炎患者中会并发心力衰竭，肾脏疾病，或其它常见的老年疾病。患有潜在慢性肺病的患者有增加肺衰竭的可能性。在对感染有抵抗力却因严重慢性病减弱的患者中，肺炎有机体几乎会无节制繁殖。对那些正在用抗癌药物治疗的患者尤其如此。

Treatment of pneumonia in a pregnant woman is complicated by the fact that some drugs that would otherwise be prescribed may harm the fetus early in pregnancy. Late in pregnancy the fetus is so large that it compresses the lung. The resulting restriction of breathing may be serious in a pneumonia patient, since the pneumonia further impairs breathing.

事实上，对孕妇肺炎的治疗很复杂，因为一些原本可开的药会伤害到早期怀孕的胎儿。在怀孕的后期，胎儿太大，会压迫到肺部。对呼吸所导致的限制对肺炎患者可能很严重，因为肺炎进一步削弱了呼吸。

Pneumonia in the alcoholic is often complicated by malnutrition and by the development of delirium tremens when the patient is withdrawn from alcohol after hospitalization.

在酒精性肺炎中常常并发营养不良，而且当患者住院后，戒酒时会并发震颤性谵妄。

The vast majority of pneumonia cases, however are neither serious nor complicated by other problems. They respond well to antibiotic therapy, and within ten days to two weeks the patient is cured and can resume his normal activities.

然而，绝大多数肺炎既不严重，也不会并发其它的问题。它们对抗生素治疗的反应很好，并在十天到两周内患者就会痊愈，并能恢复其正常活动。

                               LOUIS J. VORHAUS, M. D.

                          Cornell University Medical College

                           路易斯·J. 沃尔豪斯，医学博士

                                 康乃尔大学医学院

                                 2023年1月30日译