Pneumonia is an inflammatory condition that can involve one or both lungs. It can be caused by viruses, bacteria, fungi or other pathogens, and the main symptoms are cough, fever, difficulty in breathing and a feeling of discomfort or pain in the chest. It can be cured and the treatment depends on the specific cause and the type of etiological agent that caused its appearance.
The essential characteristics of the respiratory system will be analyzed in the following paragraph.
The various components of the respiratory system allow the body to take in oxygen and expel carbon dioxide, a waste element of the metabolic processes that allow you to obtain energy thanks to the nutrients assimilated with food and the oxygen inhaled with each respiratory act.
The respiratory system can be divided into upper respiratory system, which includes the nose and nasal passages, sinuses, pharynx and the part of the larynx above the vocal cords, and lower respiratory system, consisting of the lower part of the larynx, the trachea, the bronchi, the bronchioles and the alveoli.
The lower airways are therefore the objective responsible for the exchange of gases with the absorption of oxygen and the elimination of carbon dioxide and other compounds.
THE bronchi they are air ducts that allow air to reach the lungs after passing through the pharynx, larynx and trachea. They initially divide into two main branches called primary bronchi, that is the left bronchus and right bronchus, and then branch further inside the lung parenchyma (tree bronchial) in secondary tertiary bronchi and bronchioles. The terminal bronchioles are the smallest possible branch of the bronchi, which allows the supply of air to the alveoli.
The alveoli they are the fundamental component of the lungs, and resemble tiny bags with a thin fibromuscular wall richly supplied with blood vessels. It is through the wall that the alveoli exchange air gases, absorbing oxygen from the inhaled atmospheric air and eliminating carbon dioxide, which is then expelled with exhalation.
THE lungs they are the most important organs of the entire respiratory system. The right lung is divided into three parts called lobes, while the left one consists of only two lobes, being slightly smaller than the first (the right lung weighs in the average adult male about 600 grams, the left one about 500 g).
Both are composed of elastic and particularly spongy tissues that facilitate the processes of inhalation and exhalation and are protected on the outside by a serous coating that takes the name of pleura.
There pleura it is a membrane that envelops each one individually lung. It consists of two sheets, one called visceral pleura closely attached to the lung, and an outermost one called parietal pleura adherent to the rib cage. The two sheets come into contact continuing with each other at the level of the pulmonary hilum, creating between them a negative pressure cavity, which normally contains nothing if not minimal quantities of pleural fluid essential for the flow of the pleura between them, allowing the lungs to dilate and then deflate in respiratory exchanges. In case of accumulation of greater quantities of fluid, we speak of pleural effusion, a condition that is associated with many pathologies such as heart and ascitic decompensation, lung tumors and, precisely, inflammatory diseases such as pneumonia.
What is pneumonia?
Pneumonia is one inflammatory pathology which can affect one or both lungs, and which occurs with the formation of inflammatory liquid exudate near the alveoli. This prevents the respiratory system from carrying out the normal process of inspiration and exhalation, eliminating the contact between air and the alveolar wall necessary for the passage of gas between the alveolus and blood vessels.
Depending on the cause that triggered the pneumonia, it is possible to define an adequate cure which may consist for example of an antibiotic and anti-inflammatory treatment, in case of bacterial pneumonia, in a rest period associated with antipyretics and other symptomatic drugs, as in the case of of a viral pneumonia. In severe cases, which can be easily defined by the doctor thanks to prognostic scores such as the CURB-65, (here the online calculator) or the PSI / PORT score (calculate here), hospitalization may be necessary, especially in severe cases with severe dyspnea, tachycardia and hypotension, high fever or hypothermia and signs of general impairment.
How is pneumonia prevented? To be able to prevent the pneumonia it is possible to adopt some simple precautions, such as washing your hands often and carefully, not smoking or attending environments where other people smoke with secondhand smoke inhalation, protecting the respiratory tract with masks if you come into contact with inhaling air elements. Then there are specific vaccines which can help in the prevention by counteracting the onset of bacterial infectious pneumonia.
Pneumonia is very often confused with others respiratory pathologies with similar and partly corresponding symptoms such as bronchitis, bronchopneumonia, bronchiolitis and pleurisy.
There bronchitis it is one of the most common respiratory diseases and affects the bronchi. Bronchitis can have infectious causes or causes secondary to an increased irritability of the bronchi as in the case of asthmatic bronchitis acute and in exacerbations of chronic obstructive pulmonary disease or COPD. The main symptoms are fever, cough, shortness of breath with moans and exhalation whistles, sputum (often described as the presence of green or brown phlegm).
There bronchopneumonia instead it is a particular type of lung inflammation that involves a very extensive inflammatory state involving both lung parenchyma and bronchial tree. Bronchopneumonia can usually be viral and bacterial, its most common symptoms being wheezing, coughing, excessive sweating, and a high fever.
There bronchiolitis it affects only and exclusively the bronchioles, extreme branches of the respiratory tract, and mainly affects infants and children. Bronchiolitis is therefore much more common than pneumonia in children.
There pleurisy it mainly affects the pleura, which is the thin layer that surrounds the lungs and the inner part of the chest. The most common symptoms of pleurisy include fever, cough, and increased chest pain during breathing. The causes of pleurisy are mainly inflammatory insults, such as can be a neoplasm of the lung, a lung infection, a radiotherapy with pleural involvement. In most cases, pleurisy is accompanied by payment pulmonary pleural.
The presence of pneumonia with simultaneous pleural involvement is defined by the term pleuropneumonia.
The diagnosis of pneumonia occurs through radiological examinations and tests on blood and sputum. The main diagnostic tests are:
- radiography of Chest or chest X-ray: simple, fast, economical, it exposes to a low dose of radiation. It allows to diagnose pneumonia with good sensitivity and specificity, missing the diagnosis in some interstitial pneumonias or in early bacterial pneumonia, when a visible pulmonary focus has not yet developed.
- CT of the chest: Chest CT scan is the best test for diagnosing pneumonia, guaranteeing the maximum diagnostic accuracy, at the expense of a cost and a significantly higher radiation dose compared to simple chest rays. Also useful for differential diagnosis with other pulmonary and mediastinal pathologies.
- bronchoscopy: it allows, through a probe, or a small flexible tube monitoring a camera, to view the respiratory tract from the inside, as well as perform small operations such as biopsies, infusion of liquids (broncholwash or BAL) and suction of secretions, phlegm and other substances present in the bronchi.
- Chest ultrasound: emerging technique, even faster and cheaper than chest x-ray. Furthermore, it does not irradiate the patient with any type of ionizing radiation. Allows you to view a pulmonary thickening with equal sensitivity and specificity compared to the other methods described above.
At the level of biohumoral analyzes in the course of pneumonia we will have:
- High PCR
- High ESR
- Elevated white blood cells (leukocytosis)
- Other neutrophilic granulocytes (neutrophilia) in bacterial pneumonia
- High lymphocytes (lymphocytosis) in viral pneumonia
- High eosinophils (eosinophilia) in eosinophilic pneumonia and allergic pneumonia
- Reduced oxyhemoglobin saturation
- Positivity of the culture on the sputum
Causes of pneumonia
What are the causes of pneumonia. Although most people associate the term pneumonia with the concept of bacterial infection of the lungs, pneumonia can actually also be caused by viral or fungal infections. In addition, there are non-infectious pneumonia secondary to allergic causes or inflammation of theinterstitium, the part of lung tissue that supports the alveoli and bronchi.
Here are the main ones causes of pneumonia:
- irritants and chemicals
- autoimmune processes
There are also risk factors which increase the likelihood of getting pneumonia:
- old age
- pre-existing respiratory diseases
- invasive ventilation
- immunosuppression (HIV infection, cortisone or other immunosuppressive therapy, chemotherapies, transplant patients)
Below we will analyze the different forms of pneumonia based on their cause.
Bacterial pneumonia manifests itself radiologically with the finding of a pulmonary outbreak, that is the part of lung tissue where bacterial overgrowth is generated with the production of inflammatory substances. It can affect only one lung lobe, as in the case of lobar pneumonia, one lung (right pneumonia or left pneumonia) or both, in which case it is called pneumonia bilateral.
Normally the bacteria, although present on the mucous membranes of the airways, maintain a balance between them that does not allow any species to prevail over the others, producing multiplying in an extensive and harmful way for humans. In some cases, in the presence of a state of reduced immune defenses (immunosuppressed people, the elderly, smokers, alcoholics) there may be a massive overgrowth of a specific type of bacterium that generates an organism response with the production of inflammatory material.
In some cases, therefore, the bacteria responsible for pneumonia are part of the common bacterial flora but in particular conditions they turn into pathogens (opportunistic bacteria). In other cases, contagion can occur with a bacterium not normally present in humans, with consequences similar to what has just been described. The resulting inflammation represents the automatic defense that the body puts in place to fight bacterial infection. The bacterial pneumonia par excellence in the common imagination is pneumonia from pneumococcus (streptococcal pneumonia). In fact, there are dozens of bacteria that can cause lung outbreaks. Below we will list the most common germs responsible for secondary pneumonia ad bacterial infections:
- Streptococcus pneumoniae or pneumococcus, often responsible for winter bacterial pneumonia. There pneumococcal pneumonia, once extremely frequent, can be eradicated with a special vaccination.
- Legionella pneumophila: it is a germ that is transmitted through air contact, aerosol or contaminated water, and is typical of rooms equipped with air conditioning or water treatment systems. Legionella is called Legionellosis or missionary disease, characterized by Legionella pneumonia and gastrointestinal symptoms with abdominal pain, nausea and vomiting.
- Haemophilus influenzae: causes fearsome flu, fortunately its incidence is drastically decreasing after the inclusion of the H. influenzae type B vaccine in the hexavalent vaccine.
- Mycoplasma pneumoniae: one of the main germs responsible for atypical pneumonia, it can involve decidedly extended periods of convalescence. Mycoplasma pneumonia often does not have a real lung outbreak but diffuses the interstitium of the respiratory tract.
- Chlamydia pneumonie: causes atypical pneumonias, i.e. affecting the interstitium of the lung. They are therefore very subtle because they are not always visible on the chest x-ray and mimic a viral respiratory infection.
- Staphylococcus aureus: gram positive bacterium that causes pneumonia with disabling symptoms.
- Klebsiella pneumoniae: a germ that in recent years has become famous for its particular resistance to antibiotics.
- Pseudomonas aeruginosa: opportunistic germ, frequent cause of multi-resistant infections (that is, secondary to multi-drug resistant germs) in hospitalized patients. It often contributes to aggravating further chronic diseases, such as COPD or other chronic lung diseases.
Pneumococcus (bacterium of the Streptococcus family) is the triggering cause of lobar pneumonia, lung inflammation affecting one or more lobes and often presenting very serious symptoms.
A particular type of bacterial pneumonia is nosocomial pneumonia, caused by bacteria whose infection took place in a hospital setting, which are particularly resistant to antibiotics. Nosocomial pneumonia mainly affects patients who have been hospitalized for a long time or with frequent hospitalizations, it is a very serious pathology with a high mortality. It requires empiric antibiotic therapy with second level antibiotics (piperacillin / tazobactam, teicoplanin, vancomycin, meropenem, linezolid) to be able to coplete even the germs with greater resistance to classic antibiotic therapy.
Pneumonia associated with ventilation or VAP
Ventilation Associated Pneumonia (VAP) is defined as hospital-acquired pneumonia that develops 48 to 72 hours after endotracheal intubation and / or mechanical ventilation. In reality it is a particularly serious type of nosocomial pneumonia, for which therapy requires powerful antibiotics administered intravenously for a longer period of time than the classic community-acquired pneumonia.
Inhalation pneumonia or inhalation pneumonia
Another form of pneumonia is that of ab-ingestis, caused by the ingestion of external elements (such as food, bolus or saliva) that have come into contact with the bronchial tree. Often in cases of aspiration pneumonia some types of bacteria are involved such as Staphylococcus aureus and Haemophilus influenzae. The subjects most exposed to this type of pneumonia are those who have difficulty swallowing, i.e. elderly people or people suffering from neurological diseases.
Chemical pneumonia, which results from the inhalation of ingestions or other irritants, can then become complicated with bacterial overgrowth, leading to classic lobar pneumonia.
There viral pneumonia it is a form of respiratory infection initially characterized by less severe symptoms than bacterial or fungal pneumonia. The symptomatology is subtle and initially appears blurred with dry cough (also referred to as a peevish cough or non-productive cough), temperature usually no higher than 39 ° C and flu-like symptoms such as muscle aches (myalgia) and bone pains (arthralgia). Furthermore, theViral pneumonia initially gives a symptomatological and radiological picture similar to atypical bacterial pneumonia and interstitial pneumonia, and it is possible to distinguish them thanks to the course and additional analyzes such as blood tests.
In reality, viral pneumonia can cause very severe complications, with dyspnea, respiratory insufficiency up to the need for orotracheal intubation in the most severe cases. Also, it can aggravate pre-existing diseases such as chronic obstructive bronchitis or pulmonary emphysema. Finally, the state of inflammation and stagnation of liquids and mucus in the bronchioles and alveoli favors the bacterial overgrowth: it is therefore not uncommon for viral pneumonia to be followed by bacterial pneumonia.
Among the main viruses responsible for pneumonia we mention:
- The Influenza Virus which can complicate chronic diseases such as bronchitis or COPD
- the Respiratory Syncytial Virus
- Coronavirus one of the main culprits of colds and flu states. It is also responsible for the dreaded SARS, the Severe Acute Respiratory Syndrome or Severe acute respiratory syndrome, a highly infectious disease that was the protagonist of an epidemic in China in 2002-2003.
- Rhinovirus, the virus of the common cold
- Adenovirus, responsible for inflammation in various parts of the respiratory tract
- Herps simplex virus
- Epstein Barr Virus, the mononucleosis virus.
Fungal or fungal pneumonia
There fungal pneumonia, also defined pulmonary mycosis it is a pathological condition caused by lung infection by fungi, the symptoms of which can be differentiated according to the fungus responsible for the inflammation. Pulmonary mycosis particularly affects people with immune deficiencies, such as patients on cortisone or chemotherapy therapy, or people with AIDS. Among the most common fungi responsible for pneumonia we find:
- Aspergillus: causes the severe and fearful pulmonary Aspergillosis or aspergillary pneumonia, the diagnosis of which is radiologically with the finding of the characteristic "nail coplo", that is a transparent semicircular area at the edges of a thickening of the lung, due to the production of gas (carbon dioxide) from the fungi. Cavity thickening (aspergilloma) and, on blood tests, elevated levels of galactomannan and positivity of antibodies to aspergillus IgM and IgG can also be highlighted.
- Candida: pulmonary coandidosis affects defied, weak and immunosuppressed patients. The types of Candida most commonly involved are Candida albicans, Candida krusei and Cndida glabrata.
- Cryptococcus neoformans, present in the soil, affects mainly in large cities, it can also give neurological symptoms with motor disorders and visual impairment.
- Histoplasma capsulatum: causes an infection known as Histoplasmosis, characterized by infilitrates to the pulmonary apices, so much so that it is often confused with tuberculosis.
- Pneumocystis carinii, opportunistic pathogenic mycete that causes pulmonary pneumocystosis, an opportunistic disease that is found in people with reduced immune defenses.
- Coccidioides immitis, widespread in western USA, causes pulmonary coccidioidomycosis.
At the beginning of the century it was one of the most frequent pulmonary diseases of all, then furtively economic development led to an improvement in social and health conditions and a progressive reduction of tuberculosis until it almost disappeared. Tuberculous pneumonia can resemble normal pneumonia with bronchopneumonic thickening, which is followed by the formation of granulomas with caseous necrosis and pulmonary cavitations. In the most severe cases the stage of necrotizing pneumonia is reached, with even conspicuous loss of lung tissue.
This type of pneumonia, of non-infectious origin, is characterized by pulmonary infiltrate with eosinophilia. This pathological form occurs when there is an abnormal concentration of eosinophils in both the lungs and the blood. Excessive accumulation of eosinophils (which are an active part of the immune process of response to parasites or substances to which our body is allergic) can be caused by taking particular drugs, fungi, parasites or particular pathologies. Eosinophilic pneumonia can usually be treated with corticosteroid or other immunosuppressive treatment.
Interstitial pneumonia is a disease that affects theinterstitium, the lining tissue of the alveoli, can be caused by viruses, fungi or bacteria, but it can also have a non-infectious etiology. Between atypical bacteria linked to interstitial pneumonia we find Mycoplasma pneumoniae, Coxiella burnetii and Chlamydia pneumoniae. Between virus Responsible for interstitial pneumonia are the respiratory syncytial virus, measles virus, herpesviruses and influenza and parainfluenza viruses.
Interstitial pneumonia not infectious it is particularly common among individuals with autoimmune diseases or those who work in close contact with metal powders or other toxic inhalants. Among the various types of interstitial pneumonia we have:
Usual interstitial pneumonia (UIP) is a chronic interstitial lung disease, and is the pulmonary picture associated with idiopathic pulmonary fibrosis, a primary pathology of the interstitial parenchyma with fibrous degeneration of the lung tissue.
- Desquamative interstitial pneumonia is idiopathic interstitial lung disease due to an accumulation of macrophages in the alveoli.
- Hypersensitivity pneumonitis or allergic alveolitis encompasses a spectrum of lung diseases, especially interstitial and immune-mediated, caused by intense and prolonged exposure to organic dust and related irritating inhaled antigens in the workplace.
- Lymphocytic interstitial pneumonia (LIP) is a very rare frequency interstitial pneumonia characterized by lymphatic tissue hyperplasia.
- Acute interstitial pneumonia (AIP), also called idiopathic ARDS.
- Non-specific interstitial pneumonia (NSIP) is a further inflammatory pulmonary interstitial disease whose diagnosis is made by excluding all the above diseases.
Other types of non-infectious pneumonia
Non-infectious pneumonia often has an allergic or unknown (idiopathic) cause and causes pictures of diffuse lung disease. There Bronchiolitis obliterans - pneumonia in organization (BOOP), or cryptogenic organized pneumonia (COP), is a form of non-infectious pneumonia, an inflammatory disease that affects the lung and in particular the peribronchiolar component, that is, the part of tissue adjacent to the bronchioles. It is sometimes associated with pre-existing chronic inflammatory diseases, such as rheumatoid arthritis.
There respiratory bronchiolitis with interstitial disease (RB-ILD), or interstitial lung disease associated with bronchiolitis, is a rare lung disorder that affects smokers.
What are the main ones symptoms of pneumonia? The symptomatology of pneumonia varies according to the cause that caused it and the patient's previous health conditions. In less severe cases, the symptoms of pneumonia are very similar to those of a common flu, with cough and fever. Other possible symptoms are dyspnoea, excessive sweating, chest pain (especially in cases where the inflammation also affects the pulmonary pleura) and discomfort with breathing. In cases where pneumonia has also extended to the outermost areas of the lung, the patient may experience chest pains even during inspiration and movement.
In case of bacterial pneumonia but also in tuberculous pneumonia the patient could present episodes of cough with blood (haemoptysis) or with phlegm mixed with blood (sputum with blood), indicating the presence of tissue damage with involvement of blood vessels.
In the early stages, subjects with immune system deficiency have very mild symptoms that hinder the diagnosis and prompt initiation of treatment, presenting as pneumonia without fever or pneumonia without cough.
Let's see the main ones one by one symptoms of pneumonia:
- dry cough in cases of atypical, interstitial or viral pneumonia
- productive cough, i.e. cough with brown or greenish phlegm in case of bacterial or fungal pneumonia
- fever, sometimes shivering fever and temperatures above 39 ° C
- dyspnea: shortness of breath
- shortness of breath when performing even light efforts
- asthenia: tiredness
- general malaise
- pain when breathing
- chest pain: symptoms of a pulmonary outbreak with pleural involvement are pains in the chest wall and / or during breathing
- hemoptysis: cough or phlegm with blood
- gastrointestinal symptoms such as nausea, vomiting and abdominal pain are sometimes associated with pneumonia making diagnosis difficult
Contagion and transmission
Is pneumonia contagious? The level of contagiousness of pneumonia essentially depends on the cause and therefore on the pathogen that caused it.
Viral or fungal pneumonia has the highest degree of contagiousness. The subjects with the highest risk of contagion of the disease are children, the elderly and all patients suffering from heart disease, respiratory type or immune deficiency. In the case of bacterial pneumonia, the risk of contagion is decidedly low.
The medical treatment suitable for eliminating the triggering cause and alleviating the symptoms of pneumonia varies according to the pathogen or the patient's previous state of health.
Treatment of bacterial pneumonia
In the case of bacterial pneumonia, the therapy is antibiotic, to be carried out in strict compliance with medical indications. If the symptoms disappear before the end of the therapy, you will still continue to take the antibiotic until the end of the prescribed cycle. Only in this way will the risk of relapse be averted. The main drugs used in the treatment of bacterial pneumonia are:
- Macrolides, such as the clarithromycin (Klacid) or theazithromycin (Zithromax). They are often combined with penicillins for combined therapy.
- Penicillins such as amoxicillin (Zimox, Velamox) or amoxicillin / clavulanic acid (Augmentin, Clavulin), as mentioned often associated with macrolides, they represent the first line therapy for community acquired bacterial pneumonia.
- Quinolones, such as levofloxacin (Tavanic) or the ciprofloxacin (Ciproxin)
- Cephalosporins, such as cefpodoxin (Cefodox) or the cefixime (Cefixoral).
- In hospital or multidrug-resistant pneumonia, intravenous antibiotics such as piperacillin / tazobactam, meropenem, imipenem, teicoplanin and linezolid are used.
Viral pneumonia treatment
There therapy in case of viral pneumonia it is usually based on rest, hydration and the use of anti-inflammatory and antipyretic drugs. In severe cases, the doctor may decide to administer antiviral drugs, such as oseltamivir (Tamiflu) for the treatment of influenza or amantadine and rimantadine.
Treatment of fungal pneumonia
Pulmonary mycosis is treated with the help of antifungals, antifungal drugs such as azoles (ketoconazole, fluconazole, itraconazole), echinocandins (caspofungin, anidulafungin) or amphotericin B. Most of these drugs are taken intravenously on these occasions and require treatments lasting more than 10 days.
Supportive medications and treatments
If the inflammatory component is particularly intense, it is possible that doctors prescribe cortisone-based drugs, i corticosteroids, to speed up the resolution of lung inflammation.
If there is a component of bronchospasm, as in the case of typical symptoms of bronchopneumonia, in addition to cortisone, drugs to be taken by inhalation with bronchodilator and pulmonary anti-inflammatory properties will be useful. Aerosols are also very useful for reducing mucus production thanks to anticholinergic drugs.
THE healing times of pneumonia obviously vary according to the age and state of health of the patient: the duration of convalescence after bacterial pneumonia is usually 710 days from the disappearance of symptoms, while nosocomial pneumonia or fungal pneumonia undoubtedly require a period of rest prolonged even after complete healing.
It may happen that, despite medical therapy being followed to the letter, pneumonia is not completely eradicated or that after a relatively short period of time (such as a few weeks) the symptoms return to present themselves. In these cases it is advisable to promptly seek medical advice, to avoid any complications.
In case of bacterial pneumonia it may happen that the antibiotic prescribed by the doctor is not suitable for the type of pathogen that has attacked the respiratory system. It will therefore be necessary to carry out a careful analysis of the sputum produced by the patient, accompanied by the antibiogram which will outline the most suitable type of antibiotic.
In rarer situations, pneumonia is late in being eradicated because the lung disease is the setting for another disease that is the triggering cause.
In any case, neglecting pneumonia can cause very serious damage, even leading to the death of the patient. Among the most common complications are pleuropneumonia (presence of water in the lungs), lung abscess, pleural effusion improperly called effusion and sepsis.
Tags: Respiratory system Inflammation Infectious diseases Lungs