Pneumonia is an inflammatory condition of the lung affecting primarily the small air sacs known as alveoli. Symptoms typically include some combination of productive or dry cough, chest pain, fever and difficulty breathing.
A pneumonia pode ser classificada em hospitalar ou comunitária, em função do local onde foi adquirida.  A pneumonia geralmente tem origem numa infeção do trato respiratório superior que se desloca para o trato inferior.  A causa é geralmente uma infeção com vírus ou bactérias.
- Signs and symptoms
Pneumocystis pneumonia is a form of pneumonia that is caused by the yeast-like fungus Pneumocystis jirovecii. It is also known as PJP, for Pneumocystis jiroveci Pneumonia. Pneumocystis specimens are commonly found in the lungs of healthy people although it is usually not a cause for disease. However, they are a source of opportunistic infection and can cause a lung infection in people with a weak immune system. PCP is especially seen in people with cancer undergoing chemotherapy, HIV/AIDS cases,
Signs and symptoms of PCP include fever, nonproductive cough, shortness of breath, weight loss, and night sweats. Usually, not a large amount of sputum is produced with PCP unless the patient has an additional bacterial infection. The fungus can invade other visceral organs, but only in a minority of cases.
The risk of PCP increases when CD4-positive T-cell levels are less than 200 cells/μL. In these immunosuppressed individuals, the manifestations of the infection are highly variable. The disease attacks the interstitial, fibrous tissue of the lungs, with marked thickening of the alveolar septa and alveoli, leading to significant hypoxia, which can be fatal if not treated aggressively. In this situation, lactate dehydrogenase levels increase and gas exchange is compromised. Oxygen is less able to
The diagnosis can be confirmed by the characteristic appearance of the chest X-ray and an arterial oxygen level that is strikingly lower than would be expected from symptoms. Gallium 67 scans are also useful in the diagnosis. They are abnormal in about 90% of cases and are often positive before the chest X-ray becomes abnormal. Chest X-ray typically shows widespread pulmonary infiltrates. CT scan may show pulmonary cysts. 1. Chest X-ray of increased opacification in the lower lungs. 2. These che
In immunocompromised patients, prophylaxis with co-trimoxazole, atovaquone, or regular pentamidine inhalations may help prevent PCP.
Antipneumocystic medication is used with concomitant steroids to avoid inflammation, which causes an exacerbation of symptoms about 4 days after treatment begins if steroids are not used. By far, the most commonly used medication is trimethoprim/sulfamethoxazole, but some patients are unable to tolerate this treatment due to allergies. Other medications that are used, alone or in combination, include pentamidine, trimetrexate, dapsone, atovaquone, primaquine, pafuramidine maleate, and clindamyci
- Signs and symptoms
Viral pneumonia is a pneumonia caused by a virus. Viruses are one of the two major causes of pneumonia, the other being bacteria; less common causes are fungi and parasites. Viruses are the most common cause of pneumonia in children, while in adults bacteria are a more common cause.
Symptoms of viral pneumonia include fever, non-productive cough, runny nose, and systemic symptoms. Different viruses cause different symptoms.
Common causes of viral pneumonia are: 1. Influenza virus A and B 2. Respiratory syncytial virus (RSV) 3. Human parainfluenza viruses 4. Severe acute respiratory syndrome coronavirus 2 Rarer viruses that commonly result in pneumonia include: Adenoviruses Metapneumovirus Severe acute respiratory syndrome coronavirus Middle East respiratory syndrome virus Hantaviruses Viruses that primarily cause other diseases, but sometimes cause pneumonia include: Herpes simplex virus, mainly in newborns or youn
In the pre-antibiotic age, pneumonias had been treated with specific anti-serums of highly variable therapeutic effect and undesirable side-effects. Viral pneumonia was first described by Hobart Reimann in 1938, in an article published by JAMA, An Acute Infection of the Respiratory Tract with Atypical Pneumonia: a disease entity probably caused by a filtrable virus. Reimann, Chairman of the Department of Medicine at Jefferson Medical College, had established the practice of routinely typing the
Viruses must invade cells in order to reproduce. Typically, a virus will reach the lungs by traveling in droplets through the mouth and nose with inhalation. There, the virus invades the cells lining the airways and the alveoli. This invasion often leads to cell death either through direct killing by the virus or by self-destruction through apoptosis. Further damage to the lungs occurs when the immune system responds to the infection. White blood cells, in particular lymphocytes, are responsible
The best prevention against viral pneumonia is vaccination against influenza, adenovirus, chickenpox, herpes zoster, measles, and rubella.
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Community-acquired pneumonia (CAP) is infectious pneumonia in a person who has not recently been hospitalized. CAP is the most common type of pneumonia. The most common causes of CAP vary depending on a person's age, but they include Streptococcus pneumoniae, viruses, the atypical bacteria, and Haemophilus influenzae.
- Signs and symptoms
Aspiration pneumonia is a type of lung infection that is due to a relatively large amount of material from the stomach or mouth entering the lungs. Signs and symptoms often include fever and cough of relatively rapid onset. Complications may include lung abscess. Some include chemical induced inflammation of the lungs as a subtype, which occurs from acidic but non-infectious stomach contents entering the lungs. Infection can be due to a variety of bacteria. Risk factors include decreased level o
The person may have an insidious course with increased respiratory rate, foul-smelling sputum, hemoptysis, and fever. Complications may occur, such as exudative pleural effusion, empyema, and lung abscesses. If left untreated, aspiration pneumonia can progress to form a lung abscess. Another possible complication is an empyema, in which pus collects inside the lungs. If continual aspiration occurs, the chronic inflammation can cause compensatory thickening of the insides of the lungs, resulting
Aspiration pneumonia is often caused by a defective swallowing mechanism, such as a neurological disease or as the result of an injury that directly impairs swallowing or interferes with consciousness. Impaired consciousness can be intentional, such as the use of general anesthesia for surgery. For many types of surgical operations, people preparing for surgery are therefore instructed to take nothing by mouth for at least four hours before surgery. These conditions enable the entry of bacteria
Aspiration is defined as inhalation of oropharyngeal or gastric contents into the pulmonary tree. Depending on the composition of the aspirate, three complications have been described: 1. Chemical pneumonitis may develop whose severity depends on the pH value and quantity of aspirate. The two lung changes after acid aspiration are: a direct toxic damage to the respiratory epithelium resulting in interstitial pulmonary edema and b a few hours later, inflammatory response with production of cytoki
Evaluation of aspiration is generally performed with a video fluoroscopic swallowing study involving radiologic evaluation of the swallowing mechanism via challenges with liquid and solid food consistencies. These studies allow for evaluation of penetration to the vocal folds and below but are not a sensitive and specific marker for aspiration. Additionally, it is difficult to distinguish between aspiration pneumonia and aspiration pneumonitis. Aspiration pneumonia is typically diagnosed by a co
There have been several practices associated with decreased incidence and decreased severity of aspiration pneumonia as detailed below.
- Signs and symptoms
Atypical pneumonia, also known as walking pneumonia, is any type of pneumonia not caused by one of the pathogens most commonly associated with the disease. Its clinical presentation contrasts to that of "typical" pneumonia. A variety of microorganisms can cause it. When it develops independently from another disease, it is called primary atypical pneumonia. The term was introduced in the 1930s and was contrasted with the bacterial pneumonia caused by Streptococcus pneumoniae, at that time the be
Usually the atypical causes also involve atypical symptoms: 1. No response to common antibiotics such as sulfonamide and beta-lactams like penicillin. 2. No signs and symptoms of lobar consolidation, meaning that the infection is restricted to small areas, rather than involving a whole lobe. As the disease progresses, however, the look can tend to lobar pneumonia. 3. Absence of leukocytosis. 4. Extrapulmonary symptoms, related to the causing organism. 5. Moderate amount of sputum, or no sputum a
The most common causative organisms are bacteria: 1. Chlamydia pneumoniae Mild form of pneumonia with relatively mild symptoms. 2. Chlamydia psittaci Causes psittacosis. 3. Coxiella burnetii Causes Q fever. 4. Francisella tularensis Causes tularemia. 5. Legionella pneumophila Causes a severe form of pneumonia with a relatively high mortality rate, known as legionellosis or Legionnaires' disease. 6. Mycoplasma pneumoniae Usually occurs in younger age groups and may be associated with neurological
Chest radiographs often show a pulmonary infection before physical signs of atypical pneumonia are observable at all. This is occult pneumonia. In general, occult pneumonia is rather often present in patients with pneumonia and can also be caused by Streptococcus pneumoniae, as the decrease of occult pneumonia after vaccination of children with a pneumococcal vaccine suggests. Infiltration commonly begins in the perihilar region and spreads in a wedge- or fan-shaped fashion toward the periphery
Mycoplasma is found more often in younger than in older people. Older people are more often infected by Legionella.
"Primary atypical pneumonia" is called primary because it develops independently of other diseases. It is commonly known as "walking pneumonia" because its symptoms are often mild enough that one can still be up and about. "Atypical pneumonia" is atypical in that it is caused by atypical organisms. These atypical organisms include special bacteria, viruses, fungi, and protozoa. In addition, this form of pneumonia is atypical in presentation with only moderate amounts of sputum, no consolidation,
- Discovery and history
- Taxonomy and classification
- Cell biology
- Genomics and metabolic reconstruction
- Host and reproduction
Mycoplasma pneumoniae Scientific classification Domain: Bacteria Phylum: Tenericutes Class: Mollicutes Order: Mycoplasmatales Family: Mycoplasmataceae Genus: Mycoplasma Species: M. pneumoniae Binomial name Mycoplasma pneumoniae Somerson et al., 1963 Mycoplasma pneumoniae is a very small bacterium in the class Mollicutes. It is a human pathogen that causes the disease mycoplasma pneumonia, a form of atypical bacterial pneumonia related to cold agglutinin disease. M. pneumoniae is characterized by
In 1898, Nocard and Roux were the first to isolate an agent assumed to be the cause of cattle pneumonia and named it "microbe de la peripneumonie" Microorganisms from other sources, having properties similar to the pleuropneumonia organism of cattle, soon came to be known as pleuropneumonia-like organisms, but their true nature was unknown. Many PPLO were later proven to be the cause of pneumonias and arthritis in several lower animals. In 1944, Monroe Eaton used embryonated chicken eggs to cult
The term mycoplasma is derived from the fungal-like growth of some mycoplasma species. The mycoplasmas were classified as Mollicutes in 1960 due to their small size and genome, lack of cell wall, low G+C content and unusual nutritional needs. M. pneumoniae has also been designated as an arginine nonfermenting species. Mycoplasmas are further classified by the sequence composition of 16s rRNA. All mycoplasmas of the pneumoniae group possess similar 16s rRNA variations unique to the group, of whic
Mycoplasmas, are among the smallest self-replicating organisms, are parasitic species that lack a cell wall and periplasmic space, have reduced genomes, and limited metabolic activity. Mycoplasma pneumoniae cells have an elongated shape that is approximately 0.1–0.2 µm in width and 1-2 µm in length. The extremely small cell size means they are incapable of being examined by light microscopy; a stereomicroscope is required for viewing the morphology of M. pneumoniae colonies, which are ...
Sequencing of the M. pneumoniae genome in 1996 revealed it is 816,394 bp in size. The genome contains 687 genes that encode for proteins, of which about 56.6% code for essential metabolic enzymes; notably those involved in glycolysis and organic acid fermentation. M. pneumoniae is consequently very susceptible to loss of enzymatic function by gene mutations, as the only buffering systems against functional loss by point mutations are for maintenance of the pentose phosphate pathway and nucleotid
Mycoplasma pneumoniae grows exclusively by parasitizing mammals. Reproduction, therefore, is dependent upon attachment to a host cell. According to Waite and Talkington, specialized reproduction occurs by “binary fission, temporally linked with duplication of its attachment organelle, which migrates to the opposite pole of the cell during replication and before nucleoid separation”. Mutations that affect the formation of the attachment organelle not only hinder motility and cell ...
- Risk Factors
Pneumonia is an infection that inflames the air sacs in one or both lungs. The air sacs may fill with fluid or pus (purulent material), causing cough with phlegm or pus, fever, chills, and difficulty breathing. A variety of organisms, including bacteria, viruses and fungi, can cause pneumonia.Pneumonia can range in seriousness from mild to life-threatening. It is most serious for infants and young children, people older than age 65, and people with health problems or weakened immune systems.
The signs and symptoms of pneumonia vary from mild to severe, depending on factors such as the type of germ causing the infection, and your age and overall health. Mild signs and symptoms often are similar to those of a cold or flu, but they last longer.Signs and symptoms of pneumonia may include: 1. Chest pain when you breathe or cough 2. Confusion or changes in mental awareness (in adults age 65 and older) 3. Cough, which may produce phlegm 4. Fatigue 5. Fever, sweating and shaking chills 6...
Many germs can cause pneumonia. The most common are bacteria and viruses in the air we breathe. Your body usually prevents these germs from infecting your lungs. But sometimes these germs can overpower your immune system, even if your health is generally good.Pneumonia is classified according to the types of germs that cause it and where you got the infection.
Pneumonia can affect anyone. But the two age groups at highest risk are: 1. Children who are 2 years old or younger 2. People who are age 65 or olderOther risk factors include: 1. Being hospitalized. You're at greater risk of pneumonia if you're in a hospital intensive care unit, especially if you're on a machine that helps you breathe (a ventilator). 2. Chronic disease. You're more likely to get pneumonia if you have asthma, chronic obstructive pulmonary disease (COPD) or heart disease. 3. S...
Even with treatment, some people with pneumonia, especially those in high-risk groups, may experience complications, including: 1. Bacteria in the bloodstream (bacteremia). Bacteria that enter the bloodstream from your lungs can spread the infection to other organs, potentially causing organ failure. 2. Difficulty breathing. If your pneumonia is severe or you have chronic underlying lung diseases, you may have trouble breathing in enough oxygen. You may need to be hospitalized and use a breat...
To help prevent pneumonia: 1. Get vaccinated. Vaccines are available to prevent some types of pneumonia and the flu. Talk with your doctor about getting these shots. The vaccination guidelines have changed over time so make sure to review your vaccination status with your doctor even if you recall previously receiving a pneumonia vaccine. 2. Make sure children get vaccinated. Doctors recommend a different pneumonia vaccine for children younger than age 2 and for children ages 2 to 5 years who...