Causes Of Community Acquired Pneumonia In Adults

Causes Of Community Acquired Pneumonia In Adults Average ratng: 7,7/10 9097reviews

Community- Acquired Pneumonia - Pulmonary Disorders. Community- acquired pneumonia develops in people with limited or no contact with medical institutions or settings. The most commonly identified pathogens are Streptococcus pneumoniae, Haemophilus influenzae, atypical bacteria (ie, Chlamydia pneumoniae, Mycoplasma pneumoniae, Legionella sp), and viruses.

Symptoms and signs are fever, cough, sputum production, pleuritic chest pain, dyspnea, tachypnea, and tachycardia. Diagnosis is based on clinical presentation and chest x- ray. Treatment is with empirically chosen antibiotics. Prognosis is excellent for relatively young or healthy patients, but many pneumonias, especially when caused by S.

Legionella, Staphylococcus aureus, or influenza virus, are serious or even fatal in older, sicker patients.(See also Overview of Pneumonia.).

Pneumonia in adults. PNEUMONIA OVERVIEWPneumonia is an infection of the lungs. It is a serious illness that can affect people of any age, but it is most common and most dangerous in very young children, people older than 6.

Causes Of Community Acquired Pneumonia In Adults

Community-acquired pneumonia (CAP) is a significant cause of morbidity and mortality in adults. CAP is defined as an infection of the lung parenchyma that is not. This page includes the following topics and synonyms: Aspiration Pneumonia.

Antibiotic therapy, supportive treatment and management of immunomodulation-inflammation response in community acquired pneumonia: review of recommendations.

There is seasonal variation with more cases occurring in the winter months. This article will focus on community- acquired pneumonia (CAP), which refers to pneumonia that develops in people in the community rather than in a hospital, nursing home, or assisted- living facility. About four million cases of CAP occur each year in the United States, and approximately 2. CAP require hospitalization. LUNG FUNCTIONDuring normal breathing, air is inhaled through the nose and mouth and travels through the trachea and the bronchi to the bronchioles.

  • Pneumonia is an infection of the lungs. It is a serious illness that can affect people of any age, but it is most common and most dangerous in very young children.
  • American Thoracic Society Documents Guidelines for the Management of Adults with Hospital-acquired, Ventilator-associated, and Healthcare-associated Pneumonia.
  • Methods. We conducted active population-based surveillance for community-acquired pneumonia requiring hospitalization among adults 18 years of age or older in five.

Is pneumonia contagious and other questions on pneumonia in your baby or toddler answered for you by a pediatrician.

At the end of the bronchioles, there are small air sacs, called alveoli. Alveoli have thin, porous walls that contain tiny blood vessels called capillaries (figure 1). The mouth and respiratory tract are constantly exposed to microorganisms as air is inhaled through the nose and mouth. However, the body's defenses are usually able prevent microorganisms from entering and infecting the lungs. These defenses include the immune system, the specialized shape of the nose and pharynx (which helps trap microorganisms and particulate matter in the air, thereby preventing them from entering the lungs), the ability to cough, and fine hair- like structures called cilia located on the bronchi. The cilia help remove particles or bacteria that enter the bronchi by a beating motion that moves the material up to the trachea, where it is coughed out. You can develop pneumonia if your defenses are not adequate, you are exposed to a particularly strong microorganism, or you are exposed to a very large number of microorganisms.

As the microorganisms multiply, your immune system responds by sending white blood cells to the alveoli. The infected alveoli become inflamed (filled with white blood cells, proteins, fluid, and red blood cells). These changes lead to the symptoms of pneumonia.

See 'Pneumonia symptoms' below.)HIGH- RISK GROUPSSome groups of adults are at a greater risk of developing pneumonia. These include people who: ●Are older than 6. Smoke cigarettes●Are malnourished due to health conditions or lack of access to food●Have underlying lung disease, including cystic fibrosis, asthma, or chronic obstructive pulmonary disease (emphysema)●Have other underlying medical problems, including diabetes or heart disease●Have a weakened immune system due to HIV, organ transplant, chemotherapy, or chronic steroid use●Have difficulty coughing due to stroke, sedating drugs or alcohol, or limited mobility●Have had a recent viral upper respiratory tract infection including influenza. PNEUMONIA CAUSESPneumonia can be caused by a variety of microorganisms, including viruses, bacteria, and, less commonly, fungi. The most common bacterial cause of pneumonia in the United States is Streptococcus pneumoniae (also called pneumococcus). Other bacterial causes include Haemophilus influenzae, Legionella pneumophila, and Staphylococcus aureus.

Other bacteria, such as Mycoplasma, are a common cause of mild pneumonia but can occasionally cause serious disease. Viruses are estimated to be the cause of adult CAP in at least 2. Influenza is a common viral cause of pneumonia. More recently, rhinoviruses that cause the common cold have also been shown to cause pneumonia. Other viruses that cause pneumonia in adults are human metapneumovirus, respiratory syncytial virus, parainfluenza virus, coronavirus, and adenovirus. Fungi rarely cause pneumonia in people who are generally healthy; people with a weakened immune system (those with HIV, organ transplant patients, or those on chemotherapy) are at higher risk of fungal infection.

Let your doctor know if you have traveled recently or if you been to or lived in an area where a certain type of pneumonia is more common (eg, Valley fever or coccidioidomycosis in the southwestern United States; Middle East respiratory syndrome in the Arabian Peninsula; H7. N9 strain of avian influenza in Asia). The risk of pneumonia caused by new microbes (so- called "emerging pathogens") changes over time, but your doctor will know if any of the places that you have been to or lived in put you at increased risk for pneumonia.

PNEUMONIA SYMPTOMSCommon symptoms of pneumonia include fever, chills, shortness of breath, pain with breathing (pleurisy), a rapid heart and breathing rate, nausea, vomiting, diarrhea, and a cough that often produces green or yellow sputum; occasionally the sputum is rust colored. Most people have a fever (temperature greater than 1. F or 3. 8ºC), although older adults have fever less often. Shaking chills (called rigors) and a change in mental status (confusion, unclear thinking) can also occur.

Community- Acquired Pneumonia. Definition. Pneumonia is an infection of the lung parenchyma. Community- acquired pneumonia refers to pneumonia acquired outside of hospitals or extended- care facilities.

Nursing home–acquired pneumonia refers to infection acquired in an extended- care facility. Nosocomial pneumonia and hospital- acquired pneumonia describe infections acquired in the hospital setting. The signs and symptoms of acute pneumonia develop over hours to days, whereas the clinical presentation of chronic pneumonia often evolves over weeks to months. Back to Top. Prevalence. Despite a broad armamentarium of antimicrobials available to treat the disease, pneumonia remains the seventh leading cause of death in the United States. In 2. 00. 3, the age- adjusted death rate caused by influenza and pneumonia was 2. Estimates of the incidence of community- acquired pneumonia range from 4 million to 5 million cases per year, with about 2.

Nosocomial pneumonia is estimated to occur in 2. Back to Top. Microbiology. Streptococcus pneumoniae remains the most commonly identified pathogen in community- acquired pneumonia (Fig. Other pathogens have been reported to cause pneumonia in the community, and their order of importance depends on the location and population studied (Table 1). These include long- recognized pathogens such as Haemophilus influenzae, Mycoplasma pneumoniae, and influenza A, along with newer pathogens such as Legionella species and Chlamydophilia pneumoniae.

Other common causes in the immunocompetent patient include Moraxella catarrhalis, Mycobacterium tuberculosis, and aspiration pneumonia. The causative agent of community- acquired pneumonia remains unidentified in 3. Table 1: Identified Pathogens in Community- Acquired Pneumonia. Pathogen. Cases (%)Streptococcus pneumoniae. Haemophilus influenzae. Staphylococcus aureus. Gram- negative bacilli.

Legionella species. Mycoplasma pneumoniae. Chlamydia pneumoniae.

Viruses. 2- 1. 5Aspiration. Others. 3- 5. Adapted from Mandell LA, Bartlett JG, Dowell SF, et al: Update of practice guidelines for the management of community- acquired pneumonia in immunocompetent adults.

Clin Infect Dis 2. The Cleveland Clinic Foundation.

Previously seen mainly in extended- care facilities and acute- care hospitals, strains of methicillin- resistant Staphylococcus aureus (MRSA) have emerged as prevalent pathogens in community settings. Necrotizing pneumonia is a characteristically severe manifestation of these virulent strains. A new human pathogen, severe acute respiratory syndrome (SARS)- associated coronavirus, emerged and spread worldwide in the winter of 2. No cases have been identified since 2. Data regarding this virus and its associated syndrome, SARS,7 can be found on the SARS page of the website of the Centers for Disease Control and Prevention (CDC), available at http: //www. Loss Of Independence In Older Adults.

Influenza continues to be a prevalent seasonal disease in the United States, causing considerable morbidity, loss of productivity, and mortality. A strain of H5. N1 influenza has spread rapidly through avian flocks in Asia and Europe. Cases of transmission from birds to humans with severe disease have led to international concern about a possible avian influenza pandemic. Readers are encouraged to check the CDC influenza page, available at http: //www. Other viral causes of respiratory tract infections include parainfluenza virus, adenovirus, human metapneumovirus, herpes zoster virus (HSV), varicella- zoster virus (VZV), and measles.

Many pathogens listed as potential agents of bioterrorism are spread by the respiratory route. Among the most likely candidates are Bacillus anthracis, Francisella tularensis, and Yersinia pestis. A more extensive discussion of the agents of bioterrorism can be found elsewhere in this section (“Biologic Weapons and the Primary Care Clinician”).

Nursing home–acquired pneumonias are often caused by community- acquired pathogens. However, there is an increased influence of pathogens seen with relatively low frequency in the community, such as S. Back to Top. Pathophysiology. Six mechanisms have been identified in the pathogenesis of pneumonia in immunocompetent adults (Table 2). Inhalation of infectious particles is probably the most important pathogenetic mechanism in the development of community- acquired pneumonia, with particular importance of pneumonia caused by Legionella species and M. Table 2: Pathogenetic Mechanisms in Pneumonia. Evaluation Of Health Promotion Programs For Older Adults An Introduction.

Mechanism. Frequency. Inhalation of infectious particles. Common. Aspiration of oropharyngeal or gastric contents. Common. Hematogenous deposition.

Uncommon. Invasion from infection in contiguous structures. Rare. Direct inoculation.

Less common. Reactivation. More common in immunocompromised hosts© 2. The Cleveland Clinic Foundation. The aspiration of oropharyngeal or gastric contents is the most prevalent pathogenetic mechanism in nosocomial pneumonia, with several contributing factors.