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What Is The Most Common Cause Of Community Acquired Pneumonia

The Importance Of Defining The Etiology Of Community

Community Acquired Pneumonia

Defining the etiology of pneumonia may have significant implications for patient management. In patients who are clinically improving after initiation of broad-spectrum empiric therapy, knowing the etiology may allow streamlining the regimen with therapy directed to the identified pathogen. Antibiotic streamlining may prevent selection of resistant bacteria and decrease cost of therapy. In the hospitalized patient with pneumonia who suffers clinical deterioration after initial empiric therapy, defining the etiology of pneumonia may explain the reason for the deterioration, help in the selection of alternative therapy, and improve clinical outcome. Other potential benefits of defining the etiology of CAP include the appropriate isolation of patients infected with pathogens that can be transmitted to other patients or health care personnel .

Pearls And Other Issues

All adults 65 years and older and those considered at risk for pneumonia must receive the pneumococcal vaccination. There are two vaccines available: PPSV 23 and PCV 13.

Current ACIP recommendations for unvaccinated non-immune-compromised individuals aged 19 to 64 years old and at risk for pneumonia, first should receive PPSV 23. After age 65, a dose of PCV 13 can be given , followed by the second dose of PPSV 23 spaced at least one year from PCV 13 and 5 years from the first dose of PPSV 23. For patients who are immune-compromised or asplenic and 19 to 64 years old, first give PCV 13, followed by the first dose of PPSV 23 8 weeks or later and second dose PPSV 23 after five years. A booster PPSV 23 can be given for a patient 65 years or older after at least five years or longer from the second dose of PPSV 23.

For all unvaccinated adults 65 years or older, first vaccinate with PCV 13, followed by PPSV 23 at least a year later for immune-competent patients and at least eight weeks or more apart for patients who are immune-compromised or asplenic.

Influenza vaccination is recommended for all adult patients at risk for complications from influenza. Inactivated flu shots are usually recommended for adults. Live attenuated intranasal vaccine can be given to healthy, nonpregnant adults who are less than 49 years old. It is contraindicated in pregnancy, the immune-suppressed or health care workers caring for them, and in those with comorbidities.

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Patients Hospitalized In The General Medical Ward

According to the ATS/IDSA guidelines, patients admitted to a general ward can be classified in two groups based on the presence of risk factors for penicillin-resistantStreptococcus pneumoniae and enteric gram-negative rods. Those considered at risk of infection with penicillin-resistant organisms include the elderly, patients with multiple medical comorbidities, patients with recent use of beta lactam antibiotics, patients who are immunosuppressed, or patients in contact with a child in day care. The same factors are considered to place a patient at risk for infection with macrolide-resistantS. pneumoniae. Risk factors for the presence of enteric Gram-negative organisms include the recent use of broad-spectrum antibiotics, the use of high-dose steroids, multiple medical comorbidities, and recent hospitalization.

Which Types Of Doctors Treat Pneumonia


In some cases, primary care physicians, including pediatricians, internists, and family medicine specialists, may manage the care for patients with pneumonia. In more severe cases, other types of specialists may be involved in treating the patient with pneumonia. These include infectious-disease specialists, pulmonologists, critical care specialists, and hospitalists.

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What Should I Take For A Cat Bite

Therefore, antibiotic therapy with oral amoxicillin/clavulanic acid is considered the first-line treatment for animal bites. Patients with penicillin allergy should be prescribed fluoroquinolones or trimethoprim/sulfamethoxazole. For patients older than 10 years, doxycycline can serve as an alternative.


Diagnostic Yield With Different Viral Diagnostic Methods

Eight cases were detected by viral isolation. Serology accounted for 21 positive findings, in 1 case for both the influenza and the parainfluenza virus. The PCR results of the nasopharyngeal secretion samples of 35 patients were positive, and 5 of these patients also had serum samples that tested positive. Influenza virus was the most common finding . Nine different viral agents were identified.

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Selection Of Antimicrobial Agents

Antimicrobial stewardship principles aim to select the most appropriate antimicrobial agent and optimize the dose and duration while minimizing the potential toxicity and emergence of antimicrobial resistance. Increasing rates of hospital-acquired infections such as MRSA andClostridioides difficile infection also influence empiric antimicrobial prescribing. Whenever possible, treatment for pneumonia should use the antibiotic with the narrowest spectrum possible, selected on the basis of the underlying pathogen. However, pathogens are rarely identified at the time of presentation, especially when pneumonia is managed in the outpatient setting. Because optimal outcomes are associated with a rapid initiation of antibiotics, initial treatment for patients with pneumonia must be empirical. In selecting initial empirical antimicrobial therapy, physicians should consider the illness severity, presence of comorbidities and immunosuppression, recent antimicrobial therapy, and geographic and facility-specific epidemiology, such as the local and temporal prevalence of specific microorganisms .

In patients being admitted to the hospital, specimens for culture should be obtained before treatment. A brief delay in starting therapy while performing diagnostic procedures is reasonable in patients who are not hypotensive. However, delays of more than 4 to 8 hours may increase the length of hospitalization and have been associated with increased mortality.154,159

What Are The Symptoms Of Pneumonia

Community Acquired Pneumonia (CAP) – Exam Practice Question

If you have pneumonia, youll have symptoms that are similar to having flu or a chest infection. Symptoms may develop gradually over a few days but can progress much faster.

The main symptom is coughing. You may feel generally unwell, weak and tired, and youll probably have at least one of these symptoms too:

  • coughing up mucus that may become yellow or green
  • a high temperature you might also sweat and shiver
  • difficulty breathing or getting out of breath quicker than normal
  • chest pain or discomfort

Even if you have pneumonia, you may not have all these symptoms.

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Proportion Of Patients Evaluated For Or Given Influenza Vaccine

The proportion of patients evaluated for or given influenza vaccine can be used as a quality indicator. For this indicator, the numerator is the total number of patients that who were evaluated for of or given influenza vaccine, and the denominator is the total number of discharged patients with CAP during the influenza season. The goal is to improve quality by preventing influenza and its complications.

Criteria For Clinical Deterioration

Several parameters can be evaluated daily to assess response to therapy. The most commonly used are respiratory symptoms, fever, white blood cell count, pulmonary function, and hemodynamic function. Some patients develop a clear picture of clinical deterioration, requiring respiratory and hemodynamic support in a critical care unit. Then, the need for mechanical ventilation or transfer to an intensive care unit can be used as criteria to define clinical deterioration. Because a large number of patients who suffer clinical deterioration do not require mechanical ventilation or transfer to an intensive care unit, we have developed five criteria to define clinical deterioration based on the patient’s symptoms, temperature, white blood cell count, pulmonary function, and hemodynamic function. The five criteria are:

1.Deterioration of Symptoms:manifested as increased cough, sputum, shortness of air, or pleuritic chest pain compared to the day before.

2.Deterioration of Fever:manifested as an increase greater than 2° F from the previous clay’s maximal temperature.

4.Deterioration of Hemodynamic Function: manifested as a heart rate greater than 20%, a reduction in systolic blood pressure greater than 40 mmHg, or a deterioration of systolic blood pressure below 90 mmHg, or the use of pressors to maintain the same blood pressure as the day before.

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What Other Differential Diagnoses Would You Suspect

Community-acquired pneumonia should be considered, involving both typical and atypical pathogens . Q-fever should also be considered.

Given the history of travel to South America, endemic mycoses should also be on the list of differentials. Pulmonary blastomycosis is limited to North America rarely, cases are reported from Africa and India. Coccidioidomycosis is also more common in North America but may occur in South America in small geographical pockets.

Coburn Allen MD, Christopher Michael Wright MD, in, 2022

Adult Pneumonia And Community

Community Acquired Pneumonia (CAP), ... Community Acquired ...

Community-acquired pneumonia is an increasing health problem and the third most common reason for hospitalization for adults, especially the elderly aged > 65 years. The prevalence of CAP has been reported as 1820 cases per 1000 population with an increase from 9% in 6574 year olds to 17% in 7584 year olds, and 30% in > 85 year olds.28,29 Several predisposing factors such as impaired immunity and lung function, dysfunctional nasal mucociliary clearance, lung and heart diseases, smoking have been identified as independent predictors for CAP in adults and the elderly.24

Certain studies have reported S. pneumoniae, Legionella species, H. influenzae, Moraxella catarrhalis, and S. aureus as the predominant pathogens in CAP.30 Although the role of respiratory viruses has been well-recognized in CAP in children and infants, it is not well understood in adults and the elderly. It is still unclear whether a virus by itself can cause pneumonia or whether the virus can act in conjunction with other respiratory pathogens. One study has reported that respiratory viruses such as influenza virus, RSV, adenovirus, and rhinovirus were commonly isolated as part of a co-infection, especially with S. pneumoniae.31 Thus, viral agents in adults with CAP most often seem to be part of a mixed infection, usually with S. pneumoniae as the co-pathogen.

Rakesh Malhotra, … Ravindra L. Mehta, in, 2019

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From Colonization To Infection

Of note, it has become clear that healthy lungs are not sterile instead, they harbour a unique microbiota that includes ~100 different taxa. The main genera in healthy lower airways are Prevotella, Streptococcus, Veillonella, Fusobacterium and Haemophilus. The pathogenesis of pneumonia has been suggested to include a change in the lung microbiota, from a physiological, homeostatic state to dysbiosis, in association with a low microbial diversity and high microbial burden, and with corresponding immune responses, To further support this concept, longitudinal lung microbiota studies are required to document transitions from homeostatic to dysbiotic states during the development and resolution of pneumonia. An additional area of research lies in analysing the virome and mycobiome in airways and their influence on host defence against pneumonia. The mechanisms by which lung microbiota affect immunity in the airways have been partially elucidated. Bacteria present in the upper airways that potently stimulate nucleotide-binding oligomerization domain-containing -like receptors increase resistance to pneumonia through NOD2 and induction of release of granulocytemacrophage colony-stimulating factor.

Mechanisms of infection

What Are The Types Of Pneumonia

Sometimes, types of pneumonia are referred to by the type of organism that causes the inflammation, such as bacterial pneumonia, viral pneumonia, or fungal pneumonia. The specific organism name may also be used to describe the types of pneumonia, such as pneumococcal pneumonia or Legionella pneumonia.

Other types of pneumonia that are commonly referenced include the following:

  • Aspiration pneumonia develops as a result of inhaling food or drink, saliva, or vomit into the lungs. This occurs when the swallowing reflex is impaired, such as with brain injury or in an intoxicated person.
  • Several types of bacteria, including Legionella pneumophila, Mycoplasma pneumoniae, and Chlamydophila pneumoniae, cause atypical pneumonia. It is sometimes called “walking pneumonia” and is referred to as atypical because its symptoms differ from those of other types of bacterial pneumonia.
  • Pneumonia that arises from being on a ventilator for respiratory support in the intensive care setting is known as ventilator-associated pneumonia.

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Laboratory Investigations: Criteria For Microbiological Diagnosis

Samples were held at 4°C and transported rapidly to the Nottingham Public Health Laboratory Service laboratory for standard and specialised investigations as previously described and summarised in table . The criteria used to define infection in the 1982 BTS study were followed but updated for new techniques . The pathogens included in the term atypical pathogen are specified in table . Results for the BINAX-NOW pneumococcal antigen detection kit were read at 60 minutes instead of 15 minutes , based on the increased sensitivity of the 60 minute reading and no apparent difference in specificity determined in a series of 50 cases of non-pneumococcal proven pneumonias .

No of pathogens detected in 267 adults studied according to age

Criteria For Clinical Improvement

Treating Community-Acquired Pneumonia

In our institution, patients are considered to reach clinical improvement at the point they reach clinical stability and are candidates for switch therapy. Then, the clinical outcome is considered as clinical improvement when these three criteria are met: cough and shortness of air are improving, the patient is afebrile for at least 8 hours, and the white blood cell count is normalizing. If criteria are met during the first 3 days of hospitalization, the outcome is classified as early clinical improvement. If criteria are met from days 4 to 7, the outcome is classified as late clinical improvement.

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Length Of Stay Related To Community

The most common scenario for hospitalized patients with community-acquired pneumonia is a rapid clinical improvement after initiation of appropriate empiric therapy. The great majority of these patients can be switched to oral therapy and discharged from the hospital to complete the course of therapy at home . Once a patient is switched to oral therapy, there is no need to maintain the patient in the hospital for a period of observation to evaluate the clinical response to oral therapy .

Because length of hospitalization is not influenced by any other factor outside of the pulmonary infection, patients are considered to have length of stay related only to pneumonia. In this type of patient, the length of hospital stay can be considered inappropriate if the switch to oral antibiotic was delayed more than 24 hours after the patient was considered a candidate for switch therapy or if the patient remains hospitalized for clinical observation in oral therapy.

Clinical Deterioration Owing To Inappropriate Antimicrobial Therapy

Even in patients with selection of antibiotic therapy in accordance to guidelines, the antibiotic may not cover the etiologic agent of CAP owing to the presence of an organism with unusual susceptibility or the presence of an unusual organism . For some patients, an episode of CAP may be the first manifestation of an unrecognized immunodeficiency owing to human immunodeficiency virus infection, malignancy, or other underlying disease, and the etiology of CAP may be an unusual organism that will not be appropriately covered with the standard empiric therapy recommended in the hospital guidelines . In an attempt to identify an organism resistant to the initial antimicrobial therapy, all patients with clinical deterioration should have a more extensive microbiologic workup, The workup may include a pulmonary sample obtained by bronchoscopy with bronchoalveolar lavage.

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Influenza And Pneumococcal Vaccines

During epidemics of influenza, there is an increase in the frequency of community-acquired pneumonia due to primary influenza pneumonia as well as secondary bacterial pneumonia complicating a case of influenza. Influenza vaccine is effective in limiting the severity of disease caused by the influenza virus. The pneumococcal vaccine has been proved to prevent pneumococcal pneumonia in young adults. The efficacy of the vaccine tends to decline with age and in patients who are immunocompromised.

The population of hospitalized patients with CAP should be consider a high-risk population for re-hospitalization related to influenza or pneumonia. All national guidelines consider that hospitalized patients with CAP should be evaluated to define whether they are candidates for vaccination, and candidates should be vaccinated before hospital discharge .

There is no contraindication for the use of the pneumococcal vaccine and the influenza vaccine following an episode of CAP. These vaccines can be given simultaneously at different sites, without increasing side effects .

When patients are hospitalized during the influenza season, they can be considered at risk of acquiring influenza from an infected health care worker. The vaccination of health care workers can be seen as an important strategy for the prevention of influenza in vulnerable hospitalized patients. Influenza vaccination of health care workers has been suggested as a pneumonia quality indicator .

What Are Complications Of Pneumonia

Pin on Nursing facts

There are a number of potential complications of pneumonia. The infection that causes pneumonia can spread to the bloodstream, causing . Sepsis is a serious condition that can result in lowering of blood pressure and failure of oxygen to reach the tissues of the body, resulting in the need for intensive care management. Another complication is the accumulation of fluid in the space between the lung tissue and the chest wall lining, known as a pleural effusion. The organisms responsible for the pneumonia may infect the fluid in a pleural effusion, known as an empyema. Pneumonia can also result in the formation of an abscess within the lungs or airways.

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Clinical Deterioration With Appropriate Antimicrobial Therapy

Clinical deterioration may occur in patients infected with common pathogens that are susceptible to the selected empiric antibiotics. For example, clinical deterioration may occur in a patient infected with a susceptible Streptococcus pneumoniae who was started on appropriate empiric therapy. These are patients with severe pneumonia in whom the systemic inflammatory response to the pulmonary infection progresses even when they were started on appropriate therapy . These patients admitted to the hospital with diagnosis of CAP will evolve into a clinical picture of severe , acute respiratory distress syndrome, septic shock, multi-organ failure, and death .

The progression from CAP to severe sepsis ending with multi-organ failure due to an uncontrolled host inflammatory response is a common etiology of clinical deterioration in hospitalized patients with CAP.

Other causes of clinical deterioration in patients with appropriate antibiotic therapy of the pulmonary infection include a metastatic infection , a superimposed nosocomial infection , or a superimposed medical complication .

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