What are the main causes of typical community-acquired pneumonia. How is typical community-acquired pneumonia evaluated. What are the treatment options for typical community-acquired pneumonia. How can interprofessional teams improve outcomes for patients with typical community-acquired pneumonia.

Understanding Typical Bacterial Pneumonia: An Overview

Pneumonia is a severe form of acute lower respiratory tract infection that affects the pulmonary parenchyma in one or both lungs. It stands as a common and potentially serious infectious disease, contributing significantly to morbidity and mortality rates worldwide. In the United States, pneumonia holds the distinction of being the sixth leading cause of death and the only infectious disease among the top ten causes of mortality.

Pneumonia can be broadly classified into two main types based on how the infection is acquired:

• Community-acquired pneumonia (CAP): The most common type
• Nosocomial pneumonia, which includes:
  • Hospital-acquired pneumonia (HAP)
  • Ventilator-associated pneumonia (VAP)
  • Healthcare-associated pneumonia (HCAP)

Community-acquired pneumonia is diagnosed in non-hospitalized patients or previously ambulatory patients within 48 hours after hospital admission. CAP is further subdivided into “typical” and “atypical” categories. This article focuses primarily on typical bacterial pneumonia, its causes, evaluation, and treatment options.

Etiology of Typical Bacterial Pneumonia

Typical bacterial pneumonia occurs secondary to airborne infections caused by various microorganisms. The most common bacteria responsible for typical pneumonia include:

• Streptococcus pneumoniae
• Staphylococcus aureus
• Group A Streptococcus
• Klebsiella pneumoniae
• Haemophilus influenzae
• Moraxella catarrhalis
• Anaerobes
• Gram-negative organisms

These organisms can be easily cultured on standard media or observed under Gram stain, unlike atypical organisms. Streptococcus pneumoniae stands out as the most commonly identified bacterial cause of CAP across all age groups worldwide.

Risk Factors for Developing Pneumonia

While it’s not necessary to have predisposing conditions to acquire pneumonia, certain factors can increase the likelihood of developing a lung infection:

• Advanced age (older than 65 years)
• Immunosuppression
• Diabetes
• Cystic fibrosis
• Lung cancer
• Conditions that increase the risk of macro- or micro-aspiration (e.g., stroke, seizures, anesthesia, drug intoxication)
• Cigarette smoking
• Alcoholism
• Malnutrition
• Obstruction of bronchi from tumors

Epidemiology of Community-Acquired Pneumonia

The overall rate of community-acquired pneumonia is approximately 5-7 per 1000 persons per year. Several demographic factors influence the incidence and severity of CAP:

• Gender: CAP is more common in males
• Age: The rate of CAP increases with advancing age
• Seasonality: CAP is more prevalent during winter months

The combination of pneumonia and influenza has a significant impact on mortality rates. In 2005, this combination was the eighth most common cause of death in the United States and the seventh most common cause of death in Canada.

Pathophysiology of Typical Bacterial Pneumonia

The pulmonary system and airways are continuously exposed to particulate matter and environmental pathogens. Contrary to popular belief, healthy airways normally contain some bacterial species and are not entirely sterile. The most common mechanism through which microorganisms or pathogens reach the lung is known as micro-aspiration.

When pathogens overcome the host’s defense mechanisms and multiply within the alveoli, they trigger an inflammatory response. This response leads to the accumulation of fluid and cellular debris in the alveoli, resulting in the classic symptoms of pneumonia.

The Role of Host Defense Mechanisms

The respiratory system has several defense mechanisms to protect against infections:

• Mucociliary clearance
• Cough reflex
• Humoral and cellular immune responses
• Resident alveolar macrophages

When these defense mechanisms are compromised or overwhelmed, the risk of developing pneumonia increases significantly.

Clinical Presentation and Diagnosis of Typical Bacterial Pneumonia

The clinical presentation of typical bacterial pneumonia can vary widely, ranging from mild to severe symptoms. Common signs and symptoms include:

• Fever
• Cough (often productive with purulent sputum)
• Chest pain
• Dyspnea
• Fatigue
• Malaise

Diagnosis of typical bacterial pneumonia involves a combination of clinical assessment, physical examination, and diagnostic tests. Key diagnostic steps include:

1. Medical history and physical examination
2. Chest X-ray
3. Blood tests (complete blood count, C-reactive protein)
4. Sputum culture and Gram stain
5. Blood cultures (in severe cases)

Differential Diagnosis

Several conditions can mimic the symptoms of pneumonia, making differential diagnosis crucial. These conditions may include:

• Acute bronchitis
• Pulmonary embolism
• Congestive heart failure
• Lung cancer
• Atypical pneumonia (caused by organisms like Mycoplasma pneumoniae or Legionella pneumophila)

Treatment Strategies for Typical Bacterial Pneumonia

The treatment of typical bacterial pneumonia primarily involves antimicrobial therapy. The choice of antibiotics depends on several factors, including the severity of the illness, the patient’s age, comorbidities, and local antibiotic resistance patterns.

Outpatient Treatment

For mild to moderate cases of CAP that can be managed on an outpatient basis, common antibiotic regimens include:

• Amoxicillin
• Azithromycin
• Doxycycline
• Levofloxacin

Inpatient Treatment

For more severe cases requiring hospitalization, broader-spectrum antibiotics may be necessary:

• Combination therapy with a beta-lactam (e.g., ceftriaxone) plus a macrolide (e.g., azithromycin)
• Respiratory fluoroquinolones (e.g., levofloxacin or moxifloxacin)

In addition to antimicrobial therapy, supportive care plays a crucial role in the management of pneumonia. This may include:

• Oxygen therapy
• Hydration
• Pain management
• Respiratory therapy

Prevention Strategies and Vaccine Recommendations

Preventing pneumonia is a key aspect of public health efforts. Several strategies can help reduce the risk of developing pneumonia:

• Vaccination against Streptococcus pneumoniae (pneumococcal vaccine)
• Annual influenza vaccination
• Smoking cessation
• Maintaining good hand hygiene
• Proper nutrition and hydration

Pneumococcal Vaccine Recommendations

The Centers for Disease Control and Prevention (CDC) recommends pneumococcal vaccination for:

• All adults 65 years or older
• People 2 through 64 years old with certain medical conditions
• Children younger than 2 years old

The Role of Interprofessional Teams in Managing Typical Bacterial Pneumonia

Effective management of typical bacterial pneumonia often requires a collaborative approach involving various healthcare professionals. An interprofessional team may include:

• Primary care physicians
• Pulmonologists
• Infectious disease specialists
• Nurses
• Respiratory therapists
• Pharmacists
• Nutritionists

Each team member plays a crucial role in different aspects of patient care, from diagnosis and treatment to prevention and follow-up. Effective communication and coordination among team members are essential for optimal patient outcomes.

Improving Care Coordination

To enhance care coordination and improve outcomes for patients with typical bacterial pneumonia, healthcare teams can implement several strategies:

1. Regular team meetings to discuss patient progress and treatment plans
2. Implementing standardized protocols for diagnosis and treatment
3. Utilizing electronic health records for seamless information sharing
4. Developing clear discharge plans and follow-up procedures
5. Providing patient education on self-care and prevention strategies

By working together, interprofessional teams can ensure comprehensive care, reduce the risk of complications, and improve overall patient outcomes in the management of typical bacterial pneumonia.

Emerging Trends and Future Directions in Pneumonia Research

As our understanding of typical bacterial pneumonia continues to evolve, several emerging trends and research directions are shaping the future of pneumonia management:

Antibiotic Resistance and New Antimicrobial Agents

The rise of antibiotic-resistant strains of bacteria poses a significant challenge in treating pneumonia. Researchers are actively working on developing new antimicrobial agents and alternative treatment strategies to combat resistant pathogens. Some areas of focus include:

• Novel antibiotic classes with unique mechanisms of action
• Combination therapies to overcome resistance
• Bacteriophage therapy as an alternative to traditional antibiotics
• Immunomodulatory approaches to enhance the host’s natural defenses

Precision Medicine in Pneumonia Management

The concept of precision medicine is gaining traction in the field of infectious diseases, including pneumonia. This approach aims to tailor treatment strategies based on individual patient characteristics, pathogen profiles, and host factors. Key areas of research include:

• Biomarker-guided antibiotic therapy
• Genetic profiling to predict disease severity and treatment response
• Personalized vaccine development
• Microbiome-based interventions

Advanced Diagnostic Techniques

Improving the speed and accuracy of pneumonia diagnosis is crucial for effective treatment. Emerging diagnostic technologies include:

• Rapid molecular testing for pathogen identification
• Artificial intelligence-assisted interpretation of chest imaging
• Point-of-care testing for biomarkers of inflammation and infection
• Breath analysis for early detection of respiratory infections

Vaccine Development and Optimization

While current pneumococcal vaccines have significantly reduced the incidence of invasive pneumococcal disease, ongoing research aims to improve vaccine efficacy and coverage:

• Development of universal pneumococcal vaccines
• Exploration of novel vaccine delivery methods (e.g., intranasal vaccines)
• Optimization of vaccination schedules for different age groups and risk profiles
• Investigation of cross-protective vaccines against multiple respiratory pathogens

Global Health Initiatives and Pneumonia Prevention

Recognizing the significant global burden of pneumonia, particularly in low- and middle-income countries, several international initiatives are focusing on:

• Improving access to vaccines and essential medicines in resource-limited settings
• Strengthening healthcare systems to enhance pneumonia diagnosis and treatment capabilities
• Addressing environmental factors contributing to pneumonia risk (e.g., indoor air pollution)
• Implementing community-based interventions for pneumonia prevention and early detection

As research in these areas progresses, it is likely that our approach to managing typical bacterial pneumonia will continue to evolve, leading to more effective prevention strategies, more accurate diagnostics, and more targeted treatment options. Healthcare professionals must stay informed about these emerging trends to provide the best possible care for patients with pneumonia.

In conclusion, typical bacterial pneumonia remains a significant health concern worldwide, but ongoing research and collaborative efforts hold promise for improving outcomes and reducing the global burden of this disease. By staying abreast of the latest developments and working together in interprofessional teams, healthcare providers can continue to enhance the quality of care for patients with pneumonia and contribute to broader public health efforts in preventing and managing respiratory infections.

Typical Bacterial Pneumonia – StatPearls

Continuing Education Activity

The severe form of acute lower respiratory tract infection that affects the pulmonary parenchyma in one or both lungs is known as pneumonia. It is a common disease and a potentially serious infectious disease with considerable morbidity and mortality. Pneumonia is the sixth leading cause of death and the only infectious disease in the top ten causes of death in the United States. Community-acquired pneumonia is diagnosed in non-hospitalized patients or a previously ambulatory patient within 48 hours after admission to the hospital. CAP is further divided into “typical” and “atypical.” HAP develops more than 48 hours after hospital admission. Patients who are mechanically ventilated for more than 48 hours after endotracheal intubation can develop pneumonia known as VAP. HCAP occurs in ambulatory patients who are not hospitalized and have had extensive healthcare contact within the last 3 months. This activity reviews the evaluation and management of typical community-acquired pneumonia and highlights the role of interprofessional team members in collaborating to provide well-coordinated care and enhance patient outcomes.

Objectives:

• Explain the causes of
  typical community-acquired pneumonia.

• Describe the evaluation of a patient with typical community-acquired pneumonia.

• Summarize the treatment options for typical community-acquired pneumonia.

• Explore modalities to improve care coordination among interprofessional team members in order to improve outcomes for patients affected by typical community-acquired pneumonia.

Access free multiple choice questions on this topic.

Introduction

The severe form of acute lower respiratory tract infection that affects the pulmonary parenchyma in one or both lungs is known as pneumonia. It is a common disease and a potentially serious infectious disease with considerable morbidity and mortality. Pneumonia is the sixth leading cause of death and the only infectious disease in the top ten causes of death in the United States.

Pneumonia can be classified into 2 types based on how the infection is acquired:

1. Community-acquired pneumonia (CAP): Most common type

2. Nosocomial pneumonia  

• Hospital-acquired pneumonia (HAP)

• Ventilator-associated pneumonia (VAP)

• Healthcare-associated pneumonia (HCAP)

Community-acquired pneumonia is diagnosed in non-hospitalized patients or a previously ambulatory patient within 48 hours after admission to the hospital. CAP is further divided into “typical” and “atypical.”

HAP develops more than 48 hours after hospital admission. Patients who are mechanically ventilated for more than 48 hours after endotracheal intubation can develop pneumonia known as VAP. HCAP occurs in ambulatory patients who are not hospitalized and have had extensive healthcare contact within the last 3 months.

Etiology

Pneumonia occurs secondary to airborne infection which includes bacteria, virus, fungi, parasites, among others.

The typical bacteria which cause pneumonia are Streptococcus pneumoniae, Staphylococcus aureus, Group A Streptococcus, Klebsiella pneumoniae, Haemophilus influenzae, Moraxella catarrhalis, anaerobes, and gram-negative organisms. These organisms can be easily cultured on standard media or seen on Gram stain, unlike atypical organisms.

Streptococcus pneumoniae is the most commonly identified bacterial cause of CAP in all age groups worldwide. Methicillin-resistant Staphylococcus aureus (MRSA), Escherichia coli, and other Enterobacteriaceae are the predominant causes of HAP, VAP, and HCAP.

Although it is not necessary to have a predisposing condition to acquire pneumonia, having such factors makes a person more likely to develop the lung infection. Any condition or disease that impairs the host immune response, for example, older age (older than 65 years), immunosuppression, diabetes, cystic fibrosis, lung cancer, among others. Conditions which increase the risk of macro- or micro-aspiration include stroke, seizures, anesthesia, drug intoxication. Cigarette smoking, alcoholism, malnutrition, obstruction of bronchi from tumors are other common predisposing conditions.

Epidemiology

The overall rate of CAP is 5-7 per 1000 persons per year. The rate of CAP is higher in males and increases with increasing age. It is more commonly seen in winter months. The combination of Pneumonia and Influenza causes high mortality and was the eighth most common cause of death in the US and the seventh most common cause of death in Canada in 2005.

Pathophysiology

The pulmonary system and the airways are continuously exposed to particulate matter and environmental pathogens. The healthy airways normally contain some bacterial species and are not sterile. The most common mechanism through which the micro-organisms or pathogens reach the lung is known as micro-aspiration. Hematogenous spread and macro-aspiration are other mechanisms.

However, the pulmonary defense mechanisms such as cough reflex, mucociliary clearance system, immune response help maintain low levels of the microbiome. CAP occurs when there is a defect in normal host defense, or a virulent pathogen overwhelms the immune response or a large infectious microbial inoculum. The invasion and propagation of these virulent strains of bacteria in the lung parenchyma following micro-aspiration cause the host immune response to kick in leading to a cascade of inflammatory response causing pneumonia.

Alveolar macrophage is the predominant immune cell which responds to lower airway bacteria. However, a stronger immune response comes into play when an overwhelming virulent pathogen or a large inoculum causes these alveolar macrophages to recruit polymorphonuclear neutrophils(PMN) to phagocytose and engulf these bacteria. The alveolar macrophages release cytokines namely, tumor necrosis factor-alpha and interleukins. Interleukin-8 and granulocyte colony-stimulating factor promotes neutrophil chemotaxis and maturation. The leakage of the alveolar-capillary membrane due to cytokines can lead to a decrease in compliance and hence, dyspnea. Cytokines such as IL-1 and TNF can lead to constitutional symptoms such as fever. Bacterial pneumonia is a result of this inflammatory response. These cytokines are essential for the immunity but, the excess can lead to sepsis and multiorgan failure. The body tries to balance the deleterious effects of cytokines by attenuation of several inflammatory mechanisms by IL-10.

Microbial virulence factors and predisposing host conditions make a person more vulnerable to pneumonia. [3]

Histopathology

Based on the area of the lung involved, pneumonia can be classified histologically into lobular, lobar, bronchopneumonia, and interstitial. The major types of acute bacterial pneumonia include:

• Bronchopneumonia: A descending infection started around bronchi and bronchioles, which then spreads locally into the lungs. Lower lobes are usually involved. Patchy areas of consolidation which represents neutrophil collection in the alveoli and bronchi.

• Lobar pneumonia: Acute exudative inflammation of the entire lobe. Uniform consolidation with a complete or near complete consolidation of a lobe of a lung. Majority of these cases are caused by Streptococcus pneumoniae.

Lobar pneumonia has 4 classical stages of inflammatory response if left untreated, namely:

1. Congestion/consolidation in the first 24 hours in which the lungs are heavy, red, and, boggy. Microscopically characterized by vascular engorgement and intra-alveolar edema. Many bacteria and few neutrophils are present.

2. Red hepatization/early consolidation begins 2 to 3 days after consolidation and lasts for 2 to 4 days and named because of firm liver-like consistency. The affected lung is red-pink, dry, granular and, airless. Fibrin strands replace the edema fluid of the previous phase. Microscopically marked cellular exudate of neutrophils with some showing ingested bacteria, extravasation of erythrocytes, desquamated epithelial cells, and fibrin within the alveoli are seen. The alveolar septa become less prominent because of the exudate.

3. Grey hepatization/late consolidation occurs 2 to 3 days following red hepatization and lasts for 4 to 8 days. The lung appears gray with liver-like consistency due to fibrinopurulent exudate, progressive disintegration of red blood cells, and hemosiderin. The macrophages begin to appear.

4. Resolution and restoration of the pulmonary architecture start by the eighth day. The enzymatic action begins centrally and spreads peripherally which liquefies the previous solid fibrinous content and eventually restores aeration. Macrophages are the predominant cells which contain engulfed neutrophils and debris.

Toxicokinetics

The most common cause of typical bacterial pneumonia worldwide is Pneumococcus. The polysaccharide capsule of Streptococcus pneumoniae inhibits the complement binding to the cell surface and hence, inhibits phagocytosis. Virulent pneumococcal proteins such as IgA1 protease, neuraminidase, pneumolysin, autolysin, and the surface protein A further help the organism to counteract the host immune response and allow it to cause infection in humans.

Genetic mutations causing an active efflux of drug and eventually resistance have led to an increase in drug-resistant Streptococcus Pneumoniae (DRSP) over the last few years.

Alteration in penicillin-binding protein has increased the penicillin resistance and an increased rate of penicillin-resistant S. pneumoniae. Penicillin resistance occurs due to failure to bind to the microbe cell wall. [1][2]

History and Physical

The signs and symptoms vary according to disease severity. The common symptoms of bacterial pneumonia include fever, cough, sputum production (may or may not be present). The color and quality of sputum provide the clue to microbiological etiology. Bacterial pneumonia mostly presents with mucopurulent sputum.

Pleuritic chest pain due to localized inflammation of pleura can be seen with any kind of pneumonia but, is more common with lobar pneumonia. Constitutional symptoms such as fatigue, headache, myalgia, and arthralgias can also be seen.

Severe pneumonia can lead to dyspnea and shortness of breath. In severe cases, confusion, sepsis, and multi-organ failure can also manifest.

Tachypnea, increased vocal fremitus, egophony (E to A changes), dullness to percussion are the major clinical signs depending on the degree of consolidation and presence/absence of pleural effusion. Chest auscultation reveals crackles, rales, bronchial breath sounds.

The respiratory rate closely correlates with the degree of oxygenation and, therefore essential in determining the severity. Hypoxia is seen in severe pneumonia, which leads to hyperventilation.

Evaluation

To start with the evaluation of any pneumonia, clinical suspicion based on careful patient history and physical exam should always be followed by chest radiography which is the most important initial test.

Chest x-ray not only shows the presence of the disease and demonstrates pulmonary infiltrate, but also provides the clue to the diagnosis whether its lobar, interstitial, unilateral or bilateral. Typical bacterial pneumonia is usually lobar pneumonia with para-pneumonic pleural effusions. However, a chest x-ray cannot reliably differentiate bacterial from a non-bacterial cause. When the labs and clinical features are positive, a positive chest radiograph is considered a gold standard for diagnosis of pneumonia. Although computed tomography (CT) is a more reliable and accurate test, its use is limited due to relatively high radiation exposure and high cost. It can sometimes be done with high clinical syndrome favoring pneumonia with a negative chest x-ray. In a hospitalized patient with high clinical suspicion and negative radiograph, empiric presumptive antibiotic treatment should be started followed by a repeat chest x-ray after 24 to 48 hours.

Complete blood count (CBC) with differentials, inflammatory biomarkers ESR and acute phase reactants are indicated to confirm the evidence of inflammation and assess severity. Leukocytosis with a leftward shift is a major blood test abnormality whereas leukopenia can occur and points towards poor prognosis.

Sputum Gram stain and culture should be done next if lobar pneumonia is suspected. The most specific diagnostic test for lobar pneumonia is sputum culture. It is very important to identify the cause for the proper treatment.

It is preferable to test for influenza during the winter months as the combination of influenza and pneumonia is fatal.

CURB-65 and pneumonia severity index help in the stratification of the patients and to determine if the patient needs hospitalization for treatment.

Routine diagnostic tests are optional for outpatients with pneumonia, but hospitalized patients should undergo sputum culture, blood culture, and/or urine antigen testing preferably before the institution of antibiotic therapy.

Thoracocentesis, bronchoscopy, pleural biopsy, or pleural fluid culture are invasive tests and are carried out very occasionally.

An open lung biopsy is the ultimate specific diagnostic test.[6]

Treatment / Management

The treatment depends on the severity of the disease. It is important to determine whether the patient needs to be treated inpatient or as an outpatient. CURB-65 pneumonia severity score or expanded CURB-65 can be used to stratify patients. One point for each factor which includes:

• Confusion

• Uremia (BUN greater than 20 mg/dL

• Respiratory rate greater than 30 per minute

• Hypotension (SBP less than 90 and DBP less than 60)

• Age older than more than 65 years

Patients with comorbid conditions such as renal disease, liver disease, cancer, chronic lung disease usually do better with inpatient treatment with IV medications.

A CURB-65 score of greater than or equal to 2 is an indication for hospitalization. A score of greater than or equal to 4 is an indication for intensive care unit (ICU) admission and more intense therapy.

Depending on the clinical response, the therapy is indicated for 5 to 7 days. A favorable clinical response is the resolution of tachypnea, tachycardia, hypotension; absence of fever for more than 48 hours. In case of delayed response, the therapy should be extended.

Empiric therapy recommended for the following:

• Outpatient/non-hospitalized patient management: Empiric therapy is almost always successful and usually testing is not required. In patients with no comorbidity, monotherapy with macrolides, such as azithromycin and clarithromycin are the first choice. Alternatively, newer fluoroquinolones like levofloxacin, moxifloxacin, or gemifloxacin can be used. The therapy is targeted against mycoplasma and chlamydia pneumoniae which are the common causes of less severe CAP. Patients with comorbid conditions (chronic lung or heart disease, diabetes, smoking, HIV, among others) do well with newer fluoroquinolones alone or with a combination of beta-lactam and a macrolide.

• Inpatient non-ICU management: The recommended therapy includes newer fluoroquinolones alone or a combination of beta-lactam/second or third-generation cephalosporin and a macrolide.

• Inpatient ICU management: The recommended therapy is a combination of macrolide/newer fluoroquinolone and a beta-lactam. Ampicillin-sulbactam or ertapenem can be used in patients with risk of aspiration. If there is a risk of Pseudomonas infection, a combination of anti-pseudomonal beta-lactam with anti-pseudomonal fluoroquinolone is indicated. For MRSA, vancomycin or linezolid should be added. In case of complications such as empyema, chest tube drainage is required. Surgical decortication is needed in case of multiple loculations.

All hospitalized patients who test positive for influenza virus must be treated with oseltamivir irrespective of the onset of illness.

Once the exact cause is determined, specific therapy should be initiated.[3][4][5]

Differential Diagnosis

• Asthma or reactive airway disease

• Viral Pneumonia

• Pneumonia, Fungal

• Pneumonia, Atypical bacterial

• Lung Abscess

• Bronchiectasis

• Bronchiolitis

• Asthma

• Acute and Chronic Bronchitis

• Atelectasis

• Croup

• Respiratory distress syndrome

• Aspiration of a foreign body[6][7]

Complications

• Pleural effusion

• Empyema

• Lung Abscess

• Septicemia

• Bacteremia

Enhancing Healthcare Team Outcomes

Pneumonia is a common infectious lung disease. It requires interprofessional care and the involvement of more than one subspecialty. This patient-centered approach involving a physician with a team of other health professionals, physiotherapists, respiratory therapists, nurses, pharmacists, and support groups working together for the patient plays an important role in improving the quality of care in pneumonia patients. It not only decreases the hospital admission rates but also positively affect the disease outcome. For healthy patients, the outcomes after treatment are excellent but in the elderly and those with comorbidities, the outcomes are guarded.

Review Questions

• Access free multiple choice questions on this topic.

• Comment on this article.

Figure

Lung Abscess, CT Scan, Computer Tomography, Thick-walled cavitary lesion in the right lung is an abscess, Diffuse ground glass infiltrates that are present in both lungs represent pneumonia. Contributed by Wikimedia Commons, Yale Rosen (CC by 2.0) https://creativecommons.org/licenses/by/2.0/ (more…)

Figure

Combination of two x-rays, A represents a normal healthy Chest x-ray, B represents a Chest X-ray documenting Q fever pneumonia, Pathology. Contributed by Wikimedia Commons (Public Domain)

Figure

Lung X-ray of patient showing infection with pneumocystis carinii, Pneumonia. Contributed by The National Institutes of Health (NIH)

Figure

MAI pneumonia. Image courtesy S Bhimji MD

Figure

Streptococcus Pneumoniae example antibiogram. Contributed by Zachary Sandman, BA

References

1.

Yamaguchi M, Minamide Y, Terao Y, Isoda R, Ogawa T, Yokota S, Hamada S, Kawabata S. Nrc of Streptococcus pneumoniae suppresses capsule expression and enhances anti-phagocytosis. Biochem Biophys Res Commun. 2009 Dec 04;390(1):155-60. [PubMed: 19799870]

2.

Cools F, Torfs E, Vanhoutte B, de Macedo MB, Bonofiglio L, Mollerach M, Maes L, Caljon G, Delputte P, Cappoen D, Cos P. Streptococcus pneumoniae galU gene mutation has a direct effect on biofilm growth, adherence and phagocytosis in vitro and pathogenicity in vivo. Pathog Dis. 2018 Oct 01;76(7) [PubMed: 30215741]

3.

Segreti J, House HR, Siegel RE. Principles of antibiotic treatment of community-acquired pneumonia in the outpatient setting. Am J Med. 2005 Jul;118 Suppl 7A:21S-28S. [PubMed: 15993674]

4.

Pineda L, El Solh AA. Severe community-acquired pneumonia: approach to therapy. Expert Opin Pharmacother. 2007 Apr;8(5):593-606. [PubMed: 17376015]

5.

Liu JL, Xu F, Zhou H, Wu XJ, Shi LX, Lu RQ, Farcomeni A, Venditti M, Zhao YL, Luo SY, Dong XJ, Falcone M. Corrigendum: Expanded CURB-65: a new score system predicts severity of community-acquired pneumonia with superior efficiency. Sci Rep. 2018 Aug 09;8:47005. [PMC free article: PMC6083369] [PubMed: 30091425]

6.

Hauswaldt J, Blaschke S. [Dyspnea]. Internist (Berl). 2017 Sep;58(9):925-936. [PubMed: 28608125]

7.

Berliner D, Schneider N, Welte T, Bauersachs J. The Differential Diagnosis of Dyspnea. Dtsch Arztebl Int. 2016 Dec 09;113(49):834-845. [PMC free article: PMC5247680] [PubMed: 28098068]

Disclosure: Parul Pahal declares no relevant financial relationships with ineligible companies.

Disclosure: Venkat Rajasurya declares no relevant financial relationships with ineligible companies.

Disclosure: Sandeep Sharma declares no relevant financial relationships with ineligible companies.

Learn About Pneumonia | American Lung Association

What Is Pneumonia?

Pneumonia is an infection of the lungs that may be caused by bacteria, viruses, or fungi. The infection causes the lungs’ air sacs (alveoli) to become inflamed and fill up with fluid or pus. That can make it hard for the oxygen you breathe in to get into your bloodstream. The symptoms of pneumonia can range from mild to severe, and include cough, fever, chills, and trouble breathing.

Many factors affect how serious a case of pneumonia is, such as the type of germ causing the lung infection, the person’s age, and their overall health. The people most at risk are infants and young children, adults 65 or older, and people who have other health problems.

Pneumonia is a leading cause of hospitalization in both children and adults. Most cases can be treated successfully, although it can take weeks to fully recover. Tens of thousands of people in the U.S. die from pneumonia every year, most of them adults over the age of 65.

What Causes Pneumonia?

Pneumonia can be caused by a wide variety of bacteria, viruses and fungi in the air we breathe. Identifying the cause of your pneumonia can be an important step in getting the proper treatment.

Learn more about what causes pneumonia.

What Are the Risk Factors?

Anyone can get pneumonia, but many factors can increase your chances of getting sick and having a more severe illness. One of the most important factors is your age. People age 65 and over are at increased risk because their immune system is becoming less able to fight off infection as years go by. Infants and children two years of age or younger are also at increased risk because their immune systems are not yet fully developed.

Other risk factors can be grouped into three main categories: medical conditions, health behaviors, and environment.

Medical conditions

• Chronic lung diseases such as COPD, bronchiectasis, or cystic fibrosis that make the lungs more vulnerable.
• Other serious chronic illnesses, such as heart disease, diabetes and sickle cell disease.
• A weakened immune system due to HIV/AIDs, an organ transplant, chemotherapy or long-term steroid use.
• Difficulty swallowing, due to stroke, dementia, Parkinson’s disease, or other neurological conditions, which can result in aspiration of food, vomit or saliva into the lungs that then becomes infected.
• Recent viral respiratory infection—a cold, laryngitis, influenza, etc.
• Hospitalization, especially when in intensive care and using a ventilator to breathe.

Health behaviors

• Cigarette smoking, which damages the lungs.
• Drug and alcohol abuse, which increase the risk of aspiration pneumonia.

Environment

• Exposure to certain chemicals, pollutants or toxic fumes, including secondhand smoke.

Next:
What Causes Pneumonia?

Reviewed and approved by the American Lung Association Scientific and Medical Editorial Review Panel.

Page last updated: November 17, 2022

Pneumonia | MyPathologyReport.ca

Katerina Baranova, MD, and Matthew J. Cecchini, MD, FRCPC
May 26, 2022

What is pneumonia?

Pneumonia is an infection of the lungs caused by microorganisms such as viruses, bacteria, or fungi. Most cases of pneumonia begin when infectious particles that are inhaled through the nose and mouth travel down the respiratory tract to the lungs. Pneumonia can affect one or both lungs at the same time. The disease can affect only part of the affected lung or the whole.

What are the symptoms of pneumonia?

The most common symptoms of pneumonia include cough, fever, chills, mucus, and difficulty breathing. Other less common symptoms include confusion, chest pain, blue lips and nails, and loss of appetite. Pneumonia, like other infections, is worse in older people and people with weakened immune systems.

What are the types of pneumonia?

There are many types of pneumonia, but most are caused by bacteria or viruses. Less common types are caused by a fungus. The most common types of pneumonia will be explained in the following sections.

Bacterial pneumonia

This type of pneumonia starts when bacteria enter the lungs and alveoli, usually from the nose or mouth. Bacteria can also enter the lungs from other parts of the body through the blood. Bacteria in the alveoli will grow in the air space until they are detected by the body’s immune system, which tries to remove the bacteria from the body. To help with this process, the small capillaries surrounding the alveoli open up, increasing blood flow to the lungs. This allows more inflammatory cells including neutrophils to reach the lungs. Pathologists describe this process as acute inflammation. The green or yellow sputum produced when a person with pneumonia coughs is made up of millions of neutrophils and remnants of damaged tissue and dead bacteria. This is a sign that there is active inflammation in the lungs.

Although neutrophils are essential for killing and removing bacteria in the lungs, they can also damage the pneumocytes that line the alveoli. The combination of damaged pneumocytes with extra blood flow can lead to air spaces filling with fluid. This process is called edema. Because the fluid prevents air from entering the alveoli, a person with pneumonia may have difficulty breathing. When an x-ray or CT scan is performed, areas of the lung with infection and swelling are described as showing “consolidation”.

Once your immune system has the infection under control, specialized immune cells called macrophages will move in to clear out dead bacteria and damaged tissue. At the same time, the edematous fluid will organize itself in the air spaces and become firmer. These areas of the lung will appear gray or white on an X-ray or CT scan.

Bacterial pneumonia can be divided into lobar and bronchopneumonia. In lobar pneumonia, the bacteria have spread to cover most of a lobe of one lung. In bronchopneumonia, bacteria spread through small air spaces, affecting parts of more than one lobe of the lung. Because of this, the areas of the lung affected by bronchopneumonia are usually located near the airways.

Types of bacteria that commonly cause pneumonia include:

• Streptococcus
• Staphylococcus
• Klebsiella
• Pseudomonas
• Legionella
• Mycoplasma

Viral pneumonia

This type of pneumonia starts when viral particles enter the body, usually through the nose or mouth. The virus enters the lungs, where it infects pneumocytes or other cells in the alveoli and airways.

Viruses use specialized proteins found on their surface to attach to other proteins on the surface of lung cells. For example, SARS-CoV-2, the virus that causes Covid-19. uses a protein on its surface to attach to an angiotensin-converting enzyme 2 (ACE2) protein on lung cells. Once a virus attaches to a cell, it enters the inside of the cell, where it uses the cell’s machinery to make new copies of the virus.

Pneumocytes infected with the virus may become damaged and die. The body responds to this injury by replacing thin type 1 pneumocytes with thicker, stronger type 2 pneumocytes. Damaged pneumocytes also release signals that tell specialized virus-fighting immune cells called lymphocytes to come to the lungs. As with bacterial pneumonia, fluid fills the air spaces, making it difficult for a person with pneumonia to breathe.

Pathologists use the term hyaline membranes to describe the thick pink bands of tissue on the inner surface of the alveoli. These hyaline membranes are often found in association with type 2 pneumocytes and fluid filling the air spaces and alveolar walls. People with pneumonia have difficulty breathing because the thickened alveolar walls make it difficult for oxygen to be exchanged between the lungs and the blood. Viral pneumonia-related changes will also appear more gray or white on an x-ray or CT scan because the alveoli have less air than usual in these areas.

Types of viruses that commonly cause pneumonia include:

• Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)
• Influenza
• parainfluenza
• measles
• respiratory syncytial virus
• Cytomegaly virus
• adenovirus
• Herpes simplex virus
• Varicella zoster virus

How do pathologists diagnose pneumonia?

A pathologist can make a diagnosis of pneumonia by examining a sample of lung tissue under a microscope. A procedure in which only a small sample of tissue is removed is called a biopsy. The amount of tissue sent for microscopic examination will depend on the type of biopsy performed.

Common types of biopsy include:

• Transbronchial biopsy : A small sample of tissue is removed using forceps that are inserted through the bronchial wall into the lung.
• Cryobiopsy : A larger tissue sample is obtained by freezing a small area of ​​the lung with a tube and removing the frozen tissue from the body.
• Endobronchial biopsy : Several small tissue samples are removed using forceps to obtain tissue from inside the airways or airway walls.
• Wedge biopsy : A large piece of lung is removed by the surgeon in the operating room.

Most of the changes associated with pneumonia can be seen when tissue is stained with a combination of dyes called hematoxylin and eosin (H&E). However, to determine the type of pneumonia, your pathologist may order special stains such as Gram, Grocott (GMS), and PAS stains. Another type of test called immunohistochemistry can be ordered to look for specific types of viruses. However, the exact cause can only be determined after a tissue sample is sent to a microbiology laboratory, which has special tools to detect viruses, bacteria, and fungi.

Other Helpful Resources

Centers for Disease Control and Prevention

World Health Organization

Radiopedia – Pneumonia

Bacterial Pneumonia

Pneumonia (pneumonia) is an infectious disease that affects the lung tissue (alveoli). Fungi, viruses and bacteria can cause pathology. Bacterial pneumonia should be treated under medical supervision. The “Health Clinic” employs experienced specialists, has the most modern diagnostic base (ultrasound, CT, MRI), and the patient can undergo all the necessary diagnostics and get a doctor’s consultation without leaving the clinic.

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What is bacterial pneumonia?

Bacterial pneumonia is a lung disease that is caused by bacteria that enter the respiratory system. The inflammatory process develops when very aggressive bacteria get inside, which can resist the resistance of the body.

Species

The classification of bacterial pneumonia is based on the types of pathogen:

• pneumococcal;
• streptococcal;
• staphylococcal;
• meningococcal;
• pneumonia caused by Haemophilus influenzae, Legionella, Pseudomonas aeruginosa and so on.

According to the course and clinic, bacterial pneumonia is divided into:

• focal (bronchopneumonia) – inflammation affects some areas of the lungs and adjacent bronchi;
• lobar (croupous) – the entire lung lobe will be included in the inflammatory process. In most cases, the lower parts of the lung are affected.

Pneumonia can be:

• one-sided;
• double-sided;
• if the pleural cavity is affected, they speak of pleuropneumonia.

According to pathogenetics, bacterial pneumonia can be:

• out-of-hospital;
• hospital – the infection develops 2-3 days after the patient’s admission to the hospital.

The course of bacterial pneumonia can be:

• light;
• medium;
• severe course.

You can learn more about the disease and its treatment by calling the clinic: +7 (495) 628-22-05

Causes

The bacteria that cause pneumonia are part of the respiratory tract, that is, it is an opportunistic microflora. When the immune system is working well, these bacteria do not harm the body in any way. With a weakened immune system, they become dangerous.

Risk factors:

• influenza, SARS;
• smoking and other bad habits;
• beriberi;
• overwork and stress;
• over 70 years of age;
• unfavorable ecological situation;
• COPD;
• diabetes;
• sinusitis;
• cardiac pathologies.

Symptoms and signs

Typical manifestations of bacterial pneumonia are:

• increased body temperature;
• sweating, chills;
• cough with copious greenish sputum;
• pain in sternum, especially on deep breathing;
• weakness, headache, myalgia;
• pallor;
• low blood pressure, rapid pulse;
• shortness of breath, rapid breathing, wheezing.

Diagnostics

The doctor examines the patient, learns about the symptoms, and then prescribes laboratory tests of blood, urine, sputum.

Of the instrumental diagnostic procedures use:

• radiography;
• CT;
• MRI.

All procedures can be performed in our clinic, which is equipped with the latest generation of diagnostic equipment.

In order to make an appointment with a doctor or any type of diagnostics, choose the method convenient for you:

– Call the clinic: +7 (495) 628-22-05,
– Request a call back,
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Which doctor treats?

Bacterial pneumonia is treated by a pulmonologist or therapist. The Health Clinic is attended by specialists who will help develop the right treatment.

Methods of treatment

With a mild form of the course of the disease, treatment is carried out at home under the supervision of a doctor, severe forms are a reason for the patient to be hospitalized.

The patient is shown bed rest, drinking plenty of water, the main treatment is antibiotics. Only a doctor can select a drug, based on the results of the tests. As a rule, penicillins, macrolides or cephalosporins are prescribed. These are broad spectrum antibiotics. In some cases, the doctor selects narrowly targeted drugs. Medicines are taken orally or intramuscularly. In severe cases, intravenous injections are indicated.

As an addition appoint:

• antipyretics;
• vitamins;
• expectorants;
• short courses of hormone therapy;
• oxygen therapy.

Results

With timely and competent treatment, the prognosis is favorable.

Rehabilitation and lifestyle restoration

After the patient’s condition begins to improve, the doctor adds:

• massage;
• physiotherapy;
• LFK;
• breathing exercises;
• recommends sanatorium rehabilitation.

Bacterial pneumonia lifestyle

The recommended lifestyle for bacterial pneumonia is as follows:

• healthy eating;
• a sufficient amount of protein food;
• adequate drinking regimen;
• inclusion of vegetables and fruits in the diet;
• introduction to the diet of fatty acids Omega-3 – found in fatty fish, nuts, vegetable oils;
• exclusion of smoking and alcohol.

As a preventive measure, it is recommended to strengthen the immune system and maintain a healthy lifestyle. Without treatment, bacterial pneumonia can lead to dangerous complications – chronic bronchitis, bronchial asthma, pulmonary infarction, pleurisy, pyopneumothorax, respiratory failure.

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