Bacterial Pneumonia – StatPearls – NCBI Bookshelf

Continuing Education Activity

The word “pneumonia” originates from the ancient Greek word “pneumon,” which means “lung,” so the word “pneumonia” becomes “lung disease.” Medically it is an inflammation of lung parenchyma that is more often, but not always, caused by infections. The many causes of pneumonia include bacteria, viruses, fungi, and parasites. This activity reviews the cause, pathophysiology, presentation, and diagnosis of bacterial pneumonia and highlights the interprofessional team’s role in the management of these patients.

Objectives:

• Identify the etiology of bacterial pneumonia.

• Recall the X-ray findings in a patient with bacterial pneumonia.

• Outline the treatment and management options available for bacterial pneumonia.

• Employ interprofessional team strategies for improving care coordination and communication to advance the management of patients affected by bacterial pneumonia and improve outcomes.

Access free multiple choice questions on this topic.

Introduction

The word “pneumonia” takes its origin from the ancient Greek word “pneumon,” which means “lung,” so the word “pneumonia” becomes “lung disease.” Medically it is an inflammation of one or both lungs’ parenchyma that is more often, but not always, caused by infections. The many causes of pneumonia include bacteria, viruses, fungi, and parasites. This article will focus on bacterial pneumonia, as it is the major cause of morbidity and mortality. According to the new classification of pneumonia, there are four categories: community-acquired (CAP), hospital-acquired (HAP), healthcare-associated (HCAP), and ventilator-associated pneumonia (VAP).[1][2][3]

Types of Bacterial Pneumonia

• CAP: The acute infection of lung tissue in a patient who has acquired it from the community or within 48 hours of the hospital admission.

• HAP: The acute infection of lung tissue in a non-intubated patient that develops after 48 hours of hospitalization.

• VAP: A type of nosocomial infection of lung tissue that usually develops 48 hours or longer after intubation for mechanical ventilation.

• HCAP: The acute infection of lung tissue acquired from healthcare facilities such as nursing homes, dialysis centers, outpatient clinics, or a patient with a history of hospitalization within the past three months.

Some articles include both HAP and VAP under the category of HCAP, so defining HCAP is problematic and controversial.

Etiology

Community-acquired pneumonia can be caused by an extensive list of agents that include bacteria, viruses, fungi, and parasites, but this article will focus on bacterial pneumonia and its causes. Bacteria have classically been categorized into two divisions based on etiology, “typical” and “atypical” organisms. Typical organisms can be cultured on standard media or seen on Gram stain, but “atypical” organisms do not have such properties.[4]

• Typical pneumonia refers to pneumonia caused by Streptococcus pneumoniae, Haemophilus influenzae, Staphylococcus aureus, Group A streptococci, Moraxella catarrhalis, anaerobes, and aerobic gram-negative bacteria.

• Atypical pneumonia is mostly caused by Legionella, Mycoplasma pneumoniae, Chlamydia pneumoniae, and Chlamydia psittaci.

The most common cause of community-acquired pneumonia (CAP) is S. pneumoniae, followed by Klebsiella pneumoniae, Haemophilus influenzae, and Pseudomonas aeruginosa. The most common causes of HCAP and HAP are MRSA (methicillin-resistant Staphylococcus aureus) and Pseudomonas aeruginosa. The causative agents of VAP include both multi-drug resistant (MDR) agents (e.g., S. pneumoniae, other Strep spp, H. influenzae, and MSSA) and non-MDR (e.g., P. aeruginosa, methicillin-resistant Staphylococcus aureus, Acinetobacter spp. and antibiotic-resistant Enterobacteriaceae) bacterial pathogens.

Epidemiology

In the United States, lower respiratory tract infections account for more morbidity and mortality than any other infection. [5] The incidence of CAP in the United States is more than 5 million per year; 80% of these new cases are treated as outpatients with a mortality rate of less than 1%, and 20% are treated as inpatients with a mortality rate of 12% to 40%.

The incidence of CAP varies among different genders; for example, it is more common in males and African Americans than in females and other Americans. However, the total number of deaths has been on the rise among females.[6] The incidence rates are higher at extremes of age; the adult rate is usually 5.15 to 7.06 cases per 1000 persons per year, but in the population of age less than 4 years and greater than 60 years, the rate is more than 12 cases per 1000 persons. In 2005, influenza and pneumonia combined were the eighth most common cause of death in the United States and the seventh most common cause of death in Canada. The mortality rate is variable among different regions, such as 7.3% for the United States and Canada, 9.1% for Europe, and 13.3% for Latin America.[7][8]

Pathophysiology

The lower respiratory tract is not sterile, and it always is exposed to environmental pathogens. Invasion and propagation of the above-mentioned bacteria into lung parenchyma at the alveolar level causes bacterial pneumonia. The body’s inflammatory response against it causes the clinical syndrome of pneumonia.

To prevent this proliferation of microorganisms, several host defenses work together in the lungs, such as mechanical (e.g., hair in nostrils and mucus on nasopharynx and oropharynx) and chemical (e.g., proteins produced by alveolar epithelial cells like surfactant protein A and D, which have the intrinsic property of opsonizing bacteria). Another component of the pulmonary defense system is made up of immune cells such as alveolar macrophages, which work to engulf and kill proliferating bacteria, but once bacteria overcome the capacity of host defenses, they start proliferating. In this setting, the alveolar macrophages kickoff the inflammatory response to strengthen the lower respiratory tract defenses. This inflammatory response is the main reason for the clinical manifestation of bacterial pneumonia. Cytokines are released in response to the inflammatory reaction and cause constitutional symptoms; for example, IL-1 (interleukin-1) and TNF (tumor necrosis factor) cause fever. Chemokine-like IL-8 (interleukin-8) and colony-stimulating factors like G-CSF (granulocyte colony-stimulating factor) promote chemotaxis and neutrophil maturation, respectively, resulting in leukocytosis on serological lab and purulent secretions. These cytokines are responsible for the leakage of the alveolar-capillary membrane at the site of inflammation, causing a decrease in compliance and shortness of breath. Sometimes even erythrocytes cross this barrier and result in hemoptysis.[9][10][11]

Histopathology

Pathologically, lobar pneumonia is the acute exudative inflammation of a lung lobe. It has the following four advanced stages if left untreated:

1. Congestion: In this stage, pulmonary parenchyma is not fully consolidated, and microscopically, the alveoli have serous exudates, pathogens, few neutrophils, and macrophages.

2. Red hepatization: In this stage, the lobe becomes consolidated, firm, and liver-like. Microscopically, there are fibrin, serous exudate, pathogens, neutrophils, and macrophages. The capillaries are congested, and the alveolar walls are thickened.

3. Gray hepatization: The lobe is still liver-like in consistency but gray in color due to suppurative and exudate-filled alveoli.

4. Resolution: After a week, it starts resolving as lymphatic drainage or a productive cough clears the exudate.

History and Physical

While taking the history, it is crucial to explore the patient’s potential exposures, risks of aspiration, host factors, and presenting symptoms.

Exposure: A detailed history of possible exposures should be sought as it can help in establishing the potential etiologies. The following are some associations of exposures and etiologies of bacterial pneumonia:

• Contaminated air-conditioning and water systems may cause Legionella pneumonia.

• Crowded places, such as jails, shelters, etc., expose a person to Streptococcus pneumonia, Mycobacteria, Mycoplasma, and Chlamydia.

• Exposures to several animals, such as cats, sheep, and cattle, may lead to infection with Coxiella burnetii

• Some birds, such as chickens, turkeys, and ducks, can expose a person to Chlamydia psittaci.

Risks of Aspiration: Patients with an increased risk of aspiration are more prone to develop pneumonia secondary to aspiration. Associated risks are:

Host mechanisms: It is of utmost importance to explore a detailed history to find clues towards the etiology of pneumonia. For instance, a history of asthma, COPD, smoking, and immunocompromised status can be indicative of H. influenzae infection. H influenza most commonly appears in the winter season. Similarly, social, sexual, medication, and family history can all be useful in determining the cause of illness.

Features in the history of bacterial pneumonia may vary from indolent to fulminant. Clinical manifestation includes both constitutional findings and findings due to damage to the lung and related tissue. The following are significant history findings:

• Fever with tachycardia and/or chills and sweats.

• The cough may be either nonproductive or productive with mucoid, purulent, or blood-tinged sputum.

• Pleuritic chest pain if the pleura is involved.

• Shortness of breath with normal daily routine work.

• Other symptoms include fatigue, headache, myalgia, and arthralgia.

For unbeknownst reasons, the presence of rigors is more often indicative of pneumococcal pneumonia than other bacterial pathogens.[12]

The presence of a productive cough is the most common and significant presenting symptom. Some bacterial causes have particular manifestations, such as:

• S. pneumoniae – Rust-colored sputum

• Pseudomonas, Hemophilus – Green sputum

• Klebsiella – Red currant-jelly sputum

• Anaerobes – foul-smelling and bad-tasting sputum

Atypical pneumonia presents with pulmonary and extra-pulmonary manifestations, such as Legionella pneumonia, which often presents with altered mentation and gastrointestinal symptoms.

Physical findings also vary from patient to patient and mainly depend on the severity of lung consolidation, the type of organism, the extent of the infection, host factors, and the existence or nonexistence of pleural effusion. The following are major clinical findings:

• Increased temperature (usually more than 38 C or 100.4 F)[13]

• Decreased temperature (less than 35 C or 95 F)

• Increased respiratory rate (more than 18 breaths/min)

• Increased heart rate (more than 100/min)

• Bradycardia (less than 60/min)

• Cyanosis

• Percussion sounds vary from flat to dull.

• Tactile fremitus

• Crackles, rales, and bronchial breath sounds are heard during auscultation.

• Tracheal deviation

• Lymphadenopathy

• Pleural rub

• Egophony

Confusion manifests earlier in older patients. A critically ill patient may present with sepsis or multi-organ failure.

Some examination findings are specific for certain etiologies, such as:

• Bradycardia – Legionella

• Dental illnesses – Anaerobes

• Impaired gag reflex – Aspiration pneumonia

• Cutaneous nodules – Nocardiosis

• Bullous myringitis – Mycoplasma

Evaluation

The approach to evaluate and diagnose pneumonia depends on the clinical status, laboratory parameters, and radiological evaluation.[14]

• Clinical Evaluation

  • It includes taking a careful patient history and performing a thorough physical examination to judge the clinical signs and symptoms mentioned above.

• Laboratory Evaluation

  • This includes lab values such as complete blood count with differentials, inflammatory biomarkers like ESR and C-reactive protein, blood cultures, sputum analysis or Gram staining and/or urine antigen testing, or polymerase chain reaction for nucleic acid detection of certain bacteria.

  • An arterial blood gas may reveal hypoxia and respiratory acidosis.

  • Pulse oximetry of less than 92% indicates severe hypoxia, and elevated CRP predicts a serious infection.[15]

  • Blood cultures should be obtained before administering antibiotics. Unfortunately, they are only positive in 40% of cases.

  • If good quality, sputum evaluation may reveal more than 25 WBC per low-power field and less than 10 squamous epithelial cells.

  • Some bacterial causes present with specific biochemical evidence, such as Legionella, may present with hyponatremia and microhematuria.

Treatment / Management

In all patients with bacterial pneumonia, empirical therapy should be started as soon as possible. The first step in treatment is a risk assessment to know whether the patient should be treated in an outpatient or inpatient setting. Cardiopulmonary conditions, age, and severity of symptoms affect the risk for bacterial pneumonia, especially CAP. [17][18][19]

An expanded CURB-65 or CURB-65 pneumonia severity score can be used for risk quantification. It includes C = Confusion, U = Uremia (BUN greater than 20 mg/dL), R = Respiratory rate (greater than 30 per min), B = B.P (BP less than 90/60 mmHg) and age greater than 65 years. One point is scored for each of these risk factors. For a score of 0-1, outpatient treatment is advised. If the total score is 2 or more, it indicates medical ward admission. If the total score is 3 or more, it indicates ICU admission. Recommended therapy for different settings are as follows:

• Outpatient Setting: For patients having comorbid conditions (e.g., diabetes, malignancy, etc.), the regimen is fluoroquinolone or beta-lactams + macrolide. For patients with no comorbid conditions, macrolide or doxycycline can be used empirically. Testing is usually not performed as the empiric regimen is almost always successful.

• Inpatient Setting (non-ICU): Recommended therapy is fluoroquinolone or macrolide + beta-lactam.

• Inpatient Setting (ICU): Recommended therapy is beta-lactam + macrolide or beta-lactam + fluoroquinolone.

• MRSA: Vancomycin or linezolid can be added.

After getting a culture-positive lab result, therapy should be altered according to the culture-specific pathogen.

The patient also can benefit from smoking cessation, counseling, and vaccination for influenza and pneumococcus.

All patients treated at home should be scheduled for a follow-up visit within 2 days to assess any complications of pneumonia.

The role of corticosteroids remains controversial and may be used in patients who remain hypotensive with presumed adrenal insufficiency.

Other Measures

• Hydration

• Chest physical therapy

• Monitoring with pulse oximetry

• Upright positioning

• Respiratory therapy with bronchodilators

• Mechanical support if patients are in respiratory distress

• Nutrition

• Early mobilization

Differential Diagnosis

Distinguishing pneumonia from other pulmonary diseases can be a daunting task, particularly in patients with co-existing pulmonary pathology. The differential diagnoses are different for children and adults, as mentioned below:

Differential Diagnosis in Children

• Asthma or reactive airway disease

• Bronchiolitis

• Croup

• Respiratory distress syndrome

• Epiglottitis

Differential Diagnosis in Adults

• Acute and chronic bronchitis

• Aspiration of a foreign body

• Asthma

• Atelectasis

• Bronchiectasis

• Bronchiolitis

• Chronic obstructive pulmonary disease

• Fungal

• Lung abscess

• Pneumocystis jiroveci pneumonia

• Respiratory failure

• Viral infection

Prognosis

The prognosis of pneumonia depends on many factors, including age, comorbidities, and hospital setting (inpatient or outpatient). Generally, the prognosis is promising in otherwise healthy patients. Patients older than 60 years or younger than 4 years of age have a relatively poorer prognosis than young adults. If pneumonia is left untreated, the overall mortality may become 30%. Antibiotic resistance is very concerning due to the excessive and unjustified use of antibiotics. The Pneumonia Severity Index (PSI) may be utilized as a tool to establish a patient’s risk of mortality.

In a study conducted on etiologies of CAP, S. pneumoniae was found to be the cause of mortality in most patients; however, Pseudomonas, Staphylococcus aureus, and mixed etiologies had the highest mortality rates in those affected.[20]

Complications

The most common bacterial pneumonia complications are respiratory failure, sepsis, multiorgan failure, coagulopathy, and exacerbation of preexisting comorbidities. Other potential complications of bacterial pneumonia include:

• Lung fibrosis

• Destruction of lung parenchyma

• Necrotizing pneumonia

• Cavitation

• Empyema

• Pulmonary abscess

• Meningitis

• Death

Deterrence and Patient Education

Patients should be counseled to quit smoking, abstain from alcohol intoxication, and maintain dental hygiene. Furthermore, to prevent bacterial pneumonia, recommendations include:

• Vaccination against pneumococcus

• The annual vaccine against influenza

• Elderly and immunocompromised patients should be instructed to seek medical assistance as soon as they develop symptoms such as dyspnea, rigors, or fever.

Pearls and Other Issues

1. Most patients respond with improvement within 48 to 72 hours.

2. The chest X-ray findings lag behind clinical features and may take 6 to 12 weeks to clear.

3. If patients fail to improve within 72 hours, another cause should be suspected, antibiotic resistance or development of complications like empyema.

Enhancing Healthcare Team Outcomes

The management of pneumonia requires an interprofessional team. The reason is that most patients are managed as outpatients, but if not properly treated, the morbidity and mortality are high.

Besides administering antibiotics, these patients often require chest physical therapy, a dietary consult, physical therapy to help regain muscle mass, and a dental consult. The key is to educate the patient on the discontinuation of smoking and abstaining from alcohol.

Patients need to be referred to a dietitian to ensure that they are eating healthy.

Further, the clinicians should encourage patients to get appropriate influenza and pneumococcal vaccines. The pharmacist should teach about antibiotic compliance and ensure that the patient is prescribed the right antibiotics aimed at the target organism. An infectious disease specialty-trained pharmacist is particularly helpful in assisting the team with difficult antibiotic treatment choices. Nursing can counsel on the appropriate dosing and administration of medications and answer patient questions, as well as charting treatment progress and reporting any issues to the clinician managing the case.

Finally, it is important to educate the patient to follow up with clinicians if they want a complete resolution of the infectious process.[19][21] [Level 5] Only with open communication between the interprofessional team can the morbidity of pneumonia be lowered.

Outcomes

In healthy people, the outcome after bacterial pneumonia is excellent. However, in people with advanced age, lung disease, immunosuppression, infection with aggressive gram-negative organisms (Klebsiella), and other comorbidities, the outcomes are usually poor. When pneumonia is left untreated, it carries mortality in excess of 25%. Pneumonia can also lead to extensive lung damage and leads to residual impairment in lung function. Other reported complications of pneumonia that occur in 1 to 5% of patients include lung abscess, empyema, and bronchiectasis.[22][23] [Level 5]

Review Questions

• Access free multiple choice questions on this topic.

• Comment on this article.

References

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Leung AK, Hon KL, Leong KF, Sergi CM. Measles: a disease often forgotten but not gone. Hong Kong Med J. 2018 Oct;24(5):512-520. [PubMed: 30245481]

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Grief SN, Loza JK. Guidelines for the Evaluation and Treatment of Pneumonia. Prim Care. 2018 Sep;45(3):485-503. [PMC free article: PMC7112285] [PubMed: 30115336]

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Ashurst JV, Dawson A. StatPearls [Internet]. StatPearls Publishing; Treasure Island (FL): Jan 30, 2023. Klebsiella Pneumonia. [PubMed: 30085546]

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Calik S, Ari A, Bilgir O, Cetintepe T, Yis R, Sonmez U, Tosun S. The relationship between mortality and microbiological parameters in febrile neutropenic patients with hematological malignancies. Saudi Med J. 2018 Sep;39(9):878-885. [PMC free article: PMC6201010] [PubMed: 30251730]

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Mizgerd JP. Acute lower respiratory tract infection. N Engl J Med. 2008 Feb 14;358(7):716-27. [PMC free article: PMC2711392] [PubMed: 18272895]

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Kung HC, Hoyert DL, Xu J, Murphy SL. Deaths: final data for 2005. Natl Vital Stat Rep. 2008 Apr 24;56(10):1-120. [PubMed: 18512336]

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Shin EJ, Kim Y, Jeong JY, Jung YM, Lee MH, Chung EH. The changes of prevalence and etiology of pediatric pneumonia from National Emergency Department Information System in Korea, between 2007 and 2014. Korean J Pediatr. 2018 Sep;61(9):291-300. [PMC free article: PMC6172518] [PubMed: 30274507]

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Lat I, Daley MJ, Shewale A, Pangrazzi MH, Hammond D, Olsen KM., DEFINE study group and the Discovery Research Network. A Multicenter, Prospective, Observational Study to Determine Predictive Factors for Multidrug-Resistant Pneumonia in Critically Ill Adults: The DEFINE Study. Pharmacotherapy. 2019 Mar;39(3):253-260. [PubMed: 30101412]

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Søndergaard MJ, Friis MB, Hansen DS, Jørgensen IM. Clinical manifestations in infants and children with Mycoplasma pneumoniae infection. PLoS One. 2018;13(4):e0195288. [PMC free article: PMC5919654] [PubMed: 29698412]

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Karakuzu Z, Iscimen R, Akalin H, Kelebek Girgin N, Kahveci F, Sinirtas M. Prognostic Risk Factors in Ventilator-Associated Pneumonia. Med Sci Monit. 2018 Mar 05;24:1321-1328. [PMC free article: PMC5848715] [PubMed: 29503436]

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Phillips-Houlbracq M, Ricard JD, Foucrier A, Yoder-Himes D, Gaudry S, Bex J, Messika J, Margetis D, Chatel J, Dobrindt U, Denamur E, Roux D. Pathophysiology of Escherichia coli pneumonia: Respective contribution of pathogenicity islands to virulence. Int J Med Microbiol. 2018 Mar;308(2):290-296. [PubMed: 29325882]

12.

van der Poll T, Opal SM. Pathogenesis, treatment, and prevention of pneumococcal pneumonia. Lancet. 2009 Oct 31;374(9700):1543-56. [PubMed: 19880020]

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Claudius I, Baraff LJ. Pediatric emergencies associated with fever. Emerg Med Clin North Am. 2010 Feb;28(1):67-84, vii-viii. [PubMed: 19945599]

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Knaus WA, Draper EA, Wagner DP, Zimmerman JE. APACHE II: a severity of disease classification system. Crit Care Med. 1985 Oct;13(10):818-29. [PubMed: 3928249]

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Kang YA, Kwon SY, Yoon HI, Lee JH, Lee CT. Role of C-reactive protein and procalcitonin in differentiation of tuberculosis from bacterial community acquired pneumonia. Korean J Intern Med. 2009 Dec;24(4):337-42. [PMC free article: PMC2784977] [PubMed: 19949732]

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Franquet T. Imaging of Community-acquired Pneumonia. J Thorac Imaging. 2018 Sep;33(5):282-294. [PubMed: 30036297]

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Ayede AI, Kirolos A, Fowobaje KR, Williams LJ, Bakare AA, Oyewole OB, Olorunfemi OB, Kuna O, Iwuala NT, Oguntoye A, Kusoro SO, Okunlola ME, Qazi SA, Nair H, Falade AG, Campbell H. A prospective validation study in South-West Nigeria on caregiver report of childhood pneumonia and antibiotic treatment using Demographic and Health Survey (DHS) and Multiple Indicator Cluster Survey (MICS) questions. J Glob Health. 2018 Dec;8(2):020806. [PMC free article: PMC6150611] [PubMed: 30254744]

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Hanretty AM, Gallagher JC. Shortened Courses of Antibiotics for Bacterial Infections: A Systematic Review of Randomized Controlled Trials. Pharmacotherapy. 2018 Jun;38(6):674-687. [PubMed: 29679383]

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Julián-Jiménez A, Adán Valero I, Beteta López A, Cano Martín LM, Fernández Rodríguez O, Rubio Díaz R, Sepúlveda Berrocal MA, González Del Castillo J, Candel González FJ. , CAP group (community-acquired pneumonia) from the Infections in Emergencies – Sepsis Code working group. [Recommendations for the care of patients with community-acquired pneumonia in the Emergency Department]. Rev Esp Quimioter. 2018 Apr;31(2):186-202. [PMC free article: PMC6159381] [PubMed: 29619807]

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Cillóniz C, Ewig S, Polverino E, Marcos MA, Esquinas C, Gabarrús A, Mensa J, Torres A. Microbial aetiology of community-acquired pneumonia and its relation to severity. Thorax. 2011 Apr;66(4):340-6. [PubMed: 21257985]

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Coon ER, Maloney CG, Shen MW. Antibiotic and Diagnostic Discordance Between ED Physicians and Hospitalists for Pediatric Respiratory Illness. Hosp Pediatr. 2015 Mar;5(3):111-8. [PubMed: 25732983]

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Bickenbach J, Schöneis D, Marx G, Marx N, Lemmen S, Dreher M. Impact of multidrug-resistant bacteria on outcome in patients with prolonged weaning. BMC Pulm Med. 2018 Aug 20;18(1):141. [PMC free article: PMC6102812] [PubMed: 30126392]

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Luan Y, Sun Y, Duan S, Zhao P, Bao Z. Pathogenic bacterial profile and drug resistance analysis of community-acquired pneumonia in older outpatients with fever. J Int Med Res. 2018 Nov;46(11):4596-4604. [PMC free article: PMC6259400] [PubMed: 30027805]

Disclosure: Saud Bin Abdul Sattar declares no relevant financial relationships with ineligible companies.

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

Bacterial Pneumonia – StatPearls – NCBI Bookshelf

Continuing Education Activity

The word “pneumonia” originates from the ancient Greek word “pneumon,” which means “lung,” so the word “pneumonia” becomes “lung disease.” Medically it is an inflammation of lung parenchyma that is more often, but not always, caused by infections. The many causes of pneumonia include bacteria, viruses, fungi, and parasites. This activity reviews the cause, pathophysiology, presentation, and diagnosis of bacterial pneumonia and highlights the interprofessional team’s role in the management of these patients.

Objectives:

• Identify the etiology of bacterial pneumonia.

• Recall the X-ray findings in a patient with bacterial pneumonia.

• Outline the treatment and management options available for bacterial pneumonia.

• Employ interprofessional team strategies for improving care coordination and communication to advance the management of patients affected by bacterial pneumonia and improve outcomes.

Access free multiple choice questions on this topic.

Introduction

The word “pneumonia” takes its origin from the ancient Greek word “pneumon,” which means “lung,” so the word “pneumonia” becomes “lung disease.” Medically it is an inflammation of one or both lungs’ parenchyma that is more often, but not always, caused by infections. The many causes of pneumonia include bacteria, viruses, fungi, and parasites. This article will focus on bacterial pneumonia, as it is the major cause of morbidity and mortality. According to the new classification of pneumonia, there are four categories: community-acquired (CAP), hospital-acquired (HAP), healthcare-associated (HCAP), and ventilator-associated pneumonia (VAP). [1][2][3]

Types of Bacterial Pneumonia

• CAP: The acute infection of lung tissue in a patient who has acquired it from the community or within 48 hours of the hospital admission.

• HAP: The acute infection of lung tissue in a non-intubated patient that develops after 48 hours of hospitalization.

• VAP: A type of nosocomial infection of lung tissue that usually develops 48 hours or longer after intubation for mechanical ventilation.

• HCAP: The acute infection of lung tissue acquired from healthcare facilities such as nursing homes, dialysis centers, outpatient clinics, or a patient with a history of hospitalization within the past three months.

Some articles include both HAP and VAP under the category of HCAP, so defining HCAP is problematic and controversial.

Etiology

Community-acquired pneumonia can be caused by an extensive list of agents that include bacteria, viruses, fungi, and parasites, but this article will focus on bacterial pneumonia and its causes. Bacteria have classically been categorized into two divisions based on etiology, “typical” and “atypical” organisms. Typical organisms can be cultured on standard media or seen on Gram stain, but “atypical” organisms do not have such properties.[4]

• Typical pneumonia refers to pneumonia caused by Streptococcus pneumoniae, Haemophilus influenzae, Staphylococcus aureus, Group A streptococci, Moraxella catarrhalis, anaerobes, and aerobic gram-negative bacteria.

• Atypical pneumonia is mostly caused by Legionella, Mycoplasma pneumoniae, Chlamydia pneumoniae, and Chlamydia psittaci.

The most common cause of community-acquired pneumonia (CAP) is S. pneumoniae, followed by Klebsiella pneumoniae, Haemophilus influenzae, and Pseudomonas aeruginosa. The most common causes of HCAP and HAP are MRSA (methicillin-resistant Staphylococcus aureus) and Pseudomonas aeruginosa. The causative agents of VAP include both multi-drug resistant (MDR) agents (e.g., S. pneumoniae, other Strep spp, H. influenzae, and MSSA) and non-MDR (e.g., P. aeruginosa, methicillin-resistant Staphylococcus aureus, Acinetobacter spp. and antibiotic-resistant Enterobacteriaceae) bacterial pathogens.

Epidemiology

In the United States, lower respiratory tract infections account for more morbidity and mortality than any other infection. [5] The incidence of CAP in the United States is more than 5 million per year; 80% of these new cases are treated as outpatients with a mortality rate of less than 1%, and 20% are treated as inpatients with a mortality rate of 12% to 40%.

The incidence of CAP varies among different genders; for example, it is more common in males and African Americans than in females and other Americans. However, the total number of deaths has been on the rise among females.[6] The incidence rates are higher at extremes of age; the adult rate is usually 5. 15 to 7.06 cases per 1000 persons per year, but in the population of age less than 4 years and greater than 60 years, the rate is more than 12 cases per 1000 persons. In 2005, influenza and pneumonia combined were the eighth most common cause of death in the United States and the seventh most common cause of death in Canada. The mortality rate is variable among different regions, such as 7.3% for the United States and Canada, 9.1% for Europe, and 13.3% for Latin America.[7][8]

Pathophysiology

The lower respiratory tract is not sterile, and it always is exposed to environmental pathogens. Invasion and propagation of the above-mentioned bacteria into lung parenchyma at the alveolar level causes bacterial pneumonia. The body’s inflammatory response against it causes the clinical syndrome of pneumonia.

To prevent this proliferation of microorganisms, several host defenses work together in the lungs, such as mechanical (e.g., hair in nostrils and mucus on nasopharynx and oropharynx) and chemical (e. g., proteins produced by alveolar epithelial cells like surfactant protein A and D, which have the intrinsic property of opsonizing bacteria). Another component of the pulmonary defense system is made up of immune cells such as alveolar macrophages, which work to engulf and kill proliferating bacteria, but once bacteria overcome the capacity of host defenses, they start proliferating. In this setting, the alveolar macrophages kickoff the inflammatory response to strengthen the lower respiratory tract defenses. This inflammatory response is the main reason for the clinical manifestation of bacterial pneumonia. Cytokines are released in response to the inflammatory reaction and cause constitutional symptoms; for example, IL-1 (interleukin-1) and TNF (tumor necrosis factor) cause fever. Chemokine-like IL-8 (interleukin-8) and colony-stimulating factors like G-CSF (granulocyte colony-stimulating factor) promote chemotaxis and neutrophil maturation, respectively, resulting in leukocytosis on serological lab and purulent secretions. These cytokines are responsible for the leakage of the alveolar-capillary membrane at the site of inflammation, causing a decrease in compliance and shortness of breath. Sometimes even erythrocytes cross this barrier and result in hemoptysis.[9][10][11]

Histopathology

Pathologically, lobar pneumonia is the acute exudative inflammation of a lung lobe. It has the following four advanced stages if left untreated:

1. Congestion: In this stage, pulmonary parenchyma is not fully consolidated, and microscopically, the alveoli have serous exudates, pathogens, few neutrophils, and macrophages.

2. Red hepatization: In this stage, the lobe becomes consolidated, firm, and liver-like. Microscopically, there are fibrin, serous exudate, pathogens, neutrophils, and macrophages. The capillaries are congested, and the alveolar walls are thickened.

3. Gray hepatization: The lobe is still liver-like in consistency but gray in color due to suppurative and exudate-filled alveoli.

4. Resolution: After a week, it starts resolving as lymphatic drainage or a productive cough clears the exudate.

History and Physical

While taking the history, it is crucial to explore the patient’s potential exposures, risks of aspiration, host factors, and presenting symptoms.

Exposure: A detailed history of possible exposures should be sought as it can help in establishing the potential etiologies. The following are some associations of exposures and etiologies of bacterial pneumonia:

• Contaminated air-conditioning and water systems may cause Legionella pneumonia.

• Crowded places, such as jails, shelters, etc., expose a person to Streptococcus pneumonia, Mycobacteria, Mycoplasma, and Chlamydia.

• Exposures to several animals, such as cats, sheep, and cattle, may lead to infection with Coxiella burnetii

• Some birds, such as chickens, turkeys, and ducks, can expose a person to Chlamydia psittaci.

Risks of Aspiration: Patients with an increased risk of aspiration are more prone to develop pneumonia secondary to aspiration. Associated risks are:

Host mechanisms: It is of utmost importance to explore a detailed history to find clues towards the etiology of pneumonia. For instance, a history of asthma, COPD, smoking, and immunocompromised status can be indicative of H. influenzae infection. H influenza most commonly appears in the winter season. Similarly, social, sexual, medication, and family history can all be useful in determining the cause of illness.

Features in the history of bacterial pneumonia may vary from indolent to fulminant. Clinical manifestation includes both constitutional findings and findings due to damage to the lung and related tissue. The following are significant history findings:

• Fever with tachycardia and/or chills and sweats.

• The cough may be either nonproductive or productive with mucoid, purulent, or blood-tinged sputum.

• Pleuritic chest pain if the pleura is involved.

• Shortness of breath with normal daily routine work.

• Other symptoms include fatigue, headache, myalgia, and arthralgia.

For unbeknownst reasons, the presence of rigors is more often indicative of pneumococcal pneumonia than other bacterial pathogens.[12]

The presence of a productive cough is the most common and significant presenting symptom. Some bacterial causes have particular manifestations, such as:

• S. pneumoniae – Rust-colored sputum

• Pseudomonas, Hemophilus – Green sputum

• Klebsiella – Red currant-jelly sputum

• Anaerobes – foul-smelling and bad-tasting sputum

Atypical pneumonia presents with pulmonary and extra-pulmonary manifestations, such as Legionella pneumonia, which often presents with altered mentation and gastrointestinal symptoms.

Physical findings also vary from patient to patient and mainly depend on the severity of lung consolidation, the type of organism, the extent of the infection, host factors, and the existence or nonexistence of pleural effusion. The following are major clinical findings:

• Increased temperature (usually more than 38 C or 100.4 F)[13]

• Decreased temperature (less than 35 C or 95 F)

• Increased respiratory rate (more than 18 breaths/min)

• Increased heart rate (more than 100/min)

• Bradycardia (less than 60/min)

• Cyanosis

• Percussion sounds vary from flat to dull.

• Tactile fremitus

• Crackles, rales, and bronchial breath sounds are heard during auscultation.

• Tracheal deviation

• Lymphadenopathy

• Pleural rub

• Egophony

Confusion manifests earlier in older patients. A critically ill patient may present with sepsis or multi-organ failure.

Some examination findings are specific for certain etiologies, such as:

• Bradycardia – Legionella

• Dental illnesses – Anaerobes

• Impaired gag reflex – Aspiration pneumonia

• Cutaneous nodules – Nocardiosis

• Bullous myringitis – Mycoplasma

Evaluation

The approach to evaluate and diagnose pneumonia depends on the clinical status, laboratory parameters, and radiological evaluation. [14]

• Clinical Evaluation

  • It includes taking a careful patient history and performing a thorough physical examination to judge the clinical signs and symptoms mentioned above.

• Laboratory Evaluation

  • This includes lab values such as complete blood count with differentials, inflammatory biomarkers like ESR and C-reactive protein, blood cultures, sputum analysis or Gram staining and/or urine antigen testing, or polymerase chain reaction for nucleic acid detection of certain bacteria.

  • An arterial blood gas may reveal hypoxia and respiratory acidosis.

  • Pulse oximetry of less than 92% indicates severe hypoxia, and elevated CRP predicts a serious infection.[15]

  • Blood cultures should be obtained before administering antibiotics. Unfortunately, they are only positive in 40% of cases.

  • If good quality, sputum evaluation may reveal more than 25 WBC per low-power field and less than 10 squamous epithelial cells.

  • Some bacterial causes present with specific biochemical evidence, such as Legionella, may present with hyponatremia and microhematuria.

Treatment / Management

In all patients with bacterial pneumonia, empirical therapy should be started as soon as possible. The first step in treatment is a risk assessment to know whether the patient should be treated in an outpatient or inpatient setting. Cardiopulmonary conditions, age, and severity of symptoms affect the risk for bacterial pneumonia, especially CAP.[17][18][19]

An expanded CURB-65 or CURB-65 pneumonia severity score can be used for risk quantification. It includes C = Confusion, U = Uremia (BUN greater than 20 mg/dL), R = Respiratory rate (greater than 30 per min), B = B.P (BP less than 90/60 mmHg) and age greater than 65 years. One point is scored for each of these risk factors. For a score of 0-1, outpatient treatment is advised. If the total score is 2 or more, it indicates medical ward admission. If the total score is 3 or more, it indicates ICU admission. Recommended therapy for different settings are as follows:

• Outpatient Setting: For patients having comorbid conditions (e.g., diabetes, malignancy, etc.), the regimen is fluoroquinolone or beta-lactams + macrolide. For patients with no comorbid conditions, macrolide or doxycycline can be used empirically. Testing is usually not performed as the empiric regimen is almost always successful.

• Inpatient Setting (non-ICU): Recommended therapy is fluoroquinolone or macrolide + beta-lactam.

• Inpatient Setting (ICU): Recommended therapy is beta-lactam + macrolide or beta-lactam + fluoroquinolone.

• MRSA: Vancomycin or linezolid can be added.

After getting a culture-positive lab result, therapy should be altered according to the culture-specific pathogen.

The patient also can benefit from smoking cessation, counseling, and vaccination for influenza and pneumococcus.

All patients treated at home should be scheduled for a follow-up visit within 2 days to assess any complications of pneumonia.

The role of corticosteroids remains controversial and may be used in patients who remain hypotensive with presumed adrenal insufficiency.

Other Measures

• Hydration

• Chest physical therapy

• Monitoring with pulse oximetry

• Upright positioning

• Respiratory therapy with bronchodilators

• Mechanical support if patients are in respiratory distress

• Nutrition

• Early mobilization

Differential Diagnosis

Distinguishing pneumonia from other pulmonary diseases can be a daunting task, particularly in patients with co-existing pulmonary pathology. The differential diagnoses are different for children and adults, as mentioned below:

Differential Diagnosis in Children

• Asthma or reactive airway disease

• Bronchiolitis

• Croup

• Respiratory distress syndrome

• Epiglottitis

Differential Diagnosis in Adults

• Acute and chronic bronchitis

• Aspiration of a foreign body

• Asthma

• Atelectasis

• Bronchiectasis

• Bronchiolitis

• Chronic obstructive pulmonary disease

• Fungal

• Lung abscess

• Pneumocystis jiroveci pneumonia

• Respiratory failure

• Viral infection

Prognosis

The prognosis of pneumonia depends on many factors, including age, comorbidities, and hospital setting (inpatient or outpatient). Generally, the prognosis is promising in otherwise healthy patients. Patients older than 60 years or younger than 4 years of age have a relatively poorer prognosis than young adults. If pneumonia is left untreated, the overall mortality may become 30%. Antibiotic resistance is very concerning due to the excessive and unjustified use of antibiotics. The Pneumonia Severity Index (PSI) may be utilized as a tool to establish a patient’s risk of mortality.

In a study conducted on etiologies of CAP, S. pneumoniae was found to be the cause of mortality in most patients; however, Pseudomonas, Staphylococcus aureus, and mixed etiologies had the highest mortality rates in those affected.[20]

Complications

The most common bacterial pneumonia complications are respiratory failure, sepsis, multiorgan failure, coagulopathy, and exacerbation of preexisting comorbidities. Other potential complications of bacterial pneumonia include:

• Lung fibrosis

• Destruction of lung parenchyma

• Necrotizing pneumonia

• Cavitation

• Empyema

• Pulmonary abscess

• Meningitis

• Death

Deterrence and Patient Education

Patients should be counseled to quit smoking, abstain from alcohol intoxication, and maintain dental hygiene. Furthermore, to prevent bacterial pneumonia, recommendations include:

• Vaccination against pneumococcus

• The annual vaccine against influenza

• Elderly and immunocompromised patients should be instructed to seek medical assistance as soon as they develop symptoms such as dyspnea, rigors, or fever.

Pearls and Other Issues

1. Most patients respond with improvement within 48 to 72 hours.

2. The chest X-ray findings lag behind clinical features and may take 6 to 12 weeks to clear.

3. If patients fail to improve within 72 hours, another cause should be suspected, antibiotic resistance or development of complications like empyema.

Enhancing Healthcare Team Outcomes

The management of pneumonia requires an interprofessional team. The reason is that most patients are managed as outpatients, but if not properly treated, the morbidity and mortality are high.

Besides administering antibiotics, these patients often require chest physical therapy, a dietary consult, physical therapy to help regain muscle mass, and a dental consult. The key is to educate the patient on the discontinuation of smoking and abstaining from alcohol.

Patients need to be referred to a dietitian to ensure that they are eating healthy.

Further, the clinicians should encourage patients to get appropriate influenza and pneumococcal vaccines. The pharmacist should teach about antibiotic compliance and ensure that the patient is prescribed the right antibiotics aimed at the target organism. An infectious disease specialty-trained pharmacist is particularly helpful in assisting the team with difficult antibiotic treatment choices. Nursing can counsel on the appropriate dosing and administration of medications and answer patient questions, as well as charting treatment progress and reporting any issues to the clinician managing the case.

Finally, it is important to educate the patient to follow up with clinicians if they want a complete resolution of the infectious process.[19][21] [Level 5] Only with open communication between the interprofessional team can the morbidity of pneumonia be lowered.

Outcomes

In healthy people, the outcome after bacterial pneumonia is excellent. However, in people with advanced age, lung disease, immunosuppression, infection with aggressive gram-negative organisms (Klebsiella), and other comorbidities, the outcomes are usually poor. When pneumonia is left untreated, it carries mortality in excess of 25%. Pneumonia can also lead to extensive lung damage and leads to residual impairment in lung function. Other reported complications of pneumonia that occur in 1 to 5% of patients include lung abscess, empyema, and bronchiectasis.[22][23] [Level 5]

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• Comment on this article.

References

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Disclosure: Saud Bin Abdul Sattar declares no relevant financial relationships with ineligible companies.

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

Bacterial pneumonia – causes, symptoms, diagnosis and treatment

Bacterial pneumonia is a microbial infection of the respiratory parts of the lungs, occurring with the development of intraalveolar exudation and inflammatory infiltration of the lung parenchyma. Bacterial pneumonia is accompanied by fever, weakness, headache, cough with mucopurulent or rusty sputum, shortness of breath, chest pain, myalgia and arthralgia, and pulmonary insufficiency. Diagnosis of bacterial pneumonia is based on physical examination, chest x-ray, general and biochemical blood tests, microscopy, and sputum culture. The basis of the treatment of bacterial pneumonia is etiotropic antibiotic therapy.

General information

Bacterial pneumonia is an acute infectious and inflammatory process in the lung tissue caused by pathogenic microbial flora and characterized by the development of febrile, intoxication syndromes and respiratory failure. Among other etiological forms of pneumonia (viral, parasitic, fungal, etc.), bacterial pneumonia confidently holds the first place. Every year, about 1,000 people per 100,000 of the population fall ill with bacterial pneumonia. The most vulnerable contingent is children under 5 years of age and the elderly over 75 years of age. In pulmonology, the problem of pneumonia focuses on itself due to the steady increase in the number of cases of complicated course and the level of mortality.

Bacterial pneumonia

Causes

Bacterial pneumonia develops when the lungs are affected by gram-positive and gram-negative bacteria, many of which may be present in the normal microflora of the upper respiratory tract. The spectrum of causative agents of bacterial pneumonia is determined by the form of the disease. The community-acquired form is most often caused by pneumococci, Haemophilus influenzae. Nosocomial bacterial pneumonia is usually initiated by multidrug-resistant strains of Staphylococcus aureus, Pseudomonas aeruginosa, Friedlander’s bacillus, Enterobacteriaceae, Haemophilus influenzae, anaerobes. The causative agents of ventilator-associated pneumonia that occurs when using mechanical ventilation in the early stages (48-96 hours) are the inhabitants of the microflora of the oral cavity, in the later (> 96 hours) – nosocomial strains.

In other bacterial diseases (anthrax, gonorrhea, salmonellosis, tularemia, typhoid fever, whooping cough), pneumonia can be caused by representatives of a specific microflora. In the immunodeficient state, bacterial agents are often pneumococci, legionella, and Haemophilus influenzae.

Pathogenic microorganisms can penetrate into the lung tissue by direct, airborne and hematogenous routes. In patients with neurological symptoms and impaired consciousness, aspiration of secretions of the oral cavity and nasopharynx contaminated with bacteria is often observed. Hematogenous dissemination of the causative agent of bacterial pneumonia occurs with blood flow from an extrapulmonary focus (with infective endocarditis, pharyngeal abscess). The infection can penetrate into the lungs with chest wounds, tracheal intubation, from surrounding tissues with a rupture of a subphrenic abscess, etc.

In the pathogenesis of bacterial pneumonia, not only the virulence and mechanism of penetration of the pathogen, but also the level of local and general immunity is decisive. Predispose to the development of bacterial pneumonia:

• SARS
• smoking, drinking alcohol
• frequent stress, overwork
• hypovitaminosis
• old age
• air pollution.
• decrease in immune protection. Occurs with concomitant pathology: congestive heart failure, congenital malformations of the bronchopulmonary system, COPD, chronic ENT infection, immunodeficiency, severe and long-term diseases; due to surgery and prolonged immobilization.

Classification

The classification of nosological forms of the disease is based on the types of infectious pathogens, according to which pneumococcal, staphylococcal, streptococcal, meningococcal pneumonias are distinguished, as well as pneumonia caused by Haemophilus influenzae, Klebsiella, Escherichia coli, Pseudomonas aeruginosa, Legionella, etc. bacterial pneumonia is isolated to the clinical course:

• focal (bronchopneumonia). Inflammatory changes affect certain areas of the lung tissue and adjacent bronchi.
• equity (lobar, croup). The parenchyma of an entire lobe of the lung is affected.

The lower parts of the lungs are more commonly affected. There may be unilateral and bilateral bacterial pneumonia, with simultaneous damage to the pleura, pleuropneumonia develops.

According to clinical and pathogenetic criteria, bacterial pneumonia can be a community-acquired (outpatient) or nosocomial (hospital, nosocomial) infection with the development of symptoms 48-72 hours after the patient was admitted to the hospital. Bacterial pneumonia can be mild, moderate, severe or prolonged.

Symptoms of bacterial pneumonia

Clinical manifestations and severity of bacterial pneumonia are determined by the type of pathogen, the extent of the lesion, the age and health of the patient. With a typical variant of bacterial pneumonia, there is a sudden relapsing fever, a productive cough with mucopurulent or rusty sputum, and sometimes pleural pain in the chest. Patients are concerned about severe weakness, severe malaise, headache, shortness of breath, myalgia and arthralgia, loss of appetite. Often revealed sinus tachycardia, arrhythmia, arterial hypotension. Signs of respiratory, cardiac, and renal failure may develop.

Staphylococcal pneumonia is characterized by a rapid onset, a jump in temperature up to 40°C with recurrent chills, a general severe condition associated with destruction of the lungs, the appearance of foci of necrosis, cavities, and abscess formation of the lung tissue. Friedlander’s pneumonia resembles lobar pneumonia, has a protracted course and is accompanied by fever (39-40 ° C), persistent cough, viscous brown sputum with an unpleasant odor, general intoxication, rapid development of extensive necrosis of the lung tissue, solitary abscesses, pleurisy, pulmonary infarction, septic complications. Severe pneumonia caused by Pseudomonas aeruginosa is characterized by a high mortality rate. In pneumococcal pneumonia, necrosis and abscess formation are rare.

Atypical forms of pneumonia occur when the lungs are infected with oral anaerobes, legionella. Their feature is the gradual development of symptoms, the dominance of extrapulmonary manifestations. For example, legionella pneumonia is accompanied by neurological manifestations, liver dysfunction, and diarrhea. In the elderly, bacterial pneumonia is characterized by a protracted course with prolonged low-grade fever, a noticeable deterioration in well-being, severe shortness of breath, exacerbation of concomitant diseases, and CNS dysfunction.

Complications

Bacterial pneumonia is characterized by damage to the respiratory tract with inflammatory infiltration of the lung parenchyma; pleural effusion syndrome and pleural effusion. Perhaps the formation of foci of necrosis of the lung tissue with the formation of a cavity, complicated by necrotic pneumonia, lung abscess. Also, complications of bacterial pneumonia can be pleural empyema, lung gangrene, with severe DN – respiratory distress syndrome. Generalization of a bacterial infection is dangerous by the development of glomerulonephritis, meningitis, infectious-toxic shock, sepsis.

Diagnosis

Examination of a patient with bacterial pneumonia reveals pallor, cyanosis, heavy breathing; on palpation – increased voice tremor from the side of the lesion; with percussion – shortening and dulling of the lung sound; on auscultation – increased bronchophony, hard or bronchial breathing, moist fine bubbling rales and pleural friction noise. The inflammation syndrome in bacterial pneumonia is confirmed by leukocytosis with a shift of the formula to the left, lymphopenia, a moderate or significant increase in ESR, and the appearance of C-reactive protein.

X-ray of the lungs in direct and lateral projections determines the presence, localization and extent of areas of inflammation and destruction of the lung tissue, the presence of pleural effusion. Microscopy, as well as culture of sputum and bronchial washings, helps to establish a potential causative agent of bacterial pneumonia. Additionally, blood cultures for sterility, analysis of pleural effusion, ELISA are performed. In case of shortness of breath and chronic pulmonary pathology, FDI is studied, in severe complicated course of bacterial pneumonia, the gas composition of arterial blood is examined to assess the level of hypoxemia and hypercapnia, Hb saturation with oxygen.

Spiral CT and MRI of the lungs are used to differentiate the diagnosis. When diagnosing bacterial pneumonia, it is required to exclude infiltrative tuberculosis, lung cancer, lung infarction, eosinophilic infiltrate, congestive heart failure, lung atelectasis.

KT OGK. Multiple extensive areas of reduced pneumatization by type of consolidation in the lower lobes of both lungs.

Treatment of bacterial pneumonia

Treatment of bacterial pneumonia, depending on the severity, is carried out on an outpatient basis or in a hospital, if necessary in the IT department. In a feverish period, bed rest, plenty of fluids, easily digestible good nutrition are recommended.

Antibiotic therapy

Etiotropic antimicrobial therapy is prescribed empirically with correction after identification of the pathogen and obtaining an antibiogram. In bacterial pneumonia, aminopenicillins, macrolides, cephalosporins are used as monotherapy or a combination of several antimicrobial drugs. In case of non-severe community-acquired pneumonia, oral and intramuscular forms of drugs are prescribed; in severe cases, their intravenous administration is advisable; the duration of treatment is 10-14 days.

Pneumonia caused by staphylococci, enterobacteria and legionella requires a longer course of antibiotic therapy of 14-21 days. In aspiration and hospital-acquired bacterial pneumonia, fluoroquinolones, carbapenems, combinations with aminoglycosides, lincosamides, and metronidazole are additionally used.

Symptomatic therapy

In complicated cases, detoxification and immunotherapy, correction of microcirculatory disorders and dysproteinemia, oxygen therapy are performed. Antipyretics, analgesics, glucocorticoids, cardiac drugs may be prescribed. Patients with broncho-obstructive pathology are shown aerosol therapy with broncho- and mucolytic agents.

In case of abscess formation, sanation bronchoscopy is performed using solutions of antiseptics, antibiotics, mucolytics. Breathing exercises, massage, physiotherapy are recommended. Supervision of the therapist and pulmonologist, sanatorium-and-spa treatment is shown.

Prognosis and prevention

The prognosis of bacterial pneumonia is determined by the severity of the process, the adequacy of antibiotic therapy. Mortality in bacterial pneumonia reaches 9% (with nosocomial form – 20%, in elderly patients – 30%, in complicated cases – up to 50%). Prevention consists in the sanitation of purulent foci of the ENT organs, compliance with the rules and principles of mechanical ventilation, and an increase in immune reactivity. An important component is adequate antibiotic therapy for various infections.

How to distinguish coronavirus pneumonia from normal, symptoms of pneumonia in coronavirus, what is the temperature in pneumonia, no temperature in pneumonia – January 26, 2021

Doctors note that there are many exceptions to the rule, so it is difficult to describe clear differences between these pneumonias

Illustration: Yuriy Orlov

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Coronavirus infection is similar in symptoms to other respiratory viral infections, so it is often difficult to determine what exactly a particular patient is suffering from without special tests. The same situation is observed with pneumonia. They are definitely treated differently: for a bacterial one, antibiotics are needed, and for a viral one, antiviral ones, but how exactly to distinguish them if their symptoms are also too similar? NGS medical observer Maria Tishchenko asked Novosibirsk doctors this question, but in answering them they remind that every rule has many exceptions.

Therapist of the Zdravitsa Family Medicine Center Elena Obut notes that when it comes to the differences between bacterial pneumonia and viral (coronavirus) pneumonia, they first of all begin with a description of the clinical manifestations caused by the pathogen:

— Symptoms of bacterial pneumonia lung lesions are pronounced – this is a quick transition from dry cough to cough with copious sputum of green and yellow hues, multiple moist rales are heard during auscultation of the lungs. With viral pneumonia, there will be only symptoms of a general malaise – fever, chills, pulling pains in the muscles, headaches, and the cough may be absent or it will be dry, insignificant. During auscultation of the lungs, only hard breathing without wheezing or with single dry wheezing is heard.

MSCT helps to determine the degree of lung damage with high accuracy, but in general, pneumonia can also be seen on x-rays

Photo: Maria Tishchenko

and for bacterial pneumonia, it can last for several weeks after the onset of a bacterial infection.

– Laboratory tests differ: in the general blood test with viral pneumonia, lymphocytes and monocytes are increased, and with bacterial pneumonia, leukocytes are increased with a shift of the leukocyte formula to the left. Specific manifestations will also be on a chest x-ray or MSCT of the chest organs: dense areas of blackout in the lungs are a characteristic sign of bacterial pneumonia, since the lung tissue is filled with pus. And loose areas of blackout, the so-called blackout by the type of frosted glass, are characteristic of viral lung damage, – Elena Obut notes.

Bacterial pneumonia requires mandatory treatment with antibiotics, expectorants. If bacterial pneumonia is not treated, it threatens with serious complications – lung abscess, sepsis, the development of toxic shock, pulmonary edema, and so on. These dangerous consequences can lead to death, the therapist warns.

– Coronavirus pneumonia with a small amount of lung involvement CT-1 and even CT-2 can resolve on its own. And antibiotic treatment does not bring a positive result. The volume of lung damage CT-3 and CT-4 requires mandatory hospitalization of the patient and the use of oxygen therapy. But there are also mixed viral-bacterial pneumonias. Therefore, in order to obtain the maximum effect from the treatment, it is imperative to take into account the pathogen that caused the lesion in the lungs, emphasizes Elena Obut.

White areas are lesions in the lungs

Photo: Maria Tishchenko

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Therapist at the Avicenna Medical Center Yulia Podaneva notes that pneumonia can occur in absolutely identical ways: both there and there there will be fever, cough, weakness , malaise, respiratory symptoms. Only bacterial pneumonia is most often unilateral pneumonia, and coronavirus pneumonia is bilateral, that is, it captures both lungs:

– In the clinic, they can be distinguished only by single symptoms: for example, anosmia with covid – the sense of smell disappears in patients, but not in all. This is not a 100% sign.

The exact sign that distinguishes these types of pneumonia is the causative agent and, accordingly, the treatment, and with the rest there may be exceptions

Infographics: Yuri Orlov

0003 there are no 100% reliable signs that will allow you to make a diagnosis by searching for symptoms on the Internet. Therefore, for the time being, it will not be possible to do without doctors and replace them with a neural network, leaving them only for difficult cases. Because there is a classic course of pneumonia, but there are exceptions that can occur more often than the rules. Pneumonia can occur in different ways, for example, depending on age, the doctor explains:

— Elderly people often have atypical pneumonia without high fever. Older people with comorbidities, such as diabetes, heart failure, with the development of pneumonia, may become less active, refuse to eat, they develop weakness, shortness of breath, drowsiness, impaired consciousness, up to delirium. In young people, the classic course of pneumonia is more common: there was contact with the source of infection or hypothermia, and then high fever, chest pain, and shortness of breath.

Varvara Veretyuk, like her colleagues, differentiates pneumonia by localization – unilateral bacterial and bilateral covid, however, reminds of exceptions.

To determine what kind of pneumonia a patient has, blood counts in the analysis also help

Photo: Maria Tishchenko

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— If everything starts as an acute respiratory viral infection, then there are several days for symptomatic treatment and observation. But if there was no runny nose and nasal congestion, the temperature immediately suddenly rose to high numbers, then it is better to control this process. In a typical course of a coronavirus infection, there is no sharp rise in temperature to high numbers from the first days of illness, this is more typical for influenza. The temperature under 40 with covid does not rise so often and not from the first days of illness, the therapist believes.

There are also data that help doctors during the examination. For example, with bacterial pneumonia, there are changes when listening to the lungs from the first days, and with a coronavirus infection, they develop, as a rule, after the 5–7th day of illness.

– In the general blood test for coronavirus infection, the number of leukocytes is usually reduced, a relative increase in lymphocytes is more often noted, and with a bacterial infection, on the contrary, leukocytes are often high, neutrophils increase, a so-called shift to the left appears – an increase in the number of young forms of neutrophils , stab, – Varvara Veretyuk describes changes in blood counts.

After pneumonia, patients take a long time to recover

Photo: Maria Tishchenko

, cardiovascular system, kidneys, with diabetes mellitus), as well as those who have recovered from pneumonia should be vaccinated.

And in general, according to Varvara Veretyuk, prevention and control of the condition after pneumonia is important:

– Back in Soviet times, an order was created for dispensary observation within six months after suffering from pneumonia, and no one canceled this order, it is valid. The goals of such monitoring are several: to promote recovery, not to miss unnoticed tuberculosis or other serious lung disease, to eliminate risk factors for recurrent pneumonia. For six months of observation, a person must take a general blood test three times, come to the doctor three times for examination, and take a control picture six months later. In addition, during this time, you should make sure that there are no foci of chronic infection (in the field of dentistry, ENT organs), and if they are found, they should be eliminated.