Pneumonia
Editor(s)-in-Chief: C. Michael Gibson, M.S., M.D. [1] Phone:617-632-7753; Philip Marcus, M.D., M.P.H.[2]{{#meta: itemprop="medicalWebPageAudiences" content="patient"}}{{#meta: itemprop="medicalWebPageSpecialities" content="cardiology"}}{{#meta: itemprop="medicalWebPageInfoTypes" content="symptoms,diagnosis,treatment,causes,prognosis,complications"}} [[Natural Progression::{{{naturalProgression}}}| ]] Classification Classic::Classification Atypical::
Overview
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Pneumonia Microchapters |
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Diagnosis |
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Treatment |
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Case Studies |
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Pneumonia On the Web |
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American Roentgen Ray Society Images of Pneumonia |
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [3]; Associate Editor(s)-in-Chief: Hamid Qazi, MD, BSc [4], Priyamvada Singh, M.D. [5], Alejandro Lemor, M.D. [6]
Overview
Pneumonia is an illness of the lungs and respiratory system in which the alveoli (microscopic air-filled sacs of the lung responsible for absorbing oxygen from the atmosphere) become inflamed and flooded with fluid. Pneumonia can result from a variety of causes, including infection with bacteria, viruses, fungi, parasites, and chemical or physical injury to the lungs. Typical symptoms associated with pneumonia include cough, chest pain, fever, and difficulty in breathing. Diagnostic tools include x-rays and an examination of the sputum. Treatment depends on the cause of pneumonia; bacterial pneumonia is treated with antibiotics. Pneumonia is a common illness which occurs in all age groups, and is a leading cause of death among the elderly and people who are chronically and terminally ill. Vaccines to prevent certain types of pneumonia are available. The prognosis depends on the type of pneumonia, the appropriate treatment, any complications, and the person's underlying health.
Historical Perspective
Pneumonia has been recognized since ancient times. It was initally described by Hippocrates who recorded his observations of its symptoms and complications. Edwin Klebs was the first to identify bacteria in the lungs of patients who died from pneumonia in 1875. This discovery was soon-after substantiated by the works of Carl Friedländer and Albert Fränkel who were the first to identify Streptococcus pneumoniae as a causative agent. The introduction of the gram stain subsequently led to the discovery of other causative organisms. Despite being an important cause of mortality before the late twentieth century, the advent of antibiotics, modern surgical techniques, and vaccination drastically lowered the morbidity and mortality of pneumonia with the turn of the century.
Classification
Several pneumonia classification schemes have been described. The earliest classification was based on the anatomical distribution of the infectious process observed on autopsy and eventually on medical imaging. Advances in microbiology led to a classification based on etiologic group (bacterial, viral, fungal) despite difficulties often encountered in identifying the etiologic agent. With the advent of antibiotics and the rise in resistance, a classification scheme taking into account the setting in which the pneumonia was acquired was introduced to guide empiric therapy. Pneumonia was classified into community-acquired pneumonia (CAP), healthcare-associated pneumonia (HCAP), ventilator-associated pneumonia (VAP), and hospital-acquired pneumonia (HAP). Despite significant overlap, this classification is essential in selecting appropriate antimicrobial therapy.
Pathophysiology
Bacteria and fungi typically enter the lung with inhalation. Once inside the alveoli, these microbes travel into the spaces between the cells and also between adjacent alveoli through connecting pores. This invasion triggers the immune system response by sending white blood cells responsible for attacking microorganisms (neutrophils) to the lungs resulting in manifestations of pneumonia.
Causes
Pneumonia can result from a variety of causes including infection with bacteria, viruses, fungi, parasites, and chemical or physical injury to the lungs. The etiology will depend upon various factors such as age, immune status, geographical area, and comorbidities.
Epidemiology and Demographics
Pneumonia is a common illness in all parts of the world. It is a major cause of death among all age groups. Mortality from pneumonia generally decreases with age until late adulthood. Elderly individuals, however, are at particular risk for pneumonia and associated mortality. More cases of pneumonia occur during the winter months than during other times of the year. Pneumonia occurs more commonly in males than females, and more often in African Americans than Caucasians. People who are hospitalized for any reason are also at high risk for pneumonia. Following urinary tract infections, pneumonia is the second most common cause of nosocomial infections, and its prevalence is 15-20% of the total number.
Risk Factors
The risk factors for pneumonia include smoking, age, immuno-suppression, exposure to chemicals, underlying lung disease, and exposure to chemicals.
Diagnosis
Diagnostic Criteria
Community acquired pneumonia should be distinguished from healthcare-associated pneumonia as these diseases have different causative organism, prognosis, diagnostic, and treatment guidelines.
History and Symptoms
People with pneumonia often have a productive cough, fever, shaking chills, shortness of breath, pleuritic chest pain,hemoptysis, headaches, diaphoresis, and clammy skin. Other possible symptoms are loss of appetite, fatigue,blueness of the skin, nausea, vomiting, mood swings, andjoint pains or muscle aches. In elderly people manifestations of pneumonia may not be typical. They may develop a new or worsening confusion or may experience unsteadiness, leading to falls. Infants with pneumonia may have many of the symptoms above, but in many cases they are simply sleepy or have a decreased appetite.
Physical Examination
Physical examination may reveal fever or sometimes low body temperature, an increased respiratory rate, low blood pressure, a fast heart rate, or a low oxygen saturation, which is the amount of oxygen in the blood as indicated by either pulse oximetry or blood gas analysis. Patients who are struggling to breathe, who are confused, or who have cyanosis (blue-tinged skin) require immediate attention. Auscultation findings include lack of normal breath sounds, the presence of crackling sounds (rales), or increased loudness of whispered speech (whispered pectoriloquy) with areas of the lung that are stiff and full of fluid, called consolidation. Vital signs are useful in determining the severity of illness and have predictive values. However, a high degree of suspicion should be kept in elderly as the presentation could be subtle in them.
Laboratory Findings
Laboratory findings such as leukocytosis are helpful for the diagnosis of bacterial pneumonia or to assess the status of the patient. Sputum samples need to be collected from every patient and sent for gram staining and culture that need to be performed to determine the exact pathogen causing the pneumonia. Other tests include urine antigen test, PCR, C-reactive protein, and procalcitonin.
Chest X Ray
An important test for making a diagnosis of pneumonia is a chest x-ray. Chest x-rays can reveal areas of opacity (seen as white) which represent consolidation. Pneumonia is not always seen on x-rays, either because the disease is only in its initial stages, or because it involves a part of the lung not easily seen by x-ray.
CT
A chest CT scan is not routinely done in patients with pneumonia, but is a diagnostic test that may be useful when a chest x-ray is not conclusive. CT findings may include lobar consolidation, ground-glass opacities, pleural effusion, lymphadenopathy, and tree-in-bud appereance.
Other Imaging Findings
Bronchoscopy with bronchoalveolar lavage is useful to obtain samples for gram stain and culture in patients with certain conditions, such as immunocompromised patients, ICU admission or antibiotic failure.
Treatment
Medical Therapy
The treatment of pneumonia involves three critical decisions: firstly whether the patient truly has pneumonia, secondly what is the severity of the pneumonia, and lastly whether hospitalization is required for adequate management. Most cases of pneumonia can be treated without hospitalization. Typically, oral antibiotics, rest, fluids, and home care are sufficient for complete resolution. However, people with pneumonia who are having trouble breathing, comorbidities, and the elderly may need more advanced treatment. If the symptoms get worse, the pneumonia does not improve with home treatment, or complications occur, the person will often have to be hospitalized.
Prevention
There are several ways to prevent infectious pneumonia. Appropriately treating underlying illnesses (such as AIDS), smoking cessation, vaccination against pneumococcal, and influenza are the commonly used methods.
References
Historical Perspective
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Pneumonia Microchapters |
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Diagnosis |
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Treatment |
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Case Studies |
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Pneumonia On the Web |
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American Roentgen Ray Society Images of Pneumonia |
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [7]; Associate Editor(s)-in-Chief: Hamid Qazi, MD, BSc [8], Serge Korjian M.D., Priyamvada Singh, M.D. [9]
Overview
The pneumonia syndrome has been recognized since ancient times. It was initially described by Hippocrates who recorded his observations of its symptoms and complications. Edwin Klebs was the first to identify bacteria in the lungs of patients who died from pneumonia in 1875. This discovery was soon-after substantiated by the works of Carl Friedländer and Albert Fränkel who were the first to identify Streptococcus pneumoniae as a causative agent. The introduction of the gram stain subsequently led to the discovery of other causative organisms. Despite being an important cause of mortality before the late twentieth century, the advent of antibiotics, modern surgical techniques, and vaccination drastically lowered the morbidity and mortality of pneumonia with the turn of the century.
Historical Perspective
Discovery
- Pneumonia was first discovered by Hippocrates.
- In 1817, Dr. Simpson of United Kingdom was the first to report a case of pneumonia treated with blood letting.[1]
- In 1842, Dr. Edward Newfold of United Kingdom was the first to report a case of typhoid pneumonia.[2]
- In 1875, Dr. Edwin Klebs was the first to discover the association between bacteria and the development of pneumonia.
Landmark Events in the Development of Treatment Strategies
- In 1902, Dr. Wright discovered the pneumococcal vaccine as a preventative treatment of pneumonia.[3]
References
- ↑ "Case ofPneumonia, Where the Extent to Which Blood-Letting May Be Successfully Carried Is Fully Exemplified". Med Chir J Rev. 4 (24): 460–463. 1817. PMC 5570882. PMID 29257545.
- ↑ Newbold E (1842). "Case of Typhoid Pneumonia". Prov Med J Retrosp Med Sci. 4 (84): 87. PMC 2489819. PMID 21373079.
- ↑ Harris AB (1909). "Observations on the Therapeutic Value of the Pneumococcus Vaccine in the Treatment of Pneumonia and some of its Complications". Br Med J. 1 (2530): 1530–5. PMC 2320626. PMID 20764553.
Pathophysiology
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Pneumonia Microchapters |
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Diagnosis |
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Treatment |
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Case Studies |
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Pneumonia On the Web |
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American Roentgen Ray Society Images of Pneumonia |
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [10]; Associate Editor(s)-in-Chief: Hamid Qazi, MD, BSc [11], Priyamvada Singh, M.D. [12]
Overview
Bacteria and fungi typically enter the lung with inhalation. Once inside the alveoli, these microbes travel into the spaces between the cells and also between adjacent alveoli through connecting pores. This invasion triggers the immune system response by sending white blood cells responsible for attacking microorganisms (neutrophils) to the lungs resulting in manifestations of pneumonia.
Pathophysiology
Mode of Transmission
1. Inhalation of Aerosolized Droplets
- Inhalation of aerosolized droplets of 0.5 to 1 micrometer is the most common pathway of acquiring pneumonia.
- A few bacterial and viral infections are transmitted in this fashion.
- The lung can normally filter out particles between 0.5 to 2 micrometer by recruiting the alveolar macrophages.[1]
2. Microaspiration of Oropharyngeal Contents
- Aspiration of oropharyngeal contents containing pathogenic microorganisms is one of the mechanism of acquiring pneumonia.
- It most commonly occurs in normal persons during sleep, in unconscious persons due to gastroesopahegeal reflux or impaired gag reflex and cough reflex.[1]
3. Blood-Borne or Systemic Infection
- Microbial entered through circulation may also result in pulmonary infections.
- Blood-borne pneumonia is seen more commonly in intravenous drug users. Staphylococcus aureus causes pneumonia in this way.
- Gram negative bacteria typically account for pneumonia in immunocompromised individuals.
4. Trauma or Local Spread
- Pneumonia can occur after a pulmonary procedure or a penetrating trauma to the lungs.
- A local spread of a hepatic abscess can also lead to pneumonia.
Agent Specific Virulence Factors
Several strategies are evolved to evade host defence mechanisms and facilitate spreading before establishing an infection.
- Influenza virus possesses neuraminidases for cleavage of sialic acid residues on the cell surface and viral proteins, which prevent aggregation and facilitate propagation of viral particles.
- Chlamydophila pneumoniae induces complete abortion of cilia motions which assists colonization at the respiratory epithelium.[2]
- Mycoplasma pneumoniae produces a virulence factor with ADP-ribosylating activity which is responsible for airway cellular damage and mucociliary dysfunction.[3]
- Haemophilus influenzae, Streptococcus pneumoniae, and Neisseria meningitidis produce proteases that split mucosal IgA.
- Streptococcus pneumoniae possesses pneumolysin that aid the bacteria during colonization, by facilitating adherence to the host,[4] during invasion by damaging host cells,[5] and during infection by interfering with the host immune response.[6]
Host Factors
- The lungs can normally filter out large droplets of aerosols.
- Smaller droplets of the size of 0.5 to 2 micrometer are deposited on the alveoli and then engulfed by alevolar macrophages.
- These macrophages release cytokines and chemokines, which also includes tumor necrosis factor-alpha, interleukin-8 and LTB4.
- The neutrophils are recruited by these cells to eliminate these microorganisms.[7][8]
1. Diminished Mucociliary Clearance
- The cilia lining the respiratory epithelium serve to move secreted mucus containing trapped foreign particles including pathogens towards the oropharynx for either expectoration or swallowing.
- Elevated incidence of pneumonia in patients with genetic defects affecting mucociliary clearance such as primary ciliary dyskinesia suggests its role in the pathogenesis of community-acquired pneumonia.
2. Impaired Cough Reflex
- Cough, together with mucociliary clearance, prevent pathogens from entering the lower respiratory tract.
- Cough suppression or cough reflex inhibition seen in patients with cerebrovascular accidents and drug overdosages is associated with an enhanced risk for aspiration pneumonia.
- Another relation to cough is genetic polymorphisms in the angiotensin-converting enzyme (ACE) gene.
- The role of cough in preventing pneumonia may be explained by a higher risk for developing pneumonia in homozygotes carrying deletion/deletion (DD) genotype who are found to have lower levels of bradykinin and tachykinins such as substance P.[9][10]
3. Defective Immune System
- Pathogen-associated molecular patterns (PAMPs) are initially recognized by Toll-like receptors (TLRs) and other pattern-recognition receptors (PRRs) of the innate immune system.
- Effectors in the acquired immune system are involved in elimination of microorganisms and generation of immunological memory.
- Other components in the immune system such as complement system, cytokines, and collectins, also mediate the defense against microorganisms causing pneumonia.
Microscopic Pathology
Microbial PathogenesisVirulence FactorsSeveral mechanisms have evolved to evade host defense mechanisms and facilitate microbial spread to establish an infection.
Aspiration Pneumonia{{#ev:youtube|bTqgAfQv0p4}}
Lobar Pneumonia{{#ev:youtube|dxXrxYIXbL8}}
Pneumocystis Pneumonia{{#ev:youtube|KfF_pPUjR8o}} Pneumocystis Pneumonia{{#ev:youtube|zSdK_yWe_S4}} Aspiration Pneumonia{{#ev:youtube|bTqgAfQv0p4}} Aspiration Pneumonia, Infant{{#ev:youtube|RXnnEuEZ0BY}} Desquamative Interstitial Pneumonia{{#ev:youtube|G0TFmAAYjWU}} Legionella Pneumonia{{#ev:youtube|BDWEnPilfIQ}} Measles Pneumonia{{#ev:youtube|v80kA_dt6EE}} Abscess, Bronchopneumonia{{#ev:youtube|wO2x7O2KEZY}} |
References
- ↑ 1.0 1.1 Wunderink, RG.; Waterer, GW. (2004). "Community-acquired pneumonia: pathophysiology and host factors with focus on possible new approaches to management of lower respiratory tract infections". Infect Dis Clin North Am. 18 (4): 743–59, vii. doi:10.1016/j.idc.2004.07.004. PMID 15555822. Unknown parameter
|month=ignored (help) - ↑ 2.0 2.1 Shemer-Avni, Y.; Lieberman, D. (1995). "Chlamydia pneumoniae-induced ciliostasis in ciliated bronchial epithelial cells". J Infect Dis. 171 (5): 1274–8. PMID 7751703. Unknown parameter
|month=ignored (help) - ↑ 3.0 3.1 Kannan, TR.; Baseman, JB. (2006). "ADP-ribosylating and vacuolating cytotoxin of Mycoplasma pneumoniae represents unique virulence determinant among bacterial pathogens". Proc Natl Acad Sci U S A. 103 (17): 6724–9. doi:10.1073/pnas.0510644103. PMID 16617115. Unknown parameter
|month=ignored (help) - ↑ Rubins, JB (December 1998). "Pneumolysin in pneumococcal adherence and colonization". Microbial pathogenesis. 25 (6): 337–42. doi:10.1006/mpat.1998.0239. PMID 9895272. Unknown parameter
|coauthors=ignored (help) - ↑ Rubins, JB (January 1998). "Pneumolysin: a multifunctional pneumococcal virulence factor". The Journal of laboratory and clinical medicine. 131 (1): 21–7. PMID 9452123. Unknown parameter
|coauthors=ignored (help) - ↑ Cockeran, R (June 2002). "The role of pneumolysin in the pathogenesis of Streptococcus pneumoniae infection". Current Opinion in Infectious Diseases. 15 (3): 235–9. PMID 12015456. Unknown parameter
|coauthors=ignored (help) - ↑ Strieter, RM.; Belperio, JA.; Keane, MP. (2003). "Host innate defenses in the lung: the role of cytokines". Curr Opin Infect Dis. 16 (3): 193–8. doi:10.1097/01.qco.0000073766.11390.0e. PMID 12821807. Unknown parameter
|month=ignored (help) - ↑ Mason, CM.; Nelson, S. (2005). "Pulmonary host defenses and factors predisposing to lung infection". Clin Chest Med. 26 (1): 11–7. doi:10.1016/j.ccm.2004.10.018. PMID 15802161. Unknown parameter
|month=ignored (help) - ↑ Morimoto, S.; Okaishi, K.; Onishi, M.; Katsuya, T.; Yang, J.; Okuro, M.; Sakurai, S.; Onishi, T.; Ogihara, T. (2002). "Deletion allele of the angiotensin-converting enzyme gene as a risk factor for pneumonia in elderly patients". Am J Med. 112 (2): 89–94. PMID 11835945. Unknown parameter
|month=ignored (help) - ↑ Rigat, B.; Hubert, C.; Alhenc-Gelas, F.; Cambien, F.; Corvol, P.; Soubrier, F. (1990). "An insertion/deletion polymorphism in the angiotensin I-converting enzyme gene accounting for half the variance of serum enzyme levels". J Clin Invest. 86 (4): 1343–6. doi:10.1172/JCI114844. PMID 1976655. Unknown parameter
|month=ignored (help) - ↑ Rubins, JB (December 1998). "Pneumolysin in pneumococcal adherence and colonization". Microbial pathogenesis. 25 (6): 337–42. doi:10.1006/mpat.1998.0239. PMID 9895272. Unknown parameter
|coauthors=ignored (help) - ↑ Rubins, JB (January 1998). "Pneumolysin: a multifunctional pneumococcal virulence factor". The Journal of laboratory and clinical medicine. 131 (1): 21–7. PMID 9452123. Unknown parameter
|coauthors=ignored (help) - ↑ Cockeran, R (June 2002). "The role of pneumolysin in the pathogenesis of Streptococcus pneumoniae infection". Current Opinion in Infectious Diseases. 15 (3): 235–9. PMID 12015456. Unknown parameter
|coauthors=ignored (help)
Epidemiology and Demographics
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Pneumonia Microchapters |
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Diagnosis |
|---|
|
Treatment |
|
Case Studies |
|
Pneumonia On the Web |
|
American Roentgen Ray Society Images of Pneumonia |
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [13]; Associate Editor(s)-in-Chief: Hamid Qazi, MD, BSc [14], Priyamvada Singh, M.D. [15]; Alejandro Lemor, M.D. [16]
Overview
Pneumonia is a common illness in all parts of the world. It is a major cause of death among all age groups. Mortality from pneumonia generally decreases with age until late adulthood. Elderly individuals, however, are at particular risk for pneumonia and associated mortality. More cases of pneumonia occur during the winter months than during other times of the year. Pneumonia occurs more commonly in males than females, and more often in African Americans than caucasians. People who are hospitalized for any reason are also at high risk for pneumonia. Following urinary tract infections, pneumonia is the second most common cause of nosocomial infections, and its prevalence is 15-20% of the total number.
Epidemiology and Demographics
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United States of America
- It is the seventh most common cause of death in the United States
- It causes around 500,000 hospitalizations and 65,000 deaths annually.
International
- It is a common illness in all parts of the world, but countries like India, China, Pakistan, Bangladesh, Indonesia and Nigeria have high rates of childhood pneumonia.[2]
Age
- The incidence is higher in children and elderly.
- In children, the majority of deaths occur in the newborn period, with over two million worldwide deaths a year.
- In fact, the WHO estimates that one in three newborn infant deaths are due to pneumonia.
- Mortality decreases with age until late adulthood; elderly individuals are particularly at risk for CAP and associated mortality.
Seasonal
- More common during winter months than during other times of the year.
Gender
- CAP occurs more commonly in males than females
Race
- More common in African Americans than caucasians.
Mortality
- Patients hospitalized with pneumonia have a mortality rate of 12-14%.
Special Considerations
- Individuals with underlying illnesses such as Alzheimer's disease, cystic fibrosis, emphysema, tobacco smoking, alcoholism, or immune system problems are at increased risk for pneumonia.[18]
| Country | Predicted no. of new cases (millions) | Estimated incidence(e/cy) |
|---|---|---|
| India | 43.0 | 0.37 |
| China | 21.1 | 0.22 |
| Pakistan | 9.8 | 0.41 |
| Bangladesh | 6.4 | 0.41 |
| Nigeria | 6.1 | 0.34 |
| Indonesia | 6.0 | 0.28 |
| Ethiopia | 3.9 | 0.35 |
| Democratic Republic of the Congo | 3.9 | 0.39 |
| Viet Nam | 2.9 | 0.35 |
| Philippines | 2.7 | 0.27 |
| Sudan | 2.0 | 0.48 |
| Afghanistan | 2.0 | 0.45 |
| United Republic of Tanzania | 1.9 | 0.33 |
| Myanmar | 1.8 | 0.43 |
| Brazil | 1.8 | 0.11 |
| Table adapted from WHO [3] | ||
Community Acquired Pneumonia
 Graph obtained from CDC [4] |
- As many as 400,000 hospitalizations from pneumococcal pneumonia are estimated to occur annually in the United States. Pneumococci accounts for about 30% of adult community-acquired pneumonia. [5]
- In 2012, 59.9% of adults 65 years and older received a pneumococcal vaccination.[6]
- In 2010, the number of discharges for patient admitted with pneumonia in hospitals in the US was 1.1 million patients. The average length of stay for pneumonia patients admitted to hospitals was 5.2 days.[6]
- An increasing rate of CAP is seen with age. Approximately 5 to 6 cases of pneumonia per 1000 persons are observed among adults. A pronounced seasonal effect on the number of patients presenting to the emergency department is also noted. During the winter months, there is an approximately 50% rise in the number of cases compared to the summer months.[7]
- Streptococcus pneumoniae is the leading cause of pneumonia worldwide.[8]
Mortality
- About 3.5 million deaths yearly have been attributed to lower respiratory tract infections (LRTI). LTRIs are the third most common cause of overall death and the leading cause of death from infectious diseases worldwide.[9]
- Pneumonia is the ninth leading cause of death in the United States.
- The number of deaths in the US in 2011 attributed to pneumonia was 52,294. [6]
- Pneumonia mortality rate was 16.8 deaths per 100,000 in the US in 2011. [6]
- A higher mortality rate is seen in invasive diseases, nursing home patients and severe bacteremia.
- More than 40 % mortality rate is seen in ICU admitted patients.
- The percentage of hospital inpatient deaths from pneumonia in the US 2006 was 3.4%. [10]
Age
- Individuals older than 85 years of age are at a particularly high risk of developing CAP that can reach an annual rate of 5-10%.[11]
- Individuals younger than 3 years and older than 65 years of age are more likely to be hospitalized with severe symptoms and complications.
Gender
- The risk of CAP is similar in males and females.
Incidence of Community–Acquired Pneumonia in 2010 in Children 0–4 Years of Age in 192 Countries[12]
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Hospital Acquired Pneumonia
- Pneumonia has accounted for approximately 20% of all hospital-associated infections and 27% and 24% of all infections acquired in the medical intensive-care unit (ICU) and coronary care unit, respectively. [13]
Incidence
- The incidence of HAP is 5-15 cases per 1 000 hospital admissions. [14]
- The incidence of VAP is 6 to 20 times more than in patients without mechanical support.
| Age | Females | Males |
|---|---|---|
| 18-44 years | 5% | 4% |
| 45-64 years | 14% | 13% |
| ≥ 65 years | 34% | 30% |
| Total | 53% | 47% |
| Table adapted from 2009–2011 National Medicare Patient Safety Monitoring System [15] | ||
Mortality
- HAP and VAP are nosocomial infections with a high mortality in contrast with other nosocomial infections.
- This higher mortality rate is associated with MDR pathogens.
Age
- HAP is more commonly reported in patients > 65 years, probably due to the fact that this age population is more commonly hospitalized.
Gender
- There is no predominance in gender, although some data reports a higher incidence among females.
Ventilator-associated Pneumonia
- VAP occurs in up to 25% of all people who require mechanical ventilation.
- VAP can develop at any time during ventilation, but occurs more often in the first few days after intubation.
- This is because the intubation process itself contributes to the development of VAP.
- VAP occurring early after intubation typically involves fewer resistant organisms and is thus associated with a more favorable outcome.
- Because respiratory failure requiring mechanical ventilation is itself associated with a high mortality, determination of the exact contribution of VAP to mortality has been difficult.
- As of 2006, estimates range from 33% to 50% death in patients who develop VAP.
- Mortality is more likely when VAP is associated with certain microorganisms (Pseudomonas, Acinetobacter), blood stream infections, and ineffective initial antibiotics.
- VAP is especially common in people who have acute respiratory distress syndrome (ARDS).
References
- ↑ "Pneumococcal Disease - Epidemiology and Prevention of Vaccine-Preventable Diseases".
- ↑ Rudan I, Boschi-Pinto C, Biloglav Z, Mulholland K, Campbell H (2008). "Epidemiology and etiology of childhood pneumonia". Bull World Health Organ. 86 (5): 408–16. PMC 2647437. PMID 18545744.
- ↑ http://www.who.int/bulletin/volumes/86/5/07-048769-table-T2.html
- ↑ "CDC Early Release of Selected Estimates Based on Data From the 2012 National Health Interview Survey - Receipt of pneumococcal vaccination" (PDF).
- ↑ "CDC Pneumococcal Disease - Clinical Features".
- ↑ 6.0 6.1 6.2 6.3 "CDC Pneumonia FastStats".
- ↑ Marrie, TJ.; Huang, JQ. (2005). "Epidemiology of community-acquired pneumonia in Edmonton, Alberta: an emergency department-based study". Can Respir J. 12 (3): 139–42. PMID 15875065. Unknown parameter
|month=ignored (help) - ↑ Miniño, AM.; Murphy, SL.; Xu, J.; Kochanek, KD. (2011). "Deaths: final data for 2008". Natl Vital Stat Rep. 59 (10): 1–126. PMID 22808755. Unknown parameter
|month=ignored (help) - ↑ "WHO". Text " The top 10 causes of death " ignored (help)
- ↑ http://www.cdc.gov/nchs/data/series/sr_13/sr13_168.pdf
- ↑ Jackson ML, Neuzil KM, Thompson WW, Shay DK, Yu O, Hanson CA; et al. (2004). "The burden of community-acquired pneumonia in seniors: results of a population-based study". Clin Infect Dis. 39 (11): 1642–50. doi:10.1086/425615. PMID 15578365.
- ↑ Rudan I, O'Brien KL, Nair H, Liu L, Theodoratou E, Qazi S; et al. (2013). "Epidemiology and etiology of childhood pneumonia in 2010: estimates of incidence, severe morbidity, mortality, underlying risk factors and causative pathogens for 192 countries". J Glob Health. 3 (1): 010401. doi:10.7189/jogh.03.010401. PMC 3700032. PMID 23826505.
- ↑ Magill, Shelley S.; Edwards, Jonathan R.; Bamberg, Wendy; Beldavs, Zintars G.; Dumyati, Ghinwa; Kainer, Marion A.; Lynfield, Ruth; Maloney, Meghan; McAllister-Hollod, Laura; Nadle, Joelle; Ray, Susan M.; Thompson, Deborah L.; Wilson, Lucy E.; Fridkin, Scott K. (2014). "Multistate Point-Prevalence Survey of Health Care–Associated Infections". New England Journal of Medicine. 370 (13): 1198–1208. doi:10.1056/NEJMoa1306801. ISSN 0028-4793.
- ↑ "Guidelines for the Management of Adults with Hospital-acquired, Ventilator-associated, and Healthcare-associated Pneumonia". American Journal of Respiratory and Critical Care Medicine. 171 (4): 388–416. 2005. doi:10.1164/rccm.200405-644ST. ISSN 1073-449X.
- ↑ Eckenrode, Sheila; Bakullari, Anila; Metersky, Mark L.; Wang, Yun; Pandolfi, Michelle M.; Galusha, Deron; Jaser, Lisa; Eldridge, Noel (2014). "The Association between Age, Sex, and Hospital-Acquired Infection Rates: Results from the 2009–2011 National Medicare Patient Safety Monitoring System". Infection Control and Hospital Epidemiology. 35 (S3): S3–S9. doi:10.1086/677831. ISSN 0899-823X.
Risk Factors
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Pneumonia Microchapters |
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Pneumonia On the Web |
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American Roentgen Ray Society Images of Pneumonia |
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [19]; Associate Editor(s)-in-Chief: Hamid Qazi, MD, BSc [20], Priyamvada Singh, M.D. [21]Philip Marcus, M.D., M.P.H.[22]
Overview
The risk factors for pneumonia include: smoking, age>65, immuno-suppression, exposure to chemicals, and underlying lung disease.
Risk Factors
Airway Obstruction
- When part of the airway (bronchi) leading to the alveoli is obstructed, the lung is not able to clear fluid when it accumulates. This can lead to infection of the fluid resulting in community-acquired pneumonia (CAP).
- One cause of obstruction, especially in young children, is inhalation of a foreign object such as a marble or toy. The object is lodged in the small airways and pneumonia can form in the trapped areas of lung.
- Another cause of obstruction is lung cancer, which can grow into the airways blocking the flow of air.
Lung Disease
- Smoking, and diseases such as emphysema, result in more frequent and severe bouts of CAP.
- In children, recurrent episodes of CAP may be the first clue to diseases such as cystic fibrosis or pulmonary sequestration.
Immune Compromise
- People who have immune system problems are more likely to get CAP.
- Risk factors for increased mortality from community acquired pneumonia are: active malignancy, immuno-suppression, neurological disease, congestive heart failure, coronary artery disease, and diabetes mellitus
- People who have AIDS are much more likely to develop CAP. Pneumonia could be the first manifestation of an underlying undiagnosed HIV. It is thus recommended by the Center for Disease Control (CDC) that all patients aged 13 to 64 in a medical setting regardless of known risk factors be screened for HIV. The American College of Physicians and HIV Medicine Association recommends expanding screening for HIV from age 13 to 75 [1], [2].
- Other immune problems range from severe immune deficiencies of childhood such as Wiskott-Aldrich syndrome to less severe deficiencies such as common variable immunodeficiency.[23]
- Elderly people are affected with increased incidence and severity of community acquired pneumonia. It is the fifth most common cause of death among individuals who are > 65 years of age, and fourth in individuals who are 85 years or older. The clinical picture in elderly could be subtle and could present only as delirium without any fever, cough or sputum. Therefore, a high index of suspicion should be kept in these groups of people.
Community Acquired Pneumonia
The following are risk factors related to specific causative pathogens in community-acquired pneumonia:
Exposure to Animals
| Animals | Most Common Pathogens |
|---|---|
| Bat or bird droppings | Histoplasma capsulatum |
| Birds | Chlamydophila psittaci |
| Rabbits | Francisella tularensis |
| Farm animals or parturient cats | Coxiella burnetti (Q fever) |
| Table adapted from IDSA/ATS Guidelines for CAP in Adults [3] | |
Travel
| Condition | Most Common Pathogens |
|---|---|
| Hotel or cruise ship stay | Legionella spp |
| Travel to southwestern US | Coccidioides spp, Hantavirus |
| Travel to southeast or east Asia | Burkholderia pseudomallei, avian influenza, SARS |
| Table adapted from IDSA/ATS Guidelines for CAP in Adults [3] | |
Obstruction
- Airway obstruction may cause fluid accumulation in the lungs and result in CAP if the fluids become infected.
- One cause of obstruction, especially in young children, is inhalation of a foreign object such as a marble or toy. The object is lodged in the small airways and pneumonia can form in the trapped areas of lung.
- Another cause of obstruction is lung cancer, which can grow into the airways blocking the flow of air.
Lung Disease
- In children, recurrent episodes of CAP may be the first clue to diseases such as cystic fibrosis or pulmonary sequestration.
- Previous episode of pneumonia or chronic bronchitis
Immune Problems
- People who have immune disorders are more likely to acquire CAP.
- Risk factors for increased mortality from community-acquired pneumonia are: active malignancy, immunosuppression, neurological disease, congestive heart failure, coronary artery disease, and diabetes mellitus.
- People who have AIDS are much more likely to develop CAP. Pneumonia could be the first manifestation of an underlying undiagnosed HIV. It is, thus, recommended by the Center for Disease Control (CDC) that all patients aged 13 to 64 in a medical setting, regardless of known risk factors, be screened for HIV. The American College of Physicians and HIV Medicine Association recommends expanding screening for HIV from age 13 to 75 [1], [2].
- Other immune problems range from severe immune deficiencies from childhood, such as Wiskott-Aldrich syndrome, to less severe deficiencies, such as common variable immunodeficiency.[24]
- Elderly people are affected with increased incidence and severity of community-acquired pneumonia. It is the fifth most common cause of death amongst individuals who are greater than 65 years of age, and it is the fourth most common cause of death in individuals who are 85 years or older. The clinical picture in elderly could be subtle and it could be present only as delirium without any fever, cough or sputum. Therefore, a high index of suspicion should be kept in these groups of people.
- Immotile cilia syndrome
- Kartagener's syndrome (ciliary dysfunction, situs inversus, sinusitis, bronchiectasis)
- Young's syndrome (azoospermia, sinusitis, pneumonia)
Other Risk Factors
A few other conditions may lead to pneumonia due to altered pulmonary defense mechanisms.[4]
- Dysphagia due to esophageal lesions and motility problems
- HIV infection (especially for pneumococcal pneumonia)
Drugs
Acid-Suppressing Drugs
- Usage of H2 blockers, proton pump inhibitors, and antacids may increase the pH and, as a result, may increase the risk of pneumonia.[5][6][7]
- A similiar study showed increase risk of pneumonia after starting PPI, especially within the first 48 hours.[5][6][7] However, the association between PPI and CAP may be cofounded.[8]
Antipsychotic Drugs
- A case control study has shown a significant correlation between the use of antipsychotic drugs and community-acquired pneumonia. A 60 percent increase in the rate of pneumonia can be seen in elderly patients who utilize antipsychotic medications.[9]
- The use of atypical antipsychotics was associated with an increases risk of community-acquired pneumonia.
ACE Inhibitors
- A randomized trial has shown that ACE inhibitors reduce the risk of pneumonia.[10]
Hospital Acquired Pneumonia
| Major risk factors for hospital-acquired pneumonia |
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The following are major points for risk factors of adults with hospital-acquired, ventilator-associated, and healthcare-associated pneumonia:[12]
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Major Points and Recommendations for Modifiable Risk FactorsGeneral Prophylaxis
Intubation and Mechanical Ventilation
Aspiration, Body Position, and Enteral Feeding
Modulation of Colonization: Oral Antiseptics and Antibiotics
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For Level of evidence and classes click here.
References
- ↑ 1.0 1.1 "Summaries for patients. Screening for HIV infection in health care settings: a guidance statement from the American College of Physicians and HIV Medicine Association". Annals of Internal Medicine. 150 (2): I–44. 2009. PMID 19047021. Retrieved 2012-09-04. Unknown parameter
|month=ignored (help) - ↑ 2.0 2.1 Qaseem A, Snow V, Shekelle P, Hopkins R, Owens DK (2009). "Screening for HIV in health care settings: a guidance statement from the American College of Physicians and HIV Medicine Association". Annals of Internal Medicine. 150 (2): 125–31. PMID 19047022. Retrieved 2012-09-04. Unknown parameter
|month=ignored (help) - ↑ 3.0 3.1 3.2 Mandell, L. A.; Wunderink, R. G.; Anzueto, A.; Bartlett, J. G.; Campbell, G. D.; Dean, N. C.; Dowell, S. F.; File, T. M.; Musher, D. M.; Niederman, M. S.; Torres, A.; Whitney, C. G. (2007). "Infectious Diseases Society of America/American Thoracic Society Consensus Guidelines on the Management of Community-Acquired Pneumonia in Adults". Clinical Infectious Diseases. 44 (Supplement 2): S27–S72. doi:10.1086/511159. ISSN 1058-4838.
- ↑ Almirall, J.; Bolíbar, I.; Balanzó, X.; González, CA. (1999). "Risk factors for community-acquired pneumonia in adults: a population-based case-control study". Eur Respir J. 13 (2): 349–55. PMID 10065680. Unknown parameter
|month=ignored (help) - ↑ 5.0 5.1 Laheij, RJ.; Sturkenboom, MC.; Hassing, RJ.; Dieleman, J.; Stricker, BH.; Jansen, JB. (2004). "Risk of community-acquired pneumonia and use of gastric acid-suppressive drugs". JAMA. 292 (16): 1955–60. doi:10.1001/jama.292.16.1955. PMID 15507580. Unknown parameter
|month=ignored (help) - ↑ 6.0 6.1 Gulmez, SE.; Holm, A.; Frederiksen, H.; Jensen, TG.; Pedersen, C.; Hallas, J. (2007). "Use of proton pump inhibitors and the risk of community-acquired pneumonia: a population-based case-control study". Arch Intern Med. 167 (9): 950–5. doi:10.1001/archinte.167.9.950. PMID 17502537. Unknown parameter
|month=ignored (help) - ↑ 7.0 7.1 Hermos, JA.; Young, MM.; Fonda, JR.; Gagnon, DR.; Fiore, LD.; Lawler, EV. (2012). "Risk of community-acquired pneumonia in veteran patients to whom proton pump inhibitors were dispensed". Clin Infect Dis. 54 (1): 33–42. doi:10.1093/cid/cir767. PMID 22100573. Unknown parameter
|month=ignored (help) - ↑ Jena, AB.; Sun, E.; Goldman, DP. (2013). "Confounding in the association of proton pump inhibitor use with risk of community-acquired pneumonia". J Gen Intern Med. 28 (2): 223–30. doi:10.1007/s11606-012-2211-5. PMID 22956446. Unknown parameter
|month=ignored (help) - ↑ Knol, W.; van Marum, RJ.; Jansen, PA.; Souverein, PC.; Schobben, AF.; Egberts, AC. (2008). "Antipsychotic drug use and risk of pneumonia in elderly people". J Am Geriatr Soc. 56 (4): 661–6. doi:10.1111/j.1532-5415.2007.01625.x. PMID 18266664. Unknown parameter
|month=ignored (help) - ↑ Caldeira, D.; Alarcão, J.; Vaz-Carneiro, A.; Costa, J. (2012). "Risk of pneumonia associated with use of angiotensin converting enzyme inhibitors and angiotensin receptor blockers: systematic review and meta-analysis". BMJ. 345: e4260. PMID 22786934.
- ↑ "CDC GUIDELINES FOR PREVENTING HEALTH-CARE-ASSOCIATED PNEUMONIA, 2003" (PDF).
- ↑ "Guidelines for the management of adults with hospital-acquired, ventilator-associated, and healthcare-associated pneumonia". American Journal of Respiratory and Critical Care Medicine. 171 (4): 388–416. 2005. doi:10.1164/rccm.200405-644ST. PMID 15699079. Retrieved 2012-09-13. Unknown parameter
|month=ignored (help)
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Natural History, Complications & Prognosis
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