What is Human Metapneumovirus. How does HMPV spread. What are the symptoms of HMPV infection. How can HMPV be prevented. When does HMPV circulate. How is HMPV diagnosed. What treatments are available for HMPV.

Understanding Human Metapneumovirus (HMPV): A Respiratory Pathogen

Human Metapneumovirus (HMPV) is a significant respiratory pathogen that can affect individuals of all ages. Discovered in 2001, HMPV belongs to the Pneumoviridae family, which also includes the well-known respiratory syncytial virus (RSV). This virus has gained increased recognition as a major cause of upper and lower respiratory infections, largely due to the wider use of molecular diagnostic testing.

HMPV primarily targets the respiratory system, causing a range of symptoms from mild cold-like illness to severe respiratory distress. Its impact is particularly pronounced among young children, older adults, and those with compromised immune systems.

Who is most at risk for HMPV infection?

While HMPV can affect anyone, certain groups are more vulnerable to severe infections:

• Young children, especially those under 5 years old
• Older adults, particularly those over 65
• Individuals with weakened immune systems
• People with chronic respiratory conditions
• Residents of long-term care facilities

Recognizing HMPV Symptoms: From Mild to Severe

HMPV infections can manifest with a variety of symptoms, ranging from mild to severe. The clinical presentation often mimics other respiratory viral infections, making it challenging to distinguish HMPV based on symptoms alone.

What are the common symptoms of HMPV infection?

The most frequently reported symptoms include:

• Cough (often persistent and productive)
• Fever (which may be high-grade)
• Nasal congestion
• Shortness of breath
• Wheezing (especially in children)
• Sore throat
• Fatigue

In more severe cases, HMPV infection can progress to bronchitis or pneumonia. The estimated incubation period for HMPV is 3 to 6 days, with the duration of illness varying depending on the severity of the infection and the individual’s immune response.

HMPV Transmission: Understanding the Spread

HMPV spreads through respiratory secretions, similar to other respiratory viruses. Understanding the transmission routes is crucial for implementing effective prevention strategies.

How does HMPV spread from person to person?

HMPV transmission occurs through several mechanisms:

1. Respiratory droplets: When an infected person coughs or sneezes, they release virus-laden droplets into the air, which can be inhaled by others nearby.
2. Close personal contact: Direct contact with an infected individual, such as shaking hands or touching, can transfer the virus.
3. Fomite transmission: The virus can survive on surfaces for a short period. Touching contaminated objects and then touching one’s face can lead to infection.

The virus’s ability to spread through these routes underscores the importance of proper hygiene practices and social distancing during outbreaks.

Seasonal Patterns of HMPV: When to Be on High Alert

Understanding the seasonality of HMPV is crucial for healthcare providers and public health officials to implement timely prevention and control measures.

When is HMPV most active?

In temperate climates, HMPV exhibits a distinct seasonal pattern:

• Peak activity: Late winter to early spring
• Circulation period: Generally begins in winter and lasts through spring
• Overlap with other respiratory viruses: HMPV often circulates simultaneously with RSV and influenza

This seasonal overlap can complicate diagnosis and treatment, as symptoms of these infections can be similar. Healthcare providers should be particularly vigilant during these months and consider HMPV as a potential cause of respiratory illness.

Diagnosing HMPV: Laboratory Techniques and Challenges

Accurate diagnosis of HMPV infection is essential for appropriate patient management and epidemiological tracking. However, the similarity of symptoms to other respiratory infections necessitates specific laboratory testing for confirmation.

How is HMPV diagnosed in clinical settings?

Several laboratory methods are used to diagnose HMPV infection:

1. Polymerase Chain Reaction (PCR): This is the most sensitive and specific method for detecting HMPV. It identifies the viral genome in respiratory secretions.
2. Immunofluorescence Assays: These tests detect viral antigens in respiratory samples using fluorescent-labeled antibodies.
3. Enzyme Immunoassays: These methods detect viral antigens through enzyme-linked antibodies.

It’s important to note that many healthcare facilities may not routinely test for HMPV. Increased awareness among healthcare providers about the prevalence of HMPV, especially during its peak season, can lead to more accurate diagnoses and appropriate patient care.

Prevention Strategies: Protecting Against HMPV Infection

While there is currently no vaccine available for HMPV, several preventive measures can significantly reduce the risk of infection and transmission.

How can individuals protect themselves from HMPV infection?

Preventing HMPV infection relies on a combination of personal hygiene practices and behavioral changes:

• Hand hygiene: Frequent handwashing with soap and water for at least 20 seconds is crucial. If soap and water are unavailable, alcohol-based hand sanitizers can be effective.
• Avoid touching face: Keeping hands away from the eyes, nose, and mouth can prevent the virus from entering the body.
• Social distancing: Maintaining distance from individuals who are sick can reduce the risk of exposure.
• Respiratory etiquette: Covering the mouth and nose when coughing or sneezing, preferably with a tissue or the elbow, can prevent the spread of respiratory droplets.
• Stay home when sick: Individuals with respiratory symptoms should stay home to avoid infecting others.
• Clean and disinfect: Regularly cleaning and disinfecting frequently touched surfaces can help reduce the risk of fomite transmission.

What precautions should healthcare settings take?

In healthcare environments, additional precautions are necessary:

1. Follow CDC guidelines: Healthcare providers should adhere to the CDC’s 2007 Guideline for Isolation Precautions to prevent transmission in healthcare settings.
2. Use personal protective equipment (PPE): Appropriate PPE, including masks, gloves, and gowns, should be used when caring for patients with suspected or confirmed HMPV infection.
3. Implement isolation measures: Patients with HMPV should be placed in isolation to prevent spread to other vulnerable individuals.
4. Enhance environmental cleaning: Thorough cleaning and disinfection of patient care areas is essential.

Treatment Approaches: Managing HMPV Infections

Currently, there is no specific antiviral therapy approved for treating HMPV infections. Treatment focuses on managing symptoms and providing supportive care.

What treatment options are available for HMPV infections?

While there is no cure for HMPV, several approaches can help manage the infection:

• Symptomatic relief: Over-the-counter medications can help alleviate fever, pain, and congestion.
• Hydration: Ensuring adequate fluid intake is crucial, especially for young children and older adults.
• Rest: Allowing the body to rest and recover can help the immune system fight the infection more effectively.
• Oxygen therapy: In severe cases, supplemental oxygen may be necessary to maintain adequate blood oxygen levels.
• Bronchodilators: For patients with wheezing or difficulty breathing, inhaled bronchodilators may provide relief.
• Antiviral research: While no specific antivirals are currently approved, research is ongoing to develop targeted therapies for HMPV.

In most cases, HMPV infections resolve on their own within a week or two. However, individuals with severe symptoms or those at high risk for complications should seek medical attention promptly.

HMPV in Vulnerable Populations: Special Considerations

Certain populations are at higher risk for severe HMPV infections and may require special attention and care.

How does HMPV affect different age groups?

The impact of HMPV varies across age groups:

• Infants and young children: Often experience more severe symptoms and are at higher risk for hospitalization.
• School-age children: May have milder symptoms but can be significant vectors for transmission.
• Adults: Generally experience milder symptoms, but can still develop severe illness, especially if they have underlying health conditions.
• Older adults: At increased risk for severe complications, including pneumonia and exacerbation of existing respiratory conditions.

What additional precautions are necessary for immunocompromised individuals?

People with weakened immune systems require extra protection:

1. Strict adherence to preventive measures: Immunocompromised individuals should be vigilant about hand hygiene and avoiding exposure to infected individuals.
2. Early medical intervention: Prompt medical attention at the first sign of respiratory symptoms is crucial.
3. Potential prophylaxis: In some cases, preventive treatments may be considered during periods of high HMPV activity.
4. Enhanced monitoring: Close follow-up and monitoring for complications is essential for immunocompromised patients with HMPV infection.

Healthcare providers caring for vulnerable populations should maintain a high index of suspicion for HMPV, especially during peak seasons.

Future Directions: Research and Development in HMPV

As our understanding of HMPV grows, researchers are exploring new avenues for prevention, diagnosis, and treatment.

What are the current research priorities for HMPV?

Several areas of research are being pursued to improve HMPV management:

• Vaccine development: Efforts are underway to create an effective vaccine against HMPV, which could significantly reduce its impact.
• Antiviral therapies: Researchers are investigating potential antiviral drugs that could specifically target HMPV.
• Rapid diagnostics: Development of faster, more accurate diagnostic tests could improve timely detection and treatment.
• Epidemiological studies: Ongoing surveillance and research aim to better understand HMPV’s patterns of spread and risk factors for severe disease.
• Host-pathogen interactions: Studies examining how HMPV interacts with the human immune system could lead to new therapeutic approaches.

As research progresses, it’s likely that our ability to prevent, diagnose, and treat HMPV infections will continue to improve, potentially reducing the burden of this significant respiratory pathogen.

Global Impact of HMPV: A Public Health Perspective

HMPV has emerged as a globally significant respiratory pathogen, with implications for public health systems worldwide.

How does HMPV affect different regions globally?

The impact of HMPV varies across different geographical regions:

• Temperate climates: Experience distinct seasonal patterns, with peaks in late winter and spring.
• Tropical and subtropical regions: May see year-round circulation of HMPV, with less pronounced seasonal peaks.
• Developing countries: Face challenges in diagnosis and surveillance due to limited healthcare resources.
• High-income countries: Better equipped for detection and management but still face significant healthcare burdens during peak seasons.

What are the economic implications of HMPV infections?

The economic impact of HMPV is substantial and multifaceted:

1. Healthcare costs: Hospitalizations, especially for severe cases in children and older adults, contribute to significant medical expenses.
2. Productivity loss: Workplace absenteeism due to illness or caring for sick family members affects economic output.
3. Strain on healthcare systems: During peak seasons, HMPV can contribute to overcrowding in hospitals and clinics.
4. Research and development costs: Ongoing efforts to develop vaccines and treatments require substantial investment.

Understanding the global impact of HMPV is crucial for developing effective public health strategies and allocating resources appropriately.

HMPV and Other Respiratory Viruses: Comparative Analysis

HMPV shares many characteristics with other respiratory viruses, but also has unique features that set it apart.

How does HMPV compare to other common respiratory viruses?

Comparing HMPV to other respiratory pathogens reveals important similarities and differences:

• RSV: Both belong to the Pneumoviridae family and cause similar symptoms. However, RSV is generally more severe in infants.
• Influenza: HMPV typically causes less severe illness than influenza but can still lead to significant complications.
• Common cold viruses: HMPV often causes more severe lower respiratory tract involvement compared to typical cold viruses.
• COVID-19: While both can cause severe respiratory illness, HMPV has a lower mortality rate and different epidemiological patterns.

Understanding these comparisons helps healthcare providers in differential diagnosis and appropriate patient management.

Can HMPV co-infect with other respiratory pathogens?

Co-infections involving HMPV and other respiratory pathogens are not uncommon:

1. Increased severity: Co-infections can lead to more severe symptoms and complications.
2. Diagnostic challenges: Multiple infections can complicate accurate diagnosis and treatment planning.
3. Seasonal overlap: HMPV’s peak season often coincides with other respiratory viruses, increasing the likelihood of co-infections.
4. Impact on immune response: Co-infections may alter the body’s immune response, potentially affecting disease course and recovery.

Healthcare providers should be aware of the possibility of co-infections, especially in patients presenting with severe or atypical symptoms.

Human Metapneumovirus | CDC

About HMPV

Human metapneumovirus (HMPV) can cause upper and lower respiratory disease in people of all ages, especially among young children, older adults, and people with weakened immune systems. Discovered in 2001, HMPV is in the Pneumoviridae family along with respiratory syncytial virus (RSV). Broader use of molecular diagnostic testing has increased identification and awareness of HMPV as an important cause of upper and lower respiratory infection.

Symptoms

Symptoms commonly associated with HMPV include cough, fever, nasal congestion, and shortness of breath. Clinical symptoms of HMPV infection may progress to bronchitis or pneumonia and are similar to other viruses that cause upper and lower respiratory infections. The estimated incubation period is 3 to 6 days, and the median duration of illness can vary depending upon severity but is similar to other respiratory infections caused by viruses.

Surveillance and Seasonality

Surveillance data from CDC’s the National Respiratory and Enteric Virus Surveillance System (NREVSS) shows HMPV to be most active during late winter and spring in temperate climates.

Transmission

HMPV is most likely spread from an infected person to others through

• secretions from coughing and sneezing
• close personal contact, such as touching or shaking hands
• touching objects or surfaces that have the viruses on them then touching the mouth, nose, or eyes

In the U.S., HMPV circulates in distinct annual seasons. HMPV circulation begins in winter and lasts until or through spring. HMPV, RSV, and influenza can circulate simultaneously during the respiratory virus season.

Prevention and Treatment

Currently, there is no specific antiviral therapy to treat HMPV and no vaccine to prevent HMPV. Medical care is supportive. However, your patients can help prevent the spread of HMPV and other respiratory viruses by following these steps:

• Wash their hands often with soap and water for at least 20 seconds (see CDC’s Clean Hands Save Lives!).
• Avoid touching their eyes, nose, or mouth with unwashed hands.
• Avoid close contact with people who are sick.

Patients who have cold-like symptoms should

• cover their mouth and nose when coughing and sneezing
• wash their hands frequently and correctly (with soap and water for at least 20 seconds)
• avoid sharing their cups and eating utensils with others
• refrain from kissing others
• stay at home when they are sick

In addition, cleaning possible contaminated surfaces (such as doorknobs and shared toys) may potentially help stop the spread of HMPV.

In healthcare settings, healthcare providers should follow CDC’s 2007 Guideline for Isolation Precautions: Preventing Transmission of Infectious Agents in Healthcare Settings.

Since HMPV is a recently recognized respiratory virus, healthcare professionals may not routinely consider or test for HMPV. However, healthcare professionals should consider HMPV testing during winter and spring, especially when HMPV is commonly circulating.

Laboratory Diagnosis

Infection with HMPV can be confirmed usually by

• direct detection of viral genome by polymerase chain reaction assays, and
• direct detection of viral antigens in respiratory secretions using immunofluorescence or enzyme immunoassay.

Resources

• National Respiratory and Enteric Virus Surveillance System (NREVSS)

References

• American Academy of Pediatrics. Human metapneumovirus. Red Book 2018 Report of the Committee on Infectious Diseases [online edition].
• CDC. Notes from the Field: Severe Human Metapneumovirus Infections — North Dakota, 2016. MMWR. 2017;66(28):486-8.
• CDC. Outbreaks of human metapneumovirus in two skilled nursing facilities — West Virginia and Idaho, 2011–2012. MMWR. 2013;62(46):909-13.
• Edwards KM, Zhu Y, Griffin MR, Weinberg, GA, Hall CB, Szilagyi PG, Staat MA, Iwane MK, Prill MM, Williams JV, for the New Vaccine Surveillance Network (NVSN). Burden of Human Metapneumovirus Infection in Young Children. N Engl J Med. 2013;368:633-643
• Haynes AK, Fowlkes AL, Schneider E, Mutuc JD, Armstrong GL, Gerber SI. Human Metapneumovirus circulation in the United States, 2008 to 2014. Pediatrics. 2016; 137 (5): e20152927.
• Heikkinen T, Österback R, Peltola V, Jartti T, Vainionpää R. Human metapneumovirus infections in children. Emerg Infect Dis [serial the Internet]. 2008 Jan.
• Pelletier G, Dery P. Abed Y et al. Respiratory tract reinfections by the new human Metapneumovirus in an immunocompromised child. Emerg Infect Dis [serial on the Internet]. 2002 Sep.
• Peña SA, Davis SS, Lu X, Sakthivel SKK, Peret TCT, et al. Severe Respiratory Illness Associated with Human Metapneumovirus in Nursing Home, New Mexico, USA. Emerg Infect Dis. 2019 Feb;25(2):383-384.[AJL(1]
• Stockton J, Stephenson I, Fleming D, Zambon M. Human Metapneumovirus as a cause of community-acquired respiratory illness. Emerg Infect Dis [serial the Internet] 2002 Sep.
• Va den Hoogen BG, de Jong JC, Goen J, Kuiken T, de Groot R, et al. A newly discovered human pneumovirus isolated from young children with respiratory tract disease. Nat Med. 2001;7(6):719-24.
• Widmer K, Zhu Y, Williams JV et al. Rates of hospitalizations for respiratory syncytial virus, human metapneumovirus and influenza virus in older adults. J Infect Dis. 2012;206(1):56-62.

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

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

Pneumonia – causes, symptoms and treatment

Pneumonia (pneumonia) is an acute infectious and inflammatory disease of the lungs, in which all structural elements of the lung tissue are involved in the process.

Inflammation of the lungs before the advent of antibiotics was one of the most formidable diseases. Mortality from pneumonia at the end of the 19th century reached a record 83%. Today, despite all the achievements of modern medicine, the development of new antibacterial and antiviral drugs, this disease still remains an urgent problem: every year, 14 out of 1000 people are diagnosed with pneumonia; in the structure of mortality in the Russian Federation, pneumonia ranks fourth (9%), yielding only to oncological, cardiovascular diseases and injuries. Therefore, the treatment of pneumonia requires mandatory monitoring and supervision of a specialist.

CAUSES FOR

Acute pneumonia is caused by various infectious agents. Approximately 90% of cases are bacteria, the remaining 10% are viruses, fungi, protozoa and helminths (roundworms, toxoplasma, schistosomes).

The most common pathogens include pneumococcus, Haemophilus influenzae, Mycoplasma pneumoniae, Staphylococcus aureus, influenza viruses, and respiratory syncytial infection. Most often, pneumonia caused by these pathogens develops after hypothermia, or as a complication of SARS.

CLASSIFICATION OF PNEUMONIA

Depending on the epidemiological conditions of the occurrence of pneumonia, they are divided into:

1. Community-acquired (outpatient) – occur outside the hospital, or within 48 hours of admission to the hospital. They have a favorable prognosis.
2. Nosocomial (hospital) – occur in a hospital, 48-72 hours after admission. The prognosis largely depends on the resistance of the pathogen to antibiotics.
3. Pneumonia in immunocompromised patients. The prognosis is unfavorable, require active treatment in a hospital setting.
4. Aspiration pneumonia – pneumonia resulting from the ingestion of the contents of the gastrointestinal tract into the respiratory tract.

Depending on the extent of the lesion and the mechanism of occurrence, it is customary to subdivide pneumonia into focal and lobar.

• Focal pneumonia is a variant of pneumonia with the localization of the inflammatory process in a limited area of ​​the lung tissue, within the small structural units of the lung – lobules. Focal pneumonia usually develops as a complication of SARS or acute tracheobronchitis. The clinical picture in this case may be “erased” and resemble a protracted course of bronchitis.
• Lobar pneumonia is an inflammation of a lung infectious nature, which is characterized by the involvement in the process of one or more lobes of the lung, with the pleura covering them. The clinical picture is manifested by severe intoxication, intense cough, shortness of breath with tachypnea and tachycardia. Lobar pneumonia most often develops against the background of episodes of prolonged hypothermia.

In outpatient practice, most often there are cases of community-acquired pneumonia, which, with proper treatment, have a favorable prognosis.

SYMPTOMS OF PNEUMONIA

The clinical picture of pneumonia largely depends on the extent of the lesion. Manifestations of pneumonia are divided into pulmonary and extrapulmonary. Pulmonary manifestations include cough, chest pain, and shortness of breath. To extrapulmonary – fever, intoxication syndrome, laboratory inflammation syndrome.

Cough is a characteristic symptom of pneumonia. In the first or second day from the onset of the disease, the patient may be disturbed only by a slight cough, later the cough becomes more intense, mucopurulent sputum appears.

Pain in the chest is most characteristic of lobar pneumonia, because. in this case, the pleura is involved in the process of inflammation. Usually such pain occurs suddenly, intensifies at the depth of inspiration. With extensive damage, there may be a lag of the affected half of the chest in the act of breathing.

Shortness of breath in pneumonia is most often interconnected with the volume of the affected lung tissue. So, with small-focal pneumonia, there is an increase in shortness of breath, accompanied by an increase in the frequency of respiratory movements up to 30 per minute. At the same time, patients may complain of a feeling of congestion in the chest.

Intoxication with pneumonia is manifested by general weakness and muscle pain, at elevated temperatures, joint pain, increased sweating, headaches and decreased appetite may appear. In severe cases, there is confusion, delirium.

Fever with pneumonia can be a non-permanent symptom. As a rule, at the beginning of the disease, there is a rise in body temperature to 38-39 * C, which is stopped for a short time by antipyretics. But with a decrease in immunity, with extensive damage, pneumonia can occur without fever.
99/l) increased levels of ESR, CRP, gamma and alpha 2 globulins, seromucoid, but these indicators have low specificity.

DIAGNOSIS OF PNEUMONIA

Suspicion of pneumonia should arise if the patient has a fever, in combination with complaints of a productive cough, discharge of mucopurulent sputum, shortness of breath and / or chest pain. Also, patients with pneumonia may complain of increased sweating at night, general weakness, fatigue, increased blood pressure.

At the slightest suspicion of this disease, an additional examination should be carried out. The minimum diagnostic minimum to confirm pneumonia should include a clinical blood test, a urinalysis, a chest x-ray in two projections, as well as a specialist consultation, during which a general examination, chest palpation, percussion and auscultation of the lungs are performed.

In order to determine the pathogen and differential diagnosis with other diseases, the doctor may prescribe additional studies: general sputum analysis, sputum culture for sterility, serological tests, determination of IgG and IgM to individual pathogens, PCR diagnostics, MSCT of the chest organs with contrast, tuberculin samples, echocardiography and ECG.

TREATMENT

Most patients with community-acquired pneumonia can be treated at home, however, in each case, the appointment of antibiotics or antiviral drugs is determined by the etiological factor, history, examination data and the results of additional examination. Self-medication in the event of pneumonia is categorically impossible, since improper therapy significantly increases the risk of death.

In some cases, patients require treatment in a hospital setting. Indications for hospitalization are extensive damage to the lung tissue, an increase in the phenomena of respiratory failure, age over 60 years. Consultation of a general practitioner or pulmonologist in such situations is mandatory.

Prepared information for you:

Gusev-Shcherbakov Alexander Sergeevich

To make an appointment with a pulmonologist, call the single contact center in Moscow +7 (495) 775 75 66 or use the online appointment service. Pulmonologist Konyukhova Maria Yuryevna conducts an appointment at the clinic “Family Doctor” on Baumanskaya.