Pneumonia

Original Editor - The Open Physio project.

Top Contributors - Kim Jackson, Lucinda hampton, Tony Lowe, Nikhil Benhur Abburi and Adam Vallely Farrell

Introduction

Pneumonia is an infection of the lower respiratory tract, involving the pulmonary parenchyma.

  • Viruses, fungi, and bacteria can cause pneumonia. The lungs reaction to these foreign microbes is to cause an inflammatory response causing the bronchioles and alveoli to fill with fluid and become solid[1].
  • Pneumonia ranges in severity from mild and uncomplicated as often is the case with atypical infections, to fulminant and life-threatening, occurring more frequency in hospital-acquired pneumonia.[2]
  • It is a common disease and a potentially serious infectious disease with considerable morbidity and mortality.
  • Pneumonia is the sixth leading cause of death and the only infectious disease in the top ten causes of death in the United States[3].
  • Pneumonia can be prevented by immunization, adequate nutrition, and by addressing environmental factors.[4]
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Transmission

Cough.jpg

Pneumonia can be spread in a number of ways.

  • The viruses and bacteria that are commonly found in a child's nose or throat, can infect the lungs if they are inhaled.
  • They may also spread via air-borne droplets from a cough or sneeze. Social distancing helps reduce the spread, so important in COVID 19 pandemic.
  • Pneumonia may spread through blood, especially during and shortly after birth.
  • Research regarding the different pathogens causing pneumonia and the ways they are transmitted is of critical importance for treatment and prevention[4].

Clinically Relevant Anatomy

Healthy alveoli.png

The lungs are responsible for the gaseous exchange of carbon dioxide and oxygen and consist of bronchi, which divide into bronchioles that end in alveoli. The capillaries (small blood vessels) that are found in abundance in the lungs are responsible for gaseous exchange. The exchange of these two gases is known as respiration[6]:

  • On inhalation oxygen entering the lung where crosses into the bloodstream, via the capillaries, for distribution around the body
  • Carbon dioxide, a waste product of cell metabolism, enters the lungs from the body in the bloodstream and crosses over into the lungs where it is then exhaled into the atmosphere. moving out of the lungs.

During a Pneumonia infection, the alveoli of one or both lungs fill up with pus or fluid. This increases the work of breathing, and thus gaseous exchange cannot occur as it normally would[7] For more detailed information about lung anatomy see here

Aetiology

There are various causes of pneumonia, in most the mode of transmission is via bacteria however it can be passed from person to person and also from the environment and practising good hygiene can minimise the spread of germs. The various types of pneumonia are discussed below

Infective Agent:

  1. Bacterial Pneumonia occurs when pneumonia-causing bacteria masses and multiplies in the lungs. The alveoli become inflamed and pus is produced, which spreads around the lungs[8] eg Streptococcus pneumonia, Staphylococcus aureus, Haemophilus influenza, legionella pneumophilia and Methicillin resistant staphylococcus aureus (MRSA)[9]; Legionella pneumophila, Mycoplasma pneumoniae, and Chlamydophila pneumoniae - these are known as Atypical Pneumonia as they do not respond to the normal antibiotics used for treatment[10][11]; Mycoplasmal Pneumonia (also known as 'walking pneumonia') is similar to bacterial pneumonia, whereby the mycoplasmas proliferate and spread - causing infection.[9]eg cavitating bacterial pneumonia

2. fungal pneumonia This typically occurs in people who have a weakened immune system or other underlying health issues. This is usually inhaled from the environment and does not spread from person to person. eg Pneumocystis Jirovecii Pneumonia (formerly known as Pneumocystis carinii Pneumonia) is caused by the Pneumocystis carinii fungus. This fungus does not cause illness in healthy individuals, but rather in those with a weakened immune system.[10]

3. mycobacterial pneumonia

4. Viral Pneumonia - believed to be the cause of half of all cases of pneumonia. The viruses invade the lungs and then multiply- causing inflammation. eg coronavirus [ COVID-19, Middle East respiratory syndrome coronavirus (MERS-CoV) infection, severe acute respiratory syndrome (SARS)], varicella pneumonia,Influenza type A or B, rhinoviruses adenoviruses, respiratory syncytial virus (more common in infants and children)[9]

Setting of Infection (how aquired):

  • Community-acquired pneumonia (CAP): This is the most common form of pneumonia and describes pneumonia that is acquired outside of a hospital the main causes of CAP are bacteria, viruses and less commonly fungi. In most cases pneumonia is not spread from person to person and quite often is transmitted via droplets in the air, touching contaminated objects, poor hygiene and sharing cups or utensil or from the environment[12].
  • Nosocomial pneumonia: Hospital-acquired pneumonia (HAP); Ventilator-associated pneumonia (VAP) Biofilm formation on endotracheal tubes (ETTs) is an early and frequent event in mechanically ventilated patients. The biofilm is believed to act as a reservoir for infecting microorganisms and contributes to development and relapses of ventilator-associated pneumonia[13]; Healthcare-associated pneumonia (HCAP)[3]
  • Aspiration pneumonia[14]This is commonly caused by inhaling a foreign object, vomit, mucous, bodily fluids, or certain chemicals which causes the bronchial tubes and lungs to become inflamed.[10] It occurs predominantly in the right lung because its total capacity is greater than that of the left lung.[10] If large amounts of gastric contents can cause acute respiratory distress within 1 hour. In cases of aspiration immediate physiotherapy can help with secretion clearance

The 10 minute video below is a good summary of pneumonia.

The Body's Defence Against Pneumonia

The body has several defence mechanisms against the agents that can cause Pneumonia:

  • Coughing
  • Mucociliary escalator - lines the airway that assists the movement of bacteria out of the airways and away from the lungs
  • Macrophages

If these mechanisms fail and a microbe is successful in colonising the alveoli they then multiple and quickly move over into the lung tissue activating an inflammatory response; the result is Pneumonia.

Type and Causes

There are various causes of pneumonia, in most the mode of transmission is via bacteria however it can be passed from person to person and also from the environment and practising good hygiene can minimise the spread of germs. The various types of pneumonia are discussed below.

Epidemiology

  • 2.56 million people died from pneumonia in 2017. Almost a third of all victims were children younger than 5 years.
  • Pneumonia is the leading cause of death for children under 5 — more than 800,000 children died due to pneumonia in 2017.
  • While still too many children die today, since 1990 we’ve seen more than 3-fold reduction in child mortality rates from pneumonia globally.
  • The global mortality rates for older people remained unchanged since 1990.
  • Mortality from pneumonia is highest in Sub-Saharan Africa.
  • The greatest risk factors for developing pneumonia are undernutrition, air pollution and smoking.
  • Reducing exposure to risk factors and higher coverage of pneumococcal vaccines can reduce the number deaths from pneumonia.
  • Research suggests that pneumococcal vaccines could be saving the lives of almost 400,000 children annually.[15]
  • About 15% of COVID-19 cases are severe and have pneumonia (COVID 19 was originally called novel coronavirus-infected pneumonia)[16]

Stages of Pneumonia

Pneumonia has four stages, namely consolidation, red hepatization, grey hepatization and resolution. (may be Lobar Pneumonia or bronchopneumonia, see image R)

  • Consolidation
    • Occurs in the first 24 hours
    • Cellular exudates containing neutrophils, lymphocytes and fibrin replaces the alveolar air
    • Capillaries in the surrounding alveolar walls become congested
    • The infection spreads to the hilum and pleura fairly rapidly
    • Pleurisy occurs
    • Marked by coughing and deep breathing[17][18]
  • Red Hepatization
    • Occurs in the 2-3 days after consolidation
    • At this point, the consistency of the lungs resembles that of the liver
    • The lungs become hyperaemic
    • Alveolar capillaries are engorged with blood
    • Fibrinous exudates fill the alveoli
    • This stage is "characterized by the presence of many erythrocytes, neutrophils, desquamated epithelial cells, and fibrin within the alveoli"[17][18]
  • Grey Hepatization
    • Occurs in the 2-3 days after Red Hepatization
    • This is an avascular stage
    • The lung appears "grey-brown to yellow because of fibrinopurulent exudates, disintegration of red cells, and hemosiderin"
    • The pressure of the exudates in the alveoli causes compression of the capillaries
    • "Leukocytes migrate into the congested alveoli"[17][18]
  • Resolution
    • This stage is characterized by the "resorption and restoration of the pulmonary architecture"
    • A large number of macrophages enter the alveolar spaces
    • Phagocytosis of the bacteria-laden leucocytes occurs
    • "Consolidation tissue re-aerates and the fluid infiltrate causes sputum"
    • "Fibrinous inflammation may extend to and across the pleural space, causing a rub heard by auscultation, and it may lead to resolution or to organization and pleural adhesions"[17][18]

Risk Factors

The elderly, infants, young children and those with a weakened immune system are at a higher risk of acquiring Pneumonia. Other causes such as frequent exposure to asbestos and cigarette smoke have an increased risk of contracting community-acquired pneumonia than young and middle-aged adults. Some common risk factors are:

Signs and Symptoms

The signs and symptoms vary according to disease severity. Common symptoms include fever, cough, sputum production (may or may not be present). The color and quality of sputum provide the clue to microbiological etiology.

  • Pleuritic chest pain due to localized inflammation of pleura can be seen with any kind of pneumonia but, is more common with lobar pneumonia. Constitutional symptoms such as fatigue, headache, myalgia, and arthralgias can also be seen.
  • Severe pneumonia can lead to dyspnea and shortness of breath. In severe cases, confusion, sepsis, and multi-organ failure can also manifest.
  • Tachypnea, increased vocal fremitus, egophony (E to A changes), dullness to percussion are the major clinical signs depending on the degree of consolidation and presence/absence of pleural effusion. Chest auscultation reveals crackles, rales, bronchial breath sounds.
  • The respiratory rate closely correlates with the degree of oxygenation and, therefore essential in determining the severity. Hypoxia is seen in severe pneumonia, which leads to hyperventilation.[3]

Diagnosis

Chest auscultation.jpg

There are several ways to diagnose pneumonia:

  • Physical examination
    • Auscultation- Bronchial breath sounds or fine cracks over the affected area
    • Pleural friction rub - an adventitious breath sound heard during auscultation. The sound is caused by the movement of inflamed and roughened pleural surfaces[19]
  • Chest X-rays often lag behind the clinical presentation.The X-ray will show decreased lung expansion and patchy opacity on the affected side with ill defined margins[20][21]
    • usually done to confirm the diagnosis
  • Sputum samples and blood tests
    • done to diagnose the type of pneumonia that is present
    • sputum test is done to determine whether it is a fungal or bacterial infection
    • blood test is done to examine the White Blood Cell count of the involved patient
    • this can be used to indicate the severity of pneumonia, as well as to determine whether it is a viral or bacterial infection.
    • bacterial infection would result in a blood count that has an increased amount of neutrophils
    • a blood count that has an increased amount of lymphocytes would indicate a viral infection.
    • Increased CRP

Complications

  • Pleural effusion - When fluid accumulates between the pleura and the chest wall due to the large amount of fluid already present in the lungs. As a result of the Pneumonia, a pleural effusion may develop which could lead to the collapse of the lungs if not treated appropriately[10]
  • Empyema - Pus may be present in the lungs due to the infection. Thus pockets of pus may develop in the cavity between the pleura and the chest wall, or in the lung itself which is otherwise known as empyema[10]
  • Lung abscess - A lung abscess develops when the infection has destroyed lung tissue and a cavity filled with pus is formed[10]
  • Bacteremia - This occurs when the infection is no longer contained within the lungs and moves into the bloodstream, thus the blood is infected[10]
  • Septicemia - When bacteremia occurs septicemia can follow, as this is an infection that is spread throughout the body. The infected blood is the best way for the infection to manifest in other parts of the body (Health-cares.net, 2005).
  • Meningitis - The infection may spread to the meninges that cover the brain and spinal cord, leading to meningitis[10]
  • Septic arthritis - When bacteremia has occurred septic arthritis is also a danger, as the bacteria manifests in the joints through which blood passes[10]
  • Endocarditis or pericarditis - As blood is also circulated through the heart muscles and the pericardium, the risk of developing an infection there is very high if bacteremia is present[10]

Medical Management

Treatment will vary depending on how bad the symptoms are, and what the cause of the infection is.

  • Bacterial Pneumonia can be treated with penicillin and/or anti-biotics
  • Viral Pneumonia cannot be treated with anti-biotics, as they have no effect. This type of pneumonia normally resolves over time.
  • Mycoplasma Pneumonia is usually treated with anti-biotics.
  • Bacterial pneumonia prior to the discovery of penicillin antibiotics was a virtual death sentence. Today, antibiotics, especially given early in the course of the disease, are very effective against bacterial causes of pneumonia[22]

Doctors will also include the following when treating patients with pneumonia:

Physiotherapy Management

The Active Cycle of Breathing Technique..png

Chest physiotherapy is an adjunct commonly used in the treatment of pneumonia, however there being little reliable evidence to suggest that physiotherapy has an effect on the rate of recovery of the patient.[23] However, respiratory techniques are still commonly used to aid airway clearance and improve the rate of breathing.

  • Modified postural drainage - this allows gravity to drain secretions from specific segments of the lungs
  • Shaking and vibes - to mobilize secretions
  • Coughing and huffing exercises - to expectorate secretions
  • Administer humidification - to mobilize secretions
  • Breathing exercises - Localized and Diaphragmatic
  • IPPB administration - to increase lung volumes
  • Mobilization of the patient - done to increase air entry, increase chest expansion, and to loosen secretions[24]

A state-of-art review suggests avoiding repeated airway clearance in infants and children with acute pulmonary disease. The treatment should be based on patient assessment and presentation of symptoms[25].

A retrospective study[26] shows that skeletal muscle index measured at Intensive Care Unit Admission is a predictor of Intensive Care Unit-Acquired Weakness in patients with sepsis.

Clinical Guidelines

Clinical Guidelines for Physiotherapy management of Community-Acquired Pneumonia[27]

For Patients admitted to hospital;

  • CPAP should be considered for patients with type 1 respiratory failure who remain hypoxaemic despite optimum medical therapy and oxygen. (Grade C)
  • NIV can be considered for selected patients with type II respiratory failure, especially those with underlying COPD. (Grade C)
  • Medical conditions permitting, patients should;
    • Sit out of bed for at least 20mins within the first 24hours
    • Increase mobility each subsequent day of hospitalisation (Grade B)
  • The regular use of PEP should be considered (Grade B)
  • Patients should NOT be treated with traditional airway clearance, +/- IPPB routinely. (Grade B_

Children and Pneumonia

Why Are Children Vulnerable?

While most healthy children can fight the infection with their natural defences, children whose immune systems are compromised are at higher risk of developing pneumonia. A child's immune system may be weakened by malnutrition or undernourishment, especially in infants who are not exclusively breastfed.

Pre-existing illnesses, such as symptomatic HIV infections and measles, also increase a child's risk of contracting pneumonia.

The following environmental factors also increase a child's susceptibility to pneumonia:

  • indoor air pollution caused by cooking and heating with biomass fuels (such as wood or dung)
  • living in crowded homes
  • parental smoking.[4]

Signs and Symptoms in Children

  • In children, the signs and symptoms are similar to that of adults.
  • Sometimes a child's only sign may be rapid breathing and often when pneumonia exists in the lower part of the lungs, no breathing problems may be present but rather fever, abdominal pain or vomiting.
  • If pneumonia is caused by bacteria, the infected child becomes sick relative quickly and is prone to developing a high fever and rapid breathing.
  • If pneumonia is caused by viruses, symptoms may appear gradually and less severe than bacterial pneumonia.[28]
  • Increased breath rate: > 60 breaths/min for newborns up to 2 months; > 50 breaths/min for 2 months to 12 months; > 40 breaths/min for a child older than 1 year of age[29]

Prevention

  • Vaccines are usually administered to prevent infection by viruses and bacteria.
  • Kids usually receive routine immunisation against Haemophilus Influenzae and Pertussis at the age of 2 months of age.
  • Some vaccines are also administered against pneumococcus organism, a common cause of pneumonia[28]

References

  1. Martin, E.A. (Ed.). (2003). Oxford Concise Medical Dictionary, 6th Edition. Oxford, United Kingdom. Oxford University Press.
  2. Stamm DR, Stankewicz HA. Nursing Home Acquired Pneumonia. InStatPearls [Internet] 2019 Jan 6. StatPearls Publishing. Available from:https://www.ncbi.nlm.nih.gov/books/NBK537355/ (last accessed 29.6.2020)
  3. 3.0 3.1 3.2 Pahal P, Sharma S. Typical Bacterial Pneumonia.Available from:https://www.ncbi.nlm.nih.gov/books/NBK534295/ (last accessed 29.6.2020)
  4. 4.0 4.1 4.2 WHO Pneumonia Available from:https://www.who.int/news-room/fact-sheets/detail/pneumonia (last accessed 30.6.2020)
  5. 5.0 5.1 Primal Pictures Anatomy TV
  6. Health24. (2008). Pneumonia. Retrieved February 13, 2009 from http://health24.com/medical/Head2Toe/777-778-782,13491.asp
  7. https://www.unicef.org/health/index_91917.html
  8. Smith, B., & Ball, V. (1998). Cardiovascular/Respiratory Physiotherapy. Mosby International Limited: Italy
  9. 9.0 9.1 9.2 Healthscout. (2009). Health Encyclopedia - Diseases and Conditions: Pneumonia. Retrieved April 8, 2009 from http://www.healthscout.com/ency/68/205/main.html
  10. 10.00 10.01 10.02 10.03 10.04 10.05 10.06 10.07 10.08 10.09 10.10 Health-cares. (2005). What is pneumonia? Retrieved February 13, 2009 from http://respiratory-lung.health-cares.net/pneumonia.php
  11. Bartleby. The Lungs. Retrieved April 8, 2009 from http://education.yahoo.com/reference/gray/subjects/subject/240
  12. Koenig, S., & Truwit, J. (2006). Ventilator-associated pneumonia: Diagnosis, treatment and prevention. Clin Microbiol Rev. 2006 October; 19(4): 637–657. Retrieved April 12, 2009 from http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=1592694
  13. Thorarinsdottir HR, Kander T, Holmberg A, Petronis S, Klarin B. Biofilm formation on three different endotracheal tubes: a prospective clinical trial.Available from:https://ccforum.biomedcentral.com/articles/10.1186/s13054-020-03092-1 (last accessed 30.6.2020)
  14. Radiopedia Pneumonia Available from:https://radiopaedia.org/articles/pneumonia (last accessed 29.6.2020)
  15. Our world data 2019 Pneumonia Available from: https://ourworldindata.org/pneumonia (last accessed 29.6.2020)
  16. webmd Covid pneumonia Available from:https://www.webmd.com/lung/covid-and-pneumonia#1 (last accessed 29.6.2020)
  17. 17.0 17.1 17.2 17.3 Atkuri, L.V., & King, B.R. (2006). Pediatrics, Pneumonia. Retrieved April 10, 2009, from http://emedicine.medscape.com/article/803364-overview
  18. 18.0 18.1 18.2 18.3 Steyl, T. (2007). Applied Physiotherapy 403 notes: Intensive Care Notes. University of the Western Cape.
  19. Adderley N, Sharma S. Pleural Friction Rub. Accessed 16 March 2020
  20. Klein, J. (2008). Pneumonia. Retrieved February 13, 2009 from http://kidshealth.org/PageManager.jsp?dn=KidsHealth&lic=1&ps=107&cat_id=20043&article_set=23001
  21. Torpy, J. (2007). Ventilator associated pneumonia. Retrieved April 12, 2009 from http://jama.ama-assn.org/cgi/content/full/297/14/1616
  22. Science Rank. Pneumonia Available from:https://science.jrank.org/pages/5361/Pneumonia.html (last accessed 30.6.2020)
  23. Yang, M., Yan, Y., Yin, X., Wang, B. Y., Wu, T., Liu, G. J., & Dong, B. R. (2010). Chest physiotherapy for pneumonia in adults. Cochrane Database of Systematic Reviews. doi:10.1002/14651858.cd006338.pub2
  24. Madjoe, L., & Marais, M. (2007). Applied Physiotherapy 203 notes: Physiotherapy in Respiratory Care. University of the Western Cape.
  25. Morrow BM. Airway clearance therapy in acute paediatric respiratory illness: A state-of-the-art review. South African Journal of Physiotherapy. 2019 Jun 25;75(1):12.
  26. Mitobe Y, Morishita S, Ohashi K, Sakai S, Uchiyama M, Abeywickrama H, Yamada E, Kikuchi Y, Nitta M, Honda T, Endoh H. Skeletal Muscle Index at Intensive Care Unit Admission Is a Predictor of Intensive Care Unit-Acquired Weakness in Patients With Sepsis. Journal of Clinical Medicine Research. 2019 Dec;11(12):834.
  27. BTS Guidelines for the Physiotherapy Management of the Adult, Medical, Spontaneously Breathing Patient 2009
  28. 28.0 28.1 Kids Health. (2009). Pneumonia. Retrieved April 11, 2009 from http://kidshealth.org/parent/infections/lung/pneumonia.html
  29. Drugs information online. (2009). Pneumonia in children care Guidelines information. Retrieved April 11, 2009 from http://www.drugs.com/cg/pneumonia-in-children.html