Original Editor - The Open Physio project.

Top Contributors - Kim Jackson, Nikhil Benhur Abburi, Adam Vallely Farrell, Rachael Lowe and Evan Thomas


Pneumonia is "a severe form of an acute lower respiratory infection that specifically affects the lungs" and is typically caused by bacteria, viruses or fungi. 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].

Clinically Relevant Anatomy

Pneumonia Inflammation.jpg

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[2]:

  • 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[3] For more detailed information about lung anatomy see here

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

Community-Acquired Pneumonia

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[4].

Viral Pneumonia

Viral Pneumonia is believed to be the cause of half of all cases of pneumonia. The viruses invade the lungs and then multiply- causing inflammation.[5]

  • Influenza type A or B, coronaviruses, rhinoviruses adenoviruses, respiratory syncytial virus (more common in infants and children)

Bacterial Pneumonia

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[6]:

  • Streptococcus pneumonia, Staphylococcus aureus, Haemophilus influenza, legionella pneumophilia and Methicillin resistant staphylococcus aureus (MRSA)[5]
  • 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[7][8]
  • Mycoplasmal Pneumonia (also known as 'walking pneumonia') is similar to bacterial pneumonia, whereby the mycoplasmas proliferate and spread - causing infection.[5]

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.

  • 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.[7]

Aspiration Pneumonia

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.[7] It occurs predominantly in the right lung because its total capacity is greater than that of the left lung.[7] 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.

Hospital-Acquired Pneumonia

Hospital-acquired pneumonia refers to patients who develop symptoms during or after hospitalisation for another illness or procedure with a latency period of 72 hours. The Infectious agent is often Gram-negative bacteria such as 'Escherichia coli or Klebsiella' [6]. It is estimated that 5% of patients are reported to develop hospital-acquired pneumonia

  • Ventilator-Associated Pneumonia (VAP) - usually occurs two days after a hospitalised patient has been intubated and on mechanical ventilation.[4] This can be a life-threatening infection as patients who require mechanical support are already critically ill.[9]

Prevalence of Pneumonia

According to WHO Pneumonia kills more children than any other illness -- more than AIDS, malaria and measles combined. In 2017 pneumonia accounted 15% of all deaths of children under 5 years old, killing 808 694 children[10]. and it accounts for nearly one in five child deaths globally.[3] It has been found that 1,6 million people die from pneumonia worldwide each year. It should also be noted that pneumonia is one of the leading causes of deaths for children under the age of 5.

In South-East Asia, in the Pacific, and in Sub-Saharan Africa about 433 million young children contract the disease annually.[11] Amongst children under the age of 5, these two regions have the highest incidence of pneumonia cases and when combined, they "bear the burden of more than half the total number of pneumonia episodes worldwide".[3] Pneumonia accounts for approximately 5% of deaths in Ireland.

Stages of Pneumonia

Pneumonia has four stages, namely consolidation, red hepatization, grey hepatization and resolution.

  • 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[12][13]
  • 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"[12][13]
  • 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"[12][13]
  • 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"[12][13]

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

Signs and symptoms can vary and are also dependent on the cause and initially, symptoms are similar to that of a cold followed by[14]:

  • A high fever (pyrexia)
  • Chills
  • Productive cough

As the infection continues sputum may be discoloured and may become blood-stained as pneumonia progresses. The following may also occur:

  • Dyspnoea
  • Sharp chest pain
  • Worsening cough
  • Fever/chills
  • Tachycardia
  • Pleuritic chest pain
  • Headaches
  • Malaise
  • Muscle pains
  • Cyanosis due to poorly oxygenated blood
  • Loss of appetite
  • Rapid breathing
  • Wheezing or grunting during breathing
  • Intercostal muscle recession during breathing
  • Vomiting[15]


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[16]
  • 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[17][9]
    • 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


  • 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[7]
  • 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[7]
  • Lung abscess - A lung abscess develops when the infection has destroyed lung tissue and a cavity filled with pus is formed[7]
  • Bacteremia - This occurs when the infection is no longer contained within the lungs and moves into the bloodstream, thus the blood is infected[7]
  • 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 (, 2005).
  • Meningitis - The infection may spread to the meninges that cover the brain and spinal cord, leading to meningitis[7]
  • Septic arthritis - When bacteremia has occurred septic arthritis is also a danger, as the bacteria manifests in the joints through which blood passes[7]
  • 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[7]

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.

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

Physiotherapy Management

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.[18] 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[19]

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[20].

A retrospective study[21] 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[22]

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?

  • Unlike healthy children with many natural defenses to protect them against the invasion of pathogens in the lungs, the unhealthy children with a compromised immune system has weak defenses.
  • Children who suffer from malnutrion, particularly inadequate zinc intake and lack of exclusive breastfeeding have a higher risk of developing pneumonia.
  • Other risk factors include:
    • Being born premature
    • Having asthma or genetic disorder such as sickle-cell disease
    • Having heart defects such as ventricular septal defect (VSD), atrial septal defect (ASD) or patent ductus arteriosus (PDA)[23]
  • Several environmental factors such as overcrowding homes and exposure to parental smoke increases a child's susceptibility to pneumonia and its complications.[24]

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.[25]
  • Parents should be aware of the following signs and symptoms:
    • Nostril flaring
    • Sternal retraction
    • 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[26]


  • 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[25]

Transmission of pneumonia - Infection may occur in different ways may it be through contaminated air droplets, blood-borne infection or from coming into contact with contaminated substances during delivery. Either way, it is believed that babies already have the bacterial pathogens causing pneumonia in their nose and/ or throat and are inhaled into the lungs.


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