What is Pneumonia?

Pneumonia is an infection that inflames the lungs’ air sacs (alveoli) in one or both lungs. The air sacs may fill up with fluid or pus (purulent material), causing cough with phlegm or pus, fever, chills, and difficulty breathing

The causative agent of pneumonia including bacteria, viruses, and fungi.

Epidemiological Triad

Agent- The  causative agent of Pneumonia is Bacteria, viruses, and fungi.

Host – Most serious for infants and young children, people older than age 65 years, and people with health problems or weakened immune systems.

Environment – Indoor air pollution,Overcrowding, Second-hand smoking/passive smoking (inhale accidentally).

Incubation Period

The incubation period of pneumonia is 2-5 days with a mean of 3 days.

Pathophysiology of Pneumonia

1. Eatery of organism into the lung or blood circulation

3. Inflammatory response of pulmonary tissue, bronchus inflammation

3. To destroy the attacking the organism, white blood cells rapidly accumulate.

4. Tissue necrosis occurs, Neutrophil, bacteria, fluid fill the alveoli along with bacteria, viruses, and fungi, they fill the air sacs within the lungs (alveoli) and lead abscess into alveoli sac.

6. Alveoli fill with exudates

7. Increase production of sputum

8. Mucosal oedema of alveolar membrane occur

9. Purulent sputum

10. Breathing may be labored

Mode of Transmission

The pneumonia infection is contagious, can spread from person to person. The causative agent of pneumonia viruses and bacteria are commonly found in a child’s nose or throat.

1. Both viral and bacterial pneumonia can spread to others through inhalation of airborne droplets from cough or sneeze.

2. Spread via coming into contact with surfaces or objects that are contaminated with pneumonia-causing bacteria or viruses.

3. Spread via Contract fungal pneumonia from the environment.

Causes of Pneumonia

The causative agent are-

1. Bacterial Pneumonia

2. Viral Pneumonia

3. Fungal Pneumonia

1. Bacterial Pneumonia

Bacterial pneumonia is the most common form. It tends to be more serious than other types of pneumonia.

The symptoms of bacterial pneumonia infection  can develop suddenly or gradually. Symptoms are-

1. Fever may rise as high 105 degrees F, with profuse sweating and rapidly increased breathing and pulse rate.

2. Lips and nailbeds may turn into a bluish colour due to lack of oxygen in the blood. Patient mental state may be delirious or confused.

The most common cause of bacterial pneumonia infection is Streptococcus pneumoniae bacteria.

 Other causes include-

1. Mycoplasma pneumoniae

2. Haemophilus influenzae

3. Legionella pneumophila

2. Viral Pneumonia

The symptoms of viral pneumonia usually develop over a period of several days.

Early symptoms are similar to influenza symptoms. Such as  fever, dry cough, headache, muscle pain, and weakness. Within 1 or 2 days, symptoms typically get worse; with increasing cough, shortness of breath (S.O.B) and muscle pain, high fever and may be blueness of the lips.

Respiratory viruses are often the cause of pneumonia infection. Examples include-

1. Influenza (flu)

2. Respiratory syncytial virus (RSV)

3. Rhinoviruses (common cold)

Viral pneumonia is usually mild but in some cases it become very serious. In Coronavirus 2019, COVID-19 patient most affect from  cause pneumonia, which can become severe.

3. Fungal Pneumonia

Fungi from soil or bird droppings can cause fungal pneumonia infection. It most often causes pneumonia in people with weakened immune systems.

Examples of fungi that can cause pneumonia include-

1. Pneumocystis jirovecii

2. Cryptococcus species

3. Histoplasmosis species

Clinical Manifestation

The seriousness of Pneumonia symptoms can be mild to life-threatening. They can include –

1.Coughing that may produce phlegm (mucus) – which may produce greenish, yellow or even bloody mucus

2. Fever, sweating and shaking chills

3. Shortness of breath that happens while doing normal activities or even while resting; rapid, shallow breathing

4. Chest pain – Sharp or stabbing chest pain that gets worse when breathe deeply or cough or breathe

5. Feelings of tiredness or fatigue – low energy

6. Loss of appetite

7. Nausea or vomiting – especially in small children

8. Headaches

9. Confusion – especially in older people

10.Abnormal sounds of the lung, such as crackling, listen with a stethoscope

Types of Pneumonia

Pneumonia can be classified according to where or how it was acquired-

1. Hospital-acquired pneumonia (HAP) or Nosocomial pneumonia 

This type of bacterial pneumonia is acquired during a hospital stay and hospital environment. HAP can be more serious than other typesof acquired pneumonia. The bacteria involved may be more resistant to antibiotics treatment. It contracted by a patient at least 48-72 hours after being admitted in hospital.

2. Community-acquired pneumonia (CAP)

Community-acquired pneumonia (CAP), pneumonia that acquired from outside of a medical or institutional setting.

3. Ventilator-associated pneumonia (VAP)

When patient, who are using ventilator get pneumonia, called Ventilator-associated pneumonia.

VAP occurs in people who are on mechanical ventilation breathing machines in hospitals at intensive care unit (ICU).

4. Aspiration pneumonia

Aspiration pneumonia happens when inhale bacteria into lungs from foreign material, food, drink, or saliva.

5. Walking pneumonia

Walking pneumonia, or atypical pneumonia, is a less serious form of the lung infection pneumonia caused by bacteria or viruses; most often common bacterium Mycoplasma pneumonia. 

Laboratory Investigation

1. Blood tests- to confirm the infection and to try to identify the germ that is causing infection.

2. Chest X-ray- look for the location and extent of inflammation in lungs.

3. Sputum test-  sample of mucus (sputum) taken after a deep cough, to look for the source of the infection.

4. Pulse oximetry – to measure the oxygen level in blood. Pneumonia illness can prevent lungs from moving enough oxygen into bloodstream.

5. CT scan – to view of the lungs and look for abscesses or other complications.

6. Arterial blood gas test – to measure the amount of oxygen in a blood sample taken from an artery, usually in wrist.

7. Pleural fluid culture – to analyze and identify bacteria causing the pneumonia infection. Removes a small amount of fluid from around tissues that surrounding the lung .

8. Bronchoscopy- procedure used to look or examine into the lungs’ airways.

Pneumonia  Complication

1. Bacteremia – Bacteria in the bloodstream

Bacteria from the pneumonia infection may spread to bloodstream can spread the infection to other organs and lead to dangerously low blood pressure, septic shock, and potentially causing organ failure.

2. Lung abscesses

Abscess occurs if pus forms in a cavity in the lung. Antibiotics used to treat abscess. Sometimes, need to surgery or drainage with a long needle or tube placed into the abscess to remove the pus.

3. Impaired breathing – Difficulty breathing

If pneumonia is severe or have chronic underlying lung diseases, trouble to getting enough oxygen when breathe. In this case, need to be use a breathing machine (ventilator).

4. Acute respiratory distress syndrome (ARDS)

ARDS is a severe form of respiratory failure. It occurs when fluid builds up in the tiny air sacs (alveoli) in lungs.

5. Pleural effusion – Fluid accumulation around the lungs

If pneumonia isn’t treated, it develops fluid around your lungs in the pleura, called pleural effusion. Pneumonia can cause fluid to build up and accumulate in the thin space between layers of tissue that line the lungs and chest cavity (pleura). If the fluid becomes infected, then need to it drained through a chest tube or removed with surgery.

 

Pneumonia Stages

Pneumonia may be classified based on area of the lungs its affecting:

1. Bronchopneumonia

Bronchopneumonia can affect areas throughout both of lungs, causes inflammation in the bronchi or around bronchi. It is the tubes that lead from windpipe to lungs.

2. Lobar pneumonia

Lobar pneumonia affects one or more lobes of lungs. Both lung is composed of lobes, which have defined sections of the lung.

Lobar pneumonia can be divided into four stages based on how it’s progressed:

1. Congestion – Lung tissue appeared heavy and congested. Fluid are filled with infectious organisms, accumulated or clog in the air sacs.

2. Red hepatisation (pathologic alteration of lung tissue) –  Red bloods cells and immune cells are entered into the fluid. Lungs appear,  red and solid in appearance.

3. Gray hepatisation – The red blood cells are begun to break down while immune cells remain. The breakdown of RBCs causes a change in colour, from red to gray.

4. Resolution – Immune cells are started to clear the infection. A productive cough eject with remaining fluid from the lungs.

Pneumonia Risk Factors

Certain groups do have a higher risk of infection of Pneumonia. These groups include-

1. Infants from birth to 2 years old of age.

2. People ages 65 years and older.

3. People with weakened immune systems or due to disease or use of medications; such as steroids or certain cancer drugs.

4. People with have certain chronic medical conditions, such as asthma, cystic fibrosis, diabetes, or heart failure.

5.  People had recently respiratory infection, such as a cold or the flu.

6. People who have been recently or currently hospitalized, if they were or are on a ventilator.

8. People who use certain types of drugs, smoke, or drink excessive amounts of alcohol.

9. People who have been exposed to lung irritants, such as pollution, fumes, and certain chemicals.

Treatment of Pneumonia

Treatment of Pneumonia depends on the specific cause of pneumonia.

Bacterial pneumonia – Oral antibiotics can treat most cases of bacterial pneumonia.

Viral pneumonia  – Antibiotic medications don’t work on viruses. Doctor may prescribe an antiviral drugs.

Fungal pneumonia – Antifungal medications are used to fight fungal pneumonia.

Doctor may also recommend over-the-counter (OTC) medication to relieve pain and fever, as needed. The drug may include-

1. Aspirin

2. Ibuprofen (Advil, Motrin)

3. Acetaminophen (Tylenol)

Intravenous antibiotics injected into a vein. Respiratory therapy, which involves delivering specific medications directly into the lungs and perform breathing exercises to maximize oxygenation level.

Oxygen therapy to maintain oxygen levels in bloodstream (oxygen received through a nasal tube, face mask, or ventilator, depending on severity level).

Prevention and Control

1. Vaccination

Vaccination is the first line of defense against pneumonia infection.

Prevnar 13 and Pneumovax 23 – These two pneumonia vaccines help protect against pneumonia and meningitis caused by pneumococcal bacteria.

PCV13 (Prevnar 13) – Effective against 13 types of pneumococcal bacteria.

Vaccine to given children at 2, 4, 6, and 12 through 15 months old. Adults who need this only get 1 shot of vaccine. It can also help prevent ear infections.

The Centers for Disease Control and Prevention (CDC) recommends this vaccine for-

1. Children under the age of 2 years old

2. Adults ages 65 years and older

3. People between 2 to 64 years of ages with chronic conditions that increase their risk for pneumonia.

PPSV23 (Pneumovax 23) – Effective against 23 types of pneumococcal bacteria. Single shot of this vaccine given to people who need it.

The CDC recommends it for-

1. Adults ages 65 years and older

2. Adults ages 19 to 64 years who smoke cigarettes

3. Given to people between 2 and 64 years of ages with have chronic conditions that increase their risk for pneumonia.

2. Flu vaccine

Pneumonia can often be a complication of the flu infection, so also get an annual flu shot. The CDC recommends that everyone ages 6 months and older get vaccinated, particularly who at risk for flu complications.

3. Hib vaccine

This vaccine protects against Haemophilus influenzae type b (Hib), a type of bacteria that cause pneumonia and meningitis. The CDC recommends this vaccine for:

1. All children under age 5 years

2. Unvaccinated older children or adults; have certain health conditions

3. Individuals who have come by bone marrow transplant

4. Regularly wash hands with soap and water or can use alcohol-based hand sanitizer.

5. Cover mouth when coughs and sneezes and promptly dispose used tissues.

6. If smoke, try to quit, smoking makes more susceptible to respiratory infections, especially pneumonia.

7. Make sure children get vaccinated. Those who are at particular risk of pneumococcal disease.

8. Practice good hygiene.

9. Keep your immune system strong – exercise regularly and eat a healthy diet.

Pneumonia in Children

The causes of childhood pneumonia can vary according to age.

For example, pneumonia due to respiratory viruses, Streptococcus pneumoniae, and Haemophilus influenza, more common in children underage of 5 years old.

Pneumonia due to Mycoplasma pneumoniae is frequently observed in children between the ages of 5 and 13 years old. 

Mycoplasma pneumoniae is one of the causes of walking pneumonia,  milder form of pneumonia.

Pneumonia in Pregnancy

Pneumonia, occurs during pregnancy is called maternal pneumonia. Pregnant women are more at risk for pneumonia developing conditions. The common symptoms of pneumonia in pregnant women are cough, fever, and shortness of breath.

Pneumonia vs. Bronchitis

Infections can cause both pneumonia and acute bronchitis. Pneumonia and bronchitis are two different disease conditions.

Pneumonia is an inflammation of the air sacs in lungs.

Bronchitis is the inflammation of bronchial tubes. Chronic bronchitis can develop from inhaling pollutants, cigarette, and smoke.

Viral or bacterial infection can lead to acute bronchitis. If the bronchitis condition remains untreated, it can progress into pneumonia.

If people have bronchitis, it is important to get it treated to prevent developing pneumonia.

Acute lower respiratory infections include pneumonia as well as acute bronchitis and bronchiolitis, influenza, and whooping cough.