Pneumonia: Causes, Types, Symptoms and Treatment

Pneumonia is a life-threatening infection and it is very dangerous especially to people with compromised immune system, infants and older adults especially those above the age of 65. According to the World Health Organisation (WHO), pneumonia was responsible for 15% death of children under the age of 5 and killed about 808,694 children in 2017. In today’s article we will be talking about pneumonia infection, it causes, types, symtoms and treatment.

What is Pneumonia?

Pneumonia is a microbial infection that affects the air sacs of the lungs making breathing extremely difficult. This infection is usually caused by bacteria, fungi and viruses. Pneumonia is spread when an infected person sneezes, coughs or spits into the air and an healthy individual inhales the infectious droplets. A person can also become infected when he/she comes in contact with an object that is contaminated with the microbes that causes pneumonia. Once a person becomes infected the air sacs(also called alveoli) in the lungs becomes inflamed and filled up with mucus and pus thereby leading to cough with phlegm, chills, fever and difficulty in breathing.

Types of pneumonia

Pneumonia is primarily caused by infectious microorganisms such as bacteria, fungi and viruses. It can be categorised based on the agents of infection and mode of infection.

Agents of infection

The agent of pneumonia infection refers to all microbial pathogens that causes the disease. They include:

Bacterial pneumonia

These are pneumonia infections that are caused by bacteria. The major cause of bacterial pneumonia is Streptococcus pneumoniae. Other bacteria that cause pneumonia infection include Haemophilus influenzae and Micrococcus pneumonia. This bacteria inflame the lungs and may affect one or both part of the lungs thereby resulting into chest pain, shortness of breath and cough that comes with phlegm.

Viral pneumonia

This refers to pneumonia infections that are caused by viruses. They primarily affect the upper respiratory tract and the symptoms they bring up are usually mild but may become severe in some cases. The most common cause of viral pneumonia are Respiratory syncytial virus (RSV) and influenza. Studies have revealed that pneumonia is one of the complications of COVID-19 and this can be very fatal and may demand that patient are kept on ventilators to survive.

Fungal Pneumonia

This kind of pneumonia are caused by fungal infections. They are mostly prevalent in people with compromised immune system and those with severe underlying health conditions. Fungi that causes pneumonia can be found in the soil and bird droppings examples of these fungi include: Cryptococcus species and Pneumocystis jirovecii.

Mode of infection

This refers to various ways in which pneumonia infections are being spread. They include:

  • Hospital-acquired pneumonia: This kind of pneumonia occur in people who visit the hospital to treat another health condition. Hospital-acquired pneumonia can be more severe when a person gets infected, this is because the bacteria that causes it are more resistant to antibiotics used in treating the infection.
  • Community-acquired pneumonia: when a person get infected with pneumonia within the environment and not in a hospital setting it is known as community-acquired pneumonia.
  • Ventilator acquired pneumonia: this pneumonia occurs in people that are kept on a breathing machine called ventilator. Ventilator is a machine that helps to improve the breath of patients that are suffering from conditions that causes extreme difficulty in breathing.
  • Aspiration pneumonia: it occurs when you inhale saliva, foods, liquid or vomits into the airways that leads into the lungs thereby resulting into infection due to bacterial growth.

Symptoms of pneumonia

The symptoms of pneumonia vary and range from mild to severe depending on the causative agent of infection, age of patient and overall state of the health. The symptoms that are exhibited by people infected with pneumonia include:

  • Cough that comes with phlegm
  • Fever
  • Difficulty in breathing
  • Chest pain that becomes severe when you breathe or cough
  • Sweating or chills
  • Diarrhoea
  • Tiredness
  • Headache
  • Lost of appetite
  • Mental confusion especially in older adults above the age of 65.

The symptoms of pneumonia in infants vary, most of them do not show any symptoms while others may vomit, experience tiredness, have problem eating, drinking or breathing.

Risk factors of pneumonia

These are factors that increases your chances of developing pneumonia and suffering severe symptoms from the condition. Anyone can be infected with pneumonia but there are certain factors that can higher your risk of contracting it. The common age groups that are prone to pneumonia infection include:

  • Children younger than the age of 2
  • Adults of age 65 or older

Other condition that can higher your risk of contracting pneumonia and developing severe symptoms include:

  • Having a chronic health conditions such as heart disease, chronic obstructive pulmonary disease (COPD), diabetes, asthma and cystic fibrosis.
  • Having a weak immune system due to some diseases such as HIV and AIDS, organ transplant or use of medication such as steroids or receiving chemotherapy.
  • Being recently admitted in an intensive care unit (ICU) and placed on a ventilator in a hospital.
  • Being recently recovered from respiratory infections such as influenza and common cold
  • Being a smoker and alcohol addicts.
  • Being exposed to air pollutants such as fuels and chemicals.

When to see a doctor

You need to see your doctor for proper diagnosis test so as to detect if you are infected with pneumonia if;

  • You experience reoccurring fever and persistent cough that comes with phlegm
  • You have shortness of breath accompany with chest pain
  • You are in categories of people with higher risk of pneumonia infection such as children younger than the age of 2, older adult above the age of 65, people with compromised immune system and those with underlying chronic health conditions.

Diagnosis of Pneumonia

To diagnose pneumonia, your doctor will review your medical history and ask you question about the symptoms you are experiencing. He/She will also perform a physical exam on you which include listening to your lungs with a stethoscope to screen out cracking, wheezing and bubbling sounds which are usually associated with the symptoms of pneumonia.
Your doctor may order for the following confirmatory test in other to accurately diagnose pneumonia:

  • Chest X-ray: this test helps to reveal the location of infection on the lungs and its severity.
  • Blood tests: this test involves culturing the blood sample of the patient in order to screen out the microbial agents of the pneumonia infection.
  • Sputum test: durung this test, your sputum sample which is the thick mucus that is coughed out will be sent for laboratory analysis in order to detect the causative agent of the infection.
  • Pulse Oximetry: this test measures the amount of oxygen that is present in the blood. Pulse oximetry helps to reveal if your lungs are conveying enough oxygen into your bloodstream. People with pneumonia usually have less oxygen in their blood stream.
  • CT scan: this test helps to generate a clear and detailed image of the lungs.
  • Bronchoscopy: it is a test used to examine the airways to the lungs in order to detect blockages by using a device called bronchoscope.

Treatment of Pneumonia

The treatment of pneumonia primarily depend on the agent of infection, severity of infection and overall health of the patient. In most cases your doctor may prescribe medications to treat the infection but when your chances of having severe symptoms are high, then you may be hospitalized.


If you are suffering from bacteria pneumonia your doctor will prescribe antibiotics to combat the infection. It is important that you continue to use the entire antibiotics that is recommended by your doctor until you complete the treatment because deviating from this can increase your risk of re-infection and antibiotics resistance.
Your doctor will prescribe antiviral medications to you if the type of pneumonia you have is caused by virus. Antiviral medications will not will not work for pneumonia that are caused by fungi therefore your doctor will recommend an antifungal drug to effectively treat the infection.
Your doctor may also prescribe Nonsteroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen, aspirin and acetaminophen so as to reduce the symptoms of pains, inflammation and fever. He/she may also recommend medications that will calm your cough so that you can rest very well. Taking your drugs regularly as prescribed by your doctor in addition to staying hydrated by taking plenty of fluids and getting enough rest is an effective way of treating pneumonia and preventing its reoccurrence.


You may be required to be admitted into the hospital if your symptoms are severe or you have an underlying health condition. Children below the age of 2 and older adults above the age of 65 may also be hospitalized so as to prevent complications. In the hospital your doctor may treat you with intravenous antibiotics that are injected directly into your bloodstream through your blood vessel (vein). In severe cases you might be placed on ventilator which is a machine that will help you to breathe in more oxygen.

About Adebayo Taiwo

Adebayo Taiwo hails from Africa. He's a Microbiologist , Health Safety and Environment Specialist and a Health Advisor who is concerned about the well-being and healthy lifestyle of people around the globe. The health of my people is my pride.

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