The inflammation of the alveoli, lungs and the condition where the lungs are filled with fluid is called pneumonia. This condition occurs due to a group of diseases that together cause inflammation in the lungs. The air sacs are filled with fluids as well as pus that make it very difficult for oxygen to reach the blood. There are two types of pneumonia: 'lobar pneumonia' is where just one section of the lung is affected while 'bronchial pneumonia' affects both lung patches. Pneumonia can be caused by different types of infections such as bacterial, viral, fungal and even parasitic infections. The common causes of pneumonia include bacterial and viral infections. The pathophysiology of pneumonia in both cases is somewhat similar. But there are a few differences between viral and bacterial pneumonia. The following paragraphs on viral vs. bacterial pneumonia will help clear out the differences between the two and help you find the causative agent of this respiratory ailment. The Differences In many cases, parents are often confused as they do not seem to understand if their child is showing signs of bacterial or viral pneumonia. We shall have a look at both the infections separately that will help lay some doubts to rest and distinguish between the two of them. What is Bacterial Pneumonia? Bacterial pneumonia is generally caused by Streptococcus pneumoniae. It commonly affects people with a weak immune system like those over the age of 65 years, immunocompromised individuals with HIV/AIDS, people with diabetes, heart ailments, lung diseases, etc. Staphylococcus aureus and Streptococcus agalactiae are known to cause pneumonia in newborn babies. Other bacteria capable of causing pneumonia include Escherichia coli, Klebsiella pneumoniae, Haemophilus influenzae, Pseudomonas aeruginosa and Moraxella catarrhalis. The bacteria enter the body through inhalation of airborne droplets. These bacteria tend to live in the upper respiratory tract and can be inhaled into the lungs. When the bacteria enters the lungs, it triggers an immune response. The neutrophils reach the lungs and engulf the bacterial agents. While doing so, these cells release cytokines that trigger activation of the entire immune system. This leads to many bacterial pneumonia symptoms that include -

• High fever
• Chills
• Fatigue
• Drowsiness
• Cough with greenish mucus
• Chest pain

In severe cases, one will observe a blue tint under the nails and on the lips. Lethargy, drowsiness and the blue tint are seen because the neutrophils, bacteria and the fluid from the blood vessels fill up the alveolar sacs. This causes disruption of normal oxygen transportation leading to these symptoms. The treatment for bacterial pneumonia includes use of antibiotics like penicillin. In severe cases, the person is hospitalized and given oxygen therapy along with intravenous fluids. Analgesics and acetaminophen are given to reduce chest pain and fever. What is Viral Pneumonia? Most of the cases of pneumonia are caused due to a viral infection. The viruses that cause pneumonia are influenza virus, respiratory syncytial virus (RSV), adenovirus and parainfluenza virus. Pneumonia in newborns can be caused by herpes simplex virus in rare occasions. The viral agents reach the lungs through inhalation via the mouth and nose. After entering the lungs, the virus reaches the cells of the airways and alveoli. The viral invasion causes cell death and the immune system begins to act against the invading organism. The lymphocytes activate cytokines that cause fluid build up in alveoli. A person suffering from viral pneumonia shows the following symptoms -

• Fever
• Dry cough that will progress to wet cough
• Sore throat
• Loss of appetite
• Muscle pain
• Shortness of breath

The fluid build up in the alveoli decreases oxygen transportation to the blood. This leads to extreme breathlessness and blue tint of the lips and under the nails. Viral pneumonia is a less severe infection than bacterial pneumonia. Antibiotics and antibacterial drugs will not help in treatment of viral pneumonia. The patient is given antibiotics only if there are chances of secondary bacterial infection. Viral pneumonia is treated by giving the patient plenty of rest and warm fluids to drink. Antiviral drugs like zanamivir or amantadine may be prescribed. From the above explanations, it becomes easy to differentiate between viral vs. bacterial pneumonia. Bacterial pneumonia symptoms are more severe than viral pneumonia. The symptoms of viral pneumonia develop gradually over a couple of days while bacterial pneumonia tends to develop rapid symptoms. Hope the above information has helped you understand the difference between viral and bacterial pneumonia better.