1. How does Pneumonia develop?
Pneumonia is a disease affecting the lungs due to infection caused by bacteria, virus or fungus. Pneumonia can affect either left or right lobe of the lungs or both the lobes of lungs.
Pneumonia is a serious disease affecting people of any age, toddlers and young children are more affected by pneumonia. Pneumonia even affects elderly people who have a weak immune system. To summarize the population affected any individual who have a weak immune system gets easily affected by pneumonia. Pneumonia can also easily affect when people have other health diseases like diabetes, flu, long term lung disease, heat diseases, AIDS and other diseases that reduces the strength of body immunity. When an individual is infected by pneumonia, the fluid present in the lungs start shedding dead cells, these dead cells clog up the air sacs called alveoli which is an important mechanism associated with breathing and exchange of oxygen, resulting in difficulty in breathing, reduced absorption of oxygen into the blood stream and other organs. The individual becomes more and more weak.
Whenever the immunity is weak by inhaling infected air and being with people with infection the microorganism can easily develop itself after they enter the body because the immune system is very weak to fight and destroy the germs. Lack of strong immunity can be because of various reasons, some of them include, very young and old age, other diseases where the immune system of the body is very busy fighting it or is exhausted, alcohol dependence or other types of chronic illness. Pneumonia also affects people who live in an environment where there are people already affected by pneumonia and where the pneumonia germs are more.
In the process of breathing, we inhale air through our nostrils, this inhaled air passes through trachea, bronchi, bronchioles and finally reaches the air sacs called alveoli. The alveoli contains thin porous walls meshed by very fine blood vessels, oxygen inhaled moves into the blood capillaries and the carbon dioxide present in the blood moves into the air sacs and this carbon dioxide is exhaled out through the nostrils. Our mouth, respiratory tract and lungs are constantly exposed to microorganisms through the air we breath, food and fluids we consume. The immune system of the body destroys the microorganisms regularly and the infection is always in check when the immune system is very strong. When the immune system gets weak microorganisms multiply rapidly and spread over causing pneumonia. Later more and more white blood cells get moved to the alveoli to defend the body, resulting in dead blood cells, proteins and other fluids getting collected in the alveoli and inflammation of alveoli. Accumulation of fluids increase in the lungs and the quantity of air decrease, causing swelling of the pleurae and breathing difficulties. The body has a coughing mechanism to expel the liquid and irritants that gets accumulated. By force full expelling of air through the mechanism of coughing these fluids will reach out to the mouth and nose in the form of mucus also called as sputum. Whenever the person lies down he or she will have difficulties in breathing or sleeping.
In around two to three days the small blood vessels that surround the air sacs swell up and break, resulting in blood leaking into the air sacs. The lungs will start appearing grayish brown in color due to accumulation of red blood cells. While coughing the sputum can be greenish to brownish in color due to presence of blood cells. This is an advanced stage of infection, whenever the infected person coughs the expelled air and mucus will be highly contaminated by germs thus affecting people around them. Wearing a mask is advisable to avoid spreading the infection and getting affected by inhaling the infected air.
2. What are the pathogens involved?
The germs involved in pneumonia infection are bacteria, virus, fungus, rare parasites and other microorganisms. Virus is the common reason behind pneumonia in todlers and young children. Apart from young ones, adults who do not have a strong immunity are also very vulnurable to bacterial pneumonia.
Pneumonia causing pathogens are broadly classified into the below three categoris:
1. Common pathogens
2. Drug resistant pathogens
3. Atypical pathogens
Most common pathogens:
Streptococcus pneumoniae (Pneumococcus)
Mycoplasma pneumoniae
Chlamydophila pneumoniae
Respiratory viruses
Hemophilus influenzae,
Legionella pneumophila
Moraxella catarrhalis
Streptococcus pneumoniae also called as Pneumococcus, is one of the common pathogen, which cause community-acquired pneumonia (CAP).
Under “atypical†CAP pathogens we have Mycoplasma, Chlamydophila, and Legionella, causing one-thirid of community-acquired pneumonia. Legionella is the reason behind severe CAP; Mycoplasma and Chlamydophila cause mild pneumonia.
The common reason behind CAP is influenza respiratory virus. Influenza infection predisposes to subsequent progress of bacterial CAP known as “post-influenza pneumoniaâ€.
Moraxella and Hemophilus are the common pathogens behind patients suffering from chronic obstructive pulmonary disease or intrinsic lung disease.
“Atypical†CAP pathogens
The common microorganisms behind Atypical pathogens are:
Chlamydophila pneumoniae
Mycoplasma pneumoniae
Legionella pneumophilia
The above mentioned bacteriae are the reason behind more than 30% of CAP among people. These bacteriae are not clearly visible when Gram stain analysis is done on sputum. These atypical bacteriae survive even when penicillin or other types of beta-lactam antibiotics are administered.
Drug-resistant Pneumococcus:
One of the commonly identified reason behind CAP is Drug-resistant Streptococcus pneumoniae (DRSP)
Resistance to beta-lactam antibiotics
Drug resistant microorganisms are the germs which do not get killed by medicines administered. These microorganisms develop themselves to survive the attack of drugs used to cure the infections they cause.
Drug-resistant Streptococcus pneumoniae or DRSP has off late developed resistance to beta-lactam antibiotics, cephalosporin antibiotics, and penicillins, by inhibition of antibiotic binding of beta-lactam to bacterial enzymes involved in the synthesis of bacterial peptidoglycan.
Resistance to macrolide antibiotics
Pathogens resistant to macrolide antibiotics are developed by 2 separate mechanisms:
Mef (A)-mediated resistance involves an efflux pump, resulting in a resistance of lower level.
Erm (B) mediated resistance involves a conformational change to the macrolide binding site at the bacterial 23S ribosomal subunit. This kind of change confers to a high level of macrolide resistance.
LESS COMMON CAP PATHOGENS:
Enteric Gram negative bacilli (Klebsiella, E. coli)
Pseudomonas aeruginosa
Group A Streptococcus, other Strep
Endemic fungi
Staphylococcus aureus
PNEUMONIA CAUSING VIRUSES:
Close to one-third of pneumonia is because of viruses, these pneumonial virus affect more often children less than 5 years of age.
Respiratory syncytial virus (RSV):
Respiratory virus is considered to be one of the major reason for pneumonia and bronchiolitis infection in children.
Human rhinovirus:
Human rhinovirus is one of the reasons behind lower respiratory infection and generally followed by common cold and it usually affects people with less immunity.
Herpes Simplex Virus (HSV):
This virus is strong enough to affect people with good or weak immunity.
PNEUMONIA CAUSING FUNGUS:
Fungus that causes pneumonia infection is very commonly found in soil. Whenever the immune system of the body gets weak, the fungus present in the body multiply, spread and start attacking leading to infection.
Coccidioidomycosis:
This is one of the types of fungus causing pneumonia more often found in warm and arid regions. Whenever a person inhales spores of fungus present in air the infection starts.
Histoplasmosis:
This kind of fungus is present in the droppings of bats and birds, they grow in humid areas contaminating the soil and air around it. People get infected whenever the fungus reaches the lungs by inhaling the contaminated air or through soil contact, this infection can become very fatal if it starts spreading outside the lungs.
Cryptococcus:
This type of fungus is also present in bat and other bird droppings. It grows as yeast. Once the fungus reaches the lungs of the person through inhalation or soil contact, infection starts.
3. Who is at risk of developing pneumonia?
People of any age can get affected by pneumonia since pneumonia affects individuals who have less immunity. People who have high risk of getting infected by pneumonia fall under the below three categories:
a) Children less than 5 years of age
b) People above 65 years of age
c) People with Other medical conditions
Children less than 5 years of age: Pneumonia and other respiratory infection is the main cause for mortality of children under the age of five years. This is because the immune system of children is not fully developed to fight against any infection and make them vulnerable to any disease, so pneumonia affects them very easily.
The presence of pneumonia in children can be identified when they have difficulty breathing, continues coughing, and there can be fever. The chest wall may start drawing in, and breathing can become faster than usual.
People above 65 years of age: After an individual crosses 65 years of age, the body becomes weaker and weaker as they grow old. These individuals are susceptible to other types of diseases. This advancing age gradually suppresses the immune system in the body and the body becomes easily vulnerable to infection. When they get infected with pneumonia the suppressed immune system of the body compounded by other diseases, easily allow pneumonia to take over and grow rapidly. Therefore, the elderly people have a very high risk of developing pneumonia and getting severely affected.
c) People with other medical conditions: There are certain category of adults who have a higher chance of developing pneumonia and they are ones who are:
â— Malnutrition: Due to inadequate food intake, the body does not get enough nutrition, leading to weakness of multiple organs, the physical body as a whole and the immune system will also become weak, making the body vulnerable to any kind of infection.
â— Respiratory diseases: People having lung diseases, including cystic fibrosis, infection of upper respiratory tract, asthma, or other chronic obstructive pulmonary diseases will make the immune system of the individual go very weak, providing more opportunity for pneumonia germs to grow, multiply and aggravate itself.
â— Diabetes: People with Type 2 diabetes will also suffer from low immune system in the body. The sugar levels in the body will be high, providing a more suitable environment for pathogens to grow. These individuals can catch up cold, flu, and fever more easily than normal individuals and they take a long time to recover from these disorders.
â— Immunity deficient disorders: There are many diseases and medical conditions that can suppress the immunity of the body some of them are HIV, organ transplant, chemotherapy, or prolonged use of steroids.
â— Coughing disorder: People experiencing difficulty in coughing due to stroke, sedating drugs or alcohol or limited mobility. Suppressed coughing will not allow infected fluids to get expelled out of lungs.
â— Smoking: Smoking cigarettes has a high risk of getting infected with pneumonia, lung disease and asthma.
â— Alcoholism: The more individuals consume alcohol, less the white blood count becomes in the blood stream. White blood cells fight against any infection in the body, lack of white blood cells decrease the immunity level and the body becomes prone to pneumonia and other infections.
Hospital-acquired pneumonia: This happens more often to patients and individuals who are hospitalized for other diseases and people who visit hospitals regularly or who work in hospitals. These individuals will have more exposure to pneumonia causing bacteria, viruses and other pathogens. The common symptoms they will experience will be sore throat, coughing sometimes accompanied by sputum as the infections advances, chest pain, fever, chills, difficulty in breathing, and shortness of breath. Wearing a mask covering the nose and mouth can avoid the cough droplets to spread across into the air and to other individuals around the patient. People visiting the hospital and working in the hospital should wear these masks to avoid infection.