Pneumonia

Our lungs have tubular structures, called bronchi, which help carry the inhaled air to the lungs. These bronchi, after entering the lungs, further keep on branching to form bronchioles. Bronchioles terminate into clusters of tiny air sacs called alveoli. When the alveoli become inflamed or swollen and get filled up with fluid, the condition is known as pneumonia.

While pneumonia affects children and adults globally, its prevalence is maximum in South Asia and sub-Saharan Africa. India, with 4.3 crore cases of childhood pneumonia reported every year, tops the list of 15 countries across the world who have a high burden of pneumonia. The rate of morbidity has been found to vary between 0.2 to 0.5 episodes per child-year. Out of these, approximately 10 to 20 % of the cases are of severe intensity.

How does pneumonia spread?

• Via droplets 
  When a person with pneumonia coughs or sneezes without covering the nose and/or mouth.
• Via blood 
  Especially during and shortly after birth.

More studies are needed to understand how pneumonia pathogens spread as it is an important aspect of prevention.

The symptoms of pneumonia may either develop slowly over a period of several days or suddenly within 24-48 hours.

Common symptoms are:

• Fever.
• A general sense of being unwell.
• A cough, which may be dry, or produce a thick yellowish green, green, brown or blood-stained mucus (phlegm).
• Loss of appetite.
• Sweating.
• Shivering.
• Low energy and extreme tiredness.
• Difficulty in breathing even while resting. You may feel breathless or your breathing may turn rapid and shallow without any exertion.
• Rapid heartbeat.
• Pain in the chest of a sharp or stabbing kind, which worsens on breathing. or coughing.

Less common symptoms are as follows:

• Nausea.
• Vomiting.
• Wheezing.
• Headaches.
• Haemoptysis (coughing up blood).
• Joint pain.
• Muscle pain.
• Fatigue.
• Delirium or a confused and disoriented mental state, especially in elderly people.

Pneumonia can sometimes mimic other conditions, such as:

• Asthma - spasms in the bronchi of the lungs.
• Acute bronchitis - inflammation or swelling of the bronchi of the lungs.
• Gastroesophageal reflux disease (GERD) - a chronic condition in which acid from the stomach flows back into the food pipe.
• Lung abscess - pus accumulation in the lungs.
• Empyema - pus formation in the layers covering the lungs (pleura).
• COPD - a group of lung disorders caused by long-term obstruction of the airflow in the lung, thus interfering with breathing.
• Pulmonary embolism - a blockage in the vessels supplying blood to the lungs and preventing it from reaching the lung tissues.
• Vasculitis - inflammation or swelling of the walls of the blood vessels.
• Endocarditis - inflammation of the inner membrane lining the insides of the heart.
• Whooping cough.
• Bronchiolitis obliterans - an obstruction in the small airways of the lungs due to swelling or inflammation.
• Congestive heart failure - a condition affecting the pumping efficiency of the heart.
• Lung cancer.

Causes

Depending on the causative organism, pneumonia may be of the following types:

• Viral pneumonia
  The flu (influenza) virus commonly causes viral pneumonia and is responsible for approximately one-third of all the pneumonia cases. In children below the age of one year, respiratory syncytial virus (RSV) is the most common cause. Moreover, the occurrence of viral pneumonia makes the individual more prone to acquire the bacterial form of the disease as well. Other viruses that can cause pneumonia are rhinovirus (the common cold virus), human metapneumovirus (HMPV), and human parainfluenza virus (HPIV).
• Bacterial pneumonia
  Pneumonia caused by bacterial infection is known as bacterial pneumonia. The commonest cause is Streptococcus pneumoniae or Pneumococcus bacteria. Bacterial pneumonia usually occurs when the overall health of a person is unstable. The reasons may be illness, old age, malnutrition or even conditions like compromised immunity.
• Fungal pneumonia 
  This form of the disease is caused by fungi. A fungus known as Pneumocystis jirovecii causes a serious infection called pneumocystis pneumonia. It usually occurs in people with a weak immune system. The immune system may be weakened due to a number of causes, such as organ/blood /marrow/ or stem cell transplant, AIDS, chemotherapy or long-term steroid use. Other fungi, which can cause infections leading to pneumonia include Histoplasma and Cryptococcus (found in droppings of birds and in the soil, which is contaminated with bird droppings).
• Atypical pneumonia
  If pneumonia is caused by one of the following types of bacteria, then it is called atypical pneumonia.
  • Chlamydia pneumoniae 
    Usually causes pneumonia that is mild in nature. This type of infection is most common in the age group of 65 to 79 years.
  • Mycoplasma pneumoniae 
    Usually affects those less than 40 years of age. People who reside or work in crowded places like homeless shelters or prisons have a greater chance of getting this type of pneumonia. Although it usually causes a mild form of pneumonia and antibiotics are effective against it, sometimes it may turn serious and demonstrate other associated symptoms of hemolysis (breakdown of red blood cells) and skin rashes.
  • Legionella pneumoniae 
    It spreads through cooling towers, fountains, and spas. This type of pneumonia is called as Legionnaire's disease and most commonly takes a serious form.
• Other types 
  Some other types of pneumonia are:
  • Aspiration pneumonia
    This variant is caused by inhaling a foreign object like a peanut, or a toxic substance such as smoke, a chemical or vomit.
  • Hospital-acquired pneumonia 
    This type of pneumonia occurs in people who are in the intensive-care unit of a hospital, especially if they have been put on a ventilator. It is also called “nosocomial pneumonia”.
  • Community-acquired pneumonia (CAP) 
    This type occurs outside of hospitals or other healthcare facilities.

Risk Factors

Risk factors refer to those factors, which might increase your chances of getting pneumonia. These include:

• Age 
  While pneumonia can affect people of all age groups and genders, two age groups are particularly at a greater risk of developing the condition. These are:
  • Babies up to two years of age, as their immune systems have do not fully develop by then.
  • People aged 65 years or older, as with age the immune system begins to weaken.
• Lifestyle 
  Excessive alcohol consumption, cigarette smoking (active smoking or inhaling smoke passively), and malnourishment increase the chances of acquiring pneumonia.
• Environment 
  If you have been exposed to toxic fumes, pollutants or certain chemicals, your risk of acquiring pneumonia goes up
• Living in crowded homes
  Congested places are most commonly associated with the growth of disease-causing agents. Thus, living in congested places increases the chances of contracting pneumonia.
• Indoor air pollution 
  It is caused by cooking and/or heating with biomass fuels like wood or cow-dung.
• Other factors 
  ​Other factors that may also increase your chances of acquiring pneumonia are listed below:
  • Recent flu or a cold.
  • People in the intensive-care unit of a hospital, especially those who are on a ventilator. This increases one’s chances of getting “hospital-acquired pneumonia” (nosocomial pneumonia).
  • Those who are under the effect of sedatives or are not much ambulant.
  • Difficulty in coughing because of some medical condition (like a stroke), or difficulty swallowing.
  • A weak immune system due to various surgical and medical causes, such as organ/blood /marrow or stem cell transplant, AIDS, chemotherapy or long-term steroid use.
  • A chronic lung disorder or other serious underlying medical conditions, such as diabetes, asthma, COPD (chronic obstructive pulmonary disease), cystic fibrosis, heart failure, bronchiectasis or sickle cell disease.

You can reduce your chances of getting the infection by taking some preventive measures, such as:

Practice good hygienic measures

• When you cough or sneeze, ensure that you cover your mouth and nose with a thick tissue or a handkerchief. If these are not available, cough or sneeze in your elbow and not in your hands.
• Wash your hands regularly after wiping your mouth/nose, visiting the washroom and before having food, to avoid germs.
• Immediately discard used tissues.

Maintain a healthy lifestyle

• Quit smoking.
• Limit alcohol intake.
• Eat fresh fruits and vegetables.
• Exercise regularly.

Vaccination

Vaccines for pneumonia cannot prevent it in every case but people who get vaccinated have milder infections. Resultant pneumonia does not last long and has less serious complications as compared to the infection in those without vaccination.

• Pneumococcal pneumonia vaccine
  This type of vaccination is particularly recommended for:
  • Children less than five years of age.
  • Children older than five years old and suffering from lung ailments, heart diseases or cancer.
  • Adults more than 65 years of age
  • Smokers
  • People who have chronic diseases, such as diabetes, HIV/AIDS, asthma, or a weak immune system.
• Flu (influenza) vaccine 
  Many times, people who get the flu are more prone to getting pneumonia than their healthy counterparts. Thus, getting vaccinated every year can help prevent contracting the disease. The flu vaccine is usually administered in the months of September to November, i.e., just before the time when it is most frequently spread.
• Hib vaccine 
  Haemophilus influenzae type b (H1b) (a bacteria) causes pneumonia and meningitis. Thus, to prevent these two infections, this vaccine is administered in children. It is usually recommended for all kids less than five years old and is often given to babies starting at six months of age.

A diagnosis of pneumonia is established by the doctor based on the following:

Medical history

While taking your clinical history, your doctor may specifically ask about the following:

• Smoking habit.
• Your past and present medical conditions, if any.
• Whether you have been vaccinated for flu or pneumonia.
• Any exposure to sick people at school, workplace, or home.
• Exposure to animals,
• If you are currently on any medications.
• A recent history of travel.

Physical examination

Your doctor will place his/her stethoscope on your chest and listen for any abnormal sounds in your lungs while you breathe to suspect a pneumonia infection.

Diagnostic tests 

In case pneumonia is suspected, your doctor may advise a few of the following diagnostic tests:

• Chest X-ray 
  A chest X-ray is the best diagnostic test in case pneumonia is suspected. Your doctor will look for inflammation or swelling in your lungs.
• Blood tests 
  A complete blood count (CBC) will be carried out to assess how active your immune system is in fighting the infection.
• Blood culture 
  Blood culture is carried out to find out whether the infection has spread to your bloodstream so that accordingly, your doctor can plan the treatment.
• Sputum test 
  This test is performed to find out which microorganism is responsible for your pneumonia. Based on this test, your doctor will be able to design a specific treatment course.
• Chest computed tomography (CT) scan 
  This test can demonstrate the extent to which your lungs are affected by pneumonia or to find out whether there are any complications.
• Pleural fluid culture 
  For this test, a fluid sample is taken from the pleural space. A pleural space is a narrow and usually germ-free space that is present between the two layers of tissue that cover the outside of the lungs and the inner side of the chest cavity. This procedure is known as “thoracentesis.” The fluid thus collected, is examined to look for any microorganisms that might have caused pneumonia.
• Pulse oximetry 
  This test is carried out to check how much oxygen is present in your blood. It is performed by simply attaching a sensor to your ear or index finger. Sometimes the oxygen level in the blood may need to be measured by performing the arterial blood gas test, which is done by taking a blood sample.
• Bronchoscopy 
  It is a procedure performed using a flexible thin tube, which is passed through the mouth or nose into the windpipe to reach the lungs. It is usually carried out if the prescribed antibiotics are not working as expected.

Treatment for pneumonia mainly depends on the pneumonia type, its severity, and the causative microorganism. The treatment is mainly focused on relieving the symptoms, resolve the infection and to prevent the development or worsening of complications.

• Usually, viral pneumonia resolves by itself within one to three weeks. Antiviral medications may be prescribed by your physician.
• In the case of bacterial pneumonia, an antibiotic course is the treatment of choice. The symptoms may get relieved soon after starting the medications. However, It is recommended to take the antibiotics for the prescribed period of time to completely resolve the infection, failing to do so has a high chance of getting a relapse of pneumonia.  An improvement can be seen in one’s condition within one to three days of antibiotic course. People with severe infection or complications may require hospitalisation. If the oxygen level in the bloodstream drops, oxygen therapy may be given.
• Most people with community-acquired pneumonia are treated at home.

Lifestyle management

If you already are suffering from pneumonia, you can take the following steps to recover faster and prevent further complications.

• Take medicines regularly as prescribed by the doctor.
• Take ample rest.
• Minimise physical contact with family and friends.
• Cover your mouth and nose with a thick handkerchief or a tissue, while coughing or sneezing.
• Dispose off the used tissues immediately.
• Wash your hands frequently.

All the above-mentioned things will help prevent the spread of infection to other people.

Recovery after pneumonia takes time. Some people may heal faster and continue with their normal routines within a week, while for others, it can take up to a month or more. It is best to consult your doctor about getting back to your normal routine.

Prognosis

Most people with pneumonia recover completely, more so when prompt medical treatment and care is given. However, pneumonia can be fatal, especially for the aged and those with underlying chronic diseases. Pneumonia, however, usually does not cause any permanent damage to the lungs. 

Complications

If left untreated, pneumonia could lead to the following complications:

• Lung abscess 
  It is a condition in which bacterial infection of the lung tissue causes the affected tissues to die leading to the development of pus in that space. It is usually treated with antibiotics. Sometimes surgery or drainage (with a needle) may be needed.
• Bacteraemia 
  It is a condition when the bacteria spread from the original infection site into the bloodstream. It is a serious complication.
• Septic shock 
  Bacteraemia may lead to septic shock. Septic shock can be fatal as well.
• Pleural effusion 
  This condition leads to fluid build-up in the pleural space, which is a narrow space between the two layers (pleura), one is the inner lining of the chest cavity and the other covers the outer side of the lungs.
• Empyema 
  In this condition, the fluid build-up in the pleural space gets infected. Empyema may necessitate the drainage of fluid through a chest tube.
• Pleurisy 
  Pleurisy is said to occur when the two layers of the pleura become swollen or inflamed. This causes a sharp pain every time you inhale.
• Respiratory failure 
  Acute Respiratory Distress Syndrome (ARDS) is a severe form of respiratory failure. If this happens, a ventilator is required to help the person breathe.