What is Pneumonia?
Pneumonia is an infection of one or both lungs which is usually caused either by fungi, bacteria or viruses. It is an inflammatory illness of the lungs. Over three million people develop pneumonia each year in the United States alone. Until recent times, one-third of all people who developed pneumonia subsequently died from the infection, but this has reduced to some extent due to antibiotics.
Symptoms of Pneumonia
Some of the typical symptoms associated with pneumonia are:
01) High fever (up to 104 degrees F) with shaking chills
02) Breathing difficulty
03) Persistent Cold
04) Cough with sputum production
05) Sharp, stabbing pain in the lungs (aggravated with coughing)
06) Discolored and sometimes bloody sputum on coughing
08) Cyanosis (blue-tinged skin)
09) Sweaty and clammy skin
10) Loss of appetite
11) Fatigue and weakness
12) Nausea and vomiting
13) Mood swings
14) Joint and muscle pains
16) Low blood pressure
Diagnosis of Pneumonia
Symptoms of pneumonia need immediate medical evaluation. Physical examination would show expansion of the chest cavity. The doctor will look for signs of high fever, chills, cough, cold, stabbing pain, cyanosis, congestion despite absence of asthma, etc.
Sputum samples: Sputum samples (containing a little saliva too) are collected for microscopic examination. If the pneumonia is caused by bacteria or fungi, the organisms can be subsequently identified by this method. It is important to undertake this laboratory test fairly quickly.
Blood count: A blood test to check for white blood cell count (WBC) is undertaken. The increased number of neutrophils, one type of WBC, indicates bacterial Pneumonia; whereas, an increase in lymphocytes is a sure sign of viral Pneumonia.
Bronchoscopy: After a local anesthetic is administered, a thin, flexible, lighted viewing tube is inserted into the nose or mouth. The breathing passages are directly examined by the doctor and specimens from the infected part of the lung are taken for further testing.
X-ray: An X-ray would show a white shadow on the affected lung representing consolidation. But, other problems like lung scarring and congestive heart failure appear almost the same on an X-ray, so a CT scan may be advised.
Computer Tomography (CT) scans: In the case of inconclusive diagnosis, a CT scan may be advised by the doctor in order to distinguish pneumonia from other pulmonary infections.
Causes of Pneumonia
Pneumonia can be caused by microorganisms, irritants and unknown causes but microorganisms are the most common cause of Pneumonia. The most common organisms that cause Pneumonia are viruses and bacteria.
1) Viruses: The viruses infect the cells that are lining the airways and alveoli (branches of the respiratory tree in the lungs). This leads to spontaneous cell destruction as the immune system’s responds to viral infection. Then the WBCs, mainly lymphocytes, activate certain chemical cytokines which allow fluid to leak into the damaged alveoli. The combination of cell destruction and fluid-filled alveoli disrupts the normal carriage of oxygen into the bloodstream disrupting other bodily functions too. The usual viruses causing pneumonia are adenovirus, influenza virus, respiratory syncytial virus (RSV), etc.
2) Bacteria: Bacterium Streptococcus pneumoniae (or pneumococcus) is the common cause of pneumonia. Once inside, bacteria invade the spaces between cells and between alveoli. This triggers the immune system to send WBCs called neutrophils to the lungs as a defensive mechanism. The neutrophils, bacteria, and fluid from surrounding blood vessels fill the alveoli and interrupt normal oxygen transportation in the bloodstream. Bacteria can also infect the pleural cavity causing other complications.
3) Fungi: This type of Pneumonia is rare but it may occur in patients having immune system problems due to AIDS; who are on immuno-suppresive drugs or other medical problems. The symptoms of pneumonia and subsequent damage caused by fungi and bacteria are similar. Fungal pneumonia is most often caused by histoplasma capsulatum, blastomyces, etc.
4) Parasites: Invasion of parasites is through the skin or by swallowing. They travel through the blood into the lungs leading to the usual combination of cellular destruction and immune response causes disruption of oxygen transportation. The eosinophil, a type of white blood cell, responds vigorously to parasitic infection. Further, pneumonia caused by eosinophils adds to the complication. Toxoplasma gondii and Strongyloides stercoralis are the common parasites causing Pneumonia.
Types of Pneumonia
Pneumonia can be classified as acute Pneumonia (less than three week’s duration) and chronic Pneumonia. The treatment and care for chronic type is a lengthy process. There are various classifications of Pneumonia:
A) Community or hospital acquired: This is infectious Pneumonia and is caused by virus or atypical bacteria. Hospital-acquired usually occurs in hospitalized patients due to mechanical ventilation, prolonged malnutrition, underlying heart and lung diseases and immune disturbances.
B) Idiopathic Interstitial Pneumonia (IIP): This is a type of Pneumonia where the testing does not show any positive indications as to the type of infection. A perfect example is Desquamative Interstitial Pneumonia which is caused by cigarette smoking.
C) Lobar Pneumonia: In this type of pneumonia, only a single lobe or a section of a lung develops pneumonia. This usually happens in the case of bacterial pneumonia.
D) Multilobar Pneumonia: This is a more severe case where more than one lobe is affected. This type also causes other illnesses as it adversely affects the functions of the other organs.
E) Interstitial Pneumonia: This is a type where viruses or atypical bacteria affect the areas between the alveoli.
F) Severe Acute Respiratory Syndrome (SARS): This is a highly contagious type of pneumonia which has caused a number of deaths in China and South East Asian countries in 2002.
G) Bronchiolitis Obliterans Organizing Pneumonia (BOOP): Also called COP or Cryptogenic Organizing Pneumonitis, this type of pneumonia is caused by inflammation of the small airways of the lungs.
H) Chemical Pneumonia: This is caused by chemical toxicants such as pesticides, which may enter the body by inhalation or by skin contact. It is also called chemical Pneumonitis. When the toxic substance is oil, the pneumonia may be called lipoid Pneumonia.
I) Aspiration Pneumonia: This type of Pneumonia is caused by aspirating foreign objects which are usually oral or gastric contents, either while eating or after reflux or vomiting which results in Bronchopneumonia. The resulting lung inflammation is not an infection. This is common in hospital patients and can be fatal as the airways cannot be sufficiently protected due to impaired defenses.
J) Allergic Pneumonia: This type of Pneumonia occurs due to dust allergy. Dust settles in the lungs right to the alveoli blocking the normal transportation of oxygen in the bloodstream.
Treatment of Pneumonia
Home care & oral medication: Oral antibiotics, rest, fluids, and home care are sufficient in most cases. Antibiotics are used to cure Bacterial Pneumonia. But as they do not cure the viral type, they are used to prevent the bacterial kind infecting the lungs simultaneously. Treatment for pneumonia is ideally based on the microorganism causing it and its known sensitivity to antibiotics, although the exact cause can be identified in only 50% of the cases. Amoxicillin and clarithromycin or erythromycin are used to treat community-acquired pneumonia. Allergic type specifically requires the use of penicillin.
Hospitalization & IVs: Hospitalization becomes very essential in the case of pleural effusion (fluid collection in the pleural space around lungs). If the case is very severe, then the fluid is removed by Thoracentesis, where a needle is inserted into the chest cavity and the fluid is withdrawn with a syringe followed by artificial ventilation.
Hospital-acquired pneumonia are treated using vancomycin, cephalosporins, carbapenems, fluoroquinolones and aminoglycosides which are usually given intravenously. A combination of antibiotics is administered in order to treat all microorganisms that might be the cause. This becomes necessary to prevent a life threatening situation.
Living with Pneumonia
Circulatory and Respiratory failure and Pleural effusion: Pneumonia can cause Acute Respiratory Distress Syndrome (ARDS) due to severe infection and inflammation. The lungs quickly fill with fluid and become very stiff and the use of non-invasive breathing assistance with a bi-level positive airway pressure machine becomes essential. Sometimes, an endo-tracheal tube (breathing tube) is used along with a ventilator to help the person breathe.
Mortality: In the United States alone, 20% of the Pneumonia patients die of the disease. There are no known effective treatments for viral pneumonias caused by the parainfluenza virus, adenovirus, coronavirus or hantavirus. Avian influenza or “bird flu” is resistant to treatment as well. Also, mortality rate of those infected with MRSA Pneumonia is very high.
Prevention of Pneumonia
The Pneumonia contracted by the patient in a hospital environment cannot be prevented but has to be cured very quickly as the patient is already suffering from another disease. But community-acquired Pneumonia can be prevented to some extent by some methods:
1) Smoking cessation
2) Prevention of any respiratory infections
3) Prevention of AIDS which would weaken the immune system
4) Testing pregnant women for infection to prevent infant pneumonia
5) Vaccination of children and adults (effective for 10 years)
The World Health Organization (WHO) estimates that one in three newborn infant deaths is due to Pneumonia. Estimates also show that up to a million infant deaths are caused by the bacteria Streptococcus pneumoniae, and 90% of these deaths take place in developing countries; and that they are preventable by vaccines. Mortality due to Pneumonia is more often among infants and the elderly. Pneumonia is the sixth leading cause of death in the United States.