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Pneumonia

Category: Illness or disabilities

Type

Involuntary

Introduction and description

Pneumonia is an inflammatory condition of the lung, especially of the alveoli (microscopic air sacs in the lungs). 

Pneumonia was regarded by William Osler in the 19th century as "the captain of the men of death", however, the introduction of antibiotics and vaccines in the 20th century has seen radical improvement in the survival of patients in developed countries. In less developed countries, and among the very old, the very young and the chronically ill, pneumonia remains a leading cause of death.

Pneumonia affects approximately 450 million people a year and occurs in all parts of the world. It is a major cause of death resulting in 4 million deaths per year (7% of the worlds yearly total). Rates are greatest in children less than five and adults older than 75 years of age. It occurs about five times more frequently in the developing world versus the developed world.  

Causes

Whilst typically caused by an infection – bacteria or viruses for example -  there are a number of non infectious causes including fungi, and parasites.  Fungal pneumonia is uncommon, but it may occur in individuals with immune system problems due to AIDS, immunosuppressive drugs, or other medical problems.

Bacteria are the most common cause of community acquired pneumonia with Streptococcus pneumoniae isolated in nearly 50% of cases.  Other commonly isolated bacteria include: Haemophilus influenzae in 20%, Chlamydophila pneumoniae in 13%, , and Mycoplasma pneumoniae in 3%.

Other important Gram-positive cause of pneumonia is Staphylococcus aureus, with Streptococcus agalactiae being an important cause of pneumonia in newborn babies. Gram-negative bacteria cause pneumonia less frequently than gram-positive bacteria. Some of the gram-negative bacteria that cause pneumonia include Haemophilus influenzae, Klebsiella pneumoniae, Escherichia coli, Pseudomonas aeruginosa and Moraxella catarrhalis. These bacteria often live in the stomach or intestines and may enter the lungs if vomit is inhaled. "Atypical" bacteria which cause pneumonia include Chlamydophila pneumoniae, Mycoplasma pneumoniae, and Legionella pneumophila.

Viruses - In adults viruses account for approximately a third of pneumonia cases.Commonly implicated agents include: rhinoviruses  coronaviruses,  influenza virus,  respiratory syncytial virus (RSV), adenovirus,  and parainfluenza.   Herpes simplex virus is a rare cause of pneumonia. People with weakened immune systems are at increased risk of pneumonia caused by cytomegalovirus (CMV).

Parasites - A variety of parasites can affect the lungs. These parasites typically enter the body through the skin or by being swallowed.  The most common parasites causing pneumonia are Toxoplasma gondii, Strongyloides stercoralis, and Ascariasis.

Typical symptoms include cough, chest pain, fever, and difficulty breathing.  In acute cases the person may turn blue due to the lack of oxygen.

How it works

Pneumonia causes hypoxia, and it is the hypoxia that produces the spiritual experience. 

It does so via a complex set of actions dependent on the cause of the pneumonia….

Viruses - Typically, a virus reaches the lungs when airborne droplets are inhaled through the mouth and nose. Once in the lungs, the virus invades the cells lining the airways and alveoli. This invasion often leads to cell death, either when the virus directly kills the cells, or through a type of cell controlled self-destruction called apoptosis. When the immune system responds to the viral infection, even more lung damage occurs. White blood cells, mainly lymphocytes, activate certain chemical cytokines which allow fluid to leak into the alveoli. And it is this combination of cell destruction and fluid-filled alveoli that interrupts the normal transportation of oxygen into the bloodstream.

Bacteria  - typically enter the lung when airborne droplets are inhaled, but can also reach the lung through the bloodstream when there is an infection in another part of the body. Many bacteria live in parts of the upper respiratory tract, such as the nose, mouth and sinuses, and can easily be inhaled into the alveoli. Once inside, bacteria may invade the spaces between cells and between alveoli through connecting pores. This invasion triggers the immune system to send neutrophils, a type of defensive white blood cell, to the lungs. The neutrophils engulf and kill the offending organisms, and also release cytokines, causing a general activation of the immune system. The neutrophils, bacteria, and fluid from surrounding blood vessels fill the alveoli and interrupt normal oxygen transportation.

Parasites -  The parasites typically enter the body through the skin or by being swallowed. Once inside, they travel to the lungs, usually through the blood. There, as in other cases of pneumonia, a combination of cellular destruction and immune response causes disruption of oxygen transportation.

 

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