Why is pneumonia so dangerous? - Eve Gaus and Vanessa Ruiz

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Every time you breathe, air travels down the trachea, through a series of channels, and then reaches little clusters of air sacs in the lungs. These tiny sacs facilitate a crucial exchange: allowing oxygen from the air we breathe into the bloodstream and clearing out carbon dioxide. Pneumonia wreaks havoc on this exchange system. Eve Gaus and Vanessa Ruiz detail how pneumonia attacks the lungs.

Lesson by Eve Gaus and Vanessa Ruiz, directed by Artrake Studio.

Every time you breathe in,
air travels down the trachea,

through a series of channels
called bronchi,

and finally reaches little clusters
of air sacs called alveoli.

There are some 600 million alveoli
in the lungs,

adding up to a surface area
of roughly 75 square meters—

the size of a tennis court.

These tiny sacs, only one cell thick,
facilitate a crucial exchange:

allowing oxygen from the air
we breathe into the bloodstream

and clearing out carbon dioxide.

Pneumonia wreaks havoc
on this exchange.

Pneumonia is an infection of the alveoli
that causes them to fill with fluid.

There are many different kinds
of pathogens that can cause pneumonia.

The most common ones
are viruses or bacteria.

These microscopic invaders enter the body
via droplets either in the air we breathe,

or when we touch our eyes, noses,

or mouths after touching
a contaminated surface.

Then, they face the respiratory tract’s
first line defense:

the mucociliary escalator.

The mucociliary escalator consists of
mucus that traps invaders and tiny hairs

called cilia that carry the mucus toward
the mouth, where it can be coughed out.

But some of these invaders
may get past the mucociliary escalator

into the lungs,
where they meet the alveoli.

Because alveoli serve
as critical exchange points

between the blood and air
from the outside world,

they have their own specialized types
of white blood cells, or macrophages,

which defend against foreign organisms
by enveloping and eating them.

When pathogens enter the lungs,
the macrophages work to destroy them.

The immune system releases additional
white blood cells in the alveoli to help.

As these immune cells fight the pathogens,
they generate inflammation—

and fluid as a by-product
of the inflammation.

When this fluid builds up,

it makes gas exchange inside
the alveoli much more difficult.

As the level of carbon dioxide
in the bloodstream begins to rise,

the body breathes more quickly to try
to clear it out and get more oxygen in.

This rapid breathing is one of the most
common symptoms of pneumonia.

The body also tries to force the fluid out
of the alveoli through coughing.

Determining the cause of pneumonia
can be difficult,

but once it is established,
doctors can prescribe antibiotics,

which may include either antibacterial
or antiviral treatments.

Treatment with antibiotics helps
the body get the infection under control.

As the pathogen is cleared out,

the body gradually expels or absorbs
fluid and dead cells.

The worst symptoms typically fade out
in about a week,

though full recovery may take
as long as a month.

Otherwise healthy adults can often
manage pneumonia at home.

But for some groups, pneumonia
can be a lot more severe,

requiring hospitalization and oxygen,
artificial ventilation,

or other supportive measures
while the body fights the infection.

Smoking damages the cilia,

making them less able to clear even
the normal amount of mucus and secretions,

let alone the increased volume
associated with pneumonia.

Genetic and autoimmune disorders

can make someone more susceptible
to pathogens that can cause pneumonia.

Young children and the elderly
also have impaired clearance

and weaker immune systems.

And if someone has viral pneumonia,

their risk of bacterial respiratory
infection is higher.

Many of the deaths from pneumonia
are due to lack of access to healthcare.

But sometimes, even with appropriate care,

the body enters a sustained fight against
the infection it can’t maintain,

activating inflammatory pathways
throughout the body,

not just in the lungs.

This is actually a protective mechanism,

but after too long in this state organs
start shutting down,

causing shock and sometimes death.

So how can we prevent pneumonia?

Eating well and getting enough sleep
and exercise

helps your body fight off infections.

Vaccines can protect against common
pneumonia-causing pathogens,

while washing your hands regularly helps
prevent the spread of these pathogens—

and protect those most vulnerable
to severe pneumonia.