Definition

Laryngitis is caused by inflammation of the larynx,
resulting in hoarseness of the voice.

Description

When air is breathed in (inspired), it passes through
the nose and the nasopharynx or through the mouth and
the oropharynx. These are both connected to the larynx, a
tube made of cartilage. The vocal cords, responsible for
setting up the vibrations necessary for speech, are located
within the larynx. The air continues down the larynx to
the trachea. The trachea then splits into two branches, the
left and right bronchi (bronchial tubes). These bronchi
branch into smaller air tubes which run within the lungs,
leading to the small air sacs of the lungs (alveoli).

Either food, liquid, or air may be taken in through the
mouth. While air goes into the larynx and the respiratory
system, food and liquid are directed into the tube leading
to the stomach, the esophagus. Because food or liquid in
the bronchial tubes or lungs could cause a blockage or
lead to an infection, the airway must be protected. The
epiglottis is a leaf-like piece of cartilage extending
upwards from the larynx. The epiglottis can close down
over the larynx when someone is eating or drinking, preventing
these substances from entering the airway.

In laryngitis, the tissues below the level of the
epiglottis are swollen and inflamed. This causes swelling
around the area of the vocal cords, so that they cannot
vibrate normally. A hoarse sound to the voice is very
characteristic of laryngitis. Laryngitis is a very common
problem, and often occurs during the course of an upper
respiratory tract infection (cold).

Causes and symptoms

Laryngitis is caused almost 100% of the time by a
virus. The same viruses which cause the majority of simple
upper respiratory infections (colds, etc.) are responsible
for laryngitis. These include parainfluenzae virus,
influenza virus, respiratory syncytial virus, rhinovirus,
coronavirus, and echovirus. Extremely rarely, bacteria
such as Group A streptococcus, M. catarrhalis, or that
which causes tuberculosis may cause laryngitis. In people
with faulty immune systems (particular due to
acquired immunodeficiency syndrome, or AIDS), infections
with fungi may be responsible for laryngitis.

Symptoms usually begin along with, or following,
symptoms of a cold. A sore, scratchy throat, fever, runny
nose, achiness, and fatigue may all occur. Difficulty swallowing
sometimes occurs with streptococcal infections.

The patient may cough and wheeze. Most characteristically,
the patient