THE act of breathing consists of alternating efforts of breathing in (inhalation or inspiration) of air to the lungs through the airways and breathing out (exhalation or expiration) of air from the lungs.
The airway (respiratory tract) is composed of tubes that channels air from the nose and throat to the lungs. The tube that connects the throat with the trachea is called the larynx that contains the two vocal cords (voice box) responsible for vocalization.
The trachea, also known as windpipe, is the main tube that connects the larynx to the lungs. The trachea divides into two parts to form the bronchi (smaller respiratory tubes) that lead respectively to the right and left lungs.
The nose, throat, larynx and trachea comprise the upper airway. The bronchi, which further subdivide into smaller tubes to the lungs, constitute the lower airway.
Normal breathing efforts are not accompanied by any audible sound. If there is obstruction or narrowing at any point in the airway, the flow of air against the obstruction will result in turbulence leading to noisy breathing.
The noisy breathing may originate from obstruction anywhere in the airway. Obstruction of the nose causes the sound of snoring. Obstruction in the throat results in gurgling type of noisy breathing. Laryngeal obstruction presents with high pitched noisy breathing during inspiration, while bronchial obstruction presents with expiratory wheezing sound. The presence of both inspiratory and expiratory noisy breathing is found in tracheal obstruction.
There are 2 types of noisy breathing: 1. Stridor -- is a sound originating from upper airway obstruction, often high pitched and usually inspiratory. 2. Wheezing -- is a musical sound that originates from lower airway obstruction occurring during expiration.
Stridor
The young infant with stridor is most likely to have congenital malformation of the upper airway. Infection as a cause of stridor commonly occurs between 1 and 4 years of age. Stridor from enlargement of adenoids and tonsils usually manifest in children aged 2-8 years.
Foreign body aspiration is a problem in any age group. It should always be considered in a child with stridor.
The most common cause of stridor in infants is laryngomalacia, a benign, minor developmental variation (delayed maturation) of the larynx. Laryngomalacia or congenital stridor accounts for more than 75% of all laryngeal problems of infants.
The condition presents as a rattling, vibratory or high-pitched inspiratory sound made worse by crying and straining but usually disappears during sleep, rest or placing the child on prone position.
The onset of noisy breathing in laryngomalacia occurs during the first week of life and worsens during the first year as a result of the infant's increased activity and respiratory effort. The noisy breathing usually disappears at the age of 18 months. Some may persist for years.
Once the diagnosis is made, treatment of laryngomalacia consist of close observation and reassurance of the parents that the condition is benign, self-limited and will improve. Rarely, the condition will require hospitalization. On very rare occasions, the obstruction will become severe enough that surgical intervention may become necessary. (To be concluded next week). (PVI)
