Foreign body aspiration
The human body has numerous defense mechanisms to keep the airway free and clear of outside debris. These include the physical actions of the protective cartilages of the throat in blocking the airway, the intense spasm of the vocal cords any time objects come near them, and a highly sensitive cough reflex generated throughout the throat, trachea, and all branch points in lower respiratory tract. However, none of these mechanisms is perfect, and foreign bodies frequently lodge in the airways of children.
Children are more prone to aspirate foreign material for several reasons. The lack of molar teeth in children decreases their ability to sufficiently chew food, leaving larger chunks to swallow. The propensity of children to talk, laugh, and run while chewing also increases the chance that a sudden or large inspiration may occur with food in the mouth. Children often examine even nonfood substances with their mouth.
More foreign body aspirations occur in children younger than 3 years than in other age groups, with a peak between the first and second birthdays. However, foreign bodies have been found in the airways of individuals of all ages and sizes. Even relatively immobile infants may aspirate foreign bodies, despite not having the ability to crawl and find things or the ability to pick up objects and put them in the mouth. They have less chewing capacity and higher respiratory rates, so any objects placed in their mouths are more likely to be aspirated than in older children. They also have well-meaning siblings, who may put the wrong foods in the baby’s mouth in an attempt to help feed them.
The most common aspirated items are small food items such as nuts, raisins, sunflower seeds, improperly chewed pieces of meat and small, smooth items such as grapes, hot dogs, and sausages. All of these should be avoided until the child is able to adequately chew them while sitting. Generally, this occurs around age 5 years, with most foreign body aspirations occurring in children younger than 3 years. Small items that are round, smooth, or both (eg, grapes, hot dogs, sausages, balloons) are more likely to cause dangerous airway obstruction and choking. Dried foods may cause progressive obstruction as they absorb water.
Often, the child presents after a sudden episode of coughing or choking while eating with subsequent wheezing, coughing, or a high pitched musical wheezing called stridor. However, in numerous cases, the choking episode is not witnessed, and, in many cases, the choking episode is not recalled at the time of a medical visit.
The most tragic cases occur when acute aspiration causes total or near-total occlusion of the airway, resulting in death or brain damage from prolonged lack of oxygen.
The more difficult cases are those in which aspiration is not witnessed or is unrecognized and, therefore, is unsuspected.
In these situations, the child may present with persistent or recurrent cough, wheezing, persistent or recurrent lung infections or pneumonia and/or coughing bloody phlegm.
If the material is lodged underneath the voice box, symptoms may include high pitched wheezing, recurrent or persistent breathing difficulty with a barking cough, and voice changes.
How is the diagnosis of a foreign body made?
Most aspirated foreign bodies are food material and are appear white on an X-Ray allowing the diagnosis by a radiologist.
Occasionally, when plain X-rays do not make the diagnosis, a Chest CT scan may be ordered that will reveal the material in the airway, suspicious swelling and overinflation of the lung from an obstructed airway leading to it. If the suspicion of a foreign body is high, the definitive diagnosis and treatment will be achieved by performing bronchoscopy.
Bronchoscopy is a procedure performed under general anesthesia or heavy sedation which involves a careful insertion of a long and slender metallic tube through the mouth to visualize the throat, trachea or small branches of airway called the bronchi that lead into the lungs. The purpose of this procedure is to identify a foreign body and at the same time extract it using very fine microscopic instruments that can grasp the foreign body.
Acute choking, with respiratory failure associated with tracheal or throat foreign body obstruction, may be successfully treated at the scene with the Heimlich maneuver, back blows, and abdominal thrusts.