Causes of asphyxic death: Choking

Choking

Choking is the result of occlusion of the internal airways, occurring at any level from the pharynx (throat) to the bifurcation of the trachea (windpipe). This obstruction may be caused by foreign bodies like teeth, food (eg beans), or even marbles. There are also medical conditions which can cause severe swelling of the epiglottis (valve-like structure over the larynx) with subsequent obstruction of the airway, such as anaphylaxis (severe allergic reaction) or certain bacterial infections (haemophilusinfluenzae). An example from daily life is when someone drinks a cool drink from a can with a bee trapped inside. When the person swallows the bee, and is stung in the throat, the soft tissues of the throat can swell dramatically, causing narrowing and obstruction of the airways. Fortunately this type of swelling responds rapidly to the correct treatment.

The most important post-mortem findings is the presence of a foreign body in the airway, or swelling of the mucosa and soft tissue. In cases of suspected choking, it is important that the airways be incised with a knife, and not cut open with scissors, as the foreign body will then be displaced, being pushed downwards by the tip of the scissors. Signs of asphyxia are often absent.

When interpreting the presence of gastric contents in the airways during a post-mortem examination, the following aspects need to be considered. Gastric or stomach matter often gets into the airways due to regurgitation or passive backflow from the stomach into the oesophagus and from there into the airways. This occurs especially during handling of the body. It must not be confused with aspiration of stomach contents. Aspiration of stomach contents can only be diagnosed post mortem, if:

·              it is present in the smaller airways (bronchial structures), as it can only

·              reach these structures if actively inhaled

·              there is microscopic evidence of an inflammatory process in the lung tissue due to the presence of foreign material

·              it was witnessed by someone else

The only exception to this rule is when an individual with a high blood-alcohol level has stomach contents in the airways at the post mortem. Intoxicated individuals not only are more at risk to vomit, but are also more at risk to aspirate due to their depressed protective upper-airway reflexes.

In the 1950s a condition known as bolus death (``cafe coronary syndrome'') was described where someone died suddenly and unexpectedly while eating (photos 53 and 54). Initially it was believed that he had a heart attack (therefore the reference to coronary), but in reality the cause was neurogenic heart arrest. This condition occurs when a large piece of food stimulates the back of the throat during swallowing. It then triggers vaso-vagal inhibition of the heart.