An abbreviation for ‘acute life-threatening event’. It applies to infants, usually under one year of age, who suddenly and unexpectedly become pale or blue and appear to stop breathing. They generally recover spontaneously, although a parent or bystander often feels obliged to administer mouth-to-mouth resuscitation. By the time the baby reaches hospital he or she is usually well. In the large majority of cases the cause remains unknown, even though the events may be repeated, and the large majority of babies ‘grow out’ of the condition. In some cases, investigations show that the cause is GASTRO-OESOPHAGEAL REFLUX, when stomach acid is regurgitated into the throat and provokes reflex closure of the GLOTTIS. Other causes may be brief epileptic seizures, identified by ELECTROENCEPHALOGRAPHY (EEG); a heart ARRHYTHMIA; or a respiratory infection. Much controversy surrounds the discovery – confirmed by hidden video-recording in hospitals – that a small minority of these babies have been subjected to repeated, brief, deliberate suffocation. (See also FABRICATED AND INDUCED ILLNESS.)

Treatment is that of the underlying cause, if discovered. Parents may also be offered an APNOEA monitor, a device attached to the child – especially when asleep – which sounds an alarm if breathing stops for more than 20 seconds.