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Reflex Anoxic Seizures (RAS)

Reflex Anoxic Seizures
Download and print the RAS
information sheet

Reflex Anoxic Seizures (RAS) is the term used for a particular fit which is neither epileptic nor due to cyanotic breath-holding, but which rather results from a brief stoppage of the heart through excessive activity of the vagus nerve. I have used the term Reflex Anoxic Seizures (RAS) to describe the convulsions which accompany this particular type of syncope. Syncope (sin-co-pee) is derived from the Greek word to cut off. Syncope is the result of the temporary cutting off of the supply of oxygenated blood to the brain. The mechanism of the syncope in susceptible individuals includes reflex cardiac standstill (always reversible) commonly following a surprising bump to the head or elsewhere. Associated marked pallor of the skin has led to these attacks being called Pallid Syncope. In more recent times these attacks have been referred to as Reflex Asystolic Syncope.

Founding Patron STARS, Prof J B P Stephenson.

Dr William Whitehouse, Consultant Neurologist, Senior Lecturer in Paediatric Neurology, Nottingham Children's Hospital, provides information on the causes, triggers and symptoms associated with reflex anoxic seizures.

What are Reflex Anoxic Seizures?

These can occur mainly in young children but can occur at any age. Any unexpected stimulus, such as pain, shock, fright, causes the heart and breathing to stop, the eyes to roll up into the head, the complexion to become deathly white, often blue around the mouth and under the eyes, the jaw to clench and the body to stiffen; sometimes the arms and legs jerk. After what seems like hours, but is probably less than 30 seconds, the body relaxes, the heart starts beating (sometimes very slowly initially) and the sufferer is unconscious. One or two minutes later the person may regain consciousness but can sometimes be unconscious for over an hour. Upon recovery the person may be very emotional and then fall into a deep sleep for two to three hours and looks extremely pale with dark circles under the eyes. RAS attacks may occur several times per day/week /month. The attacks appear to come in batches.

Initial diagnosis of RAS

Step 1

Download the STARS Blackouts Checklist. This is designed to help you and your doctor to reach the correct diagnosis. If someone loses consciousness for a few seconds or minutes, they are often said to have had a blackout.

Step 2

Some General Practitioners (GPs) who are familiar with RAS will make the diagnosis themselves. If they are unsure of the condition then you should be referred to a Paediatrician. You will be asked for a full family medical history and to rule out any underlying condition, an ECG and EEG may be requested.

Further diagnosis of RAS

If there is any doubt in a diagnosis then the consultant may request an event monitor for either 24 hours or 7 days, an implantable loop recorder (ILR) or a tilt table test.

Misdiagnosis of RAS

The symptoms of RAS share common factors with a number of conditions, with the result that RAS is often misdiagnosed as temper tantrums, cyanotic breath holding (prolonged expiratory apnoea) or epilepsy.

What to do in brief.

Everyone who has responsibility for a person with RAS must know what to do in the event of an attack.

  1. Ensure the individual is placed in the recovery position in a safe environment ensuring nothing is blocking the airways.
  2. Talk reassuringly as it is known that the individual can sometimes hear but is unable to answer. Comfort upon recovery. Allow to sleep if necessary.
  3. It is not necessary to call a doctor. However, if the person has had a particularly nasty bump then it may be wise to seek medical advice.