PatientPlus articles are written by UK doctors and are based on research evidence, UK and European Guidelines. They are designed for health professionals to use, so you may find the language more technical than the condition leaflets.
Synonyms: pallid syncopal attack, white breath-holding attacks
Reflex anoxic seizures are paroxysmal, spontaneously-reversing brief episodes of asystole triggered by pain, fear or anxiety. Anoxic seizures are non-epileptic events caused by a reflex asystole due to increased vagal responsiveness. They are often misdiagnosed as epilepsy.
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- Reflex anoxic seizures occur mainly in young children (infants and preschool children) but can occur at any age.
- Misdiagnosis is common but it is estimated that 0.8% of preschool children are affected.
- One study of children referred for 'fits, faints and funny turns' found that 23% had one of the childhood epilepsies (with 48% of these having a specific epilepsy syndrome). Syncope was the most common cause of a non-epileptic event (syncope and reflex anoxic seizures were diagnosed in 42%). 14% of the children were unclassified and managed without a diagnostic label or treatment.
- They can occur at any age; however, the peak age group is from 6 months to 2 years.
- Increased vagal tone tends to be familial.
- During the episode, the child becomes suddenly pale and limp, will fall if standing and loses consciousness.
- This is followed by stiffening and clonic jerking of the limbs.
- The episode is usually brief (30-60 seconds) and recovery is rapid.
- There may also be upward eye deviation and urinary incontinence.
- On recovery, the child may feel tired and washed-out for some time.
- Reflex anoxic seizures do not cause tongue-biting and this may be useful in the differentiation from epilepsy.
- Epilepsy is frequently misdiagnosed.
- Causes of syncope in childhood include:
- Often diagnosed on the basis of the history and normal electroencephalogram (EEG).
- ECG: exclude a long QT interval, pre-excitation, heart block or ventricular hypertrophy.
- Vagal excitation tests, while under continuous EEG and ECG monitoring (ocular compression induces the oculo-cardiac reflex). This procedure is not usually advised or necessary in order to make the diagnosis in children.
- Reflex anoxic seizures can usually be managed just with reassurance. Drug treatment is rarely, if ever, needed.
- Parents should be advised to place the child in the recovery position and avoid the natural tendency to pick up the child.
- Pacemaker insertion is the only definitive treatment and is only used for frequent, severe cases.
- Apart from pacemaker insertion, most other anti-syncope therapies are ineffective. Valproate and carbamazepine are effective in abolishing anoxic-epileptic seizures but do not influence the frequency of syncope.
Reflex anoxic seizures are benign. The child usually grows out of it.
Further reading & references
- STARS; Syncope Trust and Reflex Anoxic Seizures
- Epilepsies: diagnosis and management; NICE Clinical Guideline (January 2012)
- Hindley D, Ali A, Robson C; Diagnoses made in a secondary care "fits, faints, and funny turns" clinic. Arch Dis Child. 2006 Mar;91(3):214-8.
- McLeod KA; Syncope in childhood. Arch Dis Child. 2003 Apr;88(4):350-3.
- Wilson D, Moore P, Finucane AK, et al; Cardiac pacing in the management of severe pallid breath-holding attacks. J Paediatr Child Health. 2005 Apr;41(4):228-30.
- Iyer A, Appleton R; Management of reflex anoxic seizures in children. Arch Dis Child. 2013 Sep;98(9):714-7. doi: 10.1136/archdischild-2012-303133. Epub 2013 Jun 28.
- Horrocks IA, Nechay A, Stephenson JB, et al; Anoxic-epileptic seizures: observational study of epileptic seizures induced by syncopes. Arch Dis Child. 2005 Dec;90(12):1283-7. Epub 2005 Sep 13.
Disclaimer: This article is for information only and should not be used for the diagnosis or treatment of medical conditions. EMIS has used all reasonable care in compiling the information but make no warranty as to its accuracy. Consult a doctor or other health care professional for diagnosis and treatment of medical conditions. For details see our conditions.
Dr Colin Tidy
Dr Colin Tidy
Dr Adrian Bonsall