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- Main article: Seizures
Convulsions or Non-epileptic seizures are paroxysmal events that mimic an epileptic seizure but do not involve abnormal, rhythmic discharges of cortical neurons. They are caused by either physiological or psychological conditions. The latter is discussed more fully in psychogenic non-epileptic seizures.
- Benign familial neonatal convulsions
- Jackknife convulsions also known as West syndrome
- Reflex anoxic seizures are a condition of the brain where the child may become pale and limp and cease breathing, only to recover a short time later. Anoxic seizures are caused by a reflex asystole of the heart due to increased vagal responsiveness. They are non-epileptic.
A wide spectrum of phenomena may resemble epileptic seizures, which may lead to people who do not have epilepsy being misdiagnosed. Indeed, a significant percentage of people diagnosed with epilepsy later have this revised. In one study, the majority of children referred to a secondary clinic with "fits, faints and funny turns" did not have epilepsy, with syncope (fainting) as the most common alternative. In another study, 39% of children referred to a tertiary epilepsy centre did not have epilepsy, with staring episodes in mentally retarded children as the most common alternative. In adults, the figures are similar, with one study reporting a 26% rate of misdiagnosis.
The International League Against Epilepsy (ILAE) define an epileptic seizure as "a transient occurrence of signs and/or symptoms due to abnormal excessive or synchronous neuronal activity in the brain." Epileptic seizures can occur in someone who does not have epilepsy – as a consequence of head injury, drugs, toxins, eclampsia or febrile convulsions, for example.
Medically, when used on its own, the term seizure implies an epileptic seizure. The lay use of this word can also include sudden attacks of illness, loss of control, spasm or stroke. Where the physician is uncertain as to the diagnosis, the medical term paroxysmal event and the lay terms spells, funny turns or attacks may be used.
The various pathophysiological causes include:
- Benign paroxysmal positional vertigo
- Breath-holding spells of childhood
- Hyperekplexia, also called startle syndrome
- Hypoglycemia and associated neuroglycopenia
- infantile gratification / masturbation (onanism)
- Non-epileptic myoclonus
- Parasomnias, including night terrors
- Paroxysmal kinesiogenic dyskinesia
- Repetitive or ritualistic behaviours
- Syncope (fainting)
Causes of provoked seizures include:
- Arteriovenous malformation (AVM) is a treatable medical condition that can cause seizures, headaches, and brain hemorrhages. An MRI can quickly confirm or reject this as a cause.
- head injury may cause non-epileptic post-traumatic seizures or post-traumatic epilepsy, in which the seizures chronically recur.
- intoxication with drugs
- drug toxicity, for example aminophylline or local anaesthetics
- normal doses of certain drugs that lower the seizure threshold, such as tricyclic antidepressants
- infection, such as encephalitis or meningitis
- fever leading to febrile convulsions (but see above)
- metabolic disturbances, such as hypoglycaemia, hyponatremia or hypoxia
- withdrawal from drugs (anticonvulsants and sedatives such as alcohol, barbiturates, and benzodiazepines)
- space-occupying lesions in the brain (abscesses, tumors)
- seizures during (or shortly after) pregnancy can be a sign of eclampsia.
- binaural beat brainwave entrainment may trigger seizures in both epileptics and non-epileptics
- haemorrhagic stroke can occasionally present with seizures, embolic strokes generally do not (though epilepsy is a common later complication); cerebral venous sinus thrombosis, a rare type of stroke, is more likely to be accompanied by seizures than other types of stroke
- multiple sclerosis sufferers may rarely experience seizures
- certain light patterns, such as those found in video games or other media.
Some medications produce an increased risk of seizures and electroconvulsive therapy (ECT) deliberately sets out to induce a seizure for the treatment of major depression. Many seizures have unknown causes.
Seizures which are provoked are not associated with epilepsy, and people who experience such seizures are normally not diagnosed with epilepsy. However, the seizures described above resemble those of epilepsy both outwardly, and on EEG testing.
Seizures can occur after a subject witnesses a traumatic event. This type of seizure is known as a psychogenic non-epileptic seizure and is related to posttraumatic stress disorder.
Mild seizures can be induced through a combination of quickly standing, hyperventilation and applying pressure to the sternum.
- Anticonvulsive drugs
- Audiogenic seizures
- Brain disorders
- Experimental epilepsy
- Febrile seizure
- Gelastic seizure
- Hair-grooming syncope
- Hypnic jerk
- Non-epileptic seizure
- Post-traumatic seizure
- Psychogenic non-epileptic seizures
- Reflex anoxic seizures
- Epilepsy Foundation article about non-epileptic seizures
- National Society for Epilepsy (UK) article on Non-epileptic attack disorder. A slightly more technical article aimed at health professionals.
- (October 2003) Joseph H. Ricker (ed) Differential Diagnosis in Adult Neuropsychological Assessment, 109, Springer Publishing Company. ISBN 0-8261-1665-5.
- Hindley D, Ali A, Robson C (2006). Diagnoses made in a secondary care "fits, faints, and funny turns" clinic. Arch Dis Child 91 (3): 214-8. PMID 16492885. (Free full text online)
- Uldall P, Alving J, Hansen LK, Kibaek M, Buchholt J (2006). The misdiagnosis of epilepsy in children admitted to a tertiary epilepsy centre with paroxysmal events. Arch Dis Child 91 (3): 219-21. PMID 16492886. (Free full text online)
- Smith D, Defalla BA, Chadwick DW (1999). The misdiagnosis of epilepsy and the management of refractory epilepsy in a specialist clinic. QJM 92 (1): 15-23. PMID 10209668. (Free full text online)
- Fisher R, van Emde Boas W, Blume W, Elger C, Genton P, Lee P, Engel J (2005). Epileptic seizures and epilepsy: definitions proposed by the International League Against Epilepsy (ILAE) and the International Bureau for Epilepsy (IBE).. Epilepsia 46 (4): 470-2. PMID 15816939. (Free full text online).
- Nechay A, Ross LM, Stephenson JB, O'Regan M (2004). Gratification disorder ("infantile masturbation"): a review. Arch Dis Child 89 (3): 225-6. PMID 14977696.
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