Non-epileptic seizures
Encyclopedia
Non-epileptic seizures are paroxysmal
events that mimic an epileptic seizure but do not involve abnormal, rhythmic discharges of cortical neuron
s. They are caused by either physiological
or psychological
conditions. The latter is discussed more fully in psychogenic non-epileptic seizures
.
being misdiagnosed. Indeed, a significant percentage of people initially diagnosed with epilepsy will 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 challenged children as the most common alternative. In adults, the figures are similar, with one study reporting a 26% rate of misdiagnosis.
, 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.
Paroxysmal attacks
Paroxysmal attacks are short, frequent and stereotyped symptoms that can be observed in various clinical conditions. They are usually associated with multiple sclerosis, pertussis, but they may also be observed in other disorders such as encephalitis, head trauma, stroke, asthma, trigeminal...
events that mimic an epileptic seizure but do not involve abnormal, rhythmic discharges of cortical neuron
Neuron
A neuron is an electrically excitable cell that processes and transmits information by electrical and chemical signaling. Chemical signaling occurs via synapses, specialized connections with other cells. Neurons connect to each other to form networks. Neurons are the core components of the nervous...
s. They are caused by either physiological
Physiology
Physiology is the science of the function of living systems. This includes how organisms, organ systems, organs, cells, and bio-molecules carry out the chemical or physical functions that exist in a living system. The highest honor awarded in physiology is the Nobel Prize in Physiology or...
or psychological
Psychology
Psychology is the study of the mind and behavior. Its immediate goal is to understand individuals and groups by both establishing general principles and researching specific cases. For many, the ultimate goal of psychology is to benefit society...
conditions. The latter is discussed more fully in psychogenic non-epileptic seizures
Psychogenic non-epileptic seizures
Psychogenic non-epileptic seizures , also known as Non-Epileptic Attack Disorders, are events superficially resembling an epileptic seizure, but without the characteristic electrical discharges associated with epilepsy. Instead, PNES are psychological in origin, and may be thought of as similar to...
.
Diagnosis
A wide spectrum of phenomena may resemble epileptic seizures, which may lead to people who do not have epilepsyEpilepsy
Epilepsy is a common chronic neurological disorder characterized by seizures. These seizures are transient signs and/or symptoms of abnormal, excessive or hypersynchronous neuronal activity in the brain.About 50 million people worldwide have epilepsy, and nearly two out of every three new cases...
being misdiagnosed. Indeed, a significant percentage of people initially diagnosed with epilepsy will 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
Syncope (medicine)
Syncope , the medical term for fainting, is precisely defined as a transient loss of consciousness and postural tone characterized by rapid onset, short duration, and spontaneous recovery due to global cerebral hypoperfusion that most often results from hypotension.Many forms of syncope are...
(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 challenged children as the most common alternative. In adults, the figures are similar, with one study reporting a 26% rate of misdiagnosis.
Terminology
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 injuryHead injury
Head injury refers to trauma of the head. This may or may not include injury to the brain. However, the terms traumatic brain injury and head injury are often used interchangeably in medical literature....
, drugs, toxins, eclampsia
Eclampsia
Eclampsia , an acute and life-threatening complication of pregnancy, is characterized by the appearance of tonic-clonic seizures, usually in a patient who had developed pre-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.
Causes
Possible pathophysiological causes include:- Benign paroxysmal positional vertigoBenign paroxysmal positional vertigoBenign paroxysmal positional vertigo is a disorder caused by problems in the inner ear. Its symptoms are repeated episodes of positional vertigo, that is, of a spinning sensation caused by changes in the position of the head.-Classification:...
- Breath-holding spellsBreath-holding spellsBreath holding spells are the occurrence of episodic apnea in children, possibly associated with loss of consciousness, and changes in postural tone....
of childhood - CataplexyCataplexyCataplexy is a sudden and transient episode of loss of muscle tone, often triggered by emotions. It is a rare disease , but affects roughly 70% of people who have narcolepsy...
- HyperekplexiaHyperekplexiaHyperekplexia is a neurologic disorder classically characterised by pronounced startle responses to tactile or acoustic stimuli and hypertonia. The hypertonia may be predominantly truncal, attenuated during sleep and less prominent after a year of age...
, also called startle syndrome - HypoglycemiaHypoglycemiaHypoglycemia or hypoglycæmia is the medical term for a state produced by a lower than normal level of blood glucose. The term literally means "under-sweet blood"...
and associated neuroglycopeniaNeuroglycopeniaNeuroglycopenia is a medical term that refers to a shortage of glucose in the brain, usually due to hypoglycemia. Glycopenia affects the function of neurons, and alters brain function and behavior... - MigraineMigraineMigraine is a chronic neurological disorder characterized by moderate to severe headaches, and nausea...
- NarcolepsyNarcolepsyNarcolepsy is a chronic sleep disorder, or dyssomnia, characterized by excessive sleepiness and sleep attacks at inappropriate times, such as while at work. People with narcolepsy often experience disturbed nocturnal sleep and an abnormal daytime sleep pattern, which often is confused with insomnia...
- Non-epileptic myoclonusMyoclonusMyoclonus is brief, involuntary twitching of a muscle or a group of muscles. It describes a medical sign and, generally, is not a diagnosis of a disease. Brief twitches are perfectly normal. The myoclonic twitches are usually caused by sudden muscle contractions; they also can result from brief...
- OpsoclonusOpsoclonusOpsoclonus refers to uncontrolled eye movement. Opsoclonus consists of rapid, involuntary, multivectorial , unpredictable, conjugate fast eye movements without intersaccadic intervals. It is also referred to as saccadomania or reflexive saccade...
- ParasomniaParasomniaFor the 2008 horror film, see Parasomnia Parasomnias are a category of sleep disorders that involve abnormal and unnatural movements, behaviors, emotions, perceptions, and dreams that occur while falling asleep, sleeping, between sleep stages, or during arousal from sleep...
s, including night terrors - Paroxysmal kinesiogenic dyskinesiaDyskinesiaDyskinesia is a movement disorder which consists of effects including diminished voluntary movements and the presence of involuntary movements, similar to tics or choreia. Dyskinesia can be anything from a slight tremor of the hands to uncontrollable movement of, most commonly, the upper body but...
- Reflex anoxic seizuresReflex anoxic seizuresReflex anoxic seizures are a form of syncope encountered mainly, but not exclusively, in young children. Reflex anoxic seizures are not epileptic. By definition, a syncope is from the Greek, “a cutting off,” implying an abrupt interruption in the supply of energy to the cerebral cortex. This is...
- Primary central nervous system lymphomaPrimary central nervous system lymphomaA primary central nervous system lymphoma , also known as microglioma and primary brain lymphoma, is a primary intracranial tumor appearing mostly in patients with severe immunosuppression . PCNSLs represent around 20% of all cases of lymphomas in HIV infections...
- Repetitive or ritualistic behaviours
- Syncope (fainting)
- TicTicA tic is a sudden, repetitive, nonrhythmic, stereotyped motor movement or vocalization involving discrete muscle groups. Tics can be invisible to the observer, such as abdominal tensing or toe crunching. Common motor and phonic tics are, respectively, eye blinking and throat clearing...
s - Trauma Induced SeizureHead injuryHead injury refers to trauma of the head. This may or may not include injury to the brain. However, the terms traumatic brain injury and head injury are often used interchangeably in medical literature....