The following paragraph was taken from UpToDate on 2011/12/07:
Transient ischemic attacks (TIAs) may be mistaken for seizures, but they may also induce seizures.
Brain ischemia produces reduced neural activity and "negative" symptoms such as hemiparesis or hemisensory loss. In contrast, seizures usually cause "positive" symptoms from neural overactivity. So called "limb-shaking" TIAs may represent a source of diagnostic confusion in this regard. This somewhat unusual manifestation of cerebral ischemia typically occurs in the setting of high-grade carotid stenosis.
Certain symptoms, such as aphasia, can occur in TIA or seizure. While an isolated episode of aphasia is more likely to be a TIA than a seizure, aphasic seizures are well described. In general, ictal aphasia is progressive, developing over minutes from dysphasia to paraphasic errors, and culminating in a global aphasia. In contrast, TIA symptoms develop abruptly and typically do not evolve. Although TIA is commonly considered as a cause for confusional episodes, confusion is rarely a manifestation of TIA.
Chronic, recurrent stereotyped events are much more likely to be seizure than TIA. Transient loss of consciousness only should not be diagnoed as TIA. However, since syncope can rarely occur in association stroke, care should be exercised in the evaluation of patients with syncope and limb weakness which can actually be Todd's paralysis after a seizure of no witness.
2011年12月11日 星期日
Dialeptic seizure or syncope in elderly
The following paragraph was taken from UpToDate on 2012/12/07:
Complex partial seizure was the most common seizure type in older patients; 38.3 percent of patients experienced complex partial seizures. In contrast to younger patients, complex partial seizures in older adults are more often extratemporal, usually frontal, in origin, and therefore have an "atypical" clinical presentation. Classic descriptions of seizure aura, such as deja vu and olfactory hallucinations, are uncommon. Patients may instead report antecedent symptoms that are atypical and nonspecific, such as vaguely localized paresthesias, dizziness, and muscle cramps. Observers often note episodic confusion, sleepiness, or clumsiness rather than motor manifestations such as tonic or clonic movements, or automatisms. Postictal states are frequently more prolonged in elderly patients, particularly if there is underlying brain dysfunction.
Because of the "atypical" symptomatology, elderly patients with seizures may be frequently misdiagnosed. In a study, VACS#428, 73.3 percent of patients ultimately diagnosed with epilepsy had a different referral diagnosis. These included altered mental status, confusion, blackout spells, memory disturbance, syncope, dizziness, and dementia. In another series, transient ischemic attack (TIA), depression, and metabolic or psychiatric disorders were also among the initial misdiagnoses. Misdiagnosis is more common in patients with partial complex and partial simple seizures than with generalized tonic-clonic seizures. Despite the known association of seizures and cerebrovascular disease, a history of stroke or TIA was associated with a 1.7-year delay to diagnosis. Similarly, comorbid dementia can obscure the recognition of seizures.
How about syncope? The following description is an extract from Adam’s Neurology:
Description of symptoms, as with other predominantly subjective states, is often ambiguous. The patient may refer to the experience as light-headedness, giddiness, dizziness, a "drunk feeling," a weak spell, or, if consciousness was lost, a "blackout." Careful questioning may be necessary to ascertain the exact meaning the patient has given to these words. In many instances the nature of the symptoms is clarified by the fact that they include a sensation of faintness and then a momentary loss of consciousness, which is easily recognized as a faint, or syncope. This sequence also informs us that under certain conditions any difference between faintness and syncope is only one of degree. These symptoms must be clearly set apart from certain types of epilepsy, the other major cause of episodic unconsciousness, and from disorders such as cataplexy, transient ischemic attacks (TIAs), "drop attacks," and vertigo, which are also characterized by episodic attacks of generalized weakness or inability to stand upright, but not by a loss of consciousness.
The clinical manifestations of fainting attacks vary to some extent, depending on their mechanisms and the settings in which they occur. The most common type of faint—namely, vasodepressor or vasovagal syncope conforms more or less to the following pattern. The patient is usually in the upright position at the beginning of the attack, either sitting or standing. Certain subjective symptoms, the prodrome, mark the onset of the faint. The person feels queasy, is assailed by a sense of giddiness and apprehension, may sway, and sometimes develops a headache. What is most noticeable at the beginning of the attack is pallor or an ashen-gray color of the face; often the face and body become bathed in cool perspiration. Salivation, epigastric distress, nausea, and sometimes vomiting may accompany these symptoms, and the patient tries to suppress them by yawning, sighing, or breathing deeply. Vision may dim or close in concentrically, the ears may ring, and it may be impossible to think clearly ("grayout").
This serves to introduce the common faint that is known to all physicians and most laypersons. However, if there is no such typical presentation, it is challenging to different syncope or faint from dialeptic seizure in the elderly. Seizures are the probable cause of 5 to 15 percent of apparent syncopal episodes. They can mimic syncope when the seizure is atypical and not associated with tonic-clonic movements, the seizure is not observed, or a complete history cannot be obtained. A careful clinical history is important in distinguishing syncope from epilepsy. Important features are not always volunteered and must be specifically solicited.
Features that distinguish syncope from seizures are discussed further on.
Differential diagnosis:
Syncope in an elderly patient can be accompanied by incontinence, and recovery is often slow, mimicking a postictal state. In addition, some patients with syncope present with myoclonic or other involuntary movements that are suggestive of a seizure but are actually due to cerebral hypoxia.
One distinguishing feature is recovery of consciousness. Patients usually wake up quickly after a syncopal event. Prolonged confusion or lethargy lasting several minutes or longer favors seizure.
Clinical setting - Epileptic seizures and syncope arising from cardiac arrhythmias can occur in any setting and are usually unprovoked. Vasovagal syncope tends to occur in the setting of a strong emotional or painful stimulus, but may also occur with more subtle stimuli, including a hot environment. Reflex syncopes occur with specific stimuli (eg, micturition, cough). Events in the setting of exertion suggest syncope related to structural cardiac disease. Except when caused by a cardiac arrhythmia, it is unusual for syncope to occur when patient is supine.
Warning symptoms (aura, prodrome) - In vasovagal syncope, a prodrome of presyncope is the rule. These patients may note lightheadedness, warmth, nausea, and a gradual fading or tunneling of binocular vision. In contrast, symptoms of olfactory hallucinations or deja vu suggest a seizure aura. However, not all epileptic seizures include a seizure aura. Cardiogenic syncope typically occurs without warning.
Associated symptoms - Pallor and diaphoresis strongly suggest syncope. However, it is unusual for syncope to be associated with tongue biting, head or eye turning to one side, or hypersalivation; these suggest epileptic seizure. Urinary incontinence can occur in both seizures and syncope.
Symptoms occurring in association with syncope can point toward a specific cause. As examples, dyspnea may suggest an acute pulmonary embolism; angina frequently indicates an underlying cardiac cause; a history of focal neurologic abnormalities favors a neurologic origin; and urinary and/or fecal incontinence suggest, but do not prove, a seizure.
Motor activity - While motor activity during an episode of unconsciousness often suggests a seizure diagnosis, brief motor activity, including tonic extension of the trunk and limbs or several clonic jerks, can occur in uncomplicated syncope. The severity of convulsive symptoms in syncope varies from subtle signs that are often overlooked to more dramatic symptoms that mimic an epileptic seizure. Relatively few bystanders witnessing syncopal attacks report convulsive symptoms, but clinicians systematically observing attacks (eg, during tilt table testing, invasive cardiac electrophysiologic testing, blood drawing) describe convulsive symptoms in up to half of patients. Convulsions (in syncope) are more likely to occur with more prolonged and more severe cerebral hypoperfusion.
Electroencephalography (EEG) recordings during syncopal events usually demonstrate generalized slowing followed by high voltage frontal delta activity [15,16]. Flattening of the EEG can follow if cerebral hypoperfusion persists. It is at this stage that nonepileptic, seizure-like movements are most often described. It has been suggested that these movements may represent a brainstem-release phenomenon.
The combination of seizure-like motor activity in the setting of syncope is sometimes referred to as convulsive syncope. While these convulsions are common in syncope, a true epileptic seizure ("anoxic seizure") is rare, except in susceptible people or those with prolonged cerebral ischemia.
Complex partial seizure was the most common seizure type in older patients; 38.3 percent of patients experienced complex partial seizures. In contrast to younger patients, complex partial seizures in older adults are more often extratemporal, usually frontal, in origin, and therefore have an "atypical" clinical presentation. Classic descriptions of seizure aura, such as deja vu and olfactory hallucinations, are uncommon. Patients may instead report antecedent symptoms that are atypical and nonspecific, such as vaguely localized paresthesias, dizziness, and muscle cramps. Observers often note episodic confusion, sleepiness, or clumsiness rather than motor manifestations such as tonic or clonic movements, or automatisms. Postictal states are frequently more prolonged in elderly patients, particularly if there is underlying brain dysfunction.
Because of the "atypical" symptomatology, elderly patients with seizures may be frequently misdiagnosed. In a study, VACS#428, 73.3 percent of patients ultimately diagnosed with epilepsy had a different referral diagnosis. These included altered mental status, confusion, blackout spells, memory disturbance, syncope, dizziness, and dementia. In another series, transient ischemic attack (TIA), depression, and metabolic or psychiatric disorders were also among the initial misdiagnoses. Misdiagnosis is more common in patients with partial complex and partial simple seizures than with generalized tonic-clonic seizures. Despite the known association of seizures and cerebrovascular disease, a history of stroke or TIA was associated with a 1.7-year delay to diagnosis. Similarly, comorbid dementia can obscure the recognition of seizures.
How about syncope? The following description is an extract from Adam’s Neurology:
Description of symptoms, as with other predominantly subjective states, is often ambiguous. The patient may refer to the experience as light-headedness, giddiness, dizziness, a "drunk feeling," a weak spell, or, if consciousness was lost, a "blackout." Careful questioning may be necessary to ascertain the exact meaning the patient has given to these words. In many instances the nature of the symptoms is clarified by the fact that they include a sensation of faintness and then a momentary loss of consciousness, which is easily recognized as a faint, or syncope. This sequence also informs us that under certain conditions any difference between faintness and syncope is only one of degree. These symptoms must be clearly set apart from certain types of epilepsy, the other major cause of episodic unconsciousness, and from disorders such as cataplexy, transient ischemic attacks (TIAs), "drop attacks," and vertigo, which are also characterized by episodic attacks of generalized weakness or inability to stand upright, but not by a loss of consciousness.
The clinical manifestations of fainting attacks vary to some extent, depending on their mechanisms and the settings in which they occur. The most common type of faint—namely, vasodepressor or vasovagal syncope conforms more or less to the following pattern. The patient is usually in the upright position at the beginning of the attack, either sitting or standing. Certain subjective symptoms, the prodrome, mark the onset of the faint. The person feels queasy, is assailed by a sense of giddiness and apprehension, may sway, and sometimes develops a headache. What is most noticeable at the beginning of the attack is pallor or an ashen-gray color of the face; often the face and body become bathed in cool perspiration. Salivation, epigastric distress, nausea, and sometimes vomiting may accompany these symptoms, and the patient tries to suppress them by yawning, sighing, or breathing deeply. Vision may dim or close in concentrically, the ears may ring, and it may be impossible to think clearly ("grayout").
This serves to introduce the common faint that is known to all physicians and most laypersons. However, if there is no such typical presentation, it is challenging to different syncope or faint from dialeptic seizure in the elderly. Seizures are the probable cause of 5 to 15 percent of apparent syncopal episodes. They can mimic syncope when the seizure is atypical and not associated with tonic-clonic movements, the seizure is not observed, or a complete history cannot be obtained. A careful clinical history is important in distinguishing syncope from epilepsy. Important features are not always volunteered and must be specifically solicited.
Features that distinguish syncope from seizures are discussed further on.
Differential diagnosis:
Syncope in an elderly patient can be accompanied by incontinence, and recovery is often slow, mimicking a postictal state. In addition, some patients with syncope present with myoclonic or other involuntary movements that are suggestive of a seizure but are actually due to cerebral hypoxia.
One distinguishing feature is recovery of consciousness. Patients usually wake up quickly after a syncopal event. Prolonged confusion or lethargy lasting several minutes or longer favors seizure.
Clinical setting - Epileptic seizures and syncope arising from cardiac arrhythmias can occur in any setting and are usually unprovoked. Vasovagal syncope tends to occur in the setting of a strong emotional or painful stimulus, but may also occur with more subtle stimuli, including a hot environment. Reflex syncopes occur with specific stimuli (eg, micturition, cough). Events in the setting of exertion suggest syncope related to structural cardiac disease. Except when caused by a cardiac arrhythmia, it is unusual for syncope to occur when patient is supine.
Warning symptoms (aura, prodrome) - In vasovagal syncope, a prodrome of presyncope is the rule. These patients may note lightheadedness, warmth, nausea, and a gradual fading or tunneling of binocular vision. In contrast, symptoms of olfactory hallucinations or deja vu suggest a seizure aura. However, not all epileptic seizures include a seizure aura. Cardiogenic syncope typically occurs without warning.
Associated symptoms - Pallor and diaphoresis strongly suggest syncope. However, it is unusual for syncope to be associated with tongue biting, head or eye turning to one side, or hypersalivation; these suggest epileptic seizure. Urinary incontinence can occur in both seizures and syncope.
Symptoms occurring in association with syncope can point toward a specific cause. As examples, dyspnea may suggest an acute pulmonary embolism; angina frequently indicates an underlying cardiac cause; a history of focal neurologic abnormalities favors a neurologic origin; and urinary and/or fecal incontinence suggest, but do not prove, a seizure.
Motor activity - While motor activity during an episode of unconsciousness often suggests a seizure diagnosis, brief motor activity, including tonic extension of the trunk and limbs or several clonic jerks, can occur in uncomplicated syncope. The severity of convulsive symptoms in syncope varies from subtle signs that are often overlooked to more dramatic symptoms that mimic an epileptic seizure. Relatively few bystanders witnessing syncopal attacks report convulsive symptoms, but clinicians systematically observing attacks (eg, during tilt table testing, invasive cardiac electrophysiologic testing, blood drawing) describe convulsive symptoms in up to half of patients. Convulsions (in syncope) are more likely to occur with more prolonged and more severe cerebral hypoperfusion.
Electroencephalography (EEG) recordings during syncopal events usually demonstrate generalized slowing followed by high voltage frontal delta activity [15,16]. Flattening of the EEG can follow if cerebral hypoperfusion persists. It is at this stage that nonepileptic, seizure-like movements are most often described. It has been suggested that these movements may represent a brainstem-release phenomenon.
The combination of seizure-like motor activity in the setting of syncope is sometimes referred to as convulsive syncope. While these convulsions are common in syncope, a true epileptic seizure ("anoxic seizure") is rare, except in susceptible people or those with prolonged cerebral ischemia.
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