Epilepsy & Seizures (Differential Diagnosis)

Question 1

Seizure imitators in infancy and early childhood

Answer 1

1) In infants:
- apnea, either central or obstructive, which can be a seizure manifestation but can also be nonepileptic
- Jitteriness associated with a variety of metabolic disturbances
- Exaggerated startle

2) Early childhood:
- shuddering attacks
- stereotypies or repetitive behaviors
- Gastroesophageal reflux (Sandifer syndrome)
- Breath-holding spells

Question 2

Seizure imitators in older age

Answer 2

TIA
Transient global amnesia
Nonepileptic psychogenic seizures (most common imitators)
Syncope
Classical migraine
Sleep disorders
Movement disorders

Question 3

Differential diagnosis of epilepsy and TIAs

Answer 3

1) Transient ischemia generally causes negative symptoms with loss of function such as weakness or numbness, whereas seizures involving sensory or motor cortex are more likely to produce positive symptoms such as twitching or paresthesias
* However, seizures may occasionally present with only negative symptoms, and TIAs rarely present with limb shaking
2) TIAs tend to be longer in duration than seizures (most seizures last < 2 minutes and most TIAs last >2 minutes)
3) The presence of a sensory march is suggestive of an epileptic nature

Question 4

Limb shaking TIAs: 1) with which condition are they associated 2) duration 3) how to differentiate from epileptic seizures

Answer 4

1) Limb shaking as a feature of TIAs has been associated with high-grade stenosis or occlusion of the internal carotid artery
2) Limb-shaking TIAs are short, usually shorter than 5 minutes and even shorter than 1 minute
3) . One feature that could distinguish them from seizures is precipitation by rising or exercise and association with weakness of the affected limb

Question 5

Transient global amnesia: 1) Describe and 2) how to differentiate from epileptic seizures

Answer 5

1) Transient global amnesia is a condition in older individuals characterized by memory loss without impairment of other cognitive function, and affected subjects are able to engage in complex activities.
2) Most transient global amnesia episodes last hours and are single events, although they may repeat in a minority of individuals

Question 6

Psychogenic non-epileptic seizures: 1) Antecedents, 2) predictors and 3) gender prevalence

Answer 6

1) Antecedents:
- sexual or physical abuse
- head injury
- epilepsy surgery

2) Predictors:
- fibromyalgia
- history of chronic pain

3) women 70-80%

Question 7

Patterns of clinical manifestations of PNES

Answer 7

1) psychogenic motor seizures with prominent motor activity
2) psychogenic minor motor or trembling seizures with tremor of the extremities
3) attacks with motionless unresponsiveness or collapse

Question 8

Diagnosis of psychogenic non-epileptic seizures.

Which technique can be used?

Answer 8

The diagnosis of PNES depends on prolonged video-EEG monitoring with recording of typical attacks.
The use of suggestion may facilitate the precipitation and recording of attacks. Hyperventilation and photic stimulation are usually adequate suggestion techniques; suggestion methods should not involve patient deception.
In some individuals, suggestion may precipitate atypical attacks; to verify that recorded events are typical of what occurs at home, it is crucial to seek the input of family members who have witnessed attacks

Question 9

What percentage of PNES coexist with epilepsy

Answer 9

Early studies suggested that more than 50% of patients with PNES also have epilepsy, but most studies now agree on a much smaller proportion, probably not more than 10% or 15%

Question 10

Features that suggest PNES

Answer 10

• out-of-phase upper and lower extremity movements
• absence of vocalization or vocalization at the very onset of seizures
• forward pelvic thrusting
• absence of whole-body rigidity
• side-to-side head movements

*these features were particularly strong predictors when combined, but such clinical features can also be seen in frontal lobe complex partial seizures and other hypermotor seizures.

• pseudosleep at onset
• preictal behavioral changes
• discontinuous seizure activity
• prolonged seizure duration
• eye closure during unresponsiveness
• resistance to eye opening
• eye fluttering
• certain vocalizations such as stuttering, gagging, gasping, screaming, weeping, or moaning
• emotional display during events
• emotional triggers
• precipitation of typical events by suggestion
• attacks occurring in the clinic waiting room or admitting office
• Tongue biting and incontinence occur more commonly with epileptic seizures but are also frequently reported by patients with PNES. Injuries to the tongue during epileptic seizures tend to affect the side of the tongue. Biting the tip of the tongue or the lip was suggestive of PNES.
• Self-injury was also reported by patients with PNES, but one study suggested that burn injuries were specific for epileptic seizure
• The presence of postictal stertorous respiration is very helpful to diagnose epileptic convulsive seizures, whereas shallow rapid respiration was more likely after PNES

Question 11

1) Which epilepsies are commonly challenging to differentiate from PNES and what is helpful in diagnosis

Answer 11

1) Frontal lobe onset with impairment of awareness seizures of orbitofrontal or cingulate origin commonly have no associated EEG changes, nor do supplementary motor seizures.

2) - For definitive diagnosis, it is often necessary to record multiple attacks and observe changes in conjunction with AED withdrawal.
- Epileptic seizures may secondary generalize, which provides a definitive diagnosis.
- Nocturnal occurrence, urning to a prone position short ictal duration, younger age at onset, stereotyped movements, and abnormal MRI or EEG favor frontal lobe onset with impaired awareness

Question 12

Differentiation of syncope and seizures 1) features in favor of syncope 2) features in favor of epilepsy

Answer 12

1)
- known heart disease
- prior confirmed syncope
- precipitation by prolonged standing or rising to an upright position
- presence of dehydration
- the typical neurocardiogenic syncope prodrome
- description of pronounced pallor by witnesses
- absence of tonic or clonic activity
- description of multifocal myoclonus lasting less than 15 seconds
- recollection of loss of consciousness

2)
- previous seizures
- known cortical brain lesion
- presence of tongue biting
- incontinence
- cyanosis
- postictal confusion
- postictal headache
- lack of recollection of loss of consciousness

Question 13

Common motor manifestations of syncope

Answer 13

• The most common motor manifestation is myoclonus that is most often multifocal and arrhythmic
• posturing
• head turning
• upward eye movement
• oral automatisms
• righting movements

Question 14

Types of migraine that are most likely to be confused with seizures

Answer 14

• classical migraine with visual or somatosensory aura
• basilar migraine
• acute confusional migraine

Question 15

1) Which seizures are often hard to distinguish from migraine and 2) what is helpful in diagnosis

Answer 15

1) Occipital lobe seizures may be followed by a
migraine-like headache that makes it hard to distinguish
them from a classical migraine with a visual aura.

2)
- The aura in migraine typically lasts 5 to 60 minutes. In contrast, epileptic auras are usually less than 30 seconds in duration
- visual aura in migraine is most commonly a fortification spectrum or scintillating scotoma, whereas colored circles are the most common aura in occipital lobe seizures

Question 16

Sleep disorders imitating seizures

Answer 16

• Somnambulism
• sleep talking
• night terrors
• REM behavior disorder
• narcolepsy

Question 17

1) Which parasomnias can imitate seizures and 2) differentiating features

Answer 17

1) Parasomnias (sleep walking (somnambulism), sleep talking, night terrors, confusional arousals, and REM behavior disorder may imitate frontal lobe seizures that occur preferentially or even exclusively in sleep

2)
- Somnambulism, sleep talking, and night terrors typically start in childhood and tend to disappear in adolescence.
- They are most likely to arise out of slow-wave sleep in the first half of the night, usually after a latency of 90 minutes from sleep onset. Frontal lobe seizures are more likely to arise out of stage 1 or 2 sleep. These events are more likely to be seizures if they occur in the first hour of sleep or in the transition between waking and sleep.
- REM behavior disorder is characterized by loss of muscle atonia during REM sleep, which results in acting out dreams. The behavior includes verbalization and vocalization, as well as motor activity that may be violent (e.g., kicking, punching) and getting out of bed. Affected individuals will be aware that they have been dreaming and may report the content of their dreams. REM behavior disorder is more likely in the second half of the night when REM sleep is most likely to occur. REM behavior disorder rarely starts before age 50; it is most often a chronic disorder associated with a synucleinopathy, particularly Lewy body dementia

Question 18

1) manifestations of narcolepsy that can imitate seizures and 2) differentiating features

Answer 18

1) sleep attacks, cataplexy, sleep paralysis, and hallucinations during the transition between waking and sleep
2) an important distinguishing feature is total preservation of consciousness and complete memory of the events in narcolepsy.
The association with other manifestations of narcolepsy should help establish the diagnosis

Question 19

Paroxysmal movement disorders that can be confused with epilepsy

Answer 19

1) nonepileptic myoclonus
2) paroxysmal dyskinesia (kinesigenic and nonkinesigenic)
3) hyperekplexia

Question 20

Differential diagnosis of frontal seizures and parasomnias

Answer 20

Nocturnal frontal lobe seizures can be mistaken for parasomnias, however:

1) Frontal lobe seizures are usually brief events (< 2 minutes), with stereotyped features seen from seizure to seizure and preserved awareness. Parasomnias are usually longer in duration (> 10 minutes), have variable features from event to event and are characterized by a confusional state with the patient having no memory of the event afterwards.
2) In parasomnias, clustering is rare and the common non-REM parasomnias typically occur 1-2 hours after falling asleep, in the first cycle of deep slow wave sleep. Nocturnal frontal lobe seizures typically occur throughout the night, and more frequently within half an hour of falling asleep or awakening.