Absence Versus Complex Partial Seizures Case File
Eugene C. Toy, MD, Ericka Simpson, MD, Pedro Mancias, MD, Erin E. Furr-Stimming, MD
CASE 15
A 23-year-old man was playing cards late at night. While talking to his friends, he suddenly had lip smacking and stared into space. He appeared confused and kept mumbling the same words repeatedly. The episode lasted for approximately 20 seconds. During the episode, his friends tried to restrain him, but he became combative. Within a minute, he became asymptomatic, although he was slightly confused for 5 to 10 more seconds. His friends wanted to take him to the emergency center, but after initially refusing, he finally agreed.
▶ What is the most likely diagnosis?
▶ What is the next diagnostic step?
▶ What is the next step in therapy?
ANSWERS TO CASE 15:
Absence Versus Complex Partial Seizures
Summary: A 23-year-old man appeared suddenly confused and engaged in repetitive motor (including speech) behaviors. He then abruptly became asymptomatic.
- Most likely diagnosis: Complex partial seizure (CPS).
- Next diagnostic step: Magnetic resonance imaging (MRI) of the brain, which is preferable to computed tomography (CT) of the brain; and obtain an electroencephalogram (EEG) and routine blood work.
- Next step in therapy: Consider initiating anticonvulsant medication based on diagnostic evaluation or, if he is taking antiepileptic medication, alter the dosage or prescribe new medicines; discuss driving limitations.
ANALYSIS
Objectives
- Know the diagnostic approach and differential diagnosis of paroxysmal staring episodes.
- List the medical therapies for complex partial and absence seizures.
Considerations
In this case of a 23-year-old previously healthy man, CPS is the most likely diagnosis given his age and presentation, although absence seizures are also a possibility. CPSs are defined by an impaired level of consciousness and commonly exhibit automatisms, such as lip smacking, chewing, gesturing, repeated swallowing, repeating words or phrases, walking, running, undressing, snapping fingers, clumsy perseveration of an ongoing motor task, or some other type of complex motor activity that is not specifically directed and is not appropriate. If these patients are physically restrained during a seizure, they may become hostile or aggressive. Following the seizure, these patients are often transiently confused and disoriented; these states can last several minutes or hours. In patients with CPSs, approximately three-quarters of the seizure emanates from the temporal lobe.
Simple partial seizures, however, reflect epileptic discharges occurring in a limited and often focal area of the cerebral cortex. There is no alteration of consciousness. The symptoms or signs are related to the epileptogenic focus. Thus, the patient can have any type of observable manifestations during a simple partial seizure, whether this is a simple motor movement (eg, Jacksonian seizure, adversive seizure), unilateral sensory aberration, complex emotional episode, or a visual, auditory, or olfactory hallucination. Auras are simple partial seizures manifesting as altered sensation or psychic symptoms and can occur before motor manifestations of a motor seizure. The most common aura is a sensation of abdominal discomfort.
Other auras include a feeling of unreality, detachment from the environment, déjà vu, or jamais vu. During a simple partial seizure, the patient is usually able to interact appropriately with his or her environment, except for possible limitations imposed by the seizure itself. In this case, the patient was unable to interact with his environment and therefore did not have a simple partial seizure.
Absence seizures (petit mal) are another type of seizure and commonly presents with sudden staring. They can be confused with CPSs. Absence seizures present with momentary lapses in awareness; however, they are typically not accompanied by automatisms as seen with CPSs. They are characterized by motionless staring and cessation of ongoing activity. Absence seizures typically begin and end abruptly, have no aura, and are not associated with postictal confusion. Occasionally, mild myoclonic contractions of the eyelid or facial muscles, loss of muscle tone, or automatisms can accompany longer attacks. Unlike CPSs, absence seizures occur many times a day and rarely last more than 10 to 15 seconds. These types of seizures can also be precipitated by hyperventilation. The typical 3-Hz spike and wave pattern is seen. Please refer to the EEG shown in Figure 15–1.
If the beginning and end of the absence spell are not distinct, or if tonic and autonomic components also occur, these spells are referred to as atypical absence seizures. Absence spells seldom begin de novo in adults, usually having their onset in childhood and beginning between ages 4 and 14, with 70% stopping by age 18. Children with classic absence epilepsy have normal development and intelligence. Atypical absence seizures usually occur in cognitively impaired children with epilepsy or in patients with epileptic encephalopathy, such as Lennox-Gastaut syndrome.
APPROACH TO:
Absence and Partial Complex Seizures
DEFINITIONS
ABSENCE SEIZURES: Brief episodes of staring that usually occur in childhood and last 5 to 10 seconds. If the seizure lasts beyond 10 seconds, there can also be eye blinking and lip smacking. The seizures usually occur in clusters and can occur dozens or hundreds of times a day. There is no postictal confusion, and the individual returns to baseline immediately.
COMPLEX PARTIAL SEIZURES (CPSs): Partial seizures with impaired consciousness. Complex refers to impairment of consciousness (ie, impaired awareness to self and surroundings). Patients often engage in repetitive motor behavior, known as automatisms. Patients appear to be awake but do not respond normally to their environment. CPSs typically last a few minutes rather than seconds as seen with absence seizure. This is the most common type of seizure in adults with epilepsy.
CLINICAL APPROACH
Clinical Features and Epidemiology
CPSs cause impaired consciousness and arise from a specific area in the brain. Impaired consciousness denotes decreased responsiveness and awareness of self and surroundings. During a CPS, the patient may not communicate, respond to commands, or remember events that occurred. Consciousness might not be impaired completely. During a CPS, some patients may make simple verbal responses, follow simple commands, or continue to perform simple or, less commonly, complex motor behaviors such as operating a car. CPSs classically arise from the temporal lobe but can arise from any cortical region.
Automatisms are repetitive, stereotyped, unconscious motor or verbal behaviors (automatic behaviors) that commonly accompany CPSs. The behavior is often repeated inappropriately or is inappropriate for the situation. Verbal automatisms range from simple vocalizations, such as moaning, to more complex, comprehensible, stereotyped speech. Motor automatisms are classified as simple or complex. Simple motor automatisms include oral automatisms (eg, lip smacking, chewing, swallowing) and manual automatisms (eg, picking, fumbling, patting). Unilateral manual automatisms usually indicate a seizure onset from the contralateral cerebral hemisphere.
Complex motor automatisms are more elaborate, coordinated movements involving bilateral extremities. Examples of complex motor automatisms are cycling movements of the legs and stereotyped swimming movements. De novo automatisms often begin after seizure onset. In other cases, perseverative automatisms occur as repetitions of motor activity that began before the seizure. Bizarre automatisms such as alternating limb movements, right-to-left head rolling, or sexual automatisms can occur with frontal lobe seizures.
Automatisms can also occur during nonepileptic states of confusion (eg, metabolic encephalopathy), after a seizure, and during absence seizures, and thus can be confused with CPSs. Several clinical features often help distinguish absence from CPSs (Table 15–1).
CPSs often begin with a brief aura (simple partial seizure) lasting seconds. The type of aura is related to the site of cortical onset. Temporal lobe seizures often begin with a rising abdominal sensation, fear, unreality, or déjà vu. Parietal lobe seizures can begin with an electrical sensation, tingling, or numbness. Occipital lobe seizures can begin with visual changes, such as the perception of colored lines, spots, shapes or even a loss of vision.
CPSs of the temporal lobe (previously called psychomotor seizures) often begin with a motionless stare followed by simple oral or motor automatisms. In contrast, frontal lobe seizures often begin with vigorous motor automatisms or stereotyped clonic or tonic activity. Extratemporal lobe seizures can spread quickly to the frontal lobe and produce motor behaviors similar to those associated with CPSs of the frontal lobe. Tonic and dystonic arm posturing can occur in the arm contralateral to the seizure focus. Sustained head or eye turning contralateral to the seizure focus can occur immediately before or simultaneously with clonic or tonic activity elsewhere.
CPSs often last 30 seconds to 2 minutes. Longer seizures can occur, particularly when the seizures become generalized convulsions. Complex partial status epilepticus can also occur with prolonged episodes of waxing and waning of consciousness.
In the United States, for individuals younger than 60 years, the incidence of partial seizures is 20 cases per 100,000 person-years. For people aged 60 to 80, the incidence increases to 80 cases per 100,000 person-years. The prevalence of epilepsy is 0.5 to 1 case per 100 persons. CPSs occur in approximately 35% of persons with epilepsy. Internationally, partial seizures are more common in countries where cysticercosis is prevalent.
The mortality rate among individuals with epilepsy is two to three times that of the general population. Most deaths are a result of the underlying cause of epilepsy. Individuals with epilepsy are at increased risk for trauma, burns, and aspiration. Sudden unexpected death in epilepsy (SUDEP) occurs with no apparent cause. The incidence of SUDEP is 8 to 10 per 1000 patient-years among people with epilepsy. SUDEP is most common among patients with frequent, medically intractable seizures and who are noncompliant with antiepileptic medications.
Etiology and Pathogenesis
Unlike absence seizures that have a genetic basis or are associated with abnormal neurodevelopment, the etiology of CPSs can include traumatic brain injury, encephalitis, meningitis, stroke, perinatal brain injuries, vascular malformations, cortical dysplasia, and neoplasms. Febrile seizures of childhood that are unusually prolonged, frequent, or associated with focal neurologic features can increase risk for later development of CPSs. In most patients, CPSs represent a symptom of underlying temporal lobe epilepsy, the cause of which is unknown. Characteristic pathologic changes, called mesial temporal sclerosis, are often visible on brain MRI. In addition, single-photon emission CT (SPECT) ictal studies show hypoperfusion of bilateral frontal and parietal association cortex and hyperfusion of the mediodorsal thalamus and rostral brainstem. Ictal effects on these structures by means of the spread of epileptic discharges or a transsynaptic mechanism can mediate impaired consciousness during CPSs.
Evaluation and Treatment
A thorough history and neurologic examination, as well as appropriate diagnostic studies (usually including blood tests, MRI of the brain, EEG, and often prolonged video EEG monitoring) are often necessary. First-aid care is found in Table 15–2. Laboratory studies to determine the serum anticonvulsant drug concentrations are indicated for patients with epilepsy on anticonvulsants. Otherwise, laboratory studies should be directed at ruling out metabolic or toxic triggers of seizures, including electrolyte and glucose levels and a drug screen.
For CPSs, MRI of the brain is indicated to detect focal brain lesions and often shows reduced hippocampal volume or increased signal on fluid attenuation inversion recovery (FLAIR). T2-weighted MRI identifies sclerosis of mesial temporal lobe in 80% to 90% of cases (Figure 15–2). Gadolinium enhancement is indicated if a neoplasm or vascular malformation is suspected. In addition, special imaging protocols may be required for subtle cortical changes from cortical dysplasia that are often overlooked with standard imaging protocols. In idiopathic absence seizures, neuroimaging is typically normal.
EEG should be performed in every patient who has experienced a “spell” that may be a possible seizure. Epileptiform discharges can indicate the type of seizure and site of the seizure focus. In absence seizures, the EEG is often diagnostic, showing regular and symmetrical 3 Hz, possible 2- to 4-Hz spike-and-slow-wave complexes and possible multiple spike-and-slow-wave complexes. This can be precipitated by having the patient hyperventilate during testing. However, a negative interictal EEG does not exclude a diagnosis of epilepsy, especially CPSs. If the waking EEG is negative, a sleep-deprived EEG can demonstrate epileptiform abnormalities. When the history and routine EEG are nondiagnostic, prolonged video EEG monitoring is useful for differential diagnosis. An ambulatory EEG can be used in some instances, although it provides less information about seizure behavior than video EEG monitoring. A lumbar puncture should be performed when an inflammatory or infectious brain disorder (eg, encephalitis) is suspected; however, it is unnecessary in every seizure evaluation.
Figure 15–2. Coronal T2-weighted MRI of the brain showing right mesial temporal sclerosis.
Treatment and Management
Anticonvulsant therapy is generally indicated when patients have more than one seizure or the EEG shows ongoing and frequent epileptiform discharges. The goal is to make the patient seizure free. Even one seizure per year can prevent the patient from working and/or driving. Therapy with one agent is generally preferred to therapy with two or more anticonvulsants because cognitive adverse effects are common with anticonvulsants, especially traditional drugs, including phenytoin, phenobarbital, carbamazepine, and valproic acid. The newer anticonvulsants are increasingly being used because of fewer side effects and drug-drug interactions, a higher dose tolerance, and the fact that they do not require plasma drug level monitoring. These drugs include lamotrigine, levetiracetam, oxcarbazepine, topiramate, zonisamide, and lacosamide.
Ethosuximide is an anticonvulsant that is only indicated for absence seizures and is considered to be the first-line therapy for this seizure type. If a diagnosis of absence seizures is made, the likelihood of other coexistent seizure types, such as myoclonic or tonic-clonic, should be considered, as ethosuximide would not be indicated for such case presentation. Valproic acid is also effective against absence, myoclonic, and tonic–clonic (as well as partial) seizures, and for this case it is a consideration.
Although many anticonvulsants are listed as category D (unsafe in pregnancy), the use of anticonvulsants during pregnancy is warranted if necessary to control seizures. Nevertheless, all women of childbearing age should be instructed about effective birth control while taking anticonvulsants and be prescribed up to 4 mg of folic acid daily to lower the risks of congenital defects, including neural tube defects. Of the anticonvulsants, valproate and phenobarbital are more likely to cause neural tube defects in a dose-related fashion than other anticonvulsants.
Initiation of anticonvulsant therapy requires laboratory screening and monitoring and regular patient evaluation for efficacy and/or side effects. Once therapy is initiated and maintained at therapeutic doses, subsequent, periodic blood and urine monitoring in otherwise asymptomatic patients receiving anticonvulsants does not help in identifying patients at risk for life-threatening adverse drug reactions. However, mild elevations in transaminase levels and mild depressions in blood cell counts often occur with anticonvulsant therapy and are generally observed. Patients should be educated about how to recognize the signs of a severe adverse drug reaction, which can vary depending on the drug but include dizziness, vertigo, double vision, gait disturbances or ataxia, rash, and mental confusion.
For patients in which diagnostic studies are unyielding or when seizures remain refractory to adequate treatment, a referral to an epilepsy specialist is indicated. An epilepsy specialist can evaluate the patient with prolonged video EEG monitoring, evaluate current and past therapies, optimize treatment, and evaluate the patient for possible epilepsy surgery. Surgical intervention is indicated for patients who have frequent, disabling seizures despite adequate trials of two or more anticonvulsants with different modes of action. Such procedures include temporal lobectomy, extratemporal resections, corpus callosotomy, placement of a vagus nerve stimulator, hemispherectomy, and multiple subpial transections.
Lifestyle and Activity
All persons with uncontrolled seizures must be advised to refrain from high-risk activities that put themselves and/or others in danger in the event of a seizure. These activities include, but are not limited to, the following: operating a motor vehicle, operating a stove or other dangerous machinery, and working at heights. These patients should be advised to contact the appropriate state agency regarding driving regulations. Some states require physician reporting of drivers who experience seizures. These activity restrictions should be reviewed in detail (and documented in the medical record) with the patient, family, and/or caregivers.
CASE CORRELATION
- See also Case 14 (New-Onset Seizure, Adult)
COMPREHENSION QUESTIONS
15.1 A 24-year-old woman is diagnosed with a CPS disorder. Which of the
following would be typical automatisms that can occur in CPSs?
A. Lip smacking, chewing, gesturing
B. Singing and coughing
C. Choreiform dance-like movements
D. Rigid arm motions directed laterally
15.2 A 9-year-old boy is diagnosed with absence seizures. Which of the following would most likely best describe his seizure episodes?
A. Tremulousness of the right arm in the absence of other movement
disorder
B. Momentary lapses in awareness, accompanied by motionless staring and cessation of any ongoing activity
C. Alternate flexion and extension and rigidity of the arms and legs
D. Sudden loss of posture and falling unconscious to the floor
15.3 A 68-year-old man is diagnosed with a seizure disorder. There is no history of trauma or medical condition. What is the most common type of seizure in older adults with epilepsy?
A. Absence seizures
B. Complex partial seizures
C. Grand mal seizures
D. Todd paralysis
ANSWERS
15.1 A. Lip smacking, chewing, and swallowing are common findings in CPSs.
Choreiform dance-like movements are found in conditions such as Huntington chorea.
15.2 B. Absence seizures are typified by staring off episodes without conscious awareness. These usually last a short time usually 15 seconds or less, not associated with motor activity, and can be associated with loss of tone. In contrast to tonic-clonic seizures, absence seizures are not associated with a postictal or confusion period. The diagnosis is established by clinical assessment and EEG showing generalized spike-and-slow-wave discharges.
15.3 B. As compared to younger patients, individuals older than 65 years have a higher incidence of seizures and etiologies more likely due to cerebrovascular accident (CVA), dementia, neurodegenerative disorders, tumors, or trauma. The most common type of seizure with epilepsy in older adults is CPSs likely due to a vascular event or tumor.
CLINICAL PEARLS
|
▶ The differential diagnosis for
paroxysmal staring spells, aura, and behavioral arrest includes CPSs,
atypical absence, and absence epilepsy.
▶ CPSs are the most common form of
seizures in adults.
▶ MRI and EEG are indicated to evaluate
for a seizure focus and for consideration for focal resective surgery,
especially in the case of mesial temporal sclerosis.
▶ Approximately one-third of women with
epilepsy have seizures clustered around menstrual cycles. This is called
catamenial seizure exacerbation or catamenial epilepsy.
▶ Sudden unexplained death in epilepsy
(SUDEP), defined as a sudden unexpected, nontraumatic, nondrowning death in
an individual with epilepsy, is now emerging more frequently in the research
literature, adding weight and validity to this, once questionable entity. |
REFERENCES
Bazil CW, Morrell MJ, Pedley TA. Epilepsy. In: Rowland LP, ed. Merritt’s Neurology. 11th ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2005:990-1014.
Krumholz A, Wiebe G, Gronseth GS, et al. Evidence-based guideline: management of an unprovoked first seizure in adults: report of the Guideline Development Subcommittee of the American Academy of Neurology and the American Epilepsy Society. Neurology. 2015;84;1705-1713.
Murro AM. Complex partial seizures. http://www.emedicine.com/NEURO/topic74.htm. Accessed March 20, 2007.
Schacter SC. Epilepsy. In: Evans RW, ed. Saunders Manual of Neurologic Practice. Philadelphia, PA: Saunders/Elsevier; 2003:244-265.
0 comments:
Post a Comment
Note: Only a member of this blog may post a comment.