Epilepsy DOJ Lecture Masud Seyal, M.D., Ph.D. Department of Neurology University of California, Davis

Transcription

1 Epilepsy DOJ Lecture Masud Seyal, M.D., Ph.D. Department of Neurology University of California, Davis

2 Epilepsy SEIZURE: A temporary dysfunction of the brain resulting from a self-limited abnormal discharge of cortical neurons EPILEPSY: Recurrent seizures

3 Prevalence 6.5 persons per 1000 population are affected with recurrent unprovoked seizures (active epilepsy) in the US

4 Seizure Manifestations The manifestation of a seizure depends on: The site of onset of the seizure The function of that region of brain The subsequent pattern of spread Although most seizures will result in impairment of consciousness, this is not always the case.

5 Seizure Classification Partial (focal) seizures Simple partial seizures Complex partial seizures Partial seizures evolving to secondarily generalized seizures Generalized seizures Absence Myoclonic seizures Tonic-clonic seizures Others

6 Temporal lobe epilepsy Patients may have recurrent complex partial seizures THIS IS THE MOST COMMON EPILEPSY SYNDROME IN ADULTS About half the patients are well controlled on medication Surgery may be an option in some patients

7 Frontal Lobe Epilepsy Patients with FLE may have bizarre manifestations during a seizure with vigorous motor activity The seizures may be confused with nonepileptic psychogenic spells

8 Absence Epilepsy The episodes are brief (10-15 seconds), may be subtle and difficult to recognize The is generally impairment of consciousness during these episodes Patients may have many seizures during the day

9 Epilepsy Many patients who have a first unprovoked seizure will never have a second. Our ability to predict seizure recurrence is limited. Some seizure types are almost always recurrent. After a first seizure, the overall recurrence rate is about 40% over 2 years. HOWEVER, after a second unprovoked seizure, the recurrence rate is 80%.

10 Epilepsy Seizure recurrence after a first unprovoked seizure. 25% in patients with no risk factors, normal EEG and normal examination The need for treatment in this group is questionable.

11 Epilepsy Rationale for discontinuing antiepileptic drugs % of patients with epilepsy enter a long-term remission i.e. over 5 years. Even in untreated patients 50% will remit spontaneously Discontinuation of medications can be justified in many patients who have been seizure free for 2 or more years.

12 Epilepsy Seizure free period and driving Favorable factors Seizures during medically directed medication change Simple partial seizures that do not interfere with motor control Seizures with consistent and prolonged auras Established pattern of pure nocturnal seizures Seizures secondary to acute metabolic or toxic states not likely to recur Sleep-deprived seizures Seizures related to reversible acute illness

13 Seizure free period and driving Unfavorable factors Non compliance or lack of credibility Alcohol or drug abuse in recent past Increased number of seizures in past year Prior bad driving record Non-correctable brain functional or metabolic condition Frequent seizures after seizure free period Prior crashes due to seizures in past 5 years

14 Other conditions may mimic epilepsy Syncope Resulting from transient decrease of blood flow to the brain resulting in loss of consciousness During blood draws Painful surgical procedures Watching an unpleasant movie Cough, urination, defecation Change in posture Some brief convulsive activity may occur during syncope

15 Other conditions may mimic epilepsy The duration of attacks is often the best guide. Epileptic events last seconds to minutes The patient with epilepsy may have some warning before losing consciousness Reports of attacks lasting hours should raise the suspicion of non-epileptic episodes Generalized tonic-clonic seizures usually last seconds, occasionally longer

16 Other conditions may mimic epilepsy Partial and generalized seizures are usually followed by a period of confusion. Sometimes there is a marked alteration of mood and behavior after a seizure Occasionally, a transient psychosis may occur after a seizure

17 Other conditions may mimic epilepsy Prolonged absences often occurring while driving may be reported. The patient may describe walking or driving some distance, then find themselves at their destination and are not able to recall how they got there No damage to vehicle These episodes are often benign and not a manifestation of epilepsy

18 Other conditions may mimic epilepsy Non-epileptic seizures (NES) Convulsive activity may occur but there is no electrical correlate Felt to reflect psychological stress Variability from spell to spell is common Events are often disruptive and dramatic Side to side head shaking; pelvic thrusting; back arching Have a tendency to occur in public Not unusual for the spells to wax and wane for many minutes to hours NES may be difficult to distinguish from frontal lobe epilepsy Inpatient video-eeg recordings may be necessary to establish the diagnosis

19 Other conditions may mimic epilepsy Endocrine and metabolic abnormalities Most common is hypoglycemia related to insulin therapy of diabetes Altered vision; sweating; confusion; coma and altered behavior; partial and generalized seizures Behavior during hypoglycemia may be bizarre Irritability and aggression are common

20 Other conditions may mimic epilepsy Panic Disorder Panic attacks can appear very similar to seizures Episodes of fear or discomfort accompanied by palpitations; dizziness; lightheadedness; Attacks can have an abrupt onset reaching a peak within 10 minutes Fearful patients want to escape; feel episodes indicate a lifethreatening disorder May be situational or without a clear precipitant Often associated with other psychiatric syndromes such as agoraphobia and depression