Seizures Diagnosis and Management

1. Seizures Diagnosis and Management Nisha Kanani, David Cherney 2004

2. Resources • Primary Care: Epilepsy. Browne T. R., Holmes G. L. NEJM; 344:1145-1151, Apr 12, 2001. • Current Concepts: Patients with refractory seizures. Devinsky O. NEJM; 340: 1565-1570, May 20, 1999 • Consensus statements: Medical management of epilepsy. Neurology; 51(5 suppl4): S39-43, Nov 01 1998 • Textbook of clinical neurology. Greenberg • Canadian Driving Guidelines Online

3. Objectives • First seizure evaluation in adults • Seizure classification 3. Management options

4. Case • 32 y/o male taxi-driver is referred for evaluation of a “spell” while walking to the corner store, after which he was found on the ground. • Brought in by EMS to the ER • Subsequently sent home • What are you going to do and tell the patient?

5. Definitions • Seizure: transient disturbance in cerebral function caused by abnormal neuronal discharge • Epilepsy: group of disorders represented by recurrent seizures (3% lifetime prevalence)

6. Evaluating seizures: • Is this a seizure? • What type of seizure is this? (implications on treatment) • Is there an underlying cause?

7. Is this a Seizure? Seizure Mimics: • Classic migraines • include transient neurologic symptoms (as in partial seizures). • epilepsy patients twice as likely to have migraines. • Syncope • Postural, flaccid paralysis, pre-syncope symptoms, no post-ictal state • May have fasiculations (convulsive syncope) • TIA • Usually no LOC unless basilar stroke, usually negative findings not positive. Sometimes confusing if post-ictal Todd’s paralysis • Pseudo-seizures • 10-45% of patients with refractory epilepsy. Look for history of abuse. Patients can have both. 5) Movement disorders

9. Is there an underlying cause? (rule out secondary causes of seizures)

10. History • Witness testimony is key! • Triggers, ictal behaviors, LOC, behaviour during seizure and the postictal state. • Seizure precipitants or triggers: • strong emotions, intense exercise, flashing lights, and loud music (often immediately before the seizure) • fever, menstruation, lack of sleep, and stress

11. History Ask about . . . Drugs, alcohol, constitutional symptoms, HIV risk factors, fever, head trauma. Family History (absence and myoclonic seizures may be inherited)

12. Physical examination • Generally unrevealing • Look for signs of disorders associated with seizures. • Head trauma, meningismus, sinus infection. • Focal or diffuse neurological abnormalities. • Mental status abnormalities suggest lesions in the anterior frontal, parietal, or temporal lobes. • Evaluate for lateralizing abnormalities: weakness, hyperreflexia, positive Babinski sign

13. Laboratory evaluation • Glucose, calcium, magnesium, hematology studies, renal function tests, lytes toxicology screens. • Acute postictal changes: metabolic acidosis and leukocytosis, high CK • LP if risk factors for infection (fever, HIV positive).

14. Electroencephalography • Information provided: • Presence of abnormal electrical activity • Information of type of seizure disorder • Location of seizure focus • Perform study >48hrs after seizure • Include recordings during sleep, photic stimulation, hyperventilation. • 50% of patients with epilepsy have normal single EEG

15. Electroencephalography • If normal and high suspicion, repeat study after sleep deprivation • 10% of persons with true seizure with have normal multiple EEG studies • +EEG  likelihood of second seizure over two years

16. Neuroimaging in adults with 1st seizure • Retrospective review of 148 patients studied within 30 days of the seizure • Structural lesion was identified by CT in 55 (37 percent); 16 (11 percent) had metabolic seizures • CT findings agreed with the results of neurological examination in 82 percent of cases. Ramirez-Lassepas, et al. Value of computed tomographic scan in the evaluation of adult patients after their first seizure. Ann Neurol 1984; 15:536.

17. Neuroimaging • All patients should receive neuroimaging. • MRI preferred over CT to identify small lesions such as cortical dysplasias, infarcts, or tumors. • CT scan is suitable in emergency situations to exclude a mass lesion, hemorrhage, or large stroke.

18. When to initiate Antiepileptic drug therapy • Two or more seizures • Single seizure secondary to identified CNS lesion with an epileptogenic focus • Consider if significant occupational risk if patient suffers a second event. • Consider if single seizure event with one or more risk factors for recurrent seizures • Consider in the elderly patient with increased risk of seizure related morbidity (age, prolonged post-ictal state)

19. Risk of seizure recurrence in a patient with an apparently unprovoked or idiopathic seizure • 31 to 71% risk in the first 12 months after the initial seizure. • Risk factors associated with recurrent seizures include the following: • (1) evidence of a structural lesion • (2) EEG abnormalities • (3) partial type seizure • (4) family history of seizures • (5) focal abnormalities on exam • Most patients with one or more of these risk factors should be treated

20. Antiepileptic Drugs of Choice Primary Generalized Tonic-Clonic Partial Absence Atypical Absence, Myoclonic, Atonic Valproic acid First-Line Valproic acid Carbamezepine Phenytoin CarbamazepinePhenytoin EthosuximideValproate Alternatives LamotriginePrimidonePhenobarbital GabapentinTopiramate TiagabinePrimidonePhenobarbital LamotrigineClonazepam LamotrigineTopiramateClonazepamFelbamate

21. Principles of Treatment • Start with an average dose of a first line drug • Poor control? Address compliance, maximize drug dose, confirm right diagnosis (partial complex v.s generalized) • Majority of patients are controlled with single antiepileptic drug. • This drug can be gradually withdrawn if seizure free for two years. • Seizures recur in 25% of patients without risk factors and 50% of patients without risk factors. • The drug can be reduced by 25% every two to four weeks.

22. Principles of Treatment • 20-35% of patients with epilepsy have persistent seizures despite medical therapy. • If poor control with maximal dose, monotherapy with second drug. • Continue to administer first drug until a full dose of second drug reached, then gradually withdraw first drug. • If monotherapy with two drugs fail, patient may need re-evaluation (repeat MRI/EEG) before polytherapy commenced (1998 guidelines).

23. Side effects • Idiosyncratic toxicity: • rash, bone marrow suppression, or hepatotoxicity. • Require laboratory tests (e.g., complete blood count and liver function tests) • baseline • during initial dosing and titration

24. Other management issues: • Impact on independence, self-esteem, employment. Driving regulations: • Private drivers cannot drive for 3 months after a single seizure. • Private drivers can resume driving after being seizure free for 12 months on medication.

25. Side effects Canadian Guidelines

26. Neurologic Consultation (NEJM 2001) • Change in the type of seizure • Uncertain diagnosis (e.g. normal EEG) • Lack of seizure control in 3 months • Failure of two monotherapies • Patient is considering pregnancy • Prolonged post-ictal state • History of status epilepticus

27. Summary • Management after 1st seizure involves lots of discussion with patient about risks/benefits • Remember impact on driving: tell the ministry! • When in doubt about management (especially medications), get a neurologist involved