Seizures

Approach to Unexplained Seizures

Patients with epilepsy are physically normal and asymptomatic between events

Elements of a seizure

• Patient History
  • What is the frequency and duration of seizures?
  • What happened before/after the event? (pre-ictal phase and post-ictal phase)
    • Was there a preciding aura?
    • Was there residual weakness or confusion post-ictal?
  • Are there any automatisms? (Gives a clue as to the focus of origin)
    • Was there tongue-biting?
    • Was there incontinence?
  • Has there been trauma OR drug/alcohol use? (triggers)
  • Is there a Family History?
• Conditions that trigger seizures
  • Medication non-compliance OR New drug that interferes with medication (break-through seizures)
  • Sleep deprivation
  • Stress
  • Alcohol (being drunk raises the seizure threshold, the problem is recovering from the buzz which causes a lower seizure threshold)
  • Alcohol withdrawal (chronic alcohol use going cold turkey)
  • Hypoglycemia
• Differentials for seizures (VITAMIN D)
  • Vascular malformation (CT, MRI)
  • Infection, Inherited conditions
  • Trauma
  • Alzheimer’s
  • Metabolic derangement (hypocalcemia, Hyponatremia, Hypernatremia, Hypermagnesemia, Hypomagnesemia, Hyperglycemia, Hypoglycemia)
  • Idiopathic
  • Neoplasms
  • Drugs (fluoroquinolones, bupropion, imipramine, meperidine, metronidazole, INH)
• Investigations
  • RBS: exclude extreme hypoglycemia or hyperglycemia
  • CBC: r/o systemic or CNS infections
  • U/E/Cs: Hyponatremia, hypernatremia, uremia
  • Urine toxicology screen: cocaine, amphetamines, heroin PCP, GHB
  • Blood Alcohol Concentration: >0.06 after binge drinking; alcohol withdrawal
  • Head CT: structural lesions, injury (TBI), elevated intracranial pressure (contraindication to lumbar puncture)
  • EEG
  • MRI
• Treatment
  • Seizure precautions
  • Establish IV access
  • Abort the seizure
• What should you consider if convulsions last more than 3 minutes?
  • Status epilepticus
  • Non-epileptic seizure

Focal (partial) seizure

Involves one part of the brain. The patient will not lose consciousness but will have altered awareness.

Localizing features of focal seizures

Generalized seizure

Arises from both cerebral hemispheres.

• How would you differentiate an atonic seizure from syncope?
  • Seizures have haziness and confusion after loss of consciousness. In syncope, the patient will be OK after recovering.

Common causes of seizures

Epilepsy

Chronic seizures. Idiopathic (75%), Recurrent (2 or more), unexplained seizures. Affects 1% of all people by age 20y and 3% by age 75% (increases past 50s due to increased incidence of neurodegenerative conditions). Epilepsy is the chronic condition of recurrent seizures (a single seizure does not diagnose epilepsy, not drug/substance/infection induced). The choice of drugs is very complex and is done by the neurologist.

All antiepileptic drugs are teratogenic. Valproate is the most teratogenic and can cause thrombocytopenia. Lamotrigine can cause Stevens-Johnson syndrome (start gradually…)

Sudden unexpected death in epilepsy (SUDEP) can occur in uncontrolled epilepsy as a result of nocturnal seizure-associated apnoea or asystole.

• Differentials for epilepsy
  • Migraine headache: Aura symptoms, no impaired consciousness, headache
  • Stroke: older patient, findings on CT, impairment lasts longer
  • Febrile seizure: Very high fever (>104 C) in young child; does not require treatment
  • Syncope: prodromal dizziness, sweating, No post-ictal symptoms, normal serum creatinine
  • Psychogenic non-epileptic syndrome(PNES): Conversion-like syndrome, not really seizures. ****lasts longer than 5 minutes, normal serum creatinine, dx of exclusion
• Risk factors for Psychogenic non-epileptic syndrome(PNES)
  • Psychiatric History (OCD, PTSD)
  • Female sex
  • Sexual abuse history
• Management after the second unexplained seizure
  • EEG (30-minute EEG; 5-7 day continuous video EEG)
  • Antiepileptic drugs
  • Symptom monitoring for patients with well-documented focal lesions
  • Can consider surgery for patients with well documented focal lesions
• What should you do for females of reproductive age before starting antiepileptic drugs?
  • Pregnancy determination test
  • Counseling (contraception, pregnancy, and breastfeeding)
    • Most AEDs except Carbamazepine and Valproate are present in breast milk
    • Lamotrigine is not harmful to infants
    • Enzyme-inducing AEDs may make progesterone-only contraceptives unreliable
    • Oestrogen-containing contraceptives lower Lamotrigine levels and dosage might need to be increased
  • Strictly avoid Valporate and polytherapy before and during conception
  Do not take a pregnant woman off her antiepileptic drugs. Instead, supplement with folate 5mg/d to decrease the risk of neural tube defects.
• Patient education
  • Avoid becoming drunk, especially drinking sprees during weekends
  • Eat at regular intervals
  • Manage stress (physical or mental) as it may precipitate fits
  • Avoid sleep deprivation
  • Never swim alone
  • Avoid operating heavy or sharp edged machinery
  • To prevent burns, make protective shields around braziers (”Jikos”)

Anti-epileptic drugs (AEDs)

AEDs should only be commenced by a specialist after the diagnosis of epilepsy has been confirmed. The choice of AEDs depends on seizure types, comorbidities, lifestyle and the patient’s preference. All AEDs are teratogenic. Valproate is the most teratogenic and may cause TTP. Lamotrigine may cause Stevens-Johnson syndrome (start gradually and stop gradually)

• Are antiepileptics started after the patient’s first seizure?
  • No
• Does a normal EEG rule out epilepsy?
  • No (might have a seizure every 8 months, etc.)
• Drug of choice for absence seizures?
  • Ethosuximide
• First-line agents for simple or secondary generalized seizures?
  • Carbamazepine
  • Oxcarbazepine
  • Lamotrigine
  • Topiramate
• Drug of choice for generalized epilepsy or unclassified epilepsy?
  • Valproic acid (Depakote) – has a fairly good spectrum
• Drugs with the broadest spectrum of action?
  • Lamotrigine
  • Topiramate
• Why do creatine kinase levels go up after seizures?
  • Muscle contraction → increased release of CK into bloodstream
• When to stop AEDs
  • Seizure free for > 2 years after assessing risk and benefits for the individuals (e.g. the need to drive)
  • Decrease dosage slowly over 2-3 months or > 6 months for benzodiazepines and barbiturates

Status Epilepticus

Protracted seizure. By definition, status epilepticus is a seizure that has lasted for > 30 minutes without intervening consciousness (but in reality it is considered if a seizure lasts > 5 minutes). The most common cause is non-compliance with anti-epileptic drug regimen in patients with known epilepsy. For the first minutes (atonic phase) the patient is usually not breathing. The most important first step is therefore to management is to maintain airway and breathing. Never spend more than 20 minutes on someone with status epilepticus without assistance from an anaesthetist.

• Differenitals
  • Delirium tremens: History of heavy alcohol use with sudden cessation
  • Neuroleptic malignant syndrome: antipsychotic medication. The patient is febrile, rigid and has fluctuating conscisounses
  • Drug ingestion: r/o with urine toxicaology. Needle track marks on the arms.
  • Pseudo-status epilepticus: NEVER assume that a patient is faking a seizure!
• Treatment of status epilepticus
  • 5 minutes
    • ABCs
      • Open and secure the airway (adjuncts as needed)
      • Remove false teeth if they are poorly fitting
      • Give 100% oxygen and suction as needed
      • EKG monitor
    • IV access and draw blood
      • Labs (Blood glucose, CBC, U/E/C, LFTs, Urine toxicology, AEDs level)
    • IV Lorazepam 4mg at 5 minutes or IV Diazepam 10mg STAT or Midazolam
    Lorazepam does not require refridgeration 10-20mg Diazepam can be given PR if IV access cannot be established (rectal solution at 0.5 mg/kg)Midazolam can be given Buccaly if IV access cannot be established
    • Have full resuscitation facilities on hand for all IV benzodiazepine use
    • If blood glucose is unavailable assume hypoglycemia
      • Give Thiamine 250mg IV over 30 minutes then 50mL D50 (always give glucose with thiamine to prevent Wernicke-encephalopathy)
  • No response at 10 minutes
    • Second dose IV Lorazepam if no response (or Diazepam, Midazolam)
    • IV Phenytoin if the patient is in hostpital
  • No response at 15 minutes
    • Consult Anaesthesia or Intensivist
      • Prepare for impending mechanical intubation
      • Preparr for general anesthesia
  • No response at 20 minutes
    • IV Phenobarbital
    • Insert foley
    • Start IV fluids
    • Rapid sequence induction (RSI)
    • General anaesthesia with Propofol
• Post-seizure care
  • Admit to the ICU
  • Consult neurology
  • EEG monitoring
  • Comprehensive physical examination
  • Investigate for possible cause (if the patient has no history of seizure)
• What to watch out for post-status epilepticus
  • Rhabdomyolysis (d/t muscle contractions and trauma)
  • Aspirtation pneumonitis
  • Arrhythmia

First Aid DOs and DON’Ts in Patient who are in active Seizure

• DO NOT
  • DO NOT Put anything in the patient’s mouth to prevent tongue biting (it is anatomically impossible to choke on the tongue. Also tongue biting may have already happened)
  • DO NOT Restrain the patient
• DO
  • Gently lean the patient on their side with the head turned to the same side (to prevent aspiration)
  • Cushion the patients head (to prevent head injury)
  • Loosen or remove tight or dangerous clothing around the head and neck (necklaces, glasses)
  • Remove dentures
  • Call for help immediately