Grand Mal Epilepsy (Generalized Tonic-Clonic Seizure)

DEFINITION

ETIOLOGY / PREDISPOSING FACTORS

• No structural brain lesion
• Genetic predisposition (autosomal dominant patterns in many families)
• Examples: Juvenile myoclonic epilepsy, childhood/juvenile absence epilepsy

1. Head injury / traumatic brain injury
2. Cerebrovascular disease (stroke, intracranial hemorrhage)
3. Brain tumors (primary or metastatic)
4. CNS infections (meningitis, encephalitis, neurocysticercosis)
5. Congenital malformations / cortical dysplasia
6. Metabolic disorders: hypoglycemia, hypocalcemia, hyponatremia, uremia
7. Alcohol withdrawal / drug withdrawal
8. Hypoxic-ischemic encephalopathy

PATHOPHYSIOLOGY

• Normal neuronal excitability is maintained by a balance between excitatory (glutamate) and inhibitory (GABA) neurotransmitters.
• In grand mal epilepsy, there is excessive, synchronous, paroxysmal neuronal discharge involving both cerebral hemispheres simultaneously from the onset.
• Mechanism involves:
  • Failure of inhibitory GABA-ergic mechanisms
  • Hyperactivation of voltage-gated Na+ channels and NMDA-type glutamate receptors
  • Abnormal, repetitive depolarization shifts (paroxysmal depolarizing shifts, PDS) in neurons
• The tonic phase results from sustained neuronal firing; the clonic phase results from alternating inhibitory and excitatory surges.

CLINICAL FEATURES

Phase 1: Prodrome (Hours to Days Before)

• May occur hours before the attack
• Patient may feel irritable, depressed, apathetic, or, rarely, ecstatic
• Vague symptoms: headache, nausea, mood changes
• In juvenile myoclonic epilepsy: myoclonic jerks of the trunk or limbs on awakening may herald a seizure
• Note: Many patients have NO prodrome

Phase 2: Tonic Phase (10-20 Seconds)

• Sudden, complete loss of consciousness without warning in most cases
• Falls to the ground - may cause facial injury, tongue bite, limb fracture
• Tonic contraction of all body musculature:
  • Opisthotonus (arching of back)
  • Clenching of jaw (tongue may be bitten at this stage)
  • Arms: flexion / extension
  • Legs: extension
• Epileptic cry - forced expiration through closed glottis (laryngeal spasm + abdominal compression)
• Apnea - respiratory muscles in tonic spasm; cyanosis may develop
• Eyes deviate upward / to one side; pupils dilate
• Duration: approximately 10-20 seconds

Phase 3: Clonic Phase (30 Seconds - 2 Minutes)

• Violent, rhythmic jerking movements of all four limbs
• Gradual decrease in frequency and increase in amplitude of jerks
• Frothing / foaming at mouth (saliva + air forced through clenched teeth)
• Incontinence of urine (and less commonly feces) - due to relaxation of sphincters
• Tongue biting may occur (lateral border of tongue most commonly)
• Autonomic features: tachycardia, hypertension, sweating, hypersalivation
• Duration: approximately 30 seconds to 2 minutes

Phase 4: Postictal Phase (Minutes to Hours)

• Gradual recovery of consciousness
• Deep, stertorous (snoring) breathing - muscles begin to relax
• Patient is confused, disoriented, and exhausted
• Headache is common
• Retrograde and anterograde amnesia for the ictal event
• Todd's paralysis (postictal paresis): transient focal weakness of one limb or side of body lasting minutes to hours; indicates a focal cortical seizure focus
• Patient typically falls into a deep sleep for 1-2 hours
• On waking: complete recovery with no memory of the event; may have muscle soreness

INVESTIGATIONS / DIAGNOSIS

• Description of the ictal event, duration, tongue bite, incontinence, postictal confusion
• History of previous episodes, family history
• Precipitating factors: sleep deprivation, alcohol, fever, flashing lights

• Most important investigation
• Ictal: High-voltage, generalized spike or polyspike-and-wave discharges during the attack
• Interictal (between attacks): May show generalized spike-wave complexes at 3 Hz or other abnormalities
• Normal interictal EEG does NOT rule out epilepsy
• Sleep-deprived EEG or EEG with photic stimulation may increase yield

• CT scan of brain: rapid, useful in emergency to rule out hemorrhage, mass lesion
• MRI brain (preferred): better soft-tissue resolution; detects cortical dysplasia, hippocampal sclerosis, tumors, vascular malformations

• Blood glucose (hypoglycemia)
• Serum electrolytes: Na+, K+, Ca2+, Mg2+
• Complete blood count (CBC)
• Liver function tests (LFTs) and renal function tests (RFTs)
• Toxicology screen (drugs/alcohol)
• HIV serology (in high-risk groups)

• Indicated if meningitis/encephalitis suspected
• NOT routine

MANAGEMENT

A. First Aid / Immediate Management (During a Seizure)

1. Do NOT restrain the patient forcibly
2. Protect from injury: Move sharp or hard objects away; cushion the head
3. Position: Place in lateral/recovery position to prevent aspiration of secretions
4. Nothing in the mouth - do NOT insert any object between teeth (this is an outdated practice and causes injury)
5. Maintain airway: Loosen tight clothing; suction secretions if available
6. Observe and time the seizure
7. If seizure > 5 minutes: Treat as status epilepticus (emergency)

B. Pharmacological Management

• Monotherapy is preferred; start with a single drug at low dose, increase gradually
• The target is seizure freedom with minimal side effects
• Drug level monitoring is useful for phenytoin and carbamazepine
• Continue medication for 2-5 years after the last seizure before considering withdrawal
• Abrupt discontinuation must be avoided (risk of status epilepticus)

C. Status Epilepticus (Emergency Management)

1. IV Diazepam (0.1-0.2 mg/kg) or IV Lorazepam - first-line, stops 80% of cases
2. IV Phenytoin (15-20 mg/kg) - second-line, slow infusion
3. IV Valproate or Levetiracetam - alternatives
4. General anesthesia (propofol / thiopentone) if refractory

DENTAL CONSIDERATIONS IN A PATIENT WITH GRAND MAL EPILEPSY

1. Drug history: Phenytoin causes gingival hyperplasia (in 50% of patients) - a major dental concern; lamotrigine and valproate are preferred alternatives.
2. Avoid precipitating factors: Anxiety, stress, hyperventilation, flickering lights in the dental operatory.
3. Premedication: Oral benzodiazepine (e.g., diazepam) as anxiolytic may reduce seizure threshold.
4. Drug interactions:
   • Carbamazepine: induces CYP3A4 - increases metabolism of many drugs including doxycycline, metronidazole, paracetamol.
   • Valproate: inhibits drug metabolism - can increase levels of other drugs.
5. If a seizure occurs in the dental chair: Recline chair, protect from injury, do NOT force instruments in the mouth, turn patient to side, call for help, administer IV/buccal midazolam if available.
6. Informed consent: Document seizure history and frequency.

10 MARKER QUESTIONS (Dental Student Level)

• Prodrome: Occurs hours before the attack. Irritability, mood changes, headache, myoclonic jerks (in juvenile myoclonic epilepsy). Many patients have no prodrome.
• Tonic Phase (10-20 sec): Sudden loss of consciousness, fall to ground (risk of injury), epileptic cry (forced expiration through closed glottis), opisthotonus, jaw clenching (tongue bite may occur), apnea with cyanosis, upward eye deviation, pupillary dilation.
• Clonic Phase (30 sec-2 min): Rhythmic jerking of all four limbs, frothing at mouth, urinary incontinence, tongue biting, tachycardia, hypertension.
• Postictal Phase: Deep stertorous breathing, confusion, headache, deep sleep, amnesia for the event, Todd's paralysis (transient focal paresis) if focal onset.

• Most important: EEG (electroencephalography)
  • Ictal: generalized spike/polyspike-and-wave discharges
  • Interictal: may show spike-wave complexes; normal EEG does not rule out epilepsy
• Neuroimaging: CT brain (emergency) / MRI brain (preferred) - to rule out structural causes
• Blood: Blood glucose, serum electrolytes (Na, Ca, Mg), CBC, LFT, RFT, toxicology screen, HIV serology
• Lumbar puncture: Only if meningitis / encephalitis suspected
• History from witness: Most valuable clinical tool - description of ictal event, duration, postictal features

• Mechanism: Blocks voltage-gated Na+ channels (use-dependent block) - reduces repetitive, high-frequency neuronal firing
• Dose: 200-400 mg/day (adult); can be started at full dose (unique among antiepileptics)
• Pharmacokinetics: Exhibits zero-order (saturable) kinetics at therapeutic doses - small dose increases can cause disproportionate rise in blood levels
• Adverse effects: Nystagmus, ataxia, sedation (dose-dependent); Gingival hyperplasia (most important for dentists - occurs in ~50%); hirsutism, coarse facial features, megaloblastic anemia (long-term); teratogenic (fetal hydantoin syndrome)
• IV use: Treatment of status epilepticus; must be given slowly (risk of hypotension, cardiac arrhythmia)
• Drug interactions: Induces CYP enzymes; displaces drugs from protein binding

1. Gingival Hyperplasia (Drug-Induced Gingival Overgrowth):
   • Occurs in ~50% of patients on phenytoin
   • More severe in anterior labial gingiva
   • Due to increased collagen synthesis and decreased collagen degradation in fibroblasts
   • Worsened by poor oral hygiene
   • Management: Improve oral hygiene; in severe cases, surgical gingivectomy; consider switching to a non-phenytoin antiepileptic (e.g., levetiracetam, lamotrigine)
2. Increased infection risk (some immunological effects)
3. Drug interactions with dental drugs (see above)
4. Contraindication: Lignocaine (lidocaine) - large doses can lower seizure threshold; use with care

1. STOP dental procedure immediately; remove all instruments from mouth
2. Do NOT restrain the patient; lower/recline the dental chair to supine position
3. Protect from injury: Clear the area; protect head; do NOT insert anything into mouth
4. Lateral/recovery position after tonic-clonic phase ends - to prevent aspiration
5. Monitor airway: Maintain patency; suction secretions
6. Oxygen if available via face mask (do not force)
7. Time the seizure: If > 5 minutes - medical emergency (status epilepticus)
8. Call emergency services (ambulance)
9. Midazolam (buccal/intranasal) or IV diazepam if available and trained to use
10. Do NOT give anything by mouth during or immediately after the seizure
11. Reassure patient when consciousness returns; do NOT restart dental procedure on that visit

• Stage 1 (0-5 min): Secure airway, IV access, O2, blood glucose check, thiamine if alcoholism suspected
• Stage 2 (5-20 min, Benzodiazepine phase):
  • IV Lorazepam 0.1 mg/kg (preferred) OR IV Diazepam 0.1-0.2 mg/kg
  • Buccal/Intranasal Midazolam if no IV access
• Stage 3 (20-40 min, Second-line drugs):
  • IV Phenytoin 15-20 mg/kg (slow infusion, rate < 50 mg/min) OR
  • IV Valproate OR IV Levetiracetam
• Stage 4 (> 40 min, Refractory SE):
  • General anesthesia: IV Propofol, Thiopentone, or Midazolam infusion under EEG monitoring in ICU

• Sudden loss of consciousness; patient falls (risk of head injury, fractures)
• Epileptic cry: Forced expiration through the partially closed glottis due to tonic contraction of respiratory and laryngeal muscles - produces a characteristic cry or groan
• Opisthotonus: Sustained extension/arching of the trunk and neck
• Jaw is forcibly clenched (risk of tongue bite between molars)
• Arms: initially flex then extend; legs extend
• Apnea develops due to tonic contraction of respiratory muscles - cyanosis may appear
• Eyes deviate upward or laterally; pupils dilate and are unresponsive
• Profuse sweating, tachycardia, hypertension (autonomic storm)
• Duration: approximately 10-20 seconds

1. Idiopathic/Genetic (most common in young patients): no structural lesion; genetic predisposition; juvenile myoclonic epilepsy
2. Structural: head trauma, stroke, brain tumor, cortical dysplasia, hippocampal sclerosis
3. Metabolic: hypoglycemia, hypocalcemia, hyponatremia, hypomagnesemia, uremia, hepatic failure
4. Infective: meningitis, encephalitis, cerebral abscess, neurocysticercosis
5. Toxic: alcohol withdrawal, benzodiazepine withdrawal, cocaine, isoniazid overdose
6. Perinatal: hypoxic-ischemic encephalopathy

• Sleep deprivation
• Alcohol intake / withdrawal
• Missed antiepileptic doses
• Fever / systemic illness
• Emotional stress / anxiety
• Flickering lights (photosensitivity, especially juvenile myoclonic epilepsy)
• Hyperventilation (can precipitate absence seizures; rarely tonic-clonic)
• Menstruation (catamenial epilepsy)

• Blocks voltage-gated Na+ channels (reduces high-frequency neuronal firing)
• Blocks T-type calcium channels (relevant for absence seizures)
• Increases brain GABA levels (inhibits GABA transaminase enzyme, the enzyme that degrades GABA)

• Well absorbed orally; peak levels in 1-4 hours
• Protein binding ~90%
• Hepatic metabolism (glucuronidation, beta-oxidation)
• Half-life: 8-17 hours
• Available as enteric-coated tablets, syrup, IV formulation

• Nausea, vomiting, dyspepsia (GI common; give with food)
• Weight gain
• Alopecia (hair loss) - transient
• Hepatotoxicity (rare but potentially fatal, especially in children < 2 years on polytherapy)
• Pancreatitis (rare)
• Teratogenicity: Neural tube defects (spina bifida) - avoid in pregnancy if possible; supplement folic acid
• Tremor, sedation
• Thrombocytopenia, platelet dysfunction (important for dental surgery - check bleeding time)

• Inhibits hepatic enzymes - increases levels of phenobarbital, lamotrigine
• Displaces phenytoin from protein binding

• Definition: Todd's paralysis (Todd's paresis) is a transient, focal neurological deficit - most commonly a unilateral weakness or paralysis of a limb - occurring in the postictal phase (after a seizure), lasting minutes to several hours, and resolving completely.
• Mechanism: Believed to result from exhaustion of neurons or inhibitory mechanisms in the motor cortex following the ictal discharge.
• Clinical Significance:
  1. It strongly indicates that the seizure was focal in onset (even if it appeared generalized clinically) - helps in seizure classification
  2. It can mimic a stroke or TIA (transient ischemic attack) - important differential diagnosis
  3. Its presence helps localize the seizure focus (contralateral to the paretic limb)
  4. If paralysis lasts > 24 hours, an alternative diagnosis (e.g., stroke) should be considered and neuroimaging performed
• Example: A patient who has a right-sided tonic-clonic seizure and then has a left arm weakness lasting 2 hours has Todd's paralysis pointing to a right cortical focus.

SOURCES

• Adams and Victor's Principles of Neurology, 12th Edition - Sections on Generalized Onset Seizures, Grand Mal
• Katzung's Basic and Clinical Pharmacology, 16th Edition - Chapter on Antiseizure Medications
• Swanson's Family Medicine Review - Epilepsy Section
• Note: AK Tripathi's Essentials of Medical Pharmacology was not available in the textbook library; this answer follows the AK Tripathi chapter format and style based on the dental pharmacology curriculum structure.