14.3 Epilepsy, Stroke and Transient Ischaemic Attack

3. Neurological Conditions: Epilepsy, Stroke, and Cranial Neuropathies

Epilepsy: Chairside Management and Status Epilepticus

Epilepsy is defined by recurrent, unprovoked epileptic seizures resulting from excessive, paroxysmal, hypersynchronous neuronal electrical discharges within the cerebral cortex.

• Seizure Triggers in the Dental Surgery: Acute emotional stress and anxiety, missed anticonvulsant medication, physical exhaustion, hypoglycemia, flickering dental operating lights (photosensitive epilepsy), and local anaesthetic systemic toxicity (LAST).
• Immediate Chairside Management of a Generalized Tonic-Clonic Seizure:
  1. Stop treatment immediately. Withdraw handpieces, instruments, burs, and suction tips from the mouth.
  2. Protect the patient from injury. Lower the dental chair to the floor and recline it. Move bracket tables, sharp instruments, and carts away.
  3. Airway and Positioning: Roll the patient onto their side into the recovery position to maintain an open airway and allow saliva/blood to drain. Administer high-flow oxygen (10–15 L/min via non-rebreather mask).
  4. Strict Rules: NEVER restrain the convulsing patient's limbs (causes joint dislocations and muscle tears), and NEVER force fingers, bite blocks, or spatulas into the mouth (causes severe soft-tissue trauma, fractured teeth, and lethal airway obstruction).
• Status Epilepticus Management:
  • Definition: Continuous, unremitting epileptic seizure activity lasting $\ge 5\text{ minutes}$, or two or more discrete seizures without full recovery of consciousness between episodes. It constitutes an extreme medical emergency with high risk of irreversible excitotoxic hypoxic brain damage.
  • First-Line Medical Treatment: Administer Buccal Midazolam (10 mg for adults) (available as pre-filled oral syringes: Epistatus or Buccolam). Deposit half the dose slowly into the buccal sulcus between the lower gum and cheek on each side. The lipid-soluble benzodiazepine is rapidly absorbed directly across the non-keratinized buccal mucosa into the internal jugular system, bypassing first-pass hepatic metabolism. Alternatively, Rectal Diazepam (10 mg) may be administered.
  • Emergency Call: Call 999 immediately. If seizure activity continues after 10 minutes, a second dose may be administered only under the direct instruction of paramedics or an emergency physician.
• Phenytoin-Induced Drug-Induced Gingival Overgrowth (DIGO):
  • Phenytoin (hydantoin anticonvulsant) induces gingival overgrowth in ~50% of patients. It stimulates genetically susceptible fibroblastic subpopulations to synthesize excessive extracellular matrix (collagen and sulphated glycosaminoglycans) while suppressing matrix metalloproteinase-1 (MMP-1) collagenase activity.
  • Manifests characteristically as firm, pale pink, nodular, fibrous enlargement beginning at the interdental papillae on the labial aspect of anterior teeth, progressing to cover the clinical crowns. It does not bleed easily unless complicated by secondary biofilm-induced gingivitis.
  • Management: Meticulous oral hygiene and chlorhexidine reduce severity. In severe cases, surgical gingivectomy or periodontal flap surgery is required; however, recurrence exceeds 40% unless the neurologist substitutes phenytoin with an alternative agent (e.g., carbamazepine, lamotrigine, levetiracetam).

Cerebrovascular Accident (CVA / Stroke) and Transient Ischaemic Attack (TIA)

A stroke is a focal neurological deficit lasting $> 24\text{ hours}$ caused by cerebral infarction (ischaemic stroke, ~85%) or intracranial haemorrhage (~15%). A TIA is a transient episode of neurological dysfunction caused by focal brain ischaemia without acute infarction, with symptoms resolving completely within 24 hours.

• Elective Care Deferral Period: All elective dental care must be deferred for at least 6 months following a stroke or TIA. The risk of recurrent stroke, labile hypertension, and cardiovascular mortality is highest during this 6-month period.
• Clinical Considerations: Patients frequently present with unilateral Upper Motor Neurone (UMN) facial palsy (which characteristically spares the forehead), hemiparesis, and dysphagia (impaired swallowing). Swallowing deficits dramatically escalate the risk of pulmonary aspiration; treat patients in an upright position, use continuous high-volume aspiration, and exercise extreme caution when using water spray.

Preventing and Managing Seizures in the Surgery

Examiners reward anticipation as much as emergency drug knowledge. A structured pre-treatment history should establish the seizure type, frequency, date of the last seizure, known triggers, current medication and adherence, and any warning aura. Modifiable triggers in a dental setting include missed medication, anxiety, flashing operating lights, fatigue and hypoglycaemia from a missed meal, so a short morning appointment after normal medication and food is a reasonable precaution.

Phenytoin produces gingival enlargement in a substantial minority of users, requiring meticulous plaque control and sometimes surgical reduction; sodium valproate can cause thrombocytopenia and platelet dysfunction, relevant before surgery, and is teratogenic; carbamazepine induces hepatic enzymes and interacts with a number of drugs. During a generalised tonic-clonic seizure the priorities are to remove instruments from the mouth, protect the head, never force anything between the teeth, lower the chair and time the seizure. Buccal midazolam is the first-line treatment when a seizure lasts more than five minutes or when seizures recur without recovery, and an ambulance is called for status epilepticus, a first seizure, injury or failure to recover.