5.1 Cerebrovascular Accidents (Stroke) & Epilepsy
Key Takeaways
- Ischaemic stroke accounts for 85% of cases; emergency non-contrast CT (NCCT) brain is essential to rule out intracranial hemorrhage before initiating reperfusion therapy.
- Intravenous alteplase (0.9 mg/kg, max 90 mg) must be administered within 4.5 hours of symptom onset in eligible ischaemic stroke patients, provided BP is controlled below 185/110 mmHg.
- Middle Cerebral Artery (MCA) occlusion produces contralateral hemiparesis and sensory loss affecting the face and arm more than the leg, accompanied by Broca or Wernicke aphasia in dominant hemisphere lesions.
- Status epilepticus is defined as continuous seizure activity lasting ≥5 minutes; first-line therapy is IV Lorazepam (4 mg), followed by IV Fosphenytoin/Leveacetam if seizures persist.
- Sodium Valproate is the drug of choice for broad-spectrum generalized seizures but is strictly contraindicated in women of childbearing potential due to high teratogenicity (neural tube defects).
Cerebrovascular Accidents (Stroke) & Seizure Disorders
Cerebrovascular accidents (CVA) and seizure emergencies represent core high-yield topics in UPSC CMS General Medicine. A thorough understanding of vascular anatomy, acute stroke protocols, seizure classification, and status epilepticus management is essential for clinical practice and examination success.
1. Cerebrovascular Accidents (Stroke)
Stroke is defined as an acute neurological deficit of vascular origin lasting >24 hours (or associated with acute infarction on neuroimaging). Strokes are broadly classified into Ischaemic (85%) and Haemorrhagic (15%).
Vascular Territory Syndromes
Understanding arterial anatomy allows accurate clinical localization of ischaemic stroke:
| Vascular Territory | Clinical Features & Deficits | Key Diagnostic Pearls |
|---|---|---|
| Middle Cerebral Artery (MCA) | Contralateral hemiparesis & hemisensory loss (Face + Arm > Leg); Homonymous hemianopia; Broca's Aphasia (Superior division, dominant left MCA - expressively impaired, intact comprehension); Wernicke's Aphasia (Inferior division - fluent, impaired comprehension); Global Aphasia (stem occlusion); Hemineglect (non-dominant right MCA). | Most common site of ischaemic stroke. Total anterior circulation infarct (TACI) presentation. |
| Anterior Cerebral Artery (ACA) | Contralateral hemiparesis & hemisensory loss (Leg > Arm + Face); Urinary incontinence; Transcortical motor aphasia; Abulia, apathy, and frontal release signs. | Recurrent artery of Heubner occlusion causes basal ganglia lacunar infarction. |
| Posterior Cerebral Artery (PCA) | Contralateral homonymous hemianopia with macular sparing; Alexia without agraphia (dominant PCA + splenium of corpus callosum); Dejerine-Roussy syndrome (thalamic pain); Weber syndrome (ipsilateral CN III palsy + contralateral hemiparesis). | Visual cortex and thalamic involvement dominate. |
| Vertebrobasilar System | Wallenberg Syndrome (PICA): Ipsilateral Horner syndrome, ipsilateral facial numbness (CN V), palatal paralysis/dysphagia (CN IX, X), cerebellar ataxia + contralateral spinothalamic loss of pain/temp. | Crossed deficits (ipsilateral cranial nerve + contralateral motor/sensory loss) pathognomonic for brainstem stroke. |
Acute Ischaemic Stroke Management Protocol
- Emergency Evaluation: Immediate NIH Stroke Scale (NIHSS) assessment, capillary blood glucose (to exclude hypoglycemia mimicking stroke), and urgent Non-Contrast Computed Tomography (NCCT) Brain.
- NCCT Role: Excludes intracranial hemorrhage (hypodense ischaemic changes may be subtle within the first 6 hours; early signs include hyperdense MCA sign, loss of insular ribbon, and sulcal effacement).
- Intravenous Thrombolysis:
- Drug & Dose: Recombinant tissue plasminogen activator (Alteplase / rtPA) at 0.9 mg/kg (maximum 90 mg; 10% given as IV bolus over 1 minute, remainder infused over 60 minutes).
- Time Window: Within 4.5 hours of symptom onset (or well time).
- Blood Pressure Ceiling: BP must be <185/110 mmHg before starting alteplase and maintained <180/105 mmHg for 24 hours post-thrombolysis.
- Absolute Contraindications: Active internal bleeding, intracranial hemorrhage history, head trauma/stroke within 3 months, arterial puncture at non-compressible site within 7 days, INR >1.7 or platelets <100,000/mm³, blood pressure >185/110 mmHg resistant to acute antihypertensive therapy.
- Mechanical Thrombectomy: Indicated for Large Vessel Occlusion (LVO - ICA or proximal MCA M1 segment) within 6 to 24 hours of onset using stent retrievers/aspiration catheters.
- Secondary Prevention: Aspirin 150-300 mg daily started 24 hours post-thrombolysis (or immediately if non-thrombolysed), High-intensity statin (Atorvastatin 80 mg daily), Blood pressure optimization, and oral anticoagulation (Apixaban/Dabigatran/Warfarin) for atrial fibrillation after 3-14 days depending on infarct size.
Subarachnoid Hemorrhage (SAH)
- Etiology: Rupture of saccular (berry) aneurysms (85%), most commonly located at the Anterior Communicating Artery (ACom) junction.
- Clinical Presentation: Sudden onset "thunderclap" headache ("worst headache of life"), vomiting, transient loss of consciousness, neck stiffness (nuchal rigidity), Kernig and Brudzinski signs.
- Diagnosis: Non-contrast CT brain (>95% sensitive in first 6 hours). If CT is negative but clinical suspicion remains high, lumbar puncture is mandatory to evaluate for xanthochromia (yellow CSF supernatant from hemoglobin breakdown, developing 6-12 hours post-event).
- Complication & Prevention: Cerebral vasospasm occurs between days 4-14 post-SAH. Enteral Nimodipine 60 mg every 4 hours for 21 days significantly reduces ischaemic deficits from vasospasm.
2. Epilepsy & Status Epilepticus
Epilepsy is defined as at least two unprovoked seizures occurring >24 hours apart, or one unprovoked seizure with a high risk (>60%) of recurrence over the next 10 years.
ILAE Seizure Classification & Clinical Syndromes
- Focal Seizures: Originate within networks limited to one cerebral hemisphere.
- Focal Aware: Consciousness preserved.
- Focal Impaired Awareness: Consciousness altered or lost; frequently accompanied by automatisms (lip-smacking, swallowing, hand-rubbing). Temporal lobe origin most common (associated with hippocampal sclerosis).
- Generalized Seizures: Originate at some point within and rapidly engage bilaterally distributed networks.
- Absence Seizures (Petit Mal): Brief (5-10 sec) sudden impairment of consciousness with sudden onset/offset, no post-ictal state. EEG shows classic 3 Hz generalized spike-and-wave pattern. First-line treatment: Ethosuximide or Sodium Valproate.
- Juvenile Myoclonic Epilepsy (JME): Onset in adolescence; characterized by morning myoclonic jerks (dropping coffee cup), generalized tonic-clonic seizures (GTCS), and absence seizures. EEG shows 4-6 Hz polyspike-wave pattern. First-line treatment: Sodium Valproate or Levetiracetam. Note: Carbamazepine and Phenytoin can aggravate myoclonus!
Status Epilepticus Management Protocol
Status epilepticus is defined as continuous seizure activity lasting ≥5 minutes (t1) or ≥2 recurrent seizures without recovery of consciousness between episodes. Neuronal damage becomes irreversible after 30 minutes (t2).
[0 - 5 min]: INITIAL EVALUATION & ABCs
├─ Airway maintenance, 100% Oxygen, IV access, Capillary Blood Glucose
└─ If Hypoglycaemic: Give 50 mL 50% Dextrose + 100 mg Thiamine IV
[5 - 20 min]: FIRST-LINE THERAPY (Emergent / Benzodiazepines)
├─ IV Lorazepam 4 mg (0.1 mg/kg) over 2 min [DRUG OF CHOICE]
├─ OR IV Diazepam 10 mg (0.2 mg/kg) over 2 min
└─ OR IM Midazolam 10 mg (if IV access unavailable)
[20 - 40 min]: SECOND-LINE THERAPY (Urgent Control / Non-sedating AEDs)
├─ IV Fosphenytoin 20 mg PE/kg (max 150 mg PE/min; monitor ECG & BP)
├─ OR IV Levetiracetam 60 mg/kg (max 4500 mg)
└─ OR IV Sodium Valproate 40 mg/kg (max 3000 mg)
[> 40 min]: THIRD-LINE THERAPY (Refractory Status Epilepticus)
└─ General Anaesthesia + Intubation with continuous EEG monitoring:
IV Propofol OR IV Midazolam infusion OR IV Thiopental
Comprehensive Anti-Epileptic Drug (AED) Summary Table
| Drug | Primary Mechanism of Action | Key Clinical Indications | High-Yield Side Effects & Exam Pearls |
|---|---|---|---|
| Phenytoin | Na+ channel blocker (use-dependent) | Focal seizures, GTCS, 2nd-line status epilepticus | Zero-order kinetics at therapeutic levels. Side effects: Gingival hyperplasia, hirsutism, nystagmus, ataxia, osteomalacia, megaloblastic anemia (folate deficiency), Fetal Hydantoin Syndrome (cleft lip/palate, cardiac defects). |
| Carbamazepine | Na+ channel blocker | Focal seizures (Drug of Choice), Trigeminal Neuralgia | Auto-induction of CYP3A4 enzymes. Side effects: Hyponatremia (SIADH-like effect), aplastic anemia, agranulocytosis, Stevens-Johnson syndrome (screen for HLA-B*1502 in Asian populations). |
| Sodium Valproate | Broad spectrum: Na+ block, GABA enhancement, T-type Ca2+ block | Broad-spectrum: GTCS, Focal, Absence, Myoclonic (JME) | Teratogenic: Spina bifida/neural tube defects (avoid in pregnancy). Side effects: Weight gain, alopecia, hepatotoxicity, acute pancreatitis, hyperammonemia. |
| Ethosuximide | T-type Ca2+ channel blocker in thalamic neurons | Absence Seizures (First-line choice in children) | Highly selective for absence seizures. Has no efficacy in GTCS or focal seizures. Side effects: Gastric distress, lethargy. |
| Levetiracetam | Binds SV2A synaptic vesicle protein | Focal, GTCS, Myoclonic seizures | Minimal drug interactions, excreted renally. Key side effect: Behavioral changes (irritability, agitation, depression). |
| Lamotrigine | Na+ block, inhibits glutamate release | Focal, GTCS, Absence, Bipolar depression | High risk of severe cutaneous adverse reactions (Stevens-Johnson Syndrome / TEN); dosage must be titrated very slowly. Valproate doubles lamotrigine half-life! |
A 7-year-old child is brought by his parents due to frequent 10-second episodes of sudden unresponsiveness and eye-fluttering during school, after which he immediately resumes normal activity without confusion. Electroencephalogram (EEG) demonstrates a 3 Hz generalized spike-and-wave discharge pattern. Which of the following is the first-line pharmacotherapy for this condition?
A 62-year-old male presents to the emergency department with sudden-onset right-sided hemiparesis and expressive aphasia that started 2 hours ago. Non-contrast CT scan of the brain shows no evidence of hemorrhage or early ischaemic changes. His blood pressure is 175/95 mmHg. Which of the following is the most appropriate next step in management?
A 48-year-old woman presents with severe 'thunderclap' headache and nuchal rigidity. Non-contrast CT brain reveals blood in the basal cisterns, confirming a subarachnoid hemorrhage due to a ruptured anterior communicating artery aneurysm. Which medication should be routinely administered to reduce the risk of secondary ischaemic deficits from cerebral vasospasm?
A 25-year-old male is brought to the casualty in continuous generalized tonic-clonic seizure activity lasting for 12 minutes. Airway and oxygenation are maintained. Which of the following is the initial intravenous drug of choice for rapid seizure control?