Sudden focal neurological deficit

A sudden focal neurological deficit is abrupt loss of motor, sensory, language, visual, coordination or cranial nerve function in a defined territory, developing over seconds to minutes. Stroke is the leading cause, and treatment benefit falls with each minute, so the working diagnosis is stroke until proven otherwise.

Definitions. Stroke: deficit lasting over 24 hours, or any duration with infarction on imaging. Transient ischaemic attack: transient deficit, usually under 1 hour, with no infarct on diffusion MRI. A stroke mimic is a non-vascular condition producing similar signs and accounts for 15 to 30% of suspected strokes.

Types. Ischaemic stroke (about 85%), intracerebral haemorrhage (about 10 to 15%) and subarachnoid haemorrhage (about 3%). The two cannot be distinguished at the bedside, so imaging is required before specific treatment.

Vascular syndromes.

• Middle cerebral artery: contralateral face and arm weakness, sensory loss, hemianopia, gaze deviation toward the lesion, aphasia (dominant side) or neglect (non-dominant side).
• Anterior cerebral artery: contralateral leg weakness, abulia, incontinence.
• Carotid: ipsilateral weakness, sensory loss and aphasia or neglect, plus monocular visual loss (amaurosis fugax).
• Posterior circulation: vertigo, diplopia, dysarthria, dysphagia, ataxia, crossed signs, hemianopia, reduced consciousness (basilar occlusion can progress to coma or locked-in state).
• Lacunar syndromes: pure motor, pure sensory, sensorimotor, ataxic hemiparesis, dysarthria with clumsy hand.

Large vessel occlusion. Gaze deviation, severe arm weakness, and aphasia or neglect predict an occlusion that may be treated by thrombectomy.

Time. The time the patient was last known to be well decides eligibility. A deficit on waking dates from the last time the patient was seen well.

History.

• Time last known well, onset speed, progression, and circumstances. Abrupt, maximal onset suggests embolism. Headache, vomiting and reduced consciousness suggest haemorrhage. Thunderclap headache suggests subarachnoid haemorrhage. Neck pain after trauma or neck manipulation suggests dissection. Positive visual symptoms or spreading paraesthesia suggest migraine aura.
• Risk factors: hypertension, diabetes, atrial fibrillation, previous stroke or transient ischaemic attack, valve disease or rheumatic heart disease, recent myocardial infarction, endocarditis, smoking, cocaine or amphetamines, sickle cell disease, HIV infection, pregnancy and the postpartum period, migraine, epilepsy.
• Medicines: anticoagulant name, dose and last dose time, antiplatelets, recent surgery, trauma, bleeding, and procedures.

Examination.

• Airway, vital signs, blood pressure in both arms, capillary glucose, temperature, irregular pulse, murmurs, carotid bruit, signs of trauma or tongue bite, and signs of endocarditis.
• Neurological:
  • Glasgow Coma Scale, a 42 point stroke severity scale (0 no deficit, 1 to 4 minor, 5 to 15 moderate, 16 to 20 moderate to severe, 21 to 42 severe).
  • Pupils, gaze, visual fields, face (upper motor neurone weakness spares the forehead), limb power, sensation, speech and language, neglect, ataxia, gait if safe, meningism, and fundi (papilloedema, subhyaloid haemorrhage).
• Prehospital recognition with face, arm, speech and time tests (with balance and eye signs added to find posterior strokes).

Red flags.

• Reduced consciousness, vomiting or seizure at onset, thunderclap headache, neck stiffness.
• Systolic pressure over 220 mmHg, fever, glucose under 4.0 mmol/L, recent head trauma.
• Anticoagulant use, rapid progression, and bilateral or brainstem signs.

Special groups. Young adults: dissection, cardiac embolism, sickle cell disease, cerebral venous thrombosis, vasculitis, drugs, pregnancy related causes. Children: sickle cell disease and cardiac disease. Pregnancy: eclampsia and cerebral venous thrombosis must be considered, and imaging and thrombolysis are not absolutely excluded. Sub-Saharan Africa: higher rates of hypertensive haemorrhage, HIV related vasculopathy, tuberculous meningitis vasculopathy, neurocysticercosis and rheumatic heart disease with atrial fibrillation.

Ischaemic stroke and transient ischaemic attack.

• Large artery atherosclerosis, cardioembolism (atrial fibrillation, myocardial infarction, rheumatic heart disease, mechanical valve, infective endocarditis, atrial myxoma, patent foramen ovale), small vessel disease.
• Carotid or vertebral artery dissection, cerebral venous thrombosis, vasculitis, moyamoya disease, sickle cell disease, antiphospholipid syndrome, reversible cerebral vasoconstriction syndrome, fibromuscular dysplasia, cocaine related stroke, other hypercoagulable states.

Haemorrhagic. Intracerebral haemorrhage (hypertensive, cerebral amyloid angiopathy, anticoagulant related, arteriovenous malformation, cavernous malformation, tumour bleed, sympathomimetic drug related), subarachnoid haemorrhage (aneurysm rupture), subdural haematoma, extradural haematoma.

Metabolic and toxic mimics. Hypoglycaemia, hyperosmolar hyperglycaemic state, hyponatraemia, hepatic encephalopathy, Wernicke encephalopathy, drug toxicity.

Neurological mimics.

• Seizure with Todd paralysis, migraine with aura, hemiplegic migraine, functional neurological disorder, posterior reversible encephalopathy syndrome, hypertensive encephalopathy.
• Bell palsy (lower motor neurone facial weakness involving the forehead), vestibular neuritis, peripheral nerve compression, spinal cord compression or infarction, Guillain-Barre syndrome, myasthenia gravis, multiple sclerosis relapse, optic neuritis.
• Brain tumour, brain abscess, bacterial meningitis, herpes simplex encephalitis, tuberculous meningitis, cryptococcal meningitis, cerebral toxoplasmosis, neurocysticercosis.

Cardiovascular mimic. Syncope or presyncope with a non-focal presentation.

Step 1. Airway and breathing, capillary glucose within minutes (correct if under 4.0 mmol/L), IV access, ECG, record the time last known well, and activate the stroke team.

Step 2. Non-contrast CT head immediately (aim for completion within 20 minutes of arrival). It excludes haemorrhage and some mimics, and shows early ischaemic change (10 point early change score; under 6 predicts poor outcome and large core). CT is insensitive for early ischaemia, small infarcts and the posterior fossa.

Step 3. CT angiography of head and neck for large vessel occlusion and dissection, with CT perfusion or MRI diffusion with FLAIR mismatch when onset is unknown or after 4.5 hours. MRI diffusion is the most sensitive for ischaemia (over 90%).

Step 4. Bloods (do not delay thrombolysis unless coagulopathy is suspected):

• Full blood count and platelets, urea, creatinine, electrolytes, glucose.
• Coagulation if on anticoagulant or with liver disease, troponin, lipids, HbA1c, CRP and ESR.
• Blood cultures if endocarditis is possible, group and save, pregnancy test.
• HIV, syphilis serology and sickle cell tests in selected patients.

Step 5. Mechanism work up:

• Continuous ECG monitoring 24 to 72 hours.
• Prolonged rhythm monitoring (up to 30 days or an implantable recorder) for cryptogenic stroke.
• Echocardiography (transoesophageal for young or suspected embolic source).
• Carotid duplex or CT angiography.
• A hypercoagulable and vasculitis screen in young patients.

Subarachnoid haemorrhage. CT within 6 hours of onset, read by an experienced radiologist on a modern scanner, can exclude it. If CT is negative after 6 hours, lumbar puncture at 12 hours or more after onset for xanthochromia.

Transient ischaemic attack risk. The ABCD2 score components are:

• Age 60 or over 1.
• Blood pressure 140/90 mmHg or over 1.
• Unilateral weakness 2, speech disturbance without weakness 1.
• Duration 60 minutes or more 2 or 10 to 59 minutes 1.
• Diabetes 1.

The total is 0 to 7. A score of 4 or more indicates high risk, but it misses carotid stenosis and atrial fibrillation, so every patient needs specialist assessment within 24 hours.

Limitations. A normal CT does not exclude stroke. The severity scale underestimates posterior circulation strokes. Imaging access and expertise vary, so in a setting without CT, treat only after clinical assessment by a stroke clinician and avoid thrombolysis and antithrombotics until haemorrhage is reasonably excluded.

General care.

• Oxygen only if saturation is under 94%, nil by mouth until a swallow screen is passed, head of bed flat or 30 degrees depending on tolerance, and isotonic saline for fluids (avoid glucose solutions).
• Hypoglycaemia: glucose 10% 150 to 200 mL IV over 15 minutes (or glucose 20% 75 to 100 mL), recheck at 10 to 15 minutes. Treat glucose over 10 mmol/L with insulin to a range of 7.8 to 10 mmol/L.
• Temperature over 37.5 °C: paracetamol 1 g orally or IV every 6 hours; maximum 4 g daily (3 g daily if weight under 50 kg, malnutrition, alcohol excess or liver disease); monitor liver tests with prolonged use.

Blood pressure.

• Ischaemic stroke without reperfusion therapy: treat only if over 220/120 mmHg, lowering by about 15% in the first 24 hours.
• Before thrombolysis: bring to under 185/110 mmHg and keep under 180/105 mmHg for 24 hours.
  • Labetalol 10 to 20 mg IV over 1 to 2 minutes, repeated once.
  • Or nicardipine 5 mg/hour IV, increased by 2.5 mg/hour every 5 to 15 minutes to a maximum of 15 mg/hour.
  • Monitor heart rate and pressure every 5 to 15 minutes.
  • Avoid labetalol in asthma, bradycardia under 60 beats/min, heart block and decompensated heart failure.
  • Avoid sublingual nifedipine because pressure may fall abruptly.

Thrombolysis for ischaemic stroke.

• Alteplase 0.9 mg/kg IV (maximum 90 mg): 10% as a bolus over 1 minute, the rest over 60 minutes, within 4.5 hours of last known well (later in selected patients with imaging mismatch). Alternatively tenecteplase 0.25 mg/kg IV as a single bolus over 5 to 10 seconds (maximum 25 mg).
• Monitoring: neurological observations and blood pressure every 15 minutes for 2 hours, every 30 minutes for 6 hours, then hourly for 16 hours. No antithrombotics for 24 hours, and repeat CT before starting them.
• Stop the infusion and obtain urgent CT for headache, vomiting, acute rise in blood pressure or neurological worsening. For angio-oedema, give adrenaline 0.5 mg IM and manage anaphylaxis if features are present.
• Exclusions:
  • Haemorrhage on CT, extensive hypodensity, onset time beyond the window without imaging selection.
  • Refractory blood pressure over 185/110 mmHg, glucose under 2.7 mmol/L, platelets under 100 x 10^9/L, INR over 1.7.
  • Therapeutic low molecular weight heparin within 24 hours.
  • Direct oral anticoagulant within 48 hours (unless drug level is low or reversal given, for example idarucizumab 5 g IV for dabigatran).
  • Major surgery or serious trauma within 14 days, gastrointestinal or urinary bleeding within 21 days.
  • Previous intracranial haemorrhage, ischaemic stroke in the last 3 months, intracranial neoplasm or large arteriovenous malformation, suspected aortic dissection or infective endocarditis.
  • Mild non-disabling deficits do not need thrombolysis.
• Risks: symptomatic intracranial haemorrhage in about 2 to 7%. Counsel patient and family.

Thrombectomy. For occlusion of the internal carotid or proximal middle cerebral artery, a stroke scale score of 6 or more and a good early CT score, within 6 hours, and in selected patients up to 24 hours on perfusion imaging. Basilar occlusion in selected patients up to 24 hours. Transfer without delay, and do not delay it for thrombolysis.

Antithrombotic treatment after haemorrhage is excluded.

• Not thrombolysed:
  • Aspirin 300 mg orally, rectally or by nasogastric tube as soon as possible, then 300 mg once daily for 14 days, then clopidogrel 75 mg daily long term.
  • Monitor for gastrointestinal bleeding. Avoid with active peptic ulcer or allergy. Omeprazole 20 mg daily if high risk.
  • If thrombolysed, start after 24 hours with a clear repeat scan.
• Minor stroke (scale score 3 or less) or high risk transient ischaemic attack within 24 hours:
  • Aspirin 300 mg plus clopidogrel 300 mg loading, then aspirin 75 mg plus clopidogrel 75 mg daily for 21 days, then a single antiplatelet.
  • Do not use after thrombolysis. Monitor for bleeding.
  • Ticagrelor 180 mg loading then 90 mg twice daily for 30 days with aspirin is an alternative.
• Atrial fibrillation: start a direct oral anticoagulant depending on infarct size.
  • Usually day 2 for minor, day 3 to 4 for moderate and day 6 to 7 for severe strokes (earlier starts are supported by emerging evidence).
  • Apixaban 5 mg twice daily (2.5 mg twice daily if two or more of age 80 or over, weight 60 kg or under, creatinine 133 micromol/L or over).
  • Avoid with mechanical valves or moderate to severe mitral stenosis, where warfarin is used.
• Atorvastatin 40 to 80 mg orally at night; maximum 80 mg daily; monitor liver tests and muscle symptoms; avoid in pregnancy; aim for LDL cholesterol under 1.8 mmol/L (70 mg/dL).
• Secondary blood pressure lowering after 24 to 72 hours, aiming for under 130/80 mmHg.

Intracerebral haemorrhage.

• Lower systolic pressure to 130 to 150 mmHg within 1 hour when presenting at 150 to 220 mmHg.
  • Labetalol 10 to 20 mg IV over 1 to 2 minutes, repeated once, or nicardipine 5 mg/hour IV increased by 2.5 mg/hour every 5 to 15 minutes to a maximum of 15 mg/hour.
  • Monitor heart rate and pressure every 5 to 15 minutes.
  • Avoid labetalol in asthma, bradycardia under 60 beats/min, heart block and decompensated heart failure.
  • Avoid pressures under 130 mmHg.
• Reverse anticoagulation:
  • Warfarin or INR over 1.3: 4 factor prothrombin complex concentrate 25 to 50 units/kg IV (dose from INR and product label) with vitamin K 5 to 10 mg IV over 10 minutes.
  • Dabigatran: idarucizumab 5 g IV.
  • Factor Xa inhibitors: prothrombin complex concentrate 50 units/kg IV or the specific antidote from the product label.
  • Heparin: protamine 1 mg for each 100 units given in the previous 2 to 3 hours (maximum 50 mg).
  • Platelet transfusion for antiplatelet related haemorrhage is not helpful unless surgery is planned.
• Raised pressure: head up 30 degrees, mannitol 0.5 to 1 g/kg IV over 15 to 20 minutes or 3% sodium chloride 150 to 250 mL IV over 10 to 20 minutes.
• Monitor sodium every 4 to 6 hours (stop if over 160 mmol/L) and osmolality (stop mannitol if over 320 mOsm/kg).
• Urgent neurosurgery for cerebellar haemorrhage over 3 cm or with brainstem compression or hydrocephalus, and selected superficial haematomas. External ventricular drain for hydrocephalus. No seizure prophylaxis.

Subarachnoid haemorrhage.

• Nimodipine 60 mg orally or by nasogastric tube every 4 hours for 21 days (30 mg every 2 hours if hypotension develops); never IV bolus; monitor blood pressure; avoid strong CYP3A4 inhibitors.
• Secure the aneurysm within 24 hours by coiling or clipping. Keep systolic pressure under 160 mmHg before securing, avoid hypotension, and use paracetamol 1 g every 6 hours for headache, with opioids if needed.

Other causes.

• Cerebral venous thrombosis: enoxaparin 1 mg/kg subcutaneously every 12 hours (1 mg/kg once daily if CrCl under 30 mL/min), even with haemorrhagic infarction; monitor platelets and bleeding.
• Seizure: lorazepam 4 mg IV, repeated once after 10 minutes.
• Infective endocarditis: no thrombolysis; start antimicrobials after cultures.
• Eclampsia: magnesium sulphate 4 g IV over 5 to 15 minutes, then 1 g/hour for 24 hours after the last seizure.
• Sickle cell stroke: exchange transfusion to HbS under 30%, hydration and oxygen.
• Malignant middle cerebral artery infarction: decompressive hemicraniectomy within 48 hours in selected patients aged 18 to 60 (and selected older patients).
• Symptomatic carotid stenosis of 70 to 99% (50 to 69% in selected patients): endarterectomy within 14 days.

Monitoring. Neurological observations, blood pressure, glucose, temperature, saturation and swallow screen. Intermittent pneumatic compression for immobile patients. Mobilise after 24 hours.

Referral and escalation. Stroke team or neurology immediately. Interventional neuroradiology for thrombectomy. Neurosurgery for haemorrhage, hydrocephalus and malignant infarction. Vascular surgery for carotid disease. Cardiology for atrial fibrillation, valve disease and endocarditis. Rehabilitation and palliative care.

Admission criteria. All strokes go to an acute stroke unit. Critical care or high dependency for thrombolysed patients, reduced consciousness, large infarcts and large haemorrhages. Transient ischaemic attack: specialist assessment within 24 hours, and admission for high risk, crescendo attacks, atrial fibrillation or carotid stenosis.

Discharge and safety netting. Low risk transient ischaemic attack with antiplatelet started, rapid clinic review and stable examination may be discharged. Patients and families are told to call emergency services at once for any new facial droop, arm weakness, speech difficulty, visual loss or severe headache, and to avoid driving until cleared.