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Information

Differential Diagnosis of Nervous System Disorders

= brief episode of transient focal neurological deficit ← ischemia of <24 hours duration with return to pre-attack status

Incidence: 31÷100,000 population per year; increasing with age; 105,000 new cases per year in USA; M >F

Cause:

  1. embolic: usually from ulcerated plaque at carotid bifurcation
  2. hemodynamic: fall in perfusion pressure distal to a high-grade stenosis / occlusion

Risk factors:

  1. Hypertension → linear increase in probability of stroke with increase in diastolic blood pressure
  2. Cardiac disorders: prior myocardial infarction, angina pectoris, valvular heart disease, dysrhythmia, CHF
  3. Diabetes mellitus
  4. Cigarette smoking (weak risk factor)

Prognosis: 5.3% stroke rate per year for 5 years after first TIA; per year 12% increase of stroke / myocardial infarction / death; completed stroke in 5% (33%) within (1 month) 5 years

Rx:

  1. Carotid endarterectomy (1% mortality, 5% stroke)
    • prophylactic carotid endarterectomy + chronic low-dose aspirin therapy in patients with recently symptomatic TIA / minor stroke + >70% carotid artery stenosis
  2. Anticoagulation
  3. Antiplatelet agent: aspirin, ticlopidine (Ticlid®)

Carotid Transitory Ischemic Attack (~ 66%)!!navigator!!

  • carotid attacks <6 hours in 90%
  • transient weakness / sensory dysfunction CLASSICALLY in
    1. hand / face with embolic event
    2. proximal arm + lower extremity with hemodynamic event (located to watershed area)
      • motor dysfunction = weakness, paralysis, clumsiness of one / both limbs on same side
      • sensory alteration = numbness, loss of sensation, paresthesia of one / both limbs on same side
      • speech / language disturbance = difficulty in speaking (dys- / aphasia) / writing, in comprehension of language / reading / performing calculations
      • visual disturbance = loss of vision in one eye, homonymous hemianopia, amaurosis fugax
  • paresis (mono-, hemiparesis) in 61%
  • paresthesia (mono-, hemiparesthesia) in 57%
  • amaurosis fugax (= transient premonitory attack of impaired vision due to retinal ischemia) in 12% ← transient hypotension or emboli of platelets / cholesterol crystals, (which may be revealed by funduscopy)
  • facial paresthesia in 30%

Vertebrobasilar Transient Ischemic Attack (~ 33%)!!navigator!!

  • vertebrobasilar events <2 hours in 90%
    • motor dysfunction = as with carotid TIA but sometimes changing from side to side including quadriplegia, diplopia, dysarthria, dysphagia
    • sensory alteration = as with carotid TIA usually involving one / both sides of face / mouth / tongue
    • visual loss = as with carotid TIA including uni- / bilateral homonymous hemianopia
    • disequilibrium of gait / postural disturbance, ataxia, imbalance / unsteadiness
    • drop attack = sudden fall to the ground without loss of consciousness
  • binocular visual disturbance in 57%; vertigo in 50%
  • paresthesia in 40%; diplopia in 38%; ataxia in 33%
  • paresis in 33%; headaches in 25%; seizures in 1.5%

Accelerating / Crescendo TIA!!navigator!!

= repeated periodic events of neurologic dysfunction with complete recovery to normal in interphase

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