We congratulate Johnston et al on their
study of risk factors for recurrent cerebral ischemic events in patients
presenting with transient ischemic attack (TIA).[1]
The authors focus on a distinct subgroup of patients with isolated sensory
symptoms with a high risk of recurrent TIA (40%), not
progressing to stroke. However, the
syndrome of recurrent pure sensory episodes has been documented.[2,3] C. Miller Fisher
pioneered its description (the authors cite Fisher’s papers on late life
migraine accompaniments, but not on this entity). In a series of 135
cases, Fisher found that isolated, unilateral sensory disturbance
presented in two distinct, and equally frequent manners: 1) sudden onset
of pure sensory stroke preceded by no or few TIAs; and 2) frequent
transient, unilateral hypoesthesia or paresthesias not progressing to
permanent deficit.[2]
The syndrome of recurrent pure sensory episodes has been associated
with ventroposterolateral infarcts on imaging and autopsy.[2,3] Its
pathogenesis is speculative, but likely a substantial proportion of cases
are due to waxing/waning poststroke paresthesias as a variant manifestion
of poststroke pain, and others due to recurrent ischemia beyond a fixed
stenosis in a penetrating vessel, migrainous phenomena, hyperventilation
paresthesias, and simple partial seizures. Approximately three to five patients a year
are referred to our stroke center for sensory spells that recur
despite multiple combinations of antithrombotics and anticonvulsants.
Making the diagnosis spares patients from repeated invasive imaging,
treatment with aggressive combination antithrombotic regimens likely to
produce bleeding complications, and undue worry when episodes recur.
References
1. Johnston SC, Sidney S, Bernstein AL, Gress DR. A comparison of risk
factors for recurrent TIA and stroke in patients diagnosed with TIA.
Neurology 2003;60:280-285.
2. Fisher CM. Pure sensory stroke and allied conditions. Stroke
1982;13:434-447.
3. Fernandez-Beer E, Patrick T, Biller J, Saver JL. Recurrent pure
sensory transient ischemic attacks: in vivo demonstration of associated
thalamic infarction. J Stroke Cerebrovasc Dis 1994;4:174-178.