Recurrent pure sensory transient ischemic attacks: In vivo demonstration of associated thalamic infarction

We present a case study and literature review to clarify the pathoanatomic substrate of recurrent pure sensory transient ischemic attacks (TIAs). A 60-year-old woman had had over 50 transient episodes of left hemibody hypoesthesia over the previous 15 years. Interictal neurologic examination was normal. Magnetic resonance imaging (MRI) showed a small infarct in the ventroposterolateral (VPL) nucleus of the right thalamus. Symptoms resolved with warfarin therapy. Ischemia-related pure sensory symptoms present as one of two clinical syndromes: (a) sudden onset of persistent unilateral face, arm, and/or leg hypoesthesia/paresthesias, preceded by no or few TIAs, or (b) frequent espisodes of transient unilateral hypoesthesia/paresthesias not progressing to permanent deficit. The first is widely recognized; recent computed tomography/MRI series have reported 105 cases associated with thalamic, brainstem, or thalamocortical projection sensory pathway infarction. Although equally common, the syndrome of recurrent transient hemihypoesthesia is under-recognized and has a less well-described pathologic substrate. One previous case with postmortem documentation of a VPL thalamic infarction has been reported. We believe this is the first reported case of recurrent transient hemihypoesthesia associated with VPL thalamic infarction imaged in vivo.