Thalamic infarction following lingual herpes zoster

Primary central nervous system vasculitis: pathology and mechanisms

Primary vasculitis of the central nervous system (PCNSV) is a rare and diagnostically challenging form of vasculitis limited to the brain and/or spinal cord. It is a complex and often severe disease with multifaceted clinical and pathological appearances, suggesting multiple disease subtypes and the potential existence of multiple etiologic pathways. We describe in detail the clinical, imaging, and neuropathological findings of PCNSV summarizing literature data and our observations from a cohort of 131 patients diagnosed at Mayo Clinic over a 25-year period (1983-2007). Unlike systemic vasculitis, little is known regarding PCNSV pathogenesis and the involved immunological mechanisms. Increased recognition of the disease spectrum and in-depth characterization of its histopathologic and immunological phenotype will be critical to eventually understanding the underlying derangements and mechanisms driving PCNSV. Improved understanding of the pathogenetic mechanisms of the disease may also help determine whether the different histologic patterns and clinical subsets represent more than one disease and ultimately may permit development of novel diagnostic and therapeutic strategies for it.

Acyclovir responsive brain stem disease after the Ramsay Hunt syndrome

We report an immunocompetent patient with the Ramsay Hunt syndrome (RHS) followed days later by brainstem disease. Extensive virological studies proved that varicella zoster virus (VZV) was the causative agent. Treatment with intravenous acyclovir resulted in prompt resolution of all neurological deficits except peripheral facial palsy. This case demonstrates that after geniculate zoster, brainstem disease may develop even in an immunocompetent individual and effective antiviral therapy can be curative.

Subcortical aphasia

We critically review the literature on subcortical aphasia, suggest that a number of traditional concepts regarding mechanisms of aphasia are inconsistent with now abundant data, and propose several new hypotheses. The absence of aphasia in 17 reported cases of dominant hemisphere striatocapsular infarction and the finding of nearly every conceivable pattern of language impairment in 33 different reported cases of striatocapsular infarction provide strong evidence against a major direct role of the basal ganglia in language and against disconnection or diaschisis as mechanisms of nonthalamic subcortical aphasia. However, detailed consideration of the vascular events leading to striatocapsular infarction strongly suggests that associated linguistic deficits are predominantly related to sustained cortical hypoperfusion and infarction not visible on structural imaging studies. Thalamic disconnection, as may occur with striatocapsular infarcts with extension to the temporal stem and putamenal hemorrhages, may also contribute to the language deficits in some patients. Review of the literature on thalamic infarction, in conjunction with previously unreported anatomic details of four cases, suggests that what infarcts in the tuberothalamic artery territory and the occasional infarcts in the paramedian artery territory associated with aphasia have in common is damage to the frontal lobe-inferior thalamic peduncle-nucleus reticularis-center median system that may be involved in regulating the thalamic gate in attentional processes. Disruption of attentional gating in the pulvinar and lateral posterior nuclei resulting from such lesions may impair selection of specific neuronal networks in the projection field of these nuclei that serve as the substrate for lexical-semantic function, which is in effect a disruption of a type of working memory, as defined by Goldman-Rakic. We define this as a defect of selective engagement.

Cervical (C2) herpes zoster infection followed by pontine infarction

This article reports a man who had herpes varicella zoster cervicalis with delayed stroke in the posterior circulation. Empiric treatment was acyclovir, methylprednisolone, and aspirin. Pontine infarction involving migration of the virus via cervicovascular innervation from C2 dorsal root ganglia to the vertebrobasilar circulation with attendant angiitis/angiopathy and thrombosis is proposed.