Heat Stroke Lesions in the Globus Pallidus

Single-photon emission computed tomography (SPECT) predicted neurological prognosis in heat stroke: A case report

Heat stroke may cause multi-organ dysfunction and death. Some patients with neurological abnormalities in the acute phase have neurological sequelae, particularly cerebellar ataxia, in the recovery phase. However, there is no method to predict the neurological prognosis, and the usefulness of imaging has not yet been established. We report the case of an 86-year-old woman with dementia brought to our emergency department in a coma and hyperthermia. The patient was diagnosed with heat stroke and promptly treated in the ICU but remained unconscious. The patient gained consciousness on day 19, but difficulty with stillness associated with cerebellar ataxia in her right upper extremity became apparent. On day 1, head magnetic resonance imaging (MRI) showed no obvious abnormality. However, on day 6, high-signal areas, suggestive of edema, were seen in the bilateral cerebellar hemispheres. Single-photon emission computed tomography (SPECT) on day 9 revealed significant hypoperfusion in the right cerebellum. These changes improved at the time of hospital discharge. This was a case of persistent cerebellar ataxia due to heat stroke, in which imaging findings improved over time. In most cases, MRI findings do not match clinical symptoms. However, the low cerebral blood flow in the early SPECT images was consistent with the clinical symptoms. MRI may not be a prognostic indicator; however, SPECT images may be useful for predicting sequelae.

Heatstroke-induced late-onset neurological deficits in mice caused by white matter demyelination, Purkinje cell degeneration, and synaptic impairment in the cerebellum

Global warming increases heatstroke incidence. After heatstroke, patients exhibit neurological symptoms, suggesting cerebellar damage. However, the potential long-term adverse outcomes are poorly understood. We studied the cerebellum after heatstroke in mouse heatstroke models. In this study, motor coordination disorder significantly appeared 3 weeks after heatstroke and gradually improved to some extent. Although white matter demyelination was detected at 1 and 3 weeks after heatstroke in the cerebellum, it was not found in the corpus callosum. The Purkinje cell numbers significantly decreased at 1, 3, and 9 weeks after heatstroke. The intensity of synaptophysin and postsynaptic density-95 temporarily appeared to attenuate at 3 weeks after heatstroke; however, both appeared to intensify at 9 weeks after heatstroke. Motor coordination loss occurred a few weeks after heatstroke and recovered to some extent. Late-onset motor impairment was suggested to be caused by cerebellar dysfunctions morphologically assessed by myelin staining of cerebellar white matter and immunostaining of Purkinje cells with pre- and postsynaptic markers. Purkinje cell number did not recover for 9 weeks; other factors, including motor coordination, partially recovered, probably by synaptic reconstruction, residual Purkinje cells, and other cerebellar white matter remyelination. These phenomena were associated with late-onset neurological deficits and recovery after heatstroke.