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.