Bilateral hippocampal hyperintensities: a new finding in MR imaging of heat stroke

Abstract

We present a child aged 2 years 3 months who suffered heat stroke after being accidentally locked in a car during summer. She was unconscious with hyperthermia on admission and later showed biochemical evidence of liver, cardiac and muscle injury and associated electrolyte imbalance. Her level of consciousness gradually improved, but she showed evidence of cortical blindness, which had improved on follow-up. MR imaging on the 5th day revealed bilateral hippocampal hyperintensities along with hyperintensities in the cerebellum and in the cerebral cortex. Previous case reports of imaging in heat stroke revealed involvement of the cerebellum, thalami, basal ganglia and scattered cerebral involvement. We report this unique finding of hippocampal hyperintensities due to heat stroke.

Symmetric Bilateral Caudate, Hippocampal, Cerebellar, and Subcortical White Matter Mri Abnormalities in an Adult Patient with Heat Stroke

“…A publication in 2007 showed a case of bilateral hippocampi, patchy bilateral junctional zone, and bilateral cerebellar abnormalities on T2/FLAIR images in a pediatric case of heat stroke (14). Though findings vary in the few reported cases and postmortem studies, the cerebellum seems to be especially prone to heat-induced injury.…”

Reversible Focal Cerebral Cortical Lesions in a Patient with Heat Stroke

“…The cerebellum is most susceptible to lesion formation in patients with heat stroke. Previous case studies using MRI have shown lesions or atrophy of the cerebellum as well as cerebellar symptoms such as limb ataxia (2)(3)(4)(5)(6)(7)(8). Such findings are explained by the selective vulnerability of Purkinje cells to heat-induced injury (3).…”

“…Heat stroke is often fatal, and those who do survive may sustain permanent neurologic damage (1). The brain is one of the organs that is most vulnerable to heat stroke, and brain lesions caused by heat stroke are bilateral and symmetrical in most cases (2)(3)(4)(5)(6)(7)(8). We herein report the first case of a patient with heat stroke presenting with focal reversible cortical lesions demonstrated on diffusion-weighted magnetic resonance imaging (MRI).…”

Improved Detection of Heat Stroke-Induced Brain Injury by High B-Value Diffusion-Weighted Imaging

“…Heat stroke is potentially life-threatening and usually associated with multiple organ failure (1)(2)(3). Central nervous system (CNS) is extremely vulnerable to injury by heat stroke, and is virtually involved in all cases (3)(4)(5)(6). Injury to CNS is considered to be caused by several mechanisms: direct toxicity by heat to certain cell types which contain abundant concentration of heat shock proteins (e.g., Purkinje cells of cerebellum), small vessel ischemia secondary to altered hemostasis (sepsis-like phenomenon), inflammation and apoptosis triggered by interleukin-1 release, and ischemia induced by prolonged vasogenic edema which results from cytokine-induced leakiness of blood-brain or blood-cerebrospinal fluid barrier (6)(7)(8)(9)(10).…”

“…T2-weighted imaging (T2WI) and fluid-attenuated inversion recovery (FLAIR) imaging may show heat stroke-induced brain injury as hyperintense foci (4,5,11). Diffusion-weighted imaging (DWI) usually shows abnormalities more conspicuously than T2WI or FLAIR imaging, or the abnormalities may be confined only to DWI (6,11,14).…”