Striatal hypermetabolism in limbic encephalitis

Abstract

Striatal hypermetabolism on 18FDG-PET scan is a neuroradiological finding that has been described in association with autoimmune disorders such as Sydenham chorea, lupus or antiphospholipid syndrome. Here, we report three patients with non-paraneoplastic limbic encephalitis characterized by 18FDG-PET hypermetabolism of both striata, in contrast with diffuse hypometabolism in the rest of the brain. All patients developed subacute dementia, and antibodies to voltage-gated potassium channels were found in all cases. Brain metabolism and neurological status improved within a few months of immunosuppressive therapy. The finding of striatal hypermetabolism on 18FDG-PET images could thus be highly indicative of limbic encephalitis associated with anti-neuropil antibodies. It could be of significant help in the diagnosis of this rare and treatable condition, and may also provide a useful marker of disease outcome.

Chorea, a little-known manifestation in systemic lupus erythematosus: short literature review and four case reports

“…Similar findings were also observed in other forms of suspected autoimmune chorea [16], in contrast to the striatal hypometabolism observed in vascular and hereditary neurodegenerative chorea [17]. …”

Striatal hypermetabolism in a case of IgG4-related disease

“…In our patient, even if no post-mortem was performed, 18F-FDG PET findings corroborated neurological symptoms. Striatal hypermetabolism on 18F-FDG PET scan has been previously reported in autoimmune limbic encephalitis [3] but, to the best of our knowledge, this is the first description in IgG4 related disease. Further studies are needed to elucidate its mechanism and prognostic significance.…”

18F-FDG-PET/MRI in the diagnostic work-up of limbic encephalitis

“…In addition to cerebral MRI whole-body 18 F-FDG-PET is often performed for tumor screening in LE patients to rule out paraneoplastic limbic encephalitis and has been shown to be highly sensitive for the detection of epileptogenic lesions [29,30] and may also support the diagnosis of LE. To date, most 18 F-FDG-PET publications describe changes in the mesial temporal metabolism, often accompanied by a variety of further metabolic changes in the associating cortex as well as relative metabolic sparing of primary cortices, cerebellum and striatum [8,[31][32][33][34]. Nevertheless, comparable to the wide range of variable changes in MRI, 18 F-FDG-PET has also been reported to yield varying metabolic changes from hyper-and hypometabolism involving various regions of the brain to completely normal 18 F-FDG-PET scans [8,31,35].…”