Dystonic Seizures and Intense Hyperperfusion of the Basal Ganglia in a Patient with Anti-N-Methyl-D-Aspartate Receptor Encephalitis

Psychiatric Illness or Immune Dysfunction-Brain Perfusion Imaging Providing the Answer in a Case of Anti-NMDAR Encephalitis

BACKGROUND

We investigated the potential use of SPECT quantification in addition to qualitative brain perfusion analysis for the detection of anti-NMDAR encephalitis. The question is how to normalize brain activity to be able to quantitatively detect perfusion patterns. Usually, brain activity is normalized to a structure considered unaffected by the disease.

METHODS

Brain [99mTc]-HMPAO SPECT was performed as a method to detect brain perfusion patterns. The patterns of abnormal brain perfusion cannot always be reliably and qualitatively assessed when dealing with rare diseases. Recent advances in SPECT quantification using commercial software have enabled more objective and detailed analysis of brain perfusion. The cerebellum and whole brain were used as the normalization structures and were compared with visual analysis.

RESULTS

The quantification analysis performed with whole brain normalization confirmed right parietal lobe hypoperfusion while also detecting statistically significant left-to-right perfusion differences between the temporal lobe and thalamus. Whole brain normalization further described bilateral frontal lobe hyperperfusion, predominantly of the left lobe, and was in accordance with visual analysis.

CONCLUSION

SPECT quantitative brain perfusion analysis, using the whole brain as the normalization structure rather than the cerebellum, in this case, improved confidence in the visual detection of anti-NMDAR encephalitis and provided unexpected solutions to atypical psychiatric dilemmas.

Anti-NMDAR encephalitis with bilateral basal ganglia MRI lesions at a distance of time: a case report

Background

Approximately half (55%) of anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis is known to show abnormal brain images, including high signal intensity in T2 or fluid attenuated inversion recovery (FLAIR) images. In a minority of anti-NMDAR encephalitis cases, high signal intensity on diffusion-weighted imaging (DWI) has been reported, a finding that is highly suggestive of a stroke.

Case presentation

We present the case of a 66-year-old man who experienced two separate focal seizure events, which involved first the right and then the left upper extremity in a short period of time. The patient showed focal clonic seizures involving right arm and hand, which sometimes evolved to bilateral tonic-clonic seizures on his first admission. Brain magnetic resonance imaging (MRI) showed high signal intensity on DWI and low signal intensity on the apparent diffusion coefficient (ADC) map of the left caudate nucleus and putamen. The patient was discharged symptom-free with anti-epileptic drugs for 2 weeks. The second admission occurred 4 days after the discharge. He exhibited a new symptom of focal clonic seizures involving left arm and hand while showing a brain lesion on the opposite side which is hyperintense on DWI image and hypointense on ADC map. The patient was eventually diagnosed with anti-NMDAR encephalitis according to the cerebrospinal fluid (CSF) antibody test.

Conclusions

This is the case of anti-NMDAR encephalitis patient whose DWI/ADC images revealed sequential involvement on the left and right basal ganglia with a short time interval. When stroke-like brain lesions on DWI are found in a patient with a focal seizure, a CSF study could help rule out autoimmune encephalitis. We also suggest that DWI/ADC map images may be useful for the early detection of anti-NMDAR encephalitis.

Seronegative Autoimmune Basal Ganglia Encephalitis Presenting as Acute Parkinsonism and Refractory Faciobrachial Seizures: A Case Report

Autoimmune basal ganglia encephalitis (BGE) typically presents with acute onset parkinsonism and on imaging is associated with lesions in the basal ganglia. It is associated with chorea and other movement disorders. Seizures are still rare. Various autoantibodies are associated with the development of basal ganglia encephalitis. These autoantibodies are against dopamine D2 receptor (D2R) and N-methyl-D-aspartate receptor (NMDAR). Another paraneoplastic antibody known as anti-recoverin antibodies (Abs) is also associated with basal ganglia encephalitis. We report a case of a 45-year-old male who presented in this hospital with a history of cognitive dysfunction and slowness of activities for eight days and faciobrachial seizures. Magnetic resonance imaging (MRI) of the brain revealed lesions in the putamen and caudate nucleus. Infection and antibody screening were negative. The seizures were refractory to conventional antiepileptics. The patient responded to intravenous immunoglobulin (IVIG) therapy.