Pathophysiological decrease in the regional cerebral blood flow in Hashimoto's encephalopathy: a multiple-case SPECT...

Area of Science:

• Neurology
• Neuroimaging
• Immunology

Background:

• Hashimoto's encephalopathy (HE) is a rare neurological disorder.
• It is characterized by autoimmune activity against the thyroid gland and brain.
• Anti-thyroid antibodies and anti-NH2-terminal of α-enolase autoantibodies are key diagnostic markers.

Purpose of the Study:

• To investigate alterations in regional cerebral blood flow (rCBF) in patients with Hashimoto's encephalopathy (HE).
• To correlate these rCBF changes with clinical symptoms, particularly acute neuropsychiatric manifestations.

Main Methods:

• Single photon emission computed tomography (SPECT) with N-isopropyl-p-I-123-iodoamphetamine was performed on seven untreated HE patients and ten healthy controls.
• 3D-SSP analysis was used to compare SPECT images between groups.
• Patients were diagnosed based on clinical presentation, autoantibodies, and response to corticosteroid therapy.

Main Results:

• Patients with HE exhibited significantly reduced rCBF in bilateral anterior cingulate and left prefrontal cortex areas compared to controls (p < 0.05).
• In HE patients experiencing acute neuropsychiatric symptoms (e.g., consciousness disturbance, psychosis), the reduction in rCBF was more severe.
• These patients also showed decreased rCBF in the right frontal cortex.

Conclusions:

• SPECT imaging revealed distinct regions of decreased cerebral blood flow associated with HE.
• The severity of rCBF reduction correlated with the presence and intensity of clinical symptoms, especially acute neuropsychiatric features.
• This study provides insights into the pathophysiology of reduced rCBF in Hashimoto's encephalopathy.