Very rare. Encephalopathy associated with the presence of thyroid antibodies (especially anti-thyroid peroxidase TPO, more rarely thyroglobulin) and responding to corticosteroid therapy. Strong female preponderance as in the autoimmune thyroiditis carrying the same name. Some pediatric cases have been observed.

Acute or fluctuating chronic encephalopathy with very variable clinical presentation:

-         cognitive impairment: hallucinations, drowsiness, confusion, reversible amnesia

-         behavioral disorders: psychiatric disorders, sleep problems

-         abnormal movements: tremor, ataxia, nystagmus, myoclonus

-         epileptic seizures

-         migraines with aura, transient aphasia

-         iterative pseudo-ischemic stroke.

Diagnosis of exclusion of the other causes of encephalopathy with antithyroid antibodies and responding to cortisone. Abnormal EEG.

Histopathology: pictures of vasculitis and lymphoplasmacytic infiltration of the cerebral vessels.

Treatment: high dose corticosteroids, sometimes plasmapheresis.

Anesthetic implications: 

encephalopathy, corticosteroid therapy, epilepsy; validity of the spectral analysis of the EEG to monitor depth of anaesthesia ? Given the vascular damage, intraoperative monitoring of cerebral oxygenation with NIRS (Near Infrared Spectroscopy) is useful.

References : 

• Sari E, Karaoglu A, Yesilkaya E. 
  Hashimoto’s thyroiditis in children and adolescents. 
  In Autoimmune Disorders- Current Concepts and Advances from Bedside to Mechanistic Insights. Ed Huang F-P. Intech 2011, p 27-40
• Schlienger J-L, Luca F, Grunenberger F, Vinzio S, Goichot B. 
  Encéphalopathie de Hashimoto. 
  Méd Thérap 2008; 14: 77-81.

Updated: April 2019