1. Hashimoto’s Encephalitis
Jamie Parrott, MD
Carolinas Medical Center
Dept. of Neurology

2. Hashimoto’s Thyroiditis
Chronic autoimmune thyroiditis seen in 8% of females, 3% of males, 10% of females over 55y
Hashimoto’s (chronic lymphocytic) thyroiditis is the most common form
Most common cause of sporatic goiter in children (1.2% prevalence)

3. Hashimoto’s Thyroiditis
Exponential increase in last 40 years
T-cell mediated
Usually asymptomatic
Present with hypothyroidism (20%), goiter, or both
5% incidence of hypothyroidism per year following diagnosis
95% Female, usually between ages 30-50y

4. Hashimoto’s Thyroiditis
Thyroid antibodies targeted
Thyroglobulin
Thyroid microsomal antigen (thyroid peroxidase)
TSH receptor
Association with type I DM, multiple sclerosis, rheumatoid arthritis, Turner syndrome, celiac disease, vitaligo

5. Hashimoto’s Encephalitis
Rare condition associated with HT
2 to 3 per 100,000 prevalence
Triad of encephalopathy, high serum antithyroid antibodies, and responsiveness to steroids
Majority euthyroid
82% female
All pediatric case reports female, 9-18y

6. Hashimoto’s Encephalitis
Two distinct patterns
Acute type characterized by seizures, stroke-like episodes with transient neurologic deficits, altered mental status. Recurrent.
Subacute with insidious onset over weeks. Confusion, agitation, restless, hallucinations, dementia in the absence of focal neurologic deficits
No relationship with presence of hypothyroidism and severity of symptoms

7. Hashimoto’s Encephalitis
Possible underlying mechanisms
CNS autoimmune vasculitis (lymphocytic perivascular infiltrate seen pathologically in 2 of 9 patients, Odie et al)
Formation of antineural antibodies (Archambeaud et al; alpha enolase ab, Ochi et al; antithyroid antibody titers in CSF not related to severity of disease)

8. Hashimoto’s Encephalitis
Severity of symptoms unrelated to antibody titers, thyroid function
Reported symptoms: seizures, myoclonus, Stiff-limb syndrome, stroke-like symptoms, cerebellar dysfunction, psychosis, confusion, depression, headache, hypothermia, coma

9. Hashimoto’s Encephalitis
CSF protein elevated 75%
CSF pleocytosis 25%
EEG changes nonspecific (slowing)
MRI typically normal (occasional T2-weighted abnormalities)

10. Hashimoto’s Encephalitis
Rapid response to steroids
Full recovery 3-4 weeks
Acute form is frequently recurrent, consider prophylaxis