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- Q. What is Hashimoto's encephalopathy?

- It is a form of Non-infective encephalopathy associated with Autoimmune thyroid disorder with positive Anti TPO antibody
- It has excellent response to glucocorticoids
- It is a diagnosis of exclusion


- Q. Is the term "encephalopathy" same as "encephalitis"?

- "Encephalopathy" means "brain disorder" and it is a broad term
- "Encephalitis" means "brain inflammation" and it deals with inflammatory disorder of the brain and it is a more specific term


- Q. Who was the first to describe Hashimoto's encephalopathy?

- Dr Russell Brain


- Q. What is the timing in terms of presentation?

- It is subacute in terms of onset


- Q. What is the most typical clinical presentation of HE?

- Subacute confusion with
- Seizures
- Myoclonus
- Pyschosis
- With altered consciousness


- Q. What is the epidemiology of this condition?

- Age of onset is on an average 51 years
- However, it has been reported via a wide age variation
- It is more common in females


- Q. What are the possible etiologies of Hashimoto’s encephalopathy?

- Autoimmune encephalomyelitis
- Some people think Hashimoto's encephalopathy is a subset or type of ADEM- Acute disseminated encephalomyelities
- Autoimmune cerebral vasculitis
- Some people think Hashimoto's encephalopathy is a subform of NAIM- which is Non-vasculitic inflammatory meningoencephalitis


- Q. Is it because of the thyroid dysfunction?

- The neurological features of this condition are INDEPENDENT of the thyroid disorder
- The symptoms are NOT due to the thyroid hormone itself and are a result of an associated autoimmune phenomenon

- Q. What is the typical clinical presentation of this syndrome?

- It presents as acute or subacute confusion with altered levels of consciousness

- Q. How does it progress?

- It progresses in two ways
- a) It may progress as stroke-like multiple episodes of recurrent focal neurological deficits with variable degree of cognitive dysfunction
- b) It may have a diffuse slow progression with deteriorating cognitive function characterized by dementia, hallucination, somnolence etc

- Q. Can seizures be seen in this condition?

- Yes
- 2/3rd of patients have seizures are the time of initial presentation
- it can be both focal as well as generalized seizures

- Q. What are other neurological features?

- 1. Psychosis and hallucinations
- 2. Hyperreflexia and pyramidal tract signs
- 3. Myoclonus, tremors etc

- Q. Can pyschiatric symptoms be seen in this condition?

- Yes
- In fact, 30% of patients have some form of psychosis or psychiatric symptoms

- Q. Which antibody is specific against leading to Hashimoto's encephalopathy (HE)?

- Anti NAE antibody (N-amino terminal of alpha enolase)

- Q. Can it be associated with hypothyrodism?

- Yes

- Q. Is hypothyroidism always present with Hashimoto's encephalopathy?

- No
- Thyroid dysfunction runs an independent course
- Hashimoto's encephalopathy may be associated with
- Hypothyroidism
- Euthyroidism
- Hyperthyroidism
- Subclinical thyroid disorders

- Q. Can Hashimoto's encephalopathy be associates with Graves' disease?

- Yes
- But it is very rare
- <20 cases have been reported in literature

- Q. Which is key differentiating feature of HE vs neuropsychiatric manifestation due to hypothyroidism?

- Symptoms of hypothyroidism improve with treatment with LT4 whereas HE they do not improve with LT4 treatment

- Q. Is Anti TPO positive in HE?

- It is found in 100% of cases
- Anti TPO antibody is also found in CSF and CSF anti TPO antibody may be more sensitive and specific for Hashimoto's encephalopathy

- Q. What level of Anti-TPO is associated with Hashimoto's encephalopathy?

- As such there is no correlation between Anti TPO antibody levels and Hashimoto's encephalopathy
- However median values reported in literature are 900 IU/ml

- Q. Which test is useful for follow-up of therapy?

- IgG4 level in CSF is useful for follow up of patients with HE

- Q. What are other common CSF findings?

- Elevated protein concentration has been reported in the CSF

- Q. What are neuroimaging changes seen with Hashimoto's encephalopathy?

- In many cases MRI may be normal
- However it may be associated with nonspecific focal or diffuse hyperintensities of the subcortical white matter or ischemic lesion
- These often improve with glucocorticoid therapy

- Q. How common are EEG changes seen in such patients?

- EEG changes are seen in 90% of the patients but they are generally non-specific
- Mainly persistent or episodic slow wave changes are seen

- Q. What is the anti-NMDAR encephalitis and why is it an important differential diagnosis of this case?

- Anti-NMDAR encephalitis is a form of autoimmune encephalitis which it s a paraneoplastic syndrome and it is similar in clinical presentation of this condition
- It must be ruled out in such patients

- Q. What is the drug of choice for HE ?

- Corticosteroids

- Q. Do the level of the Anti TPO antibody change with treatment?

- No

- Q. What is the new name for HE?

- SEAT
- Steroid responsive encephalopathy with autoimmune thyroiditis

- Q. Does giving Anti-psychotic medications to such patients presenting with psychosis help?

- No
- Antipsychotic medications may paradoxically worsen psychosis/psychiatricsymptoms in some cases (Tseng, 2011).
- Hence to be used cautiously.