Hashimoto's encephalopathy with psychiatric presentation.

Hashimoto's encephalopathy is an uncommon neuropsychiatric syndrome with varied clinical presentations. It presents as an encephalopathy without central nervous system infection or tumor. Mostly observed ones are seizures, cognitive impairment, movement disorders, altered sensorium, and behavioral and psychotic symptoms. Treatment with steroids and immunosuppressants has led to excellent remission rates. Here, we report a case of a 55-year-old male who presented predominantly with psychiatric symptoms and rapidly progressing dementia. The patient was managed by intravenous steroids and low-dose oral risperidone. Prompt investigations and diagnoses helped in treating the condition. This case highlights that timely diagnosis can lead to an excellent prognosis in this condition. Copyright:

Hashimoto's encephalopathy (HE) is an autoimmune disease characterized by encephalitis associated with antithyroid antibodies with a range of neurological and psychiatric symptoms.[1] Prevalence is low, estimated to be around 2:1000,000. It presents usually in the fifth decade of life with a male-to-female ratio of 1:4. Mechanisms include immune complex deposition, vasculitis, and other inflammatory conditions.[2] This condition had been usually difficult to diagnose due to vast variations in clinical presentation and lack of definite diagnostic criteria.[3] Psychiatric presentations have been commonly reported in literature and often lead to misdiagnosis and delay in diagnosis. Described below is a case which presented chiefly with behavioral symptoms, later found to be a case of HE.

CASE REPORT

A 55-year-old married male, shopkeeper from an urban background, presented to the psychiatry outpatient department with chief complaints of agitation and sleep disturbance. On exploration of history, it was found that the patient had forgetfulness over the past 1 year. He would misplace things, forget to bring all items from the grocery shop, would forget to turn off the motor pump switch, or lock his room.

Further, over a period of the last 2 months, there was a steep decline in his neurocognitive functioning. The patient started misplacing things very frequently, needed to be reminded repeatedly for a particular task, and having difficulty in remembering recent incidents and conversations. He developed difficulty in retaining dates of upcoming important events. He started facing difficulty in calculations at his shop leading to erroneous transactions. He would also take longer than usual time to finish his daily household work and sometimes would be unable to. He also started having difficulty in remembering names of neighbors and relatives.

Since past 3 weeks, he started accusing family members of stealing his belongings and would become verbally aggressive toward them. He would sleep very less at night, waking up in the middle of night, and roaming purposelessly at home and also sometimes going for a bath at night. The patient was admitted in the psychiatry ward for diagnostic clarification and unmanageability at home. He was a known case of hypertension for 20 years and well controlled on amlodipine 10 mg once daily. There was no past or family history of any psychiatric or neurological illness.

On examination, he was a well-built gentleman with a normal general physical examination. Neurological examination revealed ataxia and positive Romberg's sign. He was inattentive and had fluctuating orientation in repeated mental status examinations. Mini-Mental State Examination (MMSE), Montreal Cognitive Assessment (MoCA), Neuropsychiatric Inventory Questionnaire (NPI), and Clinical Dementia Rating (CDR) were administered. MMSE score was 15/30 and score on MoCA was 14/30. NPI showed high scores in delusion, agitation, disinhibition, motor disturbance, and nighttime behaviors. CDRI showed moderate memory loss, difficulty with orientation, unable to make a judgment, no pretense of independent function, impaired function at home, requires help for personal care and incontinence, severe behavioral changes, and moderate language difficulty. Complete hemogram, liver function tests, kidney function tests, serum electrolytes, blood sugars, serum folate, and Vitamin D3 levels were within the normal range. Serum fT3, fT4, and TSH were also within the normal range. Anti-thyroid peroxidase antibodies were raised at 170 IU/ml. Serum Vitamin B12 was 238 pg/ml. No abnormality was detected on chest X-ray and electrocardiography. The patient was nonreactive for HIV, anti-HCV, and HBsAg. No abnormality was detected in electroencephalogram and cerebrospinal fluid findings. Magnetic resonance imaging of the brain had chronic ischemic changes in bilateral periventricular white matter and in deep and subcortical white matter of bilateral parieto-occipital region. The patient was started on tablet risperidone 2 mg once a day at night for behavioral and psychotic symptoms. Adequate measures were taken to avoid harm to the patient and others. Reorientation cues and strategies were provided. Vitamin B12 supplementation was given.

After admission, he was found to be agitated most of the time, and often running around. He would often not identify his family members. Neurology consultation was sought and provisional diagnosis of HE was made. The patient was transferred to the neurology ward. He was subsequently started on injection methylprednisolone 1 g intravenous (iv) per day, for 5 days. Agitation, disorientation, ataxia, and suspiciousness subsided gradually over the next 10 days of starting this treatment. He was then given tablet methylprednisolone 40 mg/day and discharged after a week of remission of symptoms.

DISCUSSION

Presentation in HE can be chronic like in dementia or acute, resembling delirium or rapidly progressing dementia. Acute presentation may have confusion, hallucinations, seizures, myoclonus, and ataxia. Selective impairment in short-term memory without confusion or dementia has also been seen.[45] Presentation similar to bipolar affective disorder and recurrent brief psychotic episodes have also been reported. Most common clinical presentations reported in a review were cognitive function deterioration (62%) and seizures (46%). It has been hypothesized that the antithyroid antibodies cross blood–brain barrier and react with brain antigens, mainly cerebellar astrocytes.[67] Antithyroid antibodies are found in other disorders such as Graves hyperthyroidism, systemic lupus erythematosus. Further, serum concentration of these antibodies does not correlate with the severity of symptoms.[8] Hence, it has been said that anti-TPO antibodies cannot be surely the direct mediator of this condition. Hence, it is also called steroid-responsive encephalopathy associated with antithyroid antibodies.[9]

Interestingly, in previous studies, it has been seen that 42% of patients were euthyroid at the time of diagnosis despite TPO elevation.[10] This finding is similar to our case.

It has been suggested that in the presence of neuropsychiatric symptoms with pre-existing Hashimoto's thyroiditis or Graves’ disease, a diagnosis of Hashimoto's encephalopathy should be considered. First-line treatment consists of corticosteroids and usually, there is rapid response.[9] For steroid unresponsive cases, IV immunoglobulins, methotrexate, azathioprine, and rituximab have been found useful.[11]

In summary, the present case presented with rapidly worsening cognition, namely recent memory, immediate memory, naming difficulties, executive dysfunction, and fluctuating orientation. Behavioral and psychotic symptoms included agitation, delusion of persecution, and delusion of theft. This is an atypical presentation of psychosis, thus such cases need to be screened for all reversible causes of dementia. Differential diagnosis of HE should be kept in mind since it responds fairly good to treatment.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient has given his consent for his images and other clinical information to be reported in the journal. The patient understands that his name and initials will not be published and due efforts will be made to conceal identity, but anonymity cannot be guaranteed.

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