A patient with steroid responsive encephalopathy associated with autoimmune thyroiditis.

We present a 58-year-old female with gradual cognitive decline and gait instability over 6 months. Her motor examination was notable for myoclonus, brisk reflexes with flexor plantar responses, and a cautious gait without ataxia. Cognitive testing revealed mildly impaired attention, but profoundly impaired calculation, judgment and visual memory. There were no manifestations of autoimmune thyroid disease. Routine laboratory analysis was unrevealing. Cerebrospinal fluid analysis was remarkable only for an elevated protein of 0.64 g/L (normal <0.45 g/L). Electroencephalography demonstrated intermittent bitemporal slowing. Brain MRI with gadolinium demonstrated extensive bilateral subcortical and periventricular white matter T2-weighted and hyperintensity on fluid attenuated inversion recovery MRI. Elevated anti-thyroperoxidase antibody of 8.07 IU/mL (<5.61 IU/mL) and thyroglobin antibody of 9.85 IU/mL (<4.11 IU/mL) were found and steroid responsive encephalopathy associated with autoimmune thyroiditis was diagnosed. Methylprednisolone (1 g daily for 3 days) resulted in dramatic improvement in cognition and mobility, which remained on follow-up.

Steroid responsive encephalopathy associated with autoimmune thyroiditis presenting with late onset depression.

Steroid responsive encephalopathy associated withSteroid responsive encephalopathy associated with autoimmune thyroiditis (SREAT), (also known as Hashimoto's encephalopathy) is a rare autoimmune encephalitis associated with high antithyroid antibodies, and presents with a relapsing-remitting or monophasic course, consisting of confusion, seizures, psychosis, dementia, or stroke-like episodes. In this report, a late onset depression was the initial presentation of SREAT in a middle aged patient, something rarely described before, indicating the need to suspect SREAT as a possible etiology for depression in this age group.

GAD65 IgG autoantibodies in stiff person syndrome: clonality, avidity and persistence.

BACKGROUND AND PURPOSE: Persistent intrathecal production of IgG autoantibodies against glutamic acid decarboxylase 65 (GAD65 IgG) and oligoclonal IgG of undetermined specificity has been reported in stiff person syndrome (SPS). METHODS: To chart the avidity and clonal patterns of GAD65 IgG, we performed scatchard plot of binding characteristics and isoelectric focusing-immunoblot of cerebrospinal fluid (CSF) and serum from five SPS patients. RESULTS: Oligoclonal GAD65 IgG bands, predominantly restricted to the IgG1 subclass, were detected in CSF and serum in all patients. The distribution of GAD65-specific IgG bands in serum and CSF revealed intrathecal synthesis of oligoclonal GAD65 IgG in all five patients, whilst radioimmunoassay demonstrated intrathecal synthesis of GAD65 IgG in four. The binding avidity of GAD65 IgG from CSF was more than 10 times higher than in serum in two of the patients but did not differ substantially in the remaining three. These differences were not related to symptom severity. The pattern of oligoclonal GAD65 IgG bands in CSF and serum in three patients examined remained unchanged for up to 7 years after symptom debut. CONCLUSION: This study confirms the persistent systemic and intrathecal production of GAD65-specific IgG in SPS, and further shows that this immune response is oligoclonal and mediated by a stable population of affinity maturated B cell clones.

Hashimoto's encephalopathy and motor neuron disease: a common autoimmune pathogenesis?

Hashimoto's encephalopathy is a rare complication of autoimmune thyroiditis not associated with thyroidal function decline. We report a 50-year-old man presenting with lower motor neuron symptoms evolving over 3 years and changes in behavior associated with attentive and cognitive impairment occurring in the last few months. Memory deficits, emotional instability, marked dysarthria, mild symmetric weakness of the lower extremities and fasciculations were the most striking clinical features. EEG was diffusely slow, cranial MRI revealed multiple subcortical white matter lesions, CSF protein was slightly elevated, electromyographic recordings showed acute and chronic denervation and extremely high TPO antibody titers were found in the serum. Hashimoto's encephalopathy and lower motor neuron disease were diagnosed. As repeated high-dose intravenous methylprednisolone administration followed by oral tapering improved both central nervous system and lower motor neuron symptoms, the question was raised whether there was a common autoimmune pathogenesis of both clinically distinct diseases.

Tremor of the mouth floor and anti-glutamic acid decarboxylase autoantibodies.

Involuntary movements of the mouth can present as palatal tremor, which is frequently associated with hypertrophy of the inferior olivary nucleus and can be accompanied by contraction of other muscles of the head. We report the case of a 39-year-old man with autoimmune thyroiditis and diabetes who complained of involuntary rhythmic tremor involving the muscles of the floor of the mouth, which interfered with breathing and swallowing. Cerebrospinal fluid (CSF) examination showed the presence of oligoclonal bands and screening for anti-neuronal antibodies revealed high titres of anti-glutamic acid decarboxylase autoantibodies (GAD-Ab). Tremor responded to treatment with benzodiazepines. The correlation between the tremor and antibody positivity is unclear although an alteration of the gabaergic system mediated by the antibodies may be hypothesised on the basis of an inflammatory CSF profile.