Abstracts

Rationale:
Hashimoto’s encephalopathy (HE) is a rare, autoimmune encephalopathy, which occurs in the context of elevated serum levels of thyroid associated antibodies, such as anti-thryroperoxidase antibodies (anti-TPO). A condition with diverse presentations, the clinical manifestations of HE can range from stroke-like episodes, gait abnormalities, and aphasia, to encephalopathy, seizures, hallucinations, and other neuropsychiatric symptoms. Rarely, the initial clinical presentation consists of an isolated explosive onset of seizures, most commonly focal or bilateral convulsive, but may include myoclonic, epilepsia partialis continua (EPC) or status epilepticus. Iter-ictal electroencephalograms (EEGs) most commonly show diffuse, non-specific delta-theta slowing, or occasionally admixed focal epileptiform discharges, most commonly of the frontal or central head regions.
Method:
Here, we report an unusual case of HE in a previously well, developmentally appropriate 9-year-old boy, and briefly review the literature.
Results:
Our patient presented to the emergency department with a 19-day history of new onset nightly enuresis and two-night history of observed, bilateral convulsive seizures with associated ictal enuresis. This explosive onset of nocturnal motor seizures came in the absence of significant encephalopathy or developmental regression, but was accompanied by a preceding 1-week history of abdominal pain and mildly depressed mood. Physical examination at presentation did not show any significant focal neurological deficits. EEG within 24 hours of presentation to the emergency department was severely abnormal, with very frequent focal spike and wave discharges recorded over the bi-frontal head regions. Interestingly, the posterior-dominant rhythm was normal. Unique to this case, rare epochs of paroxysmal fast activity and very rare delta brush complexes were seen, maximal over the left frontal head region. The diagnosis of HE was supported with elevated levels of anti-thyroglobulin and anti-thyroid peroxidase at 122 IU/mL and >600 kU/L respectively (reference ranges: 0-35 and < 50 respectively). TSH was elevated at 188.84 mU/L (ref range: 0.30-5.00), with low free T3/T4.  Other pituitary hormones were within normal limits. Extensive testing for paraneoplastic antibodies was negative. CSF studies were significant for elevated total nucleated cells at 23 106/L (ref: < =5), with otherwise normal cell count, glucose, protein, and lactate. CSF cultures were negative for bacteria, HSV, VZV, and enterovirus and parechovirus. MRI of the brain showed enlargement of the adenohypophysis of the pituitary glad, and mild thickening of the infandibular stalk, without any identifiable, discrete pituitary lesion. Findings were favored to reflect lymphocytic hypophysitis in the context of the diagnosis of autoimmune encephalitis and hypothyroidism.
Conclusion:
To our knowledge, this is the only pediatric case report of HE presenting as new onset enuresis, with two unique electroencephalographic elements on EEG: rare delta brush, and paroxysmal fast activity. This report highlights the need to consider a broad differential in children who present with new-onset enuresis. Moreover, beyond primary epilepsies, HE and other auto-immune encephalitides should be considered when children present with explosive onsets of seizures, even in the absence of encephalopathy.
Funding:
:None