Grave's Hyperthyroidism presenting as Thyroid Encephalopathy without typical hyperthyroid features

Abstract

Presentation
69 year old male patient, presented to emergency department of University Hospital Kerry, with complaints of forgetfulness, agitation, intermittent myoclonic jerks and Parkinsonian features. He had the symptoms for nearly 3-4 weeks and had noted them to be progressively worsening. During the course of admission, he deteriorated even further and agitation and aggressive behaviour became the dominant features.

Diagnosis
Baseline blood and urine investigations were reported to be normal. The initial workup comprised of imaging modalities, including the CT-brain and MRI-Brain, both of which were noted to be unremarkable. Lumbar Puncture was organized and the CSF analysis was noted to be normal as well. EEG was done which showed evidence of encephalopathy. As part of workup for encephalopathy, Thyroid profile was done which showed marked hyperthyroidism and the presence of TSH-receptor antibodies was noted, confirming the diagnosis of Grave’s hyperthyroidism and possible Thyroid Encephalopathy.

Treatment
Patient received initial treatment with Intravenous methylprednisolone (followed by oral prednisolone as tapering), carbimazole with thyroxine (block and replace regimen) and levetiracetam (anti-epileptic). Patient improved on the treatment but symptoms would return as soon as steroids tapering was initiated. Patient steroids were continued along with initiation of IVIG and rituximab. Agitation settled completely with mild improvement of confusion on initiation of IVIG and rituximab. Block and replace regimen with carbimazole and thyroid profile was continued.

Discussion
Presentation of Grave’s hyperthyroidism usually presents with more typical features. Encephalopathy is one of the rare features that usually is present with typical Grave’s features, but is even rarer for Thyroid encephalopathy to present without any other Grave’s disease features. Therefore, in any case presenting with features of encephalopathy, thyroid profile should be part of regular work up for encephalopathy, even if there are no other features of hyperthyroidism.