Endocrine Abstracts

We present an unusual case of encephalopathy. Paramedics were called to a 13 year old boy with acute confusion, agitation and incoherent speech. Subsequently he reported he had arm twitching and transient episodes of loss of consciousness for the preceding two weeks with increased thirst and lethargy over the preceding year. He had also progressed rapidly through puberty in the year prior. On presentation his parents denied any infective symptoms or likelihood of substance misuse. On initial assessment he was found to have a fluctuating GCS and due to his level of agitation and combativeness he required intubation for transfer. He was normotensive and normoglycemic. Initial investigations for encephalopathy including a CT brain, lactate and ammonia were normal with no obvious cause identified. He was clinically noted to have a large goitre, left proptosis and a post pubertal status. An EEG confirmed an encephalopathic state but no epileptiform activity was seen. He was extensively investigated for an infective or inflammatory cause of encephalopathy but results were all negative. In view of the goitre TFTS were performed showing a low Thyroxine at 7.9 pmol/l (12.6-21.0 pmol/l) and an elevated TSH of 24.9 mIU/l (0.51-4.3 mIU/l); this widened the differential diagnosis. Anti-Thyroid peroxidase (TPO) antibodies were the performed and found to be significantly elevated at >600 (Upper limit of normal 25 IU/ml). An US neck showed a swollen, hypervascularised thyroid gland. Early morning Cortisol was satisfactory at 400nmol/l. With the above results a diagnosis of Hashimoto’s Encephalopathy/SREAT (Steroid responsive encephalopathy associated with autoimmune thyroiditis) and autoimmune hypothyroidism was made, and he was commenced on IV Methylprednisolone and Levothyroxine. His GCS normalised over the next 48 hours and he was extubated on day 4. He was changed to weaning oral Prednisolone. On review two weeks post discharge he was clinically euthyroid with no palpable goitre, a normal neurological exam and no proptosis. Anti-TPO antibodies had fallen to 414 IU/ml and thyroid function was normalising. This case demonstrates and the importance of a thorough history and clinical examination and it highlights that it is essential to maintain a wide working differential diagnosis.