Cerebral blood flow abnormality observed with Tc-99M HMPAO SPECT in reversible dementia caused by hypotyroidism
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CitationŞahin, Ş., Tan, D., Fehime, B. ve Karşıdağ, S. (2007). Cerebral blood flow abnormality observed with Tc-99M HMPAO SPECT in reversible dementia caused by hypotyroidism. Yeni Symposium. 45(4), s. 147-149.
The clinical presentation of hypothyroidism varies considerably and may be dominated by cognitive deficits and psychological symptoms. A 49 year-old male patient came to our clinic with symptoms of forgetfulness, decrease in communication, difficulty in remembering and learning, and difficulty in building sentences. Due to these complaints he was diagnosed as suffering from depressive pseudodementia and possible Alzheimer's disease by other physicians. His routine blood investigation revealed a decrease in T3 and T4 levels, an increase in TSH level, and high levels of antithyroid antibodies. In addition, thyroid ultrasound showed diffuse hypoechogenity of the thyroid gland. The patient was diagnosed as suffering from Hashimoto's Thyroiditis. In addition, his depressive and dementia symptoms were thought to be caused by hypothyroidism. Neuropsychological testing supported the diagnosis of depression and dementia. No pathological findings were found in the patient's cranial magnetic resonance imaging (MRI), but single-photon emission computed tomography (SPECT) analysis labelled with 99m Technetium hexamethylpropyleneamineoxime (Tc-99m-HMPAO) demonstrated regional cerebral hypoperfusion, as is mostly seen in degenerative dementias. After treatment with L-thyroxine, his depressive symptoms and impairment in the neuropsychological testing mostly disappeared. However, cerebral hypoperfusion in his following brain SPECT continued over an observation period of one year. In this article, we aim to review neuropsychiatric disorders related to hypothyroidism and the importance of SPECT analysis in their diagnostic investigations.