Hypothyroidism and Severe Neuropsychiatric Symptoms: A Rapid Response to Levothyroxine

Abstract

Hypothyroidism is often associated with altered cognitive function and depression, although patients may also present with disorientation, memory impairment, dementia, auditory distortions, psychomotor retardation and psychosis. Although most patients achieve symptom resolution with levothyroxine replacement therapy, a minority have persistent symptoms. This report presents a case of rapid improvement of neu -ropsychiatric symptoms with levothyroxine replacement. To prepare this case report, we reviewed studies published in PubMed up to February 2012. The following mesh terms were used as keywords in our search: “hypothyroidism”, “dementia” and “cognition disorders”. An 81-year-old man presented to the hospital with behav -ioral disturbance, memory impairment, agnosia, apraxia and paranoid delusions but demonstrated no sensory disturbance. His symptoms had started 4 years previously but had worsened over the past year. His daughter reported that he had hyperten -sion, seizures and inguinal hernia, all of which had remained untreated, and stated that he was not taking any medications. He had no personal history of mood or psychotic disorders; however, one brother had committed suicide, and two of his daughters had mental retardation. He had dry skin, no tendon reflexes, an abnormal tandem gait and suffered from fatigue and intolerance to cold. His Mini-Mental score was 15 (one year of studies). His TSH was 222.28, free thyroxine 1,000. An EEG revealed diffuse slowing, and an MRI showed possible ischemic sequelae and posterior-parietal encephalomalacia, most likely due to an old trauma. We administered up to 100 µg levothyroxine, haloperidol, and valproate. After ten days, he felt no fatigue and had no delusions, his memory and orientation had improved, and his Mini-Mental score had increased to 19. After 40 days, his Mini-Mental score had increased to 21, his free thyroxine was 0.7 and his TSH was 23. He was sent home with a planned outpatient follow-up.The main diagnosis was reversible dementia due to hypo -thyroidism, but mental retardation and vascular or Alzheimer dementia cannot be excluded. Hashimoto’s encephalopathy (HE) was also considered due to his high anti-TPO levels.Regarding overt hypothyroidism, we identified one study that documented a deficit in verbal memory that improved with levothyroxine therapy, suggesting that this deficit is reversible.