The correlations between hyperthyroidism and Parkinsonism have been excellently covered in a recent paper in this journal.1 The following observations may serve as a modest complement.
Firstly, there is a syndrome, mostly encountered in young women, which at the surface is extremely suggestive of hyperthyroidism: they have exophthalmus, anxiety, restlessness, tachycardia, and tremor. The real cause of this syndrome is encephalitis, and it is, as a matter of fact, rather easy to distinguish the syndrome from hyperthyroidism: 1. The tremor is rather more coarse than in hyperthyroidism. 2. The basal metabolic rate is decreased, say to -20% or -30%. 3. There is a pleocytosis in the cerebrospinal fluid. I have personally observed this syndrome repeatedly and more often than not have these patients been interpreted by the general practitioner as hyperthyroidism. Why the syndrome is especially apt to occur in young women I cannot say.
Secondly, the time-honored belief in
ASK-UPMARK E. Hyperthyroidism and Parkinsonism. AMA Arch Intern Med. 1959;103(5):818-819. doi:10.1001/archinte.1959.00270050140022