There are two issues that can occur with the thyroid: hyperthyroidism (overactive thyroid) or hypothyroidism (underactive thyroid). Both can occur after parathyroid surgery, but are both uncommon. When we operate on the parathyroids, we are manipulating the thyroid somewhat - we may need to push it over to reach the parathyroids, for example. Most thyroids are fine with that, and most peop...

Although the word "thyroid" is in parathyroid, the glands are completely separate. Hypothyroidism is very common, so there are many patients with primary hyperparathyroidism who also happen to have hypothyroidism. The hypothyroidism did not cause the parathyroid condition. You just happen to have an underactive thyroid and overactive parathyroids.