When I saw an endocrinologist in 1990 he said my thyroid was dead and I was going to have to be on synthroid for the rest of my life. It just came to me after reading different things about the thyroid that when I had the mono my throat was very swollen and painful for 4 days .I was on an antibiotic because at first he thought it was strep but when I was not getting any better he did bloodwork and said I had mono. A few months after that I was getting depressed and I was taking medication for it. It was not till 4 years later I found out about my thyroid.That was 22 years ago.
It's possible, sure. However, it's very difficult, usually impossible, to narrow down the factors that contributed to developing an autoimmune disease such as Hashimoto's. There are so many factors. Any extreme life stressor seems like it could trigger an autoimmune attack, such as illness or pregnancy, but even less obvious things such as environmental exposure to various substances or vitamin D deficiency have been studied as possible contributing factors.
Excerpt from Outsmart Disease: Triggers of autoimmune thyroiditis. Part 2. Environmental factors...
"Bacterial, viral and parasitic infections are known to initiate and worsen autoimmune diseases. They may act alone or together with environmental chemicals. Hashimoto’s thyroiditis has been linked to infections with hepatitis C, Epstein-Barr virus (EBV), HTLV-1 virus, Helicobacter pylori and Yersinia enterocolitica. There is strong evidence that acute parvovirus B19 infections are involved in some cases of Hashimoto’s thyroiditis. (2)"