It can be difficult to tell the difference between strep throat symptoms and symptoms of a viral infection, like mononucleosis (mono), which is also common in teens. Just like strep throat symptoms, with mono you will experience a sore throat, fever, swollen lymph nodes, rash and body aches.
Type 1 Diabetes. Type 1 diabetes is an autoimmune disease. An autoimmune disease results when the body's system for fighting infection (the immune system) turns against a part of the body. In diabetes, the immune system attacks the insulin-producing beta cells in the pancreas and destroys them. The pancreas then produces little or no insulin.
Since Graves' disease is an autoimmune disease which appears suddenly, often quite late in life, a viral or bacterial infection may trigger antibodies which cross-react with the human TSH receptor (a phenomenon known as antigenic mimicry, also seen in some cases of type I diabetes).