Both Hypo- and Hyperthyroidism may be discovered when patients present with complaints such as fatigue, or even by simple screening. Classic symptoms are typically diametrical opposites. See the handy figure below (excuse the pose; other images were too blurry). [NOTE: Hyperthyroidism can also present with new-onset Atrial Fib, Hypertension, or CHF]:
DiagnosisDude 